The authors thank the North Carolina Department of Labor for permission to re-use materials developed during the writing of an NCDOL industry guide on hearing conservation.

The primary objective of occupational hearing conservation programmes (HCPs) is to prevent on-the-job noise-induced hearing loss due to hazardous workplace noise exposures (Royster and Royster 1989 and 1990). However, the person—who shall later be characterized as the “key individual”—who is responsible for making the HCP effective should use common sense to modify these practices to fit the local situation in order to achieve the desired goal: protection of workers from harmful occupational noise exposures. A secondary objective of these programmes should be to so educate and motivate individuals that they also elect to protect themselves from harmful non-occupational noise exposures and translate their knowledge about hearing conservation to their families and friends.

Figure 1 shows the distributions of over 10,000 noise exposure samples from four sources in two countries, including a variety of industrial, mining and military work environments. The samples are 8-hour time-weighted-average values based on exchange rates of 3, 4 and 5 dB. These data indicate that about 90% of daily equivalent noise exposures are 95 dBA or below, and only 10% exceed 95 dBA.

Figure 1. Estimated noise exposure hazard for different populations

The importance of the data in figure 1, assuming that they apply to most countries and populations, is simply that a vast majority of noise-exposed employees need to achieve only 10 dBA of protection from noise to eliminate the hazard. When hearing protection devices (HPDs) are worn to achieve this protection, those responsible for worker health must take the time to fit each individual with a device that is comfortable, practical for the environment, takes into account the individual’s auditory needs (ability to hear warning signals, speech, etc.), and provides an acoustic seal when worn day in and day out in real-world environments.

This article presents a condensed set of good hearing conservation practices, as summarized in the checklist presented in figure 2.

Figure 2. Checklist of good HCP practices

Benefits of Hearing Conservation

Prevention of occupational hearing loss benefits the employee by preserving hearing abilities which are critical to good quality of life: interpersonal communication, enjoyment of music, detection of warning sounds, and many more. The HCP provides a health screening benefit, since non-occupational hearing losses and potentially treatable ear diseases are often detected through annual audiograms. Lowering noise exposure also reduces potential stress and fatigue related to noise.

The employer benefits directly by implementing an effective HCP which maintains employees’ good hearing, since workers will remain more productive and more versatile if their communication abilities are not impaired. Effective HCPs can reduce accident rates and promote work efficiency.

Phases of an HCP

Refer to the checklist in the figure 2 for details of each phase. Different personnel may be responsible for different phases, and these personnel comprise the HCP team.

Sound exposure surveys

Sound level meters or personal noise dosimeters are used to measure workplace sound levels and estimate workers’ noise exposures to determine if an HCP is needed; if so, the data so gathered will help establish appropriate HCP policies to protect employees (Royster, Berger and Royster 1986). Survey results identify which employees (by department or job) will be included in the HCP, which areas should be posted for required hearing protector use, and which hearing protection devices are adequate. Adequate samples of representative production conditions are needed to classify exposures into ranges (below 85 dBA, 85-89, 90-94, 95-99 dBA, etc.). The measurement of A-weighted sound levels during the general noise survey often identifies dominant noise sources in areas of the plant where follow-up engineering noise control studies may significantly reduce employee exposures.

Engineering and administrative noise controls

Noise controls may reduce employees’ noise exposures to a safe level, eliminating the need for a hearing conservation programme. Engineering controls (see “Engineering noise control” [NOI03AE] in this chapter) involve modifications of the noise source (such as fitting mufflers to air exhaust nozzles), the noise path (such as placing sound-blocking enclosures around equipment) or the receiver (such as constructing an enclosure around the employee’s workstation). Worker input is often needed in designing such modifications to ensure that they are practical and will not interfere with his or her tasks. Obviously, hazardous employee noise exposures should be reduced or eliminated by means of engineering noise controls whenever practical and feasible.

Administrative noise controls include replacement of old equipment with quieter new models, adherence to equipment maintenance programmes related to noise control, and changes in employee work schedules to reduce noise doses by limiting exposure time when practical and technically advisable. Planning and designing to achieve non-hazardous noise levels when new production facilities are brought on-line is an administrative control which can also eliminate the need for an HCP.

Education and motivation

HCP team members and employees will not actively participate in hearing conservation unless they understand its purpose, how they will benefit directly from the programme, and that compliance with the company’s safety and health requirements is a condition of employment. Without meaningful education to motivate individual actions, the HCP will fail (Royster and Royster 1986). Topics to be covered should include the following: the purpose and benefits of the HCP, sound survey methods and results, using and maintaining engineering noise control treatments to reduce exposures, hazardous off-the-job noise exposures, how noise damages hearing, consequences of hearing loss in daily life, selection and fitting of hearing protection devices and importance of consistent wear, how audiometric testing identifies hearing changes to indicate the need for greater protection and the employer’s HCP policies. Ideally, these topics can be explained to small groups of employees in safety meetings, given ample time for questions. In effective HCPs the educational phase is a continuous process—not just an annual presentation—as HCP personnel take daily opportunities to remind others about conserving their hearing.

Hearing protection

The employer provides hearing protection devices (earplugs, earmuffs, and semi-insert devices) for employees to wear as long as hazardous noise levels exist in the workplace. Because feasible engineering noise controls have not been developed for many types of industrial equipment, hearing protectors are the best current option for preventing noise-induced hearing loss in these situations. As indicated earlier, most noise-exposed workers need to achieve only 10 dB of attenuation to be adequately protected from noise. With the large selection of hearing protectors available today, adequate protection can be readily achieved (Royster 1985; Royster and Royster 1986) if devices are individually fitted to each employee to achieve an acoustic seal with acceptable comfort, and if the worker is taught how to wear the device correctly to maintain an acoustic seal, but consistently whenever a noise hazard exists.

Audiometric evaluations

Each exposed individual should receive a baseline hearing check followed by annual rechecks to monitor hearing status and detect any hearing change. An audiometer is used in a sound-attenuating booth to test the employee’s hearing thresholds at 0.5, 1, 2, 3, 4, 6 and 8 kHz. If the HCP is effective, employees’ audiometric results will not show significant changes associated with on-the-job noise-induced hearing damage. If suspicious hearing changes are found, the audiometric technician and the audiologist or physician who reviews the record can counsel the employee to wear HPDs more carefully, assess whether better-fitting HPDs are needed and motivate the individual to be more careful in protecting his or her hearing both on and off the job. Sometimes non-occupational causes of hearing change may be identified, such as gunfire or hobby noise exposure, or medical ear problems. Audiometric monitoring is useful only if quality control of testing procedures is maintained and if the results are used to trigger follow-up for individuals with significant hearing changes (Royster 1985).

Record Keeping

Requirements for the type of records to be kept and the duration for maintaining them vary among countries. In countries where litigation concerns and worker’s compensation are important issues, records should be maintained longer than required by occupational regulations since they are often useful for legal purposes. The goal of record keeping is to document how employees have been protected from noise (Royster and Royster 1989 and 1990). Especially important records include the sound survey procedures and findings, audiometric calibration and results, follow-up actions in response to employees’ hearing changes and documentation of hearing protector fitting and training. Records should include the names of the personnel who carried out the HCP tasks as well as the results.

Programme Evaluation

Characteristics of effective programmes

Successful HCPs share the following characteristics and promote a “safety culture” with respect to all safety programmes (safety eyeglasses, “hard hats”, safe lifting behaviour, etc.).

The “key individual”

The most important strategy for making the five phases of the HCP function together effectively is to unite them under the supervision of one individual of central importance (Royster and Royster 1989 and 1990). In smaller companies where one person may actually carry out all facets of the HCP, lack of coordination is not usually a problem. However, as the size of the organization increases, different types of staff become involved in the HCP: safety personnel, medical personnel, engineers, industrial hygienists, tool crib supervisors, production supervisors and others. With personnel from varying disciplines carrying out different aspects of the programme, it becomes very difficult to coordinate their efforts unless one “key individual” is able to oversee the entire HCP. The choice of who this person should be is critical to the success of the programme. One of the primary qualifications for the key individual is genuine interest in the company’s HCP.

The key individual is always approachable and is sincerely interested in comments or complaints that can help to improve the HCP. This individual does not take a remote attitude or stay in an office, running the HCP on paper by mandate, but spends time on the production floors or wherever workers are active in order to interact with them and observe how problems can be prevented or solved.

Active communications and roles

The primary HCP team members should meet together regularly to discuss the progress of the programme and ensure that all duties are being carried out. Once people with different tasks understand how their own roles contribute to the overall outcome of the programme, they will cooperate better to prevent hearing loss. The key individual can achieve this active communication and cooperation if management provides him or her with the authority to make HCP decisions and the resource allocations to act on decisions once they are made. The success of the HCP depends on everyone from the top boss to the most recently hired trainee; everyone has an important role. Management’s role is largely to support the HCP and enforce its policies as one facet of the company’s overall health and safety programme. For middle managers and supervisors the role is more direct: they help carry out the five phases. The role of employees is to participate actively in the programme and be aggressive in making suggestions to improve HCP operation. However, for employee participation to succeed, management and the HCP team must be receptive to comments and actually respond to employee input.

Hearing protectors—effective and enforced

The importance of hearing protection policies to HCP success is underscored by two desired characteristics of effective HCPs: strict enforcement of hearing protector utilization (there must be actual enforcement, not just a paper policy) and the availability of protectors which are potentially effective for use by the wearers in the work environment. Potentially effective devices are practical and comfortable enough for employees to wear consistently, and they provide adequate sound attenuation without impairing communication through overprotection.

Limited external influences on the HCP

If local HCP decisions are limited by policies mandated by corporate headquarters, the key individual may need top management’s assistance in obtaining exceptions to the corporate or external rules in order to meet local needs. The key individual also must keep strict control over any services provided by outside consultants, contractors or government officials (such as sound surveys or audiograms). When contractors are used, it is more difficult to integrate their services cohesively into the overall HCP, but it is critical to do so. If in-plant personnel do not follow through by using the information provided by the contractors, then the contracted elements of the programme lose effectiveness. Experience clearly indicates that it is very difficult to establish and maintain an effective HCP which depends predominantly on external contractors.

In contrast to the previous characteristics, the following is a listing of some common causes of HCP ineffectiveness.

• inadequate communication and coordination among HCP personnel
• insufficient or erroneous information used to make decisions
• inadequate training for hearing protector fitters and issuers
• inadequate or inappropriate selection of protectors in stock
• over-reliance on number ratings in choosing devices
• failure to fit and train each HPD wearer individually
• over-reliance on external sources (government or contractors) to provide HCP services
• failure to use audiometric monitoring results to educate and motivate employees
• failure to use audiometric data to evaluate HCP effectiveness.

Objective evaluation of the audiometric data

The audiometric data for the noise-exposed population provide evidence of whether the HCP is preventing occupational hearing loss. Over time, the rate of hearing change for noise-exposed employees should be no greater than that of matched controls without noisy jobs. To give an early indication of HCP effectiveness, procedures for audiometric database analysis have been developed using year-to-year variability in threshold values (Royster and Royster 1986; ANSI 1991).

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Ideally, the most effective means of noise control is to prevent the source of noise from entering into the plant environment in the first place—by establishing an effective “Buy Quiet” programme to furnish the workplace with equipment engineered for low noise output. To carry out such a programme, a clear, well-written statement of specifications for limiting noise characteristics of new plant equipment, facilities and processes must be designed to take the hazard of noise into account. A good programme builds in monitoring and maintenance as well.

Once equipment is installed and excess noise identified through sound level measurements, the problem of controlling noise becomes more complicated. However, there are engineering controls available which can be retrofitted to existing equipment. In addition, there is usually more than one noise control option for each problem. Therefore, it becomes important for the individual managing the noise control programme to determine the most feasible and economical means available for noise reduction in each given situation.

Controlling Noise in Factory and Product Design

The use of written specifications to define the requirements for equipment, its installation, and acceptance are standard practice in today’s environment. One of the foremost opportunities in the area of noise control available to the factory designer is to influence the selection, purchase and layout of new equipment. When properly written and administered, implementation of a “Buy Quiet” programme through purchase specifications can prove to be an effective means of controlling noise.

The most proactive approach towards controlling noise in the facility design and equipment procurement stage exists in Europe. In 1985, the twelve member states of the European Community (EC)—now the European Union (EU)— adopted “New Approach” Directives designed to address a broad class of equipment or machinery, rather than individual standards for each type of equipment. By the end of 1994 there had been three “New Approach” Directives issued that contain requirements on noise. These Directives are:

1. Directive 89/392/EEC, with two amendments 91/368/EEC and 93/44/EEC
2. Directive 89/106/EEC
3. Directive 89/686/EEC, with one amendment 93/95/EEC.

The first item listed above (89/392/EEC) is commonly called the Machinery Directive. This Directive compels equipment manufacturers to include noise control as an essential part of machine safety. The basic aim of these measures is that for machinery or equipment to be sold within the EU, it must satisfy the essential requirements regarding noise. As a result, there has been a major emphasis on the design of low-noise equipment since the late 1980s by manufacturers interested in marketing within the EU.

For companies outside the EU attempting to implement a voluntary “Buy Quiet” programme, the degree of success achieved is largely dependent upon the timing and commitment of the entire management hierarchy. The first step in the programme is to establish acceptable noise criteria for construction of a new plant, expansion of an existing facility and purchase of new equipment. For the programme to be effective, the specified noise limits must be viewed by both the purchaser and vendor as an absolute requirement. When a product does not meet other equipment design parameters, such as size, flow rate, pressure, allowable temperature rise, and so forth, it is deemed unacceptable by company management. This is the same commitment that must be followed regarding noise levels in order to achieve a successful “Buy Quiet” programme.

As regards the timing aspect mentioned above, the earlier in the design process that consideration is given to the noise aspects of a project or equipment purchase, the greater the probability of success. In many situations, the factory designer or equipment buyer will have a choice of equipment types. Knowledge of the noise characteristics of the various alternatives will allow him or her to specify the quieter ones.

Besides selection of the equipment, early involvement in the design of the equipment layout within the plant is essential. Relocating equipment on paper during the design phase of a project is clearly much easier than physically moving the equipment later, especially once the equipment is in operation. A simple rule to follow is to keep machines, processes and work areas of approximately equal noise level together; and separate particularly noisy and particularly quiet areas by buffer zones having intermediate noise levels.

Validation of noise criteria as an absolute requirement requires a cooperative effort between company personnel from departments such as engineering, legal, purchasing, industrial hygiene and environment. For example, the industrial hygiene, safety, and/or personnel departments may determine the desired noise levels for equipment, as well as conduct sound surveys to qualify equipment. Next, company engineers may write the purchase specification, as well as select quiet types of equipment. The purchasing agent will most likely administer the contract and rely upon the law department representatives for assistance with enforcement. Involvement from all these parties should begin with the inception of the project and continue through funding requests, planning, design, bidding, installation and commissioning.

Even the most thorough and concise specification document is of little value unless the onus of compliance is placed on the supplier or manufacturer. Clear contract language must be used to define the means of determining compliance. Company procedures designed to enact guarantees should be consulted and followed. It may be desirable to include penalty clauses for non-compliance. Foremost in one’s enforcement strategy is the purchaser’s commitment to seeing that the requirements are met. Compromise on the noise criteria in exchange for cost, delivery date, performance, or other concessions should be the exception and not the rule.

Within the United States, ANSI has published the standard ANSI S12.16: Guidelines for the Specification of Noise of New Machinery (1992). This standard is a useful guide for writing an internal company noise specification. In addition, this standard provides direction for obtaining sound level data from equipment manufacturers. Once obtained from the manufacturer, the data may then be used by plant designers in planning equipment layouts. Because of the various types of distinctive equipment and tools for which this standard has been prepared, there is no single survey protocol appropriate for the measurement of sound level data. As a result, this standard contains reference information on the appropriate sound measurement procedure for testing a variety of stationary equipment. These survey procedures were prepared by the appropriate trade or professional organization in the United States responsible for a particular type or class of equipment.

Retrofitting Existing Equipment

Before one can decide what needs to be done, it becomes necessary to identify the root cause of noise. Towards this end, it is useful to have an understanding as to how noise is generated. Noise is created for the most part by mechanical impacts, high-velocity air flow, high-velocity fluid flow, vibrating surface areas of a machine, and quite often by the product being manufactured. As regards the lattermost item, it is often the case in manufacturing and process industries such as metal fabrication, glass manufacturing, food processing, mining, and so forth, that the interaction between the product and machines imparts the energy that creates the noise.

Source identification

One of the most challenging aspects of noise control is identification of the actual source. In a typical industrial setting there are usually multiple machines operating simultaneously, which makes it difficult to identify the root cause of noise. This is especially true when a standard sound level meter (SLM) is used to evaluate the acoustical environment. The SLM typically provides a sound pressure level (SPL) at a specific location, which is most likely the result of more than one noise source. Therefore, it becomes incumbent upon the surveyor to employ a systematic approach that will help separate out the individual sources and their relative contribution to the overall SPL. The following survey techniques may be used to help with identifying the origin or source of noise:

• Measure the frequency spectrum and graph the data.
• Measure the sound level, in dBA, as a function of time.
• Compare frequency data from similar equipment or production lines.
• Isolate components with temporary controls, or by turning on and off individual items whenever possible.

One of the most effective methods for locating the source of the noise is to measure its frequency spectrum. Once the data are measured, it is very useful to graph the results so that one can visually observe the characteristics of the source. For most noise abatement problems, the measurements can be accomplished with either full (1/1) or one-third (1/3) octave-band filters used with the SLM. The advantage of 1/3 octave-band measurement is that it provides more detailed information about what is emanating from a piece of equipment. Figure 1 exhibits a comparison between 1/1 and 1/3 octave-band measurements conducted near a nine-piston pump. As depicted in this figure, the 1/3 octave-band data clearly identifies the pumping frequency and many of its harmonics. If one used only 1/1, or full octave-band data, as depicted by the solid line and plotted at each centre-band frequency in figure 1, it becomes more difficult to diagnose what is occurring within the pump. With 1/1 octave-band data there are a total of nine data points between 25 Hertz (Hz) and 10,000 Hz, as shown in this figure. However, there are a total of 27 data points in this frequency range with the use of 1/3 octave-band measurements. Clearly, 1/3 octave-band data will provide more useful data towards identifying the root cause of a noise. This information is critical if the objective is to control noise at the source. If the only interest is to treat the path along which sound waves are transmitted, then 1/1 octave-band data will be sufficient for purposes of selecting acoustically appropriate products or materials.

Figure 1. Comparison between 1/1 and 1/3 octave-band data

Figure 2 shows a comparison between the 1/3 octave-band spectrum measured 3 feet from the crossover pipe of a liquid chiller compressor and the background level measured approximately 25 feet away (please note the approximations given in the footnote). This position represents the general area where employees typically walk through this room. For the most part the compressor room is not routinely occupied by workers. The only exception exists when maintenance workers are repairing or overhauling other equipment in the room. Besides the compressor, there are several other large machines operating in this area. To assist with the identification of the primary noise sources, several frequency spectrums were measured near each of the equipment items. When each spectrum was compared to the data at the background position in the walkway, only the crossover pipe of the compressor unit exhibited a similar spectrum shape. Consequently, it may be concluded this is the primary noise source controlling the level measured at the employee walkway. So as depicted in figure 2, through the use of frequency data measured near the equipment and graphically comparing individual sources to the data recorded at employee workstations or other areas of interest, it is often possible to identify the dominant sources of noises clearly.

Figure 2. Comparison of crossover pipe versus background level

When the sound level fluctuates, as with cyclic equipment, it is useful to measure the overall A-weighted sound level versus time. With this procedure it is important to observe and document what events are occurring over time. Figure 3 exhibits the sound level measured at the operator’s workstation over one full machine cycle. The process depicted in figure 3 represents that of a product wrapping machine, which has a cycle time of approximately 95 seconds. As shown in the figure, the maximum noise level of 96.2 dBA occurs during the release of compressed air, 33 seconds into the machine cycle. The other important events are also labelled in the figure, which permits the identification of the source and relative contribution of each activity during the full wrapping cycle.

Figure 3. Workstation for packaging operator

In industrial settings where there are multiple process lines with the same equipment, it is a worthwhile effort to compare the frequency data for similar equipment to one another. Figure 4 depicts this comparison for two similar process lines, both of which manufacture the same product and operate at the same speed. Part of the process involves the use of a pneumatically actuated device that punches a one-half inch hole in the product as a final phase in its production. Inspection of this figure clearly reveals that line #1 has an overall sound level 5 dBA higher than line #2. In addition, the spectrum depicted for line #1 contains a fundamental frequency and many harmonics that do not appear in the spectrum for line #2. Consequently, it is necessary to investigate the cause of these differences. Often significant differences will be an indication of the need for maintenance, such as was the situation for the final punch mechanism of line #2. However, this particular noise problem will require additional control measures since the overall level on line #1 is still relatively high. But the point of this survey technique is to identify the different noise problems that may exist between similar items of equipment and processes that may be easily remedied with effective maintenance or other adjustments.

Figure 4. Final punch operation for identical process lines

As mentioned above, an SLM typically provides an SPL that comprises acoustical energy from one or more noise sources. Under optimum measurement conditions, it would be best to measure each item of equipment with all other equipment turned off. Although this situation is ideal, it is rarely practical to shut down the plant to allow isolation of a particular source. In order to circumvent this limitation, it is often effective to use temporary control measures with certain noise sources that will provide some short-term noise reduction so as to allow measurement of another source. Some materials available that can provide a temporary reduction include plywood enclosures, acoustical blankets, silencers and barriers. Often, permanent application of these materials will create long-term problems such as heat build-up, interference with the operator’s access or product flow, or costly pressure drops associated with improperly selected silencers. However, for assisting with the isolation of individual components, these materials can be effective as a short-term control.

Another method available for isolating a particular machine or component is to turn different equipment on and off, or sections of a production line. To effectively conduct this type of diagnostic analysis the process must be capable of functioning with the selected item turned off. Next, for this procedure to be legitimate it is critical that the manufacturing process not be affected in any manner. If the process is affected, then it is entirely possible that the measurement will not be representative of the noise level under normal conditions. Finally, all valid data may then be ranked by magnitude of the overall dBA value to help prioritize equipment for engineering noise control.

Selecting the appropriate noise control options

Once the cause or source of noise is identified and it is known how it radiates to employee work areas, the next step is to decide what the available noise control options may be. The standard model used with respect to the control of almost any health hazard is to examine the various control options as they apply to the source, path and receiver. In some situations, control of one of these elements will be sufficient. However, under other circumstances it may be the case that treatment of more than one element is required to obtain an acceptable noise environment.

The first step in the noise control process should be to attempt some form of source treatment. In effect, source modification addresses the root cause of a noise problem, whereas control of the sound transmission path with barriers and enclosures only treats the symptoms of noise. In those situations where there are multiple sources within a machine and the objective is to treat the source, it will be necessary to address all noise-generating mechanisms on a component-by-component basis.

For excessive noise generated by mechanical impacts, the control options to investigate may include methods to reduce the driving force, reduce the distance between components, balance rotating equipment and install vibration isolation fittings. As regards noise arising from high-velocity air flow or fluid flow, the primary modification is to reduce the velocity of the medium, assuming this is a feasible option. Sometimes the velocity can be reduced by increasing the cross sectional area of the pipeline in question. Obstructions in the pipeline must be eliminated to allow for a streamlined flow, which in turn will reduce pressure variations and turbulence in the medium being transported. Finally, installation of a properly sized silencer or muffler can provide a significant reduction in the overall noise. The silencer manufacturer should be consulted for assistance with selection of the proper device, based on the operating parameters and constraints set forth by the purchaser.

When vibrating surface areas of a machine act as a sounding board for airborne noise, the control options include a reduction in the driving force associated with the noise, creation of smaller sections out of larger surface areas, perforation of the surface, increasing the substrate stiffness or mass, and application of damping material or vibration isolation fittings. As regards the use of vibration isolation and damping materials, the product manufacturer should be consulted for assistance with the selection of the appropriate materials and installation procedures. Finally, in many industries the actual product being manufactured will often be an efficient radiator of airborne sound. In these situations it is important to evaluate ways to tightly secure or better support the product during fabrication. Another noise control measure to investigate would be to reduce the impact force between the machine and product, between parts of the product itself, or between separate product items.

Often process or equipment redesign and source modification may prove to be infeasible. In addition, there may be situations when it is virtually impossible to identify the root cause of the noise. When any of these situations exist, the use of control measures for treatment of the sound transmission path would be an effective means for reducing the overall noise level. The two primary abatement measures for path treatments are acoustical enclosures and barriers.

The development of acoustical enclosures is well advanced in today’s marketplace. Both off-the-shelf and custom-made enclosures are available from several manufacturers. In order to procure the appropriate system it is necessary for the buyer to provide information as to the current overall noise level (and possibly frequency data), the dimensions of the equipment, the noise reduction goal, the need for product flow and employee access, and any other operating constraints. The vendor will then be able to use this information to select a stock item or fabricate a custom enclosure to satisfy the needs of the buyer.

In many situations it may be more economical to design and build an enclosure instead of purchasing a commercial system. In designing enclosures, many factors must be taken into consideration if the enclosure is to prove satisfactory from both an acoustical and a production point of view. Specific guidelines for enclosure design are as follows:

Enclosure dimensions. There is no critical guideline for the size or dimensions of an enclosure. The best rule to follow is the bigger the better. It is critical that sufficient clearance be provided to permit the equipment to perform all intended movement without contacting the enclosure.

Enclosure wall. The noise reduction provided by an enclosure is dependent upon the materials used in the construction of the walls and how tightly the enclosure is sealed. Selection of the appropriate materials for the enclosure wall should be determined using the following rules of thumb (Moreland 1979):

• for an enclosure, with no internal absorption:

TL_reqd=NR+20 dBA

• with approximately 50% internal absorption:

TL_reqd=NR+15 dBA

• with 100% internal absorption:

TL_reqd=NR+10 dBA.

In these expressions TL_reqd is the transmission loss required of the enclosure wall or panel, and NR is the noise reduction desired to meet the abatement goal.

Seals. For maximum efficiency, all enclosure wall joints must be tight fitting. Openings around pipe penetrations, electrical wiring and so on, should be sealed with non-hardening mastic such as silicon caulk.

Internal absorption. To absorb and dissipate acoustical energy the internal surface area of the enclosure should be lined with acoustically absorptive material. The frequency spectrum of the source should be used to select the appropriate material. The manufacturer’s published absorption data provides the basis for matching the material to the source of noise. It is important to match the maximum absorption factors to those frequencies of the source that have the highest sound pressure levels. The product vendor or manufacturer can also assist with selection of the most effective material based on the frequency spectrum of the source.

Enclosure isolation. It is important that the enclosure structure be separated or isolated from the equipment in order to ensure that mechanical vibration is not transmitted to the enclosure itself. When parts of the machine, such as pipe penetrations, do come in contact with the enclosure, it is important to include vibration isolation fittings at the point of contact to short-circuit any potential transmission path. Finally, if the machine causes the floor to vibrate then the base of the enclosure should also be treated with vibration isolation material.

Providing for product flow. As with most production equipment, there will be a need to move product into and out of the enclosure. The use of acoustically lined channels or tunnels can permit product flow and yet provide acoustical absorption. To minimize the leakage of noise, it is recommended that all passageways be three times longer than the inside width of the largest dimension of the tunnel or channel opening.

Providing for worker access. Doors and windows may be installed to provide physical and visual access to the equipment. It is critical that all windows have at least the same transmission loss properties as the enclosure walls. Next, all access doors must tightly seal around all edges. To prevent operation of the equipment with the doors open, it is recommended that an interlocking system be included that permits operation only when the doors are fully closed.

Ventilation of enclosure. In many enclosure applications, there will be excessive heat build-up. To pass cooling air through the enclosure, a blower with a capacity of 650 to 750 cubic feet/metres should be installed on the outlet or discharge duct. Finally, the intake and discharge ducts should be lined with absorptive material.

Protection of absorptive material. To prevent the absorptive material from becoming contaminated, a splash barrier should be applied over the absorptive lining. This should be of a very light material, such as one-mil plastic film. The absorptive layer should be retained with expanded metal, perforated sheet metal or hardware cloth. The facing material should have at least 25% open area.

An alternative sound transmission path treatment is to use an acoustic barrier to block or shield the receiver (the worker at risk of the noise hazard) from the direct sound path. An acoustic barrier is a high transmission loss material, such as a solid partition or wall, inserted between the noise source and the receiver. By blocking the direct line-of-sight path to the source, the barrier causes the sound waves to reach the receiver by reflection off various surfaces in the room and by diffraction at the edges of the barrier. As a result, the overall noise level is reduced at the receiver’s location.

The effectiveness of a barrier is a function of its location relative to the noise source or receivers and of its overall dimensions. To maximize the potential noise reduction, the barrier should be located as closely as practical to either the source or receiver. Next, the barrier should be as tall and wide as possible. To block the sound path effectively, a high-density material, on the order of 4 to 6 lb/ft³, should be used. Finally, the barrier should not contain any openings or gaps, which can significantly reduce its effectiveness. If it is necessary to include a window for visual access to the equipment, then it is important that the window have a sound transmission rating at least equivalent to that of the barrier material itself.

The final option for reducing worker noise exposure is to treat the space or area where the employee works. This option is most practical for those job activities, such as product inspection or equipment monitoring stations, where employee movement is confined to a relatively small area. In these situations, an acoustical booth or shelter may be installed to isolate the employees and provide relief from excessive noise levels. Daily noise exposures will be reduced as long as a significant portion of the workshift is spent inside the shelter. To construct such a shelter, the previously described guidelines for enclosure design should be consulted.

In conclusion, implementation of an effective “Buy Quiet” programme should be the initial step in a total noise control process. This approach is designed to prevent the purchase or installation of any equipment that might present a noise problem. However, for those situations where excessive noise levels already exist, it is then necessary to evaluate the noise environment systematically in order to develop the most practical engineering control option for each individual noise source. In determining the relative priority and urgency of implementing noise control measures, employee exposures, occupancy of the space, and overall area noise levels should be considered. Obviously, an important aspect of the desired result is to obtain the maximum employee noise exposure reduction for the monetary funds invested and that the greatest degree of employee protection is secured at the same time.

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For the prevention of adverse effects of noise on workers, attention should be paid to the choice of appropriate instrumentation, measuring methods and procedures for evaluating workers’ exposures. It is important to evaluate correctly the different types of noise exposures, such as continuous, intermittent and impulse noise, to distinguish noise environments with differing frequency spectra, as well as to consider the variety of working situations, such as drop-forge hammering shops, rooms housing air compressors, ultrasonic welding processes, and so forth. The main purposes of noise measurement in occupational settings are to (1) identify overexposed workers and quantify their exposures and (2) assess the need both for engineering noise control and the other types of control that are indicated. Other uses of noise measurement are to evaluate the effectiveness of particular noise controls and to determine the background levels in audiometric rooms.

Measuring Instruments

Instruments for noise measurement include sound level meters, noise dosimeters and auxiliary equipment. The basic instrument is the sound level meter, an electronic instrument consisting of a microphone, an amplifier, various filters, a squaring device, an exponential averager and a read-out calibrated in decibels (dB). Sound level meters are categorized by their precision, ranging from the most precise (type 0) to the least (type 3). Type 0 is usually used in the laboratory, type 1 is used for other precision sound level measurements, type 2 is the general purpose meter, and type 3, the survey meter, is not recommended for industrial use. Figure 1 and figure 2, illustrate a sound level meter.

Figure 1. Sound level meter—calibration check. Courtesy of Larson Davis

Figure 2. Sound level meter with wind screen. Courtesy of Larson Davis

Specifications for sound level meters may be found in national and international standards, such as the International Organization for Standardization (ISO), the International Electrotechnical Commission (IEC) and the American National Standards Institute (ANSI). The IEC publications IEC 651 (1979) and IEC 804 (1985) pertain to sound level meters of types 0, 1, and 2, with frequency weightings A, B, and C, and “slow,” “fast”                                                                                                                         and “impulse” time constants. ANSI S1.4-1983, as amended by                                                                                                                       ANSI S1.4A-1985, also provides specifications for sound level                                                                                                                         meters.

To facilitate more detailed acoustical analysis, full octave-band and 1/3 octave-band filter sets may be attached to or included in modern sound level meters. Nowadays, sound level meters are becoming increasingly small and easy to use, while at the same time their measurement possibilities are expanding.

For measuring non-steady noise exposures, such as those that occur in intermittent or impulse noise environments, an integrating sound level meter is most convenient to use. These meters can simultaneously measure the equivalent, peak and maximum sound levels, and calculate, log and store several values automatically. The noise dose meter or “dosimeter” is a form of integrating sound level meter that can be worn in the shirt pocket or attached to the worker’s clothing. Data from the noise dosimeter may be computerized and printed out.

It is important to make sure that noise measuring instruments are always properly calibrated. This means checking the instrument’s calibration acoustically before and after each day’s use, as well as making electronic assessments at appropriate intervals.

Measurement Methods

The noise measurement methods to be used depend on the measurement objectives, namely, to assess the following:

• the risk of hearing impairment
• the need for and appropriate types of engineering controls
• the “noise load” for compatibility with the type of job to be performed
• the background level necessary for communication and safety.

International standard ISO 2204 gives three types of method for noise measurement: (1) the survey method, (2) the engineering method and (3) the precision method.

The survey method

This method requires the least amount of time and equipment. Noise levels of a working zone are measured with a sound level meter using a limited number of measuring points. Although there is no detailed analysis of the acoustic environment, time factors should be noted, such as whether the noise is constant or intermittent and how long the workers are exposed. The A-weighting network is usually used in the survey method, but when there is a predominant low-frequency component, the C-weighting network or the linear response may be appropriate.

The engineering method

With this method, A-weighted sound level measurements or those using other weighting networks are supplemented with measurements using full octave or 1/3 octave-band filters. The number of measuring points and the frequency ranges are selected according to the measurement objectives. Temporal factors should again be recorded. This method is useful for assessing interference with speech communication by calculating speech interference levels (SILs), as well as for engineering noise abatement programmes and for estimating the auditory and non-auditory effects of noise.

The precision method

This method is required for complex situations, where the most thorough description of the noise problem is needed. Overall measurements of sound level are supplemented with full octave or 1/3 octave-band measurements and time histories are recorded for appropriate time intervals according to the duration and fluctuations of the noise. For example, it may be necessary to measure peak sound levels of impulses using an instrument’s “peak hold” setting, or to measure levels of infrasound or ultrasound, requiring special frequency measuring capabilities, microphone directivity, and so forth.

Those who use the precision method should make sure that the instrument’s dynamic range is sufficiently great to prevent “overshoot” when measuring impulses and that the frequency response should be broad enough if infrasound or ultrasound is to be measured. The instrument should be capable of making measurements of frequencies as low as 2 Hz for infrasound and up to at least 16 kHz for ultrasound, with microphones that are sufficiently small.

The following “common sense” steps may be useful for the novice noise measurer:

1. Listen for the main characteristics of the noise to be measured (temporal qualities, such as steady-state, intermittent or impulse qualities; frequency characteristics, such as those of wide-band noise, predominant tones, infrasound, ultrasound, etc.). Note the most prominent characteristics.
2. Choose the most suitable instrumentation (type of sound level meter, noise dosimeter, filters, tape recorder, etc.).
3. Check the instrument’s calibration and performance (batteries, calibration data, microphone corrections, etc.).
4. Make notes or a sketch (if using a system) of the instrumentation, including model and serial numbers.
5. Make a sketch of the noise environment to be measured, including major noise sources and the size and important characteristics of the room or outdoor setting.
6. Measure the noise and note down the level measured for each weighting network or for each frequency band. Also note the meter response (such as “slow,” “fast,” “impulse,” etc.), and note the extent to which the meter fluctuates (e.g., plus or minus 2 dB).

If measurements are made outdoors, pertinent meteorological data, such as wind, temperature and humidity should be noted if they are considered important. A windscreen should always be used for outdoor measurements, and even for some indoor measurements. The manufacturer’s instructions should always be followed to avoid the influence of factors such as wind, moisture, dust and electrical and magnetic fields, which may affect the readings.

Measuring procedures

There are two basic approaches to measuring noise in the workplace:

• The exposure of each worker, worker type or worker representative may be measured. The noise dosimeter is the preferable instrument for this purpose.
• Noise levels may be measured in various areas, creating a noise map for the determination of risk areas. In this case, a sound level meter would be used to take readings at regular points in a coordinate network.

Worker Exposure Evaluation

To assess the risk of hearing loss from specific noise exposures, the reader should consult the international standard, ISO 1999 (1990). The standard contains an example of this risk assessment in its Annex D.

Noise exposures should be measured in the vicinity of the worker’s ear and, in assessing the relative hazard of workers’ exposures, subtractions should not be made for the attenuation provided by hearing protection devices. The reason for this caveat is that there is considerable evidence that the attenuation provided by hearing protectors as they are worn on the job is often less than half the attenuation estimated by the manufacturer. The reason for this is that the manufacturer’s data are obtained under laboratory conditions and these devices are not usually fitted and worn so effectively in the field. At the moment, there is no international standard for estimating the attenuation of hearing protectors as they are worn in the field, but a good rule of thumb would be to divide the laboratory values in half.

In some circumstances, especially those involving difficult tasks or jobs requiring concentration, it may be important to minimize the stress or fatigue related to noise exposure by adopting noise control measures. This may be true even for moderate noise levels (below 85 dBA), when there is little risk of hearing impairment, but the noise is annoying or fatiguing. In such cases it may be useful to perform loudness assessments using ISO 532 (1975), Method for Calculating Loudness Level.

Interference with speech communication may be estimated according to ISO 2204 (1979) using the “articulation index”, or more simply by measuring the sound levels in the octave bands centred at 500, 1,000 and 2,000 Hz, resulting in the “speech interference level”.

Exposure criteria

The selection of noise exposure criteria depends on the goal to be attained, such as the prevention of hearing loss or the prevention of stress and fatigue. Maximum permissible exposures in terms of daily average noise levels vary among nations from 80, to 85, to 90 dBA, with trading parameters (exchange rates) of 3, 4, or 5 dBA. In some countries, such as Russia, permissible noise levels are set anywhere from 50 to 80 dBA, according to the type of job performed and taking into account the mental and physical work load. For example, the allowable levels for computer work or the performance of demanding clerical work are 50 to 60 dBA. (For more information on exposure criteria, see the article “Standards and regulations” in this chapter.)

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The Pervasive Nature of Occupational Noise

Noise is one of the most common of all the occupational hazards. In the United States, for example, more than 9 million workers are exposed to daily average A-weighted noise levels of 85 decibels (abbreviated here as 85 dBA). These noise levels are potentially hazardous to their hearing and can produce other adverse effects as well. There are approximately 5.2 million workers exposed to noise above these levels in manufacturing and utilities, which represents about 35% of the total number of workers in US manufacturing industries.

Hazardous noise levels are easily identified and it is technologically feasible to control excessive noise in the vast majority of cases by applying off-the-shelf technology, by redesigning the equipment or process or by retrofitting noisy machines. But all too often, nothing is done. There are several reasons for this. First, although many noise control solutions are remarkably inexpensive, others can be costly, especially when the aim is to reduce the noise hazard to levels of 85 or 80 dBA.

One very important reason for the absence of noise control and hearing conservation programmes is that, unfortunately, noise is often accepted as a “necessary evil”, a part of doing business, an inevitable part of an industrial job. Hazardous noise causes no bloodshed, breaks no bones, produces no strange-looking tissue, and, if workers can manage to get through the first few days or weeks of exposure, they often feel as though they have “got used” to the noise. But what has most likely happened is that they have started to incur a temporary hearing loss which dulls their hearing sensitivity during the work day and often subsides during the night. Thus, the progress of noise-induced hearing loss is insidious in that it creeps up gradually over the months and years, largely unnoticed until it reaches handicapping proportions.

Another important reason why the hazards of noise are not always recognized is that there is a stigma attached to the resulting hearing impairment. As Raymond Hétu has demonstrated so clearly in his article on rehabilitation from noise-induced hearing loss elsewhere in this Encyclopaedia, people with hearing impairments are often thought of as elderly, mentally slow and generally incompetent, and those at risk of incurring impairments are reluctant to acknowledge either their impairments or the risk for fear of being stigmatized. This is an unfortunate situation because noise-induced hearing losses become permanent, and, when added to the hearing loss that naturally occurs with ageing, can lead to depression and isolation in one’s middle and old age. The time to take preventive steps is before the hearing losses begin.

The Scope of Noise Exposure

As mentioned above, noise is especially prevalent in the manufacturing industries. The US Department of Labor has estimated that 19.3% of the workers in manufacturing and utilities are exposed to daily average noise levels of 90 dBA and above, 34.4% are exposed to levels above 85 dBA, and 53.1% to levels above 80 dBA. These estimates should be fairly typical of the percentage of workers exposed to hazardous levels of noise in other nations. The levels are likely to be somewhat higher in less developed nations, where engineering controls are not used as widely, and somewhat lower in nations with stronger noise control programmes, such as the Scandinavian countries and Germany.

Many workers throughout the world experience some very hazardous exposures, well above 85 or 90 dBA. For example, the US Labor Department has estimated that nearly half a million workers are exposed to daily average noise levels of 100 dBA and above, and more than 800,000 to levels between 95 and 100 dBA in the manufacturing industries alone.

Figure 1 ranks the noisiest manufacturing industries in the United States in descending order according to the percentage of workers exposed above 90 dBA and gives estimates of noise-exposed workers by industrial sector.

Figure 1. Occupational noise exposure—the US experience

Research Needs

In the following articles of this chapter, it should become clear to the reader that the effects on hearing of most types of noise are well-known. Criteria for the effects of continuous, varying and intermittent noise were developed some 30 years ago and remain essentially the same today. This is not true, however, of impulse noise. At relatively low levels, impulse noise seems to be no more damaging and possibly less so than continuous noise, given equal sound energy. But at high sound levels, impulse noise appears to be more damaging, especially when a critical level (or, more correctly, a critical exposure) is exceeded. Further research needs to be performed to define more exactly the shape of the damage/risk curve.

Another area that needs to be clarified is the adverse effect of noise, both on hearing and on general health, in combination with other agents. Although the combined effects of noise and ototoxic drugs are fairly well known, the combination of noise and industrial chemicals is of growing concern. Solvents and certain other agents appear to be increasingly neurotoxic when experienced in conjunction with high levels of noise.

Around the world, noise-exposed workers in the manufacturing industries and the military receive the major share of attention. There are, however, many workers in mining, construction, agriculture and transportation who are also exposed to hazardous levels of noise, as pointed out in figure 1. The unique needs associated with these occupations need to be assessed, and noise control and other aspects of hearing conservation programmes need to be extended to these workers. Unfortunately, the provision of hearing conservation programmes to noise-exposed workers does not guarantee that hearing loss and the other adverse effects of noise will be prevented. Standard methods to evaluate the effectiveness of hearing conservation programmes do exist, but they can be cumbersome and are not widely used. Simple evaluation methods need to be developed that can be used by small as well as large companies, and those with minimal resources.

The technology exists to abate most noise problems, as mentioned above, but there is a large gap between the existing technology and its application. Methods need to be developed by which information on all kinds of noise control solutions can be disseminated to those who need it. Noise control information needs to be computerized and made available not only to users in developing nations but to industrialized nations as well.

Future Trends

In some countries there is a growing trend to place more emphasis on non-occupational noise exposure and its contribution to the burden of noise-induced hearing loss. These kinds of sources and activities include hunting, target shooting, noisy toys and loud music. This focus is beneficial in that it highlights some potentially significant sources of hearing impairment, but it can actually be detrimental if it diverts attention from serious occupational noise problems.

A very dramatic trend is evident among the nations belonging to the European Union, where standardization for noise is progressing at an almost breathless pace. This process includes standards for product noise emissions as well as for noise exposure standards.

The standard-setting process is not moving rapidly at all in North America, especially in the United States, where regulatory efforts are at a standstill and movement toward deregulation is a possibility. Efforts to regulate the noise of new products were abandoned in 1982 when the Noise Office in the US Environmental Protection Agency was closed, and occupational noise standards may not survive the deregulatory climate in the current US Congress.

The developing nations appear to be in the process of adopting and revising noise standards. These standards are tending toward conservatism, in that they are moving toward a permissible exposure limit of 85 dBA, and toward an exchange rate (time/intensity trading relation) of 3 dB. How well these standards are enforced, especially in burgeoning economies, is an open question.

The trend in some of the developing nations is to concentrate on controlling noise by engineering methods rather than to struggle with the intricacies of audiometric testing, hearing protection devices, training and record keeping. This would appear to be a very sensible approach wherever feasible. Supplementation with hearing protectors may be necessary at times to reduce exposures to safe levels.

The Effects of Noise

Certain of the materials which follow have been adapted from Suter, AH, “Noise and the conservation of hearing”, Chapter 2 in Hearing Conservation Manual (3rd ed.), Council for Accreditation in Occupational Hearing Conservation, Milwaukee, WI, USA (1993).

Loss of hearing is certainly the most well-known adverse effect of noise, and probably the most serious, but it is not the only one. Other detrimental effects include tinnitus (ringing in the ears), interference with speech communication and with the perception of warning signals, disruption of job performance, annoyance and extra-auditory effects. Under most circumstances, protecting workers’ hearing should protect against most other effects. This consideration provides additional support for companies to implement good noise control and hearing conservation programmes.

Hearing impairment

Noise-induced hearing impairment is very common, but it is often underrated because there are no visible effects and, in most cases, no pain. There is only a gradual, progressive loss of communication with family and friends, and a loss of sensitivity to sounds in the environment, such as birdsong and music. Unfortunately, good hearing is usually taken for granted until it is lost.

These losses may be so gradual that individuals do not realize what has happened until the impairment becomes handicapping. The first sign is usually that other people do not seem to speak as clearly as they used to. The hearing-impaired person will have to ask others to repeat themselves, and he or she often becomes annoyed with their apparent lack of consideration. Family and friends will often be told, “Don’t shout at me. I can hear you, but I just can’t understand what you’re saying.”

As the hearing loss becomes worse, the individual will begin to withdraw from social situations. Church, civic meetings, social occasions and theatre begin to lose their attraction and the individual will choose to stay at home. The volume of the television becomes a source of contention within the family, and other family members are sometimes driven out of the room because the hearing-impaired person wants it so loud.

Presbycusis, the hearing loss that naturally accompanies the ageing process, adds to the hearing handicap when the person with noise-induced hearing loss becomes older. Eventually, the loss may progress to such a severe stage that the individual can no longer communicate with family or friends without great difficulty, and then he or she is indeed isolated. A hearing aid may help in some cases, but the clarity of natural hearing will never be restored, as the clarity of vision is with eyeglasses.

Occupational hearing impairment

Noise-induced hearing impairment is usually considered an occupational disease or illness, rather than an injury, because its progression is gradual. On rare occasions, an employee may sustain immediate, permanent hearing loss from a very loud event such as an explosion or a very noisy process, such as riveting on steel. In these circumstances the hearing loss is sometimes referred to as an injury and is called “acoustic trauma”. The usual circumstance, however, is a slow decrease in hearing ability over many years. The amount of impairment will depend on the level of the noise, the duration of the exposure and the susceptibility of the individual worker. Unfortunately, there is no medical treatment for occupational hearing impairment; there is only prevention.

The auditory effects of noise are well documented and there is little controversy over the amount of continuous noise that causes varying degrees of hearing loss (ISO 1990). That intermittent noise causes hearing loss is also uncontested. But periods of noise that are interrupted by periods of quiet can offer the inner ear an opportunity to recover from temporary hearing loss and may therefore be somewhat less hazardous than continuous noise. This is true mainly for outdoor occupations, but not for inside settings such as factories, where the necessary intervals of quiet are rare (Suter 1993).

Impulse noise, such as the noise from gunfire and metal stamping, also damages hearing. There is some evidence that the hazard from impulse noise is more severe than that from other types of noise (Dunn et al. 1991; Thiery and Meyer-Bisch 1988), but this is not always the case. The amount of damage will depend mainly on the level and duration of the impulse, and it may be worse when there is continuous noise in the background. There is also evidence that high-frequency sources of impulse noise are more damaging than those composed of lower frequencies (Hamernik, Ahroon and Hsueh 1991; Price 1983).

Hearing loss due to noise is often temporary at first. During the course of a noisy day, the ear becomes fatigued and the worker will experience a reduction in hearing known as temporary threshold shift (TTS). Between the end of one workshift and the beginning of the next the ear usually recovers from much of the TTS, but often, some of the loss remains. After days, months and years of exposure, the TTS leads to permanent effects and new amounts of TTS begin to build onto the now permanent losses. A good audiometric testing programme will attempt to identify these temporary hearing losses and provide for preventive measures before the losses become permanent.

Experimental evidence indicates that several industrial agents are toxic to the nervous system and produce hearing loss in laboratory animals, especially when they occur in combination with noise (Fechter 1989). These agents include (1) heavy metal hazards, such as lead compounds and trimethyltin, (2) organic solvents, such as toluene, xylene and carbon disulphide, and (3) an asphyxiant, carbon monoxide. Recent research on industrial workers (Morata 1989; Morata et al. 1991) suggests that certain of these substances (carbon disulphide and toluene) can increase the damaging potential of noise. There is also evidence that certain drugs which are already toxic to the ear can increase the damaging effects of noise (Boettcher et al. 1987). Examples include certain antibiotics and cancer chemotherapy drugs. Those in charge of hearing conservation programmes should be aware that workers exposed to these chemicals or using these drugs may be more susceptible to hearing loss, especially when exposed to noise in addition.

Non-occupational hearing impairment

It is important to understand that occupational noise is not the only cause of noise-induced hearing loss among workers, but hearing loss can also be caused by sources outside the workplace. These sources of noise produce what is sometimes called “sociocusis”, and their effects on hearing are impossible to differentiate from occupational hearing loss. They can only be surmised by asking detailed questions about the worker’s recreational and other noisy activities. Examples of sociocusic sources could be woodworking tools, chain saws, unmuffled motorcycles, loud music and firearms. Frequent shooting with large-calibre guns (without hearing protection) may be a significant contributor to noise-induced hearing loss, whereas occasional hunting with smaller-calibre weapons is more likely to be harmless.

The importance of non-occupational noise exposure and the resulting sociocusis is that this hearing loss adds to the exposure that an individual might receive from occupational sources. For the sake of workers’ overall hearing health, they should be counselled to wear adequate hearing protection when they engage in noisy recreational activities.

Tinnitus

Tinnitus is a condition that frequently accompanies both temporary and permanent hearing loss from noise, as well as other types of sensorineural hearing loss. Often referred to as a “ringing in the ears”, tinnitus may range from mild in some cases to severe in others. Sometimes individuals report that they are more bothered by their tinnitus than they are by their hearing impairment.

People with tinnitus are likely to notice it the most in quiet conditions, such as when they are trying to go to sleep at night, or when they are sitting in a sound-proof booth taking an audiometric test. It is a sign that the sensory cells in the inner ear have been irritated. It is often a precursor to noise-induced hearing loss and therefore an important warning signal.

Communication interference and safety

The fact that noise can interfere with or “mask” speech communication and warning signals is only common sense. Many industrial processes can be carried out very well with a minimum of communication among workers. Other jobs, however, such as those performed by airline pilots, railroad engineers, tank commanders and many others rely heavily on speech communication. Some of these workers use electronic systems that suppress the noise and amplify the speech. Nowadays, sophisticated communication systems are available, some with devices that cancel unwanted acoustic signals so that communication can take place more easily.

In many cases, workers just have to make do, straining to understand communications above the noise and shouting above it or signalling. Sometimes people may develop hoarseness or even vocal nodules or other abnormalities on the vocal cords from excessive strain. These individuals may need to be referred to for medical care.

People have learned from experience that in noise levels above about 80 dBA they have to speak very loudly, and in levels above 85 dBA they have to shout. In levels much above 95 dBA they have to move close together to communicate at all. Acoustical specialists have developed methods to predict the amount of communication that can take place in industrial situations. The resulting predictions are dependent upon the acoustical characteristics of both the noise and the speech (or other desired signal), as well as the distance between talker and listener.

It is generally known that noise can interfere with safety, but only a few studies have documented this problem (e.g., Moll van Charante and Mulder 1990; Wilkins and Acton 1982). There have been numerous reports, however, of workers who have got clothing or hands caught in machines and have been seriously injured while their co-workers were oblivious to their cries for help. To prevent communication breakdowns in noisy environments, some employers have installed visual warning devices.

Another problem, recognized more by noise-exposed workers themselves than by professionals in hearing conservation and occupational health, is that hearing protection devices may sometimes interfere with the perception of speech and warning signals. This appears to be true mainly when the wearers already have hearing losses and the noise levels fall below 90 dBA (Suter 1992). In these cases, workers have a very legitimate concern about wearing hearing protection. It is important to be attentive to their concerns and either to implement engineering noise controls or to improve the kind of protection offered, such as protectors built into an electronic communication system. In addition, hearing protectors are now available with a flatter, more “high fidelity” frequency response, which may improve workers’ abilities to understand speech and warning signals.

Effects on job performance

The effects of noise on job performance have been studied both in the laboratory and in actual working conditions. The results have shown that noise usually has little effect on the performance of repetitive, monotonous work, and in some cases can actually increase job performance when the noise is low or moderate in level. High levels of noise can degrade job performance, especially when the task is complicated or involves doing more than one thing at a time. Intermittent noise tends to be more disruptive than continuous noise, particularly when the periods of noise are unpredictable and uncontrollable. Some research indicates that people are less likely to help each other and more likely to exhibit antisocial behaviour in noisy environments than in quiet ones. (For a detailed review of the effects of noise on job performance see Suter 1992).

Annoyance

Although the term “annoyance” is more often connected with community noise problems, such as airports or race-car tracks, industrial workers may also feel annoyed or irritated by the noise of their workplace. This annoyance may be related to the interference of speech communication and job performance described above, but it may also be due to the fact that many people have an aversion to noise. Sometimes the aversion to noise is so strong that a worker will look for employment elsewhere, but that opportunity is not often feasible. After a period of adjustment, most will not appear to be bothered as much, but they may still complain about fatigue, irritability and sleeplessness. (The adjustment will be more successful if young workers are properly fitted with hearing protectors from the start, before they develop any hearing loss.) Interestingly, this kind of information sometimes surfaces after a company starts a noise control and hearing conservation programme because the workers would have become aware of the contrast between earlier and subsequently improved conditions.

Extra-auditory effects

As a biological stressor, noise can influence the entire physiological system. Noise acts in the same way that other stressors do, causing the body to respond in ways that may be harmful in the long run and lead to disorders known as the “stress diseases”. When facing danger in primitive times, the body would go through a series of biological changes, preparing either to fight or to run away (the classic “fight or flight” response). There is evidence that these changes still persist with exposure to loud noise, even though a person may feel “adjusted” to the noise.

Most of these effects appear to be transitory, but with continued exposure some adverse effects have been shown to be chronic in laboratory animals. Several studies of industrial workers also point in this direction, while some studies show no significant effects (Rehm 1983; van Dijk 1990). The evidence is probably strongest for cardiovascular effects such as increased blood pressure, or changes in blood chemistry. A significant set of laboratory studies on animals showed chronic elevated blood pressure levels resulting from exposure to noise around 85 to 90 dBA, which did not return to baseline after cessation of the exposure (Peterson et al. 1978, 1981 and 1983).

Studies of blood chemistry show increased levels of the catecholamines epinephrine and norepinephrine due to noise exposure (Rehm 1983), and a series of experiments by German investigators found a connection between noise exposure and magnesium metabolism in humans and animals (Ising and Kruppa 1993). Current thinking holds that the extra-auditory effects of noise are most likely mediated psychologically, through aversion to noise, making it very difficult to obtain dose-response relationships. (For a comprehensive overview of this problem, see Ising and Kruppa 1993.)

Because the extra-auditory effects of noise are mediated by the auditory system, meaning that it is necessary to hear the noise for adverse effects to occur, properly fitted hearing protection should reduce the likelihood of these effects in just the way it does with hearing loss.

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Seeing the possibilities and making them happen is what pollution prevention is all about. It is a commitment to products and processes that have a minimal impact on the environment.

Pollution prevention is not a new idea. It is the manifestation of an environmental ethic that was practised by the original inhabitants of many cultures, including Native Americans. They lived in harmony with their environment. It was the source of their shelter, their food and the very foundation of their religion. Although their environment was exceedingly harsh, it was treated with honour and respect.

As nations developed and the Industrial Revolution advanced, a very different attitude toward the environment emerged. Society came to view the environment as an endless source of raw materials and a convenient dumping ground for wastes.

Early Efforts to Reduce Waste

Even so, some industries have practised a type of pollution prevention since the first chemical processes were developed. Initially, industry focused on efficiency or increasing process yield through waste reduction, rather than specifically preventing pollution by keeping wastes from entering the environment. However, the end result of both activities is the same—less material waste is released to the environment.

An early example of pollution prevention under another guise was practised in a German sulphuric acid production facility during the 1800s. Process improvements at the plant reduced the amount of sulphur dioxide emitted per pound of product produced. These actions were most likely labelled as efficiency or quality improvements. Only recently has the concept of pollution prevention been directly associated with this type of process change.

Pollution prevention as we know it today began to emerge in the mid-1970s in response to the growing volume and complexity of environmental requirements. The US Environmental Protection Agency (EPA) was created then. The first efforts at pollution reduction were mostly installations of end-of-pipe or costly add-on pollution control equipment. Eliminating the source of a pollution problem was not a priority. When it occurred, it was more a matter of profit or efficiency than an organized effort to protect the environment.

Only recently have businesses adopted a more specific environmental point of view and kept track of progress. However, the processes by which businesses approach pollution prevention can differ significantly.

Prevention versus Control

In time, the focus began to change from pollution control to pollution prevention. It became apparent that the scientists who invent the products, engineers who design the equipment, process experts who operate the manufacturing facilities, marketers who work with customers to improve product environmental performance, sales representatives who bring environmental concerns from customers back to the laboratory for solutions and office employees who work to reduce paper usage all can help reduce the environmental impact of operations or activities under their control.

Developing effective pollution prevention programmes

In state-of-the-art pollution prevention, pollution prevention programmes as well as specific pollution prevention technologies must be examined. Both the overall pollution prevention programme and the individual pollution prevention technologies are equally important in achieving environmental benefit. While the development of technologies is an absolute requirement, without the organizational structure to support and implement those technologies, the environmental benefits will never be fully achieved.

The challenge is to obtain total corporate participation in pollution prevention. Some companies have implemented pollution prevention at every level of their organization through well organized, detailed programmes. Perhaps the three most widely recognized of these in the United States are 3M’s Pollution Prevention Pays (3P) programme, Chevron’s Save Money and Reduce Toxics (SMART) and Dow Chemical’s Waste Reduction Always Pays (WRAP).

The goal of such programmes is to reduce waste as much as technologically possible. But relying on source reduction alone is not always technically feasible. Recycling and reuse also must be part of the pollution prevention effort, as they are in the above programmes. When every employee is asked not only to make processes as efficient as possible, but also to find a productive use for every by-product or residual stream, pollution prevention becomes an integral part of the corporate culture.

In late 1993, The Business Roundtable in the US released the results of a pollution prevention benchmark study of successful efforts. The study identified best-in-class facility pollution prevention programmes and highlighted elements necessary to fully integrate pollution prevention into company operations. Included were facilities from Proctor & Gamble (P&G), Intel, DuPont, Monsanto, Martin Marietta and 3M.

Pollution prevention initiatives

The study found that successful pollution prevention programmes in these companies shared the following elements:

• top management support

• involvement of all employees

• recognition of accomplishments

• facilities had freedom to choose the best method to reach corporate goals

• transfer of information between facilities

• measurement of results

• all included recycling and reuse of waste.

In addition, the study found that each of the facilities had advanced from concentrating on pollution prevention in the manufacturing process to integrating pollution prevention in pre-manufacturing decisions. Pollution prevention had become a core corporate value.

Top management support is a necessity for a fully operational pollution prevention programme. Top officials at both the corporate and facility levels must send a strong message to all employees that pollution prevention is an integral part of their jobs. This must begin at the chief executive officer (CEO) level because that person sets the tone for all corporate activities. Speaking out publicly and within the company gets the message heard.

The second reason for success is employee involvement. Technical and manufacturing people are most involved in develop-ing new processes or product formulations. But employees in every position can be involved in waste reduction through reuse, reclamation and recycling as part of pollution prevention. Employees know the possibilities in their area of responsibility much better than environmental professionals. In order to spur employee involvement, the company must educate employees about the challenge the company faces. For example, articles on environmental issues in the corporate newsletter can increase employee awareness.

Recognition of accomplishments can be done in many ways. The CEO of 3M presents a special environmental leadership award not only to employees who contribute to the company’s goals, but also to those who contribute to community environmental efforts. In addition, environmental achievements are recognized in annual performance reviews.

Measuring results is extremely important because that is the driving force for employee action. Some facilities and corporate programmes measure all wastes, while others focus on Toxic Release Inventory (TRI) emissions or on other measurements which best fit within their corporate culture and their specific pollution prevention programmes.

Environmental Programme Examples

Over the course of 20 years, pollution prevention has become imbedded in 3M’s culture. 3M management pledged to go beyond government regulations, in part by developing environmental management plans that merge environmental goals with business strategy. The 3P programme focused on preventing pollution, not control.

The idea is to stop pollution before it starts, and seek out prevention opportunities at all stages of a product’s life, not just at the end. Successful companies recognize that prevention is more environmentally effective, more technically sound and less costly than conventional control procedures, which do not eliminate the problem. Pollution prevention is economical, because if pollution is avoided in the first place, it does not have to be dealt with later.

3M employees have developed and implemented more than 4,200 pollution prevention projects since the inception of the 3P programme. Over the past 20 years, these projects have resulted in the elimination of more than 1.3 billion pounds of pollutants and saved the company $750 million.

Between 1975 and 1993, 3M reduced the amount of energy needed per unit of production by 3,900 BTUs, or 58%. The annual energy savings for 3M in the United States alone totals 22 trillion BTUs each year. This is enough energy to heat, cool and light more than 200,000 homes in the United States and eliminates more than 2 million tons of carbon dioxide. And in 1993, 3M facilities in the United Sates recovered and recycled more solid waste (199 million pounds) than they sent to landfills (198 million pounds).

Pollution Prevention Technologies

The concept of designing for the environment is becoming important, but technologies used for pollution prevention are as diverse as the companies themselves. In general, this concept can be realized through technical innovation in four areas:

• product reformulation—developing nonpolluting or lesspolluting products or processes by using different raw materials
• process modification—changing manufacturing processes so they become nonpolluting or less polluting
• equipment redesign—modifying equipment to perform better under specific operating conditions or to make use of available resources
• resource recovery—recycling by-products for sale or for use by other companies or for use in the company’s other products or processes.

Concentrated efforts in each of these areas can mean new and safer products, cost savings and greater customer satisfaction.

Product reformulation can be the most difficult. Many of the attributes which make materials ideal for their intended uses may also contribute to problems for the environment. One example of product reformulation led a team of scientists to eliminate the ozone-depleting chemical methyl chloroform from a fabric protector product. This new water-based product greatly reduces the use of solvents and gives the company a competitive edge in the marketplace.

In making medication tablets for the pharmaceutical industry, employees developed a new water-based coating solution for the solvent-based coating solution that had been used to coat the tablets. The change cost $60,000, but eliminated the need to spend $180,000 for pollution control equipment, saves $150,000 in material cost and prevents 24 tons a year of air pollution.

An example of process modification resulted in a move away from hazardous chemicals to thoroughly clean copper sheeting prior to using it to make electric products. In the past, the sheeting was cleaned by a spray with ammonium persulphate, phosphoric acid and sulphuric acid—all hazardous chemicals. This procedure has been replaced by one that employs a light citric acid solution, a nonhazardous chemical. The process change eliminated the generation of 40,000 pounds of hazardous waste per year and saves the company about $15,000 per year in raw material and disposal costs.

Redesigning equipment also reduces waste. In the resin product area, a company regularly sampled a particular liquid phenolic resin by using a tap on the process flow line. Some of the product was wasted before and after the sample was collected. By installing a simple funnel under the sample tape and a pipe leading back to the process, the company now takes samples without any loss of product. This prevents about 9 tons of waste per year, saves about $22,000, increases the yield and decreases the disposal cost, all for a capital cost of about $1,000.

Resource recovery, the productive use of waste material, is extremely important in pollution prevention. One brand of wool soap pads is now made entirely of post-consumer recycled plastic soda bottles. In the first two years of this new product, the company used in excess of a million pounds of this recycled material to make soap pads. This is the equivalent of more than 10 million two-litre soda bottles. Also, waste rubber trimmed from floor mats in Brazil is used to make sandals. In 1994 alone, the plant recovered about 30 tons of material, enough to make more than 120,000 pairs of sandals.

In another example, Post-it(T) Recycled Paper Notes use 100% recycled paper. One ton of recycled paper alone saves 3 cubic yards of landfill space, 17 trees, 7,000 gallons of water and 4,100 kilowatt hours of energy, enough to heat the average home for six months.

Life-Cycle Analysis

Life-Cycle Analysis or a similar process is in place at every successful company. This means that each phase of a product’s life cycle from development through manufacturing, use and disposal offers opportunities for environmental improvement. The response to such environmental challenges has led to products with strong environmental claims throughout industry.

For example, P&G was the first commercial-goods manufacturer to develop concentrated detergents which require 50 to 60% smaller packaging than the previous formula. P&G also manufacturers refills for more than 57 brands in 22 countries. Refills typically cost less and save up to 70% in solid waste.

Dow has developed a new highly effective herbicide that is non-toxic. It is less risky for people and animals and is applied in ounces rather than pounds per acre. Using biotechnology, Monsanto developed a potato plant that is resistant to insects, so it reduced the need for chemical insecticides. Another herbicide from Monsanto helps restore the natural habitat of wetlands by controlling weeds in a safer way.

Commitment to a Cleaner Environment

It is critical that we approach pollution prevention on a comprehensive scale, including commitment to both programmatic and technological improvements. Increasing efficiency or process yield and reducing waste production has long been a practice of the manufacturing industry. However, only within the last decade have these activities focused more directly on pollution prevention. Substantial efforts are now aimed at improving source reduction as well as tailoring processes to separate, recycle and reuse by-products. All these are proven pollution prevention tools.

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The Evolution of Environmental Response Strategies

In the past thirty years there has been a dramatic increase in environmental problems due to many different factors: demographic expansion (this pace is continuing, with an estimated 8 billion people by the year 2030), poverty, dominant economic models based on growth and quantity rather than quality, high consumption of natural resources driven particularly by industrial expansion, reduction of biological diversity especially as a result of increased agricultural production through monoculture, soil erosion, climate change, the unsustainable use of natural resources and the pollution of air, soils and water resources. However, the negative effects of human activity upon the environment have also accelerated the awareness and social perception of people in many countries, leading to changes in traditional approaches and response models.

Response strategies have been evolving: from no recognition of the problem, to ignoring the problem, to diluting and controlling pollution through a top-down approach—that is, the so-called end-of-pipe strategies. The 1970s marked the first widely relevant local environmental crises and the development of new awareness of environmental pollution. This led to the adoption of the first major series of national legislation, regulations and international conventions aimed at the control and regulation of pollution. This end-of-pipe strategy soon showed its failure, for it was directed in an authoritarian way to interventions related to the symptoms and not the causes of environmental problems. At the same time, industrial pollution also drew attention to the growing contradictions in philosophy between employers, workers and environmental groups.

The 1980s was the period of global environmental issues such as the Chernobyl disaster, acid rain, ozone depletion and the ozone hole, the greenhouse effect and climate change, and the growth in toxic wastes and their export. These events and the resulting problems enhanced public awareness and helped to generate support for new approaches and solutions focusing on environmental management tools and cleaner production strategies. Organizations such as UNEP, OECD, the European Union and many national institutions started to define the issue and work together within a more global framework based on principles of prevention, innovation, information, education and the participation of relevant stakeholders. As we entered the 1990s there was another dramatic increase in awareness that the environmental crisis was deepening, particularly in the developing world and in Central and Eastern Europe. This reached a critical threshold at the United Nations Conference on Environment and Development (UNCED) in Rio de Janeiro in 1992.

Today, the precautionary approach has become one of the most important factors necessary to take into account when assessing environmental policies and solutions. The precautionary approach suggests that even when there is scientific uncertainty or controversy on environmental problems and policies, decisions should reflect the need to take precautions to avoid future negative implications whenever economically, socially and technically feasible. The precautionary approach should be pursued when developing policies and regulations, and when planning and implementing projects and programmes.

In effect, both the preventive and precautionary approaches seek a more integrated approach to environmental action, shifting from an almost exclusive focus on the production process to the development of environmental management tools and techniques applicable to all forms of human economic activity and decision-making processes. Unlike pollution control, which implied a limited, react-and-retreat approach, the environmental management and cleaner production approach is aimed at the integration of a precautionary approach within broader strategies to create a process that will be assessed, monitored and continuously improved. To be effective, however, environmental management and cleaner production strategies need to be carefully implemented through the involvement of all stakeholders and at all levels of intervention.

These new approaches must not be considered as simply technical instruments related to the environment, but rather should be seen as holistic integrating approaches which will help to define new models of an environmentally and socially sound market economy. To be fully effective, these new approaches will also require a regulatory framework, incentive instruments and social consensus defined through the involvement of institutions, social partners and interested environmental and consumer organizations. If the scope of environmental management and cleaner production strategies is to lead to more sustainable socio-economic development scenarios, various factors will need to be taken into consideration in policy-setting, in the development and enforcement of standards and regulations, and in collective agreements and action plans, not only at the company or enterprise level, but at the local, national and international levels as well. Given the wide disparities in economic and social conditions around the world, the opportunities for success also will depend on local political, economic and social conditions.

Globalization, the liberalization of markets and structural adjustment policies, will also create new challenges to our capacity to analyse in an integrated fashion the economic, social and environmental implications of these complex changes within our societies, not the least of which will be the risk that these changes may lead to quite different power relationships and responsibilities, perhaps even ownership and control. Attention will need to be given to ensuring that these changes do not lead to the risk of powerlessness and paralysis in the development of environmental management and cleaner production technologies. On the other hand, this changing situation, in addition to its risks, also offers new opportunities to promote improvements in our present social, economic, cultural, political and environmental conditions. Such positive changes, however, will require a collaborative, participatory and flexible approach to managing change within our societies and within our enterprises. To avoid paralysis, we will need to take measures which will build confidence and emphasize a step-by-step, partial and gradual approach which will generate growing support and capacity aimed at facilitating more substantial changes in our conditions of life and work in future.

Main International Implications

As mentioned above, the new international situation is characterized by the liberalization of markets, the elimination of trade barriers, new information technologies, rapid and enormous daily capital transfers and the globalization of production, especially through multinational enterprises. Deregulation and competitiveness are the dominant criteria for investment strategies. These changes also, however, facilitate the delocalization of plants, the fragmentation of production processes and the establishment of special Export Processing Zones, which exempt industries from labour and environmental regulations and other obligations. Such effects may promote excessively low labour costs and consequently higher profits for industry, but this is frequently accompanied by situations of deplorable human and environmental exploitation. In addition, in the absence of regulations and controls, obsolete plants, technologies and equipment are being exported just as dangerous chemicals and substances which have been banned, withdrawn or severely restricted in one country for environmental or safety reasons are also being exported, particularly to developing countries.

In order to respond to these issues, it is of particular importance that the new World Trade Organization (WTO) rules are defined so as to promote socially and environmentally acceptable trade. This means that WTO, in order to ensure fair competition, should require all countries to fulfil basic international labour standards (e.g., basic ILO Conventions) and environmental conventions and regulations. Moreover, guidelines such as those prepared by OECD on technology transfer and regulations should be effectively implemented in order to avoid the export of highly polluting and unsafe production systems.

International factors to be considered include:

• international trade in equipment and plants
• financial mechanisms and technical assistance
• WTO regulations
• raw material pricing
• tax systems
• transfer of technology and know-how
• transboundary migration of pollution
• multinational companies’ production strategies
• development and implementation of international conventions, agreements, guidelines and regulations
• involvement of international organizations of employers, workers and relevant environmental groups.

Developing and other countries in need of assistance should be given special financial assistance, reduction in taxes, incentives and technical assistance to help them implement the above-mentioned basic labour and environmental regulations and to introduce cleaner production technologies and products. An innovative approach which deserves further attention in the future is the development of codes of conduct negotiated by certain companies and their trade unions with a view to promoting the respect of basic social rights and environmental rules. A unique role in the assessment of the process at the international level is being played by the ILO, given its tripartite structure, and in strict coordination with other United Nations agencies and international financial institutions responsible for international aid and financial assistance.

Main National and Local Implications

An appropriate general regulatory framework also has to be defined at both the national and local level in order to develop appropriate environmental management procedures. This will require a decision-making process which links budgetary, fiscal, industrial, economic, labour and environmental policies, and also provides for the full consultation and participation of the social actors most concerned (i.e., employers, trade union organizations, environmental and consumer groups). Such a systematic approach would include linkages between different programmes and policies, for example:

• The taxation system should provide incentives which will encourage the penetration of environmentally sound goods and raw materials into the market and penalize those products, economic activities and collective or individual behaviour which are environmentally unsound.
• Adequate policies and resources should be available to promote research and development of environmentally and socially sound technologies, production processes and infrastructure.
• Advisory, information and training centres for cleaner production technologies should be established to assist enterprises, especially small- and medium-sized enterprises, to procure, adapt and use the technologies safely and effectively.

National and local industrial policies should be designed and implemented in full consultation with trade union organizations so that business policies and labour policies can match social and environmental needs. Direct negotiations and consultations at the national level with trade unions can help to prevent potential conflicts arising from safety, health and environmental implications of new industrial policies. Such negotiations at the national level, however, should be matched by negotiations and consultations at the level of individual companies and enterprises so as to ensure that adequate controls, incentives and assistance are also available at the workplace.

In summary, national and local factors to be considered include:

• national and local regulations, guidelines, agreements and policies
• industrial relations procedures
• involvement of social partners (trade unions and employers’ organizations), environmental NGOs and consumer organizations in all decision-making processes
• industrial policies
• raw material pricing policies
• trade policies
• tax systems
• incentives for research and development
• incentives for introduction of innovative environmental management initiatives
• integration of health and safety procedures/standards
• establishment of advisory, information and training centres for the dissemination of cleaner production technologies
• assistance for overcoming obstacles (conceptual, organizational, technical, skills and financial) to the introduction of new technologies, policies, regulations.

Environmental Management at Company Level

Environmental management within a given company, enterprise or other economic structure requires an ongoing assessment and consideration of environmental effects—at the workplace (i.e., the working environment) and outside the plant gates (i.e., the external environment)—as regards the full range of activities and decisions related to operations. It implies, as well, the consequent modification of the organization of work and production processes to respond efficiently and effectively to those environmental effects.

It is necessary for enterprises to foresee potential environmental consequences of a given activity, process or product from the earliest planning stages in order to ensure the implementation of adequate, timely and participatory response strategies. The objective is to make industry and other economic sectors economically, socially and environmentally sustainable. Most certainly, in many cases there still will need to be a transition period which will require pollution control and remediation activities. Therefore, environmental management should be seen as a composite process of prevention and control that aims to bring company strategies in line with environmental sustainability. To do this, companies will need to develop and implement procedures within their overall management strategy to assess cleaner production processes and to audit environmental performance.

Environmental management and cleaner production will lead to a range of benefits that will not only effect environmental performance but may also lead to improvements in:

• health and safety of workers
• rates of absenteeism
• preventing and resolving conflict with workers and communities
• promoting a cooperative climate within the company
• the company public image
• the market penetration of new green products
• efficient use of energy and raw materials
• waste management, including the safe disposal of wastes
• the productivity and quality of products.

Companies should not simply focus on evaluating company conformity with existing legislation and regulations but should define possible environmental targets to be reached through a time-bound, step-by-step process which would include:

• the definition of company environmental objectives and policy
• the definition of short-, medium- and long-term strategies
• the adoption of a cradle-to-grave approach
• the allocation of appropriate budget resources
• the integration of health and safety within environmental audit procedures
• the participation of workers and trade union representatives in the analysis and decision-making process
• the establishment of an environmental audit team with worker representatives.

There are many different approaches to assessing activities, and the following are important potential components of any such programme:

• definition of flow diagrams for each operational unit
• monitoring of process inputs by operational unit—for example, water, energy, raw materials used, number of workers involved, health, safety and environmental risk assessment, organization of work
• monitoring of process outputs by operational unit—for example, quantification of products/byproducts, waste water, gaseous emissions, solid wastes for disposal on and off site
• adoption of company targets
• feasibility analysis of potential barriers (economic, technical, environmental, social) and adoption of consequent programmes
• adoption and implementation of an information strategy
• adoption and implementation of training strategy to promote worker awareness and full participation
• monitoring and evaluation of performance/results.

Industrial Relations and Environmental Management

While in some countries basic trade union rights are still not recognized and workers are prevented from protecting their health and safety and working conditions and improving environmental performance, in various other countries the participatory approach to company environmental sustainability has been tried with good results. In the last ten years, the traditional approach of industrial relations has shifted more and more to include not only health and safety issues and programmes reflecting national and international regulations in this area, but also has begun to integrate environmental issues into the industrial relations mechanisms. Partnerships between employers and trade union representatives at company, sector and national level have been defined, according to different situations, through collective agreements and sometimes also have been covered in regulations and consultation procedures set up by local or national authorities to manage environmental conflicts. See table 1, table 2 and table 3.

Table 1. Actors involved in voluntary agreements relevant to the environment

Source: Hildebrandt and Schmidt 1994.

Table 2. Scope of application voluntary agreements on environment-protection measures between parties to collective agreements

Source: Hildebrandt and Schmidt 1994.

Table 3. Nature of agreements on environment protection measures between parties to collective agreements

Source: Hildebrandt and Schmidt 1994.

Pollution Remediation: Cleaning Up

Cleaning up contaminated sites is a procedure which has become increasingly evident and costly since the 1970s, when awareness was enhanced about the serious cases of soil and water contamination from accumulated chemical wastes, abandoned industrial sites and so on. These contaminated sites have been generated from such activities as the following:

• waste disposal sites (industrial and public)

• abandoned industrial sites (e.g., chemical, metal processing)

• mining activities

• agricultural sites

• major accidents

• incinerator sites

• industrial water discharges

• small and medium enterprise zones.

The design of a remediation/clean-up plan requires complex technical activities and procedures which must be accompanied by the definition of clear management responsibilities and consequent liability. Such initiatives should be carried out in the context of harmonized national legislation, and provide for the participation of interested populations, for the definition of clear conflict resolution procedures and for the avoidance of possible socio-environmental dumping effects. Such regulations, agreements and plans should clearly encompass not only natural biotic and abiotic resources such as water, air, soil or flora and fauna but should also include cultural heritage, other visual aspects of landscapes and damage to physical persons and properties. A restrictive definition of environment will consequently reduce the definition of environmental damage and therefore limit actual remediation of sites. At the same time, it should also be possible not only for the subjects directly affected by damages to be granted certain rights and protection, but it also should be possible for collective group action to be taken to protect collective interests in order to ensure the restoration of previous conditions.

Conclusion

Significant action will be required to respond to our rapidly changing environmental situation. The focus of this article has been on the need for action to be taken to improve the environmental performance of industry and other economic activities. To do this efficiently and effectively, workers and their trade unions must play an active role not only at the enterprise level, but as well within their local communities and at the national level. Workers must be seen and actively mobilized as key partners in meeting future environment and sustainable development objectives. The ability of workers and their trade unions to contribute as partners in this process of environmental management is not dependent simply on their own capacity and awareness—although efforts are indeed needed and underway to increase their capacity—but it will also depend on the commitment of management and communities to create an enabling environment which promotes the development of new forms of collaboration and participation in the future.

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Origins of Environmental Auditing

Environmental safety and health auditing developed in the early 1970s, largely among companies operating in environmentally intensive sectors such as oils and chemicals. Since then environmental auditing has spread rapidly with a corresponding development of the approaches and techniques adopted. Several factors have influenced this growth.

• Industrial accidents. Major incidents such as the Bhopal, Chernobyl and Exxon-Valdez disasters have reminded companies that it is not sufficient to set corporate policies and standards on environmental health and safety matters without ensuring that they are being implemented. Audits can help reduce the risk of unpleasant surprises.
• Regulatory developments. Since the early 1970s regulations on environmental topics have increased substantially. This has made it steadily more difficult for a company to ascertain whether a specific plant in a particular country is complying with all of the relevant legislation.
• Public awareness. The public has become increasingly aware of, and vocal about, environmental and safety issues. Companies have had to demonstrate to the public that they are managing environmental risks effectively.
• Litigation. The growth of legislation has led to a corresponding explosion of litigation and liability claims, particularly in the United States. In Europe and elsewhere, there is growing emphasis on the responsibilities of individual directors and on making information available to the public.

What is an Environmental Audit?

It is important to draw the distinction between auditing and techniques such as environmental impact assessment (EIA). The latter assesses the potential environmental effects of a proposed facility. The essential purpose of an environmental audit is the systematic scrutiny of environmental performance throughout a company’s existing operations. At best, an audit is a comprehensive examination of management systems and facilities; at worst, it is a superficial review.

The term environmental audit means different things to different people. Terms such as assessment, survey and review are used to describe the same type of activity. Furthermore, some organizations consider that an “environmental audit” addresses only environmental matters, whereas others use the term to mean an audit of health, safety and environmental matters. Although there is no universal definition, auditing, as practised by many leading companies, follows the same basic philosophy and approach summarized by the broad definition adopted by the International Chambers of Commerce (ICC) in its publication Environmental Auditing (1989). The ICC defines environmental auditing as:

a management tool comprising a systematic, documented periodic and objective evaluation of how well environmental organization, management and equipment are performing, with the aim of helping safeguard the environment by:

(i) facilitating management control of environmental practices and

(ii) assessing compliance with company policies which would include meeting regulatory requirements.

The European Commission in its proposed regulation on environmental auditing also adopts the ICC definition of environmental audit.

Objectives of Environmental Auditing

The overall objective of environmental auditing is to help safeguard the environment and minimize risks to human health. Clearly, auditing alone will not achieve this goal (hence the use of the word help); it is a management tool. The key objectives of an environmental audit therefore are to:

• determine how well the environmental management systems and equipment are performing
• verify compliance with the relevant national, local or other laws and regulations
• minimize human exposure to risks from environmental, health and safety problems.

Scope of the Audit

As the prime objective of audits is to test the adequacy of existing management systems, they fulfil a fundamentally different role from the monitoring of environmental performance. Audits can address one topic, or a whole range of issues. The greater the scope of the audit, the greater will be the size of the audit team, the time spent onsite and the depth of investigation. Where international audits need to be carried out by a central team, there can be good reasons for covering more than one area while onsite to minimize costs.

In addition, the scope of an audit can vary from simple compliance testing to a more rigorous examination, depending on the perceived needs of the management. The technique is applied not only to operational environmental, health and safety management, but increasingly also to product safety and product quality management, and to areas such as loss prevention. If the intention of auditing is to help ensure that these broad areas are managed properly, then all of these individual topics must be reviewed. Items which may be addressed in audits, including environment, health, safety and product safety are shown in table 1.

Table 1. Scope of environmental audit

Although some companies have a regular (often annual) audit cycle, audits are primarily determined by need and priority. Thus not all facilities or aspects of a company will be assessed at the same frequency or to the same extent.

The Typical Audit Process

An audit is usually conducted by a team of people who will assemble factual information prior to and during a site visit, analyse the facts and compare them with the criteria for the audit, draw conclusions and report their findings. These steps are usually conducted within some kind of formal structure (an audit protocol), such that the process can be repeated reliably at other facilities and quality can be maintained. To ensure that an audit is effective, a number of key steps must be included. These are summarized and explained in table 2.

Table 2. Basic steps in environmental auditing

Basic Steps in Environmental Auditing

Criteria—what do you audit against?

An essential step in establishing an audit programme is to decide the criteria against which the audit will be conducted and to ensure that management throughout the organization knows what these criteria are. Typically criteria used for audits are:

• company policies and procedures on environmental matters
• applicable legislation and regulations
• good environmental management practice.

Pre-audit steps

Pre-audit steps include the administrative issues associated with planning the audit, selecting the personnel for the audit team (often from different parts of the company or from a specialized unit), preparing the audit protocol used by the organization and obtaining background information about the facility.

If auditing is new, the need for education of those involved in the audit process (the auditors or those being audited) should not be underestimated. This also applies to a multinational company extending an audit programme in its home country to subsidiaries abroad. In these situations, the time spent on explanation and education will pay dividends by ensuring that the audits are approached in a spirit of cooperation and are not seen as a threat by the local management.

When one major US company proposed extending its auditing programme to its operations in Europe, it was particularly concerned to ensure that the plants were properly briefed, that audit protocols were appropriate for European operations and that audit teams understood the relevant regulations. Pilot audits were conducted at selected plants. In addition, the audit process was introduced in a way that stressed the benefits of a cooperative rather than a “policing” approach.

Obtaining background information about a site and its processes can help to minimize the time spent onsite by the audit team and to focus its activities, thus saving resources.

The composition of the audit team will depend on the approach adopted by a particular organization. Where there is a lack of internal expertise, or where resources cannot be devoted to the audit activity, companies frequently use independent consultants to conduct the audits for them. Other companies employ a mix of in-house staff and external consultants on each team to ensure an “independent” view. Some large companies use only in-house staff for audits, and have environmental audit groups for this specific function. Many major companies have their own dedicated audit staff, but also include an independent consultant on many of the audits they carry out.

Onsite steps

• Understanding the internal controls. As a first step, it is necessary to develop an understanding of the controls that are in place or are thought to be in place. These will include assessing formal procedures and practices; record keeping and monitoring; inspection and maintenance programmes and physical controls for containing spills. The audit team gathers information on the various controls by observation, interviewing staff and the use of detailed questionnaires.
• Assessing strengths and weaknesses of internal controls. Evaluating the strengths and weaknesses of internal controls provides the rationale for conducting subsequent audit steps. Auditors will look for indicators such as clearly defined responsibilities, competence of personnel, appropriate documentation and records and systems of authorization. It is more important to determine whether the system is effective than whether it is sophisticated.
• Gathering audit evidence. The audit team attempts to verify that the steps and controls work as intended. Evidence may be collected through inquiry (e.g., asking a plant operator what he or she would do if there were a major chemical spill), observation (e.g., watching specific activities and operations in progress) and testing (checking records to confirm compliance with regulations).
• Recording audit findings. All the information obtained is recorded (usually on the audit protocol document and as working papers), and a comprehensive record of the audit and the state of the facility at the time is thus produced. Where a deficiency is found, it is noted as an audit “finding”.
• Evaluating the audit findings. The audit team integrates and evaluates the findings of the individual team members. There may also be common findings. For some observations, an informal discussion with the plant manager may be sufficient; for others, inclusion in the formal report will be appropriate.

Reporting the audit findings. This usually is done at a meeting with the plant management at the end of the team’s visit. Each finding and its significance can be discussed with the plant personnel. Prior to leaving the site, the audit team will often provide a written summary of findings for the plant management, to ensure that there are no surprises in the final report.

Post-audit steps

Following the onsite work, the next step is to prepare a draft report, which is reviewed by the plant management to confirm its accuracy. It is then distributed to senior management according to the requirements of the company.

The other key step is to develop an action plan to address the deficiencies. Some companies ask for recommendations for corrective action to be included in the formal audit report. The plant will then base its plan on implementing these recommendations. Other companies require the audit report to state the facts and the deficiencies, with no reference to how they should be corrected. It is then the responsibility of the plant management to devise the means of remedying the failings.

Once an audit programme is in place, future audits will include past reports—and progress in the implementation of any recommendations made therein—as part of their evidence.

Extending the Audit Process—Other Types of Audit

Although the most widespread use of environmental auditing is to assess the environmental performance of a company’s operations, there are variations on the theme. Other types of audit used in particular circumstances include the following:

• Pre-acquisition audits. Concern about potential liabilities has promoted the dramatic increase in environmental auditing prior to acquisition. Pre-acquisition audits are a means of identifying actual or potential problems, and taking these into account in the final negotiations of the deal. Time scales are often very short. However, the information obtained on past operations (perhaps before the present owner), current activities, past incidents and so on can be invaluable.
• Pre-sale audits. Less common than pre-acquisition audits, but becoming more popular, are audits conducted by the owner prior to selling a plant or a subsidiary company. A growing number of major organizations, such as the Dutch chemical company DSM and the Finnish conglomerate Neste, undertake pre-sale audits as part of corporate policy. The rationale is that the company will then know the status of environmental issues before the plant is sold, and can take action to remedy any problems if it feels that is appropriate. Equally important, it can present the results of an independent audit to a potential purchaser as confirmation of the situation. Should any environmental problems arise after the sale, a baseline has been established against which issues of liability can be decided.

Issues audits. Some organizations apply the audit technique to a specific issue that may have implications for the whole company, such as waste. The UK-based oil multinational BP has carried out audits examining the impact of ozone depletion and the implications of public concern about tropical deforestation.

Benefits of Environmental Auditing

If environmental auditing is implemented in a constructive way there are many benefits to be derived from the process. The auditing approach described in this paper will help to:

• safeguard the environment
• verify compliance with local and national laws
• indicate current or potential future problems that need to be addressed
• assess training programmes and provide data to assist in training
• enable companies to build on good environmental performance, give credit where appropriate and highlight deficiencies
• identify potential cost savings, such as from waste minimization
• assist the exchange and comparison of information between different plants or subsidiary companies
• demonstrate company commitment to environmental protection to employees, the public and the authorities.

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Government, industry and the community recognize the need to identify, assess and control the industrial risks (occupational and public) to people and the environment. Awareness of hazards and of the accidents that may result in significant loss of life and property have led to the development and application of systematic approaches, methods and tools for risk assessment and communication.

The risk assessment process involves: system description, the identification of hazards and the development of accident scenarios and outcomes for events associated with a process operation or a storage facility; the estimation of the effects or consequences of such hazardous events on people, property and the environment; the estimation of the probability or likelihood of such hazardous events occurring in practice and of their effects, accounting for the different operational and organizational hazard controls and practices; the quantification of ensuing risk levels outside the plant boundaries, in terms of both consequences and probabilities; and the assessment of such risk levels by reference to quantified risk criteria.

The process of quantified risk assessment is probabilistic in nature. Because major accidents may or may not occur over the entire life of a plant or a process, it is not appropriate to base the assessment process on the consequences of accidents in isolation. The likelihood or probability of such accidents actually occurring should be taken into account. Such probabilities and resultant risk levels should reflect the level of design, operational and organizational controls available at the plant. There are a number of uncertainties associated with the quantification of risk (e.g., mathematical models for consequence estimation, setting of probabilities for different accident scenarios, probability effects of such accidents). The risk assessment process should, in all cases, expose and recognize such uncertainties.

The main value of the quantified risk assessment process should not rest with the numerical value of the results (in isolation). The assessment process itself provides significant opportunities for the systematic identification of hazards and evaluation of risk. The risk assessment process provides for the identification and recognition of hazards and enables the allocation of relevant and appropriate resources to the hazards control process.

The objectives and uses of the hazard identification process (HIP) will determine in turn the scope of the analysis, the appropriate procedures and methods, and the personnel, expertise, funding and time required for the analysis, as well as the associated documentation necessary. Hazard identification is an efficient and necessary procedure to assist risk analysts and decision making for risk assessment and management of occupational safety and health. A number of major objectives may be identified:

• to establish what dangerous situations exist within a plant or a process operation
• to establish how these dangerous situations may come about
• to assist in the assessment of the safety of a hazardous installation.

The first general objective aims at extending the general understanding of the important issues and situations that might affect the risk analysis process for individual plants and processes; the synergy of individual hazards to the area study level has its special significance. Design and operational problems can be identified and a hazard classification scheme can be considered.

The second objective contains elements of risk assessment and deals with accident scenario development and interpretation of results. Consequence evaluation of various accidents and their impact propagation in time and space has special significance in the hazard identification phase.

The third objective aims at providing information that can later assist further steps in risk assessment and plant operations safety management. This may be in the form of improving the scenario specifications for risk analysis or identifying appropriate safety measures to comply with given risk criteria (e.g., individual or societal), or advice for emergency preparedness and accident management.

After defining objectives, the definition of the scope of the HIP study is the second most relevant element in the management, organization and implementation of the HIP. The scope of the HIP in a complex risk assessment study can be described mainly in terms of the following parameters: (1) potential sources of hazards (e.g., radioactive releases, toxic substances, fire, explosions); (2) plant or process damage states; (3) initiating events; (4) potential consequences; and (5) prioritization of hazards. The relevant factors that determine the extent to which these parameters are included in the HIP are: (a) the objectives and intended uses of the HIP; (b) the availability of appropriate information and data; and(c) the available resources and expertise. Hazard identification requires the consideration of all relevant information regarding the facility (e.g., plant, process). This might typically include: site and plant layout; detailed process information in the form of engineering diagrams and operating and maintenance conditions; the nature and quantities of materials being handled; operational, organizational and physical safeguards; and design standards.

In dealing with the external consequences of an accident, a number of such consequences may result (e.g., number of fatalities, number of people being hospitalized, various types of damage to the ecosystem, financial losses, etc.). The external consequences from an accident caused by the substance i for an identified activity j, can be calculated from the relationship:
Cij = Aa f_a f_m, where: Cij = number of fatalities per accident caused by the substance i for an identified activity j; A = affected area (ha); a = population density in populated areas within the affected zone (persons/ha); f_a and f_m are correction factors.

The consequences of (major) accidents to the environment are more difficult to estimate due to the variety of substances that can be involved, as well as the number of environmental impact indicators relevant in a given accident situation. Usually, a utility scale is associated with various environmental consequences; the relevant utility scale could include events related to incidents, accidents or catastrophic outcomes.

Evaluating monetary consequences of (potential) accidents requires a detailed estimate of possible consequences and their associated costs. A monetary value for special classes of consequences (e.g., loss of life or special biological habitats) is not always accepted a priori. The monetary evaluation of consequences should also include external costs, which are very often difficult to assess.

The procedures for identifying hazardous situations which may arise in process plants and equipment are generally considered to be the most developed and well established element in the assessment process of hazardous installations. It must be recognized that (1) the procedures and techniques vary in terms of comprehensiveness and level of detail, from comparative checklists to detailed structured logic diagrams, and (2) the procedures may apply at various stages of project formulation and implementation (from the early decision-making process to determine the location of a plant, through to its design, construction and operation).

Techniques for hazard identification essentially fall into three categories. The following indicates the most commonly used techniques within each category.

• Category 1: Comparative Methods: Process or System Checklist; Safety Audit Review; Relative Ranking (Dow and Mond Hazard Indices); Preliminary Hazard Analysis
• Category 2: Fundamental Methods: Hazard Operability Studies (HAZOP); “What If” Analysis; Failure Mode and Effect Analysis (FMEA)
• Category 3: Logic Diagrams Methods: Fault Tree Analysis; Event Tree Analysis.

Cause Consequence Analysis; Human Reliability Analysis

The appropriateness and relevancy of any one particular technique of hazard identification largely depend on the purpose for which the risk assessment is being undertaken. When further technical details are available one can combine them in the overall process for risk assessment of various hazards. Expert and engineering judgements can often be employed for further evaluation of risk for installations or processes. The primary principle is to first examine the plant or operations from the broadest viewpoint possible and systematically identify possible hazards. Elaborate techniques as a primary tool may cause problems and result in missing some obvious hazards. Sometimes it may be necessary to adopt more than one technique, depending on the level of detail required and whether the facility is a new proposed installation or an existing operation.

Probabilistic safety criteria (PSC) are associated with a rational decision-making process which requires the establishment of a consistent framework with standards to express the desired level of safety. Societal or group risks should be considered when assessing the acceptability of any hazardous industrial facility. A number of factors should be borne in mind when developing PSC based on societal risk, including public aversion to accidents with high consequences (i.e., the risk level chosen should decrease as the consequence increases). Whilst individual fatality risk levels include all components of risk (i.e., fires, explosions and toxicity), there may be uncertainties in correlating toxic concentrations with fatality risk levels. The interpretation of “fatal” should not rely on any one dose-effect relationship, but should involve a review of available data. The concept of societal risk implies that risk of higher consequences, with smaller frequency, are perceived as more important than those of smaller consequences with higher probabilities.

Irrespective of the numerical value of any risk criteria level for risk assessment purposes, it is essential that certain qualitative principles be adopted as yardsticks for risk assessment and safety management: (1) all “avoidable” risks should be avoided; (2) the risk from a major hazard should be reduced whenever practicable; (3) the consequences of more likely hazardous events should, wherever possible, be contained within the boundaries of the installation; and (4) where there is an existing high risk from a hazardous installation, additional hazardous developments should not be allowed if they add significantly to that existing risk.

In the 1990s an increasing importance has been given to risk communication, which has become a separate branch of risk science.

The main tasks in risk communication are:

• identifying controversial aspects of perceived risks
• presenting and explaining risk information
• influencing risk-related behaviour of individuals
• developing information strategies for emergency cases
• evolving cooperative/participative conflict resolution.

The scope and objectives of risk communication can differ, depending on the actors involved in the communication process as well as the functions and expectations they attribute to the communication process and its environment.

Individual and corporate actors in risk communication use manifold communicative means and channels. The main issues are health and environmental protection, safety improvement and risk acceptability.

According to general communication theory, communication can have the following functions:

• presentation of information
• appeal
• self-presentation
• definition of a relationship or decision path.

For the risk communication process in particular it can be helpful to distinguish between these functions. Depending on the function, different conditions for a successful communication process should be considered.

Risk communication can sometimes play the role of a simple presentation of facts. Information is a general need in a modern society. In environmental matters in particular there exist laws which, on the one hand, give the authorities the duty to inform the public and, on the other hand, give the public the right to know about the environmental and risk situation (e.g., the so-called Seveso Directive of the European Community and “Community Right-to-Know” legislation in the United States). Information can also be determined for a special public segment; for example, the employees in a factory must be informed about the risks they face within their workplace. In this sense risk communication must be:

• as neutral and objective as possible
• complete
• comprehensible for those who should get the information.

Appeals tend to incite someone to do something. In risk-related matters the following appeal functions can be distinguished:

• appeal to the general public or to a special segment of the public about risk prevention measures which could or should be taken (e.g., appeal to employees in a factory to take safety measures at work)
• appeal to the general public or to a special segment of the public about preventive measures for emergency cases
• appeal to the general public or to a special segment of the public about measures to be taken in case of an emergency situation (crisis management).

Appeal communication must be:

• as simple and comprehensible as possible, and as complete as necessary
• reliable; having confidence in the persons, authorities or other bodies which make the appeal is essential for the success of the appeal.

Self-presentation does not impart neutral information, but is mainly part of a persuasion or marketing strategy in order to improve the public image of an individual or to achieve public acceptance for a certain activity or to get public support for some kind of position. The criterion for the success of the communication is whether the public believes in the presentation. In a normative view, although the self-presentation aims at convincing someone, it should be honest and sincere.

These forms of communication are mainly of a one-way type. Communication aimed at reaching a decision or agreement is of a two-way or many-way type: there is not only one side which gives information—various actors are involved in a risk communication process and communicate with each other. This is the usual situation in a democratic society. Especially in risk- and environment-related matters communication is considered as an alternative regulatory instrument in complex situations, where easy solutions are not possible or accessible. Therefore the risky decisions with a relevant political importance have to be taken in a communicative atmosphere. Risk communication, in this sense, may include, among others, communication about highly politicized risk topics, but it may also mean, for example, the communication between an operator, the employees and the emergency services in order that the operator be best prepared in case of accident. Thus, depending on the scope and objective of the risk communication, different actors can participate in the communication process. The potential main actors in a risk communication environment are:

• the operator of a risky facility
• the potential victims of an undesired event (e.g., employees, neighbours)
• the regulatory authorities and appropriate political bodies
• the emergency services and general public
• interest groups
• the media
• insurers
• scientists and experts.

In a systems-theory approach all these categories of actors correspond to a certain social system and therefore have different codes of communication, different values and interests to be communicated. Very often it is not easy to find a common basis for a risk dialogue. Structures must be found in order to combine these different views and to achieve a practical result. Topics for such types of risk communication are, for example, a consensus decision about siting or not siting a hazardous plant in a certain region.

In all societies there exist legal and political procedures in order to deal with risk-related issues (e.g., parliamentary legislation, government or administrative decisions, legal procedures before a court, etc.). In many cases these existing procedures do not result in solutions that are entirely satisfactory for the peaceful settlement of risk disputes. Proposals reached by integrating elements of risk communication into the existing procedures have been found to improve the political decision process.

Two main issues have to be discussed when proposing risk communication procedures:

• the formal organization and legal significance of the process and of its results
• the structure of the communication process itself.

For the formal organization of risk communication there are various possibilities:

• The communication can take place inside or between existing bodies (e.g., between an agency of the central government, a local authority and existing interest groups).
• New bodies can be established specifically for the process of risk communications; various models have been developed (e.g., citizen juries, citizen panels, negotiation and mediation structures, mixed commissions consisting of operators, authorities and citizens). Most of these models are based on the idea of organizing a structured discourse in small groups. Significant differences of opinion exist about whether these groups should consist of experts, laymen, representatives of the political system, etc.

In any case the relationship between these communication structures and the existing legal and political decision-making bodies has to be clarified. Usually the result of a risk communication process has the effect of a non-binding recommendation to the deciding bodies.

Concerning the structure of the communication process, under the general rules of practical discourse, any argument is allowed if it fulfils the following conditions:

• adequate logical consistency
• sincerity (This means: The discourse should not be influenced by strategic or tactical thinking.)
• that the one who promotes an argument must be ready to accept the consequences of that argument also against himself or herself.

In the risk communication process various special rules and proposals have been developed in order to concretize these rules. Among these, the following rules are worth mentioning:

In the risk communication process a distinction must be made between:

• communicative claims
• cognitive claims
• normative claims
• expressive claims.

Correspondingly, differences of opinion can have various reasons, namely:

• differences in information
• differences in the understanding of facts
• differences in normative values.

It may be helpful to make clear through the risk communication process the level of differences and their significance. Various structural proposals have been made for improving the conditions for such a discourse and, at the same time, to help decision-makers to find fair and competent solutions—for example:

• For a fair discourse the result must be open-ended; if the aim is just to achieve acceptance for a decision that has already been made, it would not be sincere to open a discourse.
• If some solutions are simply not possible for factual, political or legal reasons, this must be clarified from the beginning.
• It may be helpful first to discuss not the alternatives, but the criteria which should be applied in evaluating the alternatives.

Effectiveness of risk communication can be defined as the degree to which an initial (undesired) situation is changed toward an intended state, as defined by initial goals. Procedural aspects are to be included in the evaluation of risk communication programmes. Such criteria include practicability (e.g., flexibility, adaptability, implementability) and costs (in terms of money, personnel and time) of the programme.

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The need to safeguard the environment for future generations makes it necessary not only to discuss the emerging environmental problems, but to make progress in identifying strategies that are cost-effective and environmentally sound to solve them and to take actions to enforce the measures that result from such discussion. There is ample evidence that enhancing the state of the environment as well as establishing policies to sustain the environment must take on greater priority within this generation and those that follow. While this belief is commonly held by governments, environmental groups, industry, academics and the general public, there is considerable debate on how to achieve improved environmental conditions without sacrificing current economic benefits. Furthermore, environmental protection has become an issue of great political importance, and ensuring ecological stability has been pushed to the top of many political agendas.

Past and present efforts to protect the environment are to a large extent characterized as single-issue approaches. Each problem has been dealt with on a case-by-case basis. With regard to problems caused by point-source pollution from easily identified emissions, this was an effective way of reducing environmental impacts. Today, the situation is more complex. Much pollution now originates from a large number of non-point sources easily transported from one country to another. Furthermore, each of us contributes to this total environmental pollution load through our daily patterns of living. The different non-point sources are difficult to identify, and the way in which they interact in impacting the environment is not well known.

The increasing environmental problems of more complex and global character will most likely entail great implications for several sectors of society in enforcing remedial actions. To be able to play a role in environmental protection, sound and universal policies must be applied jointly as an additional, multi-issue approach by all those actors taking part in the process—the scientists, trade unions, non-governmental organizations, companies and agencies of authority at the national and governmental levels, as well as the media. Therefore, it is important that all areas of sectoral interest be coordinated in their environmental ambitions, in order to get necessary interactions and responses to proposed solutions. It is likely that there may be a unanimous view with regard to the ultimate objectives of better environmental quality. However, it is equally likely that there may be disagreement about the pace, means and time required to achieve them.

Environmental protection has become a strategic issue of increasing importance for industry and the business sector, both in the siting of plants and in the technical performance of processes and products. Industrialists are increasingly becoming interested in being able to look holistically at the environmental consequences of their operations. Legislation is no longer the sole dimensioning factor following the growing importance of product-related environmental issues. The concepts of environmentally sound product development and environmentally friendly or “green” products are assuming wider acceptance among producers and consumers.

Indeed, this is a great challenge for industry; yet environmental criteria are often not considered at the beginning of the design of a product, when it may be easiest to avoid adverse impacts. Until recently, most environmental impacts were reduced through end-of-pipe controls and process design rather than product design. As a result, many companies spend too much time fixing problems instead of preventing them. A great deal of work, however, is needed to develop a suitable and accepted approach to incorporate environmental impacts into the various production stages and industrial activities—from raw material acquisition and manufacture to product use and final disposal.

The only known concept to deal with all these new complex issues seems to be a life-cycle approach to the problem. Life-cycle assessments (LCAs) have been widely recognized as an environmental management tool for the future, as product-related issues assume a more central role in the public debate. Although LCAs promise to be a valuable tool for programmes on cleaner production strategies and design for the environment, the concept is relatively new and will require future refinement to be accepted as a general tool for environmentally sound process and product development.

The Business Framework for Life-Cycle Assessment

The necessary new approach to environmental protection in the business sector, to look at products and services in their totality, must be linked to development of a common, systematic and structured approach which enables relevant decisions to be made and priorities to be set. Such an approach must be flexible and expandable to cover various decision-making situations in industry as well as new input as science and technology progress. However, it should rest upon some basic principles and issues, for example: problem identification, survey of remedial measures, cost/benefit analysis and final assessment and evaluation (figure 1).

Figure 1. Outline of consecutive steps for setting priorities in decisions on  environmental protection measures in industry

The problem identification ought to highlight different types of environmental problems and their causes. These judgements are multidimensional, taking into account various background conditions. There is indeed a close relationship between the work environment and the external environment. The ambition to safeguard the environment should therefore include two dimensions: to minimize the burden on the external environment following all kinds of human activities, and to promote the welfare of employees in terms of a well-planned and safe work environment.

A survey of potential remedial measures should include all the available practical alternatives for minimizing both pollutant emissions and the use of non-renewable natural resources. The technical solutions should be described, if possible, giving their expected value both in reducing resource use and pollution loads as well as in monetary terms. The cost/benefit analysis aims at producing a priority list by comparing the different identified approaches of remedial measures from the perspectives of product specifications and requirements to be met, economic feasibility and ecological efficiency. However, experience has shown that great difficulties often arise when seeking to express environmental assets in monetary terms.

The assessment and evaluation phase should be regarded as an integral part of the procedure of setting priorities to give the necessary input for the final judgement of the efficiency of the suggested remedial measures. The continuous exercise of assessment and evaluation following any measure that is implemented or enforced will give additional feedback for optimization of a general decision model for environmental priority strategies for product decision. The strategic value of such a model will likely increase in industry when it becomes gradually apparent that environmental priorities might be an equally important part of the future planning procedure for new processes or products. As LCA is a tool for identifying the environmental releases and evaluating the associated impacts caused by a process, product or activity, it will likely serve as the major vehicle for industry in their search for practical and user-friendly decision-making models for environmentally sound product development.

Concept of Life-Cycle Assessment

The concept of LCA is to evaluate the environmental effects associated with any given activity from the initial gathering of raw material from the earth until the point at which all residuals are returned to the earth. Therefore, the concept is often referred to as a “cradle-to-grave” assessment. While the practice of conducting life-cycle studies has existed since the early 1970s, there have been few comprehensive attempts to describe the full procedure in a manner that would facilitate understanding of the overall process, the underlying data requirements, the inherent assumptions and possibilities to make practical use of the methodology. However, since 1992 a number of reports have been published focusing on describing the various parts of a LCA from a theoretical viewpoint (Heijungs 1992; Vigon et al. 1992; Keoleian and Menerey 1993; Canadian Standards Association 1993; Society of Environmental Toxicology and Chemistry 1993). A few practical guides and handbooks have been published taking on the specific perspectives of product designers in making practical use of a complete LCA in environmentally sound product development (Ryding 1996).

LCA has been defined as an objective process to evaluate the environmental burdens associated with a process, product, activity or service system by identifying and quantifying energy and materials used and released to the environment in order to assess the impact of those energy and material uses and releases to the environment, and to evaluate and implement opportunities to effect environmental improvements. The assessment includes the entire life cycle of the process, product, activity or service system, encompassing extracting and processing raw materials, manu-facturing, transportation and distribution, use, reuse, maint-enance, recycling and final disposal.

The prime objectives of carrying out LCA are to provide as complete a picture as possible of the interactions of an activity with the environment, to contribute to the understanding of the overall and interdependent nature of environmental consequences of human activities and to provide decision-makers with information which identifies opportunities for environmental improvements.

The LCA methodological framework is a stepwise calculation exercise comprising four components: goal definition and scoping, inventory analysis, impact assessment and interpretation. As one component of a broader methodology, none of these components alone can be described as an LCA. LCA ought to include all four. In many cases life-cycle studies focus on the inventory analysis and are usually referred to as LCI (life-cycle inventory).

Goal definition and scoping consists of a definition of the purpose and the system of the study—its scope, definition of the functional unit (the measure of performance which the system delivers), and the establishment of a procedure for quality assurance of the results.

When initiating an LCA study, it is of vital importance to clearly define the goal of the study, preferably in terms of a clear and unambiguous statement of the reason for carrying out the LCA, and the intended use of the results. A key consideration is to decide whether the results should be used for in-company applications to improve the environmental performance of an industrial process or a product, or whether the results should be used externally, for example, to influence public policy or consumer purchase choices.

Without setting a clear goal and purpose for the LCA study in advance, the inventory analysis and the impact assessment may be overdone, and the final results may not be properly used for practical decisions. Defining whether the results should focus on environmental loads, a specific environmental problem or a holistic environmental impact assessment will directly clarify whether to conduct an inventory analysis, classification/characterization or a valuation (figure 2). It is important to make all consecutive LCA components “visible” in order to make it easier for any user to choose the level of complexity they wish to use.

Figure 2.  Purposes and completeness of life-cycle assessment

In many general programmes for cleaner production strategies, design for the environment or environmentally sound product development, the principal objective is often to lower the overall environmental impact during a product’s life cycle. To meet these demands it is sometimes necessary to arrive at a highly aggregated form of the environmental impact assessment which in turn emphasizes the need for identifying a general accepted valuation approach for a scoring system to weigh the different environmental effects against each other.

The scope of an LCA defines the system, boundaries, data requirements, assumptions and limitations. The scope should be defined well enough to ensure that the breadth and depth of analysis are compatible with and sufficient to address the stated purpose and all boundaries, and that assumptions are clearly stated, comprehensible and visible. However, as an LCA is an iterative process, it may be advisable in some cases not to permanently fix all aspects included in the scope. The use of sensitivity and error analysis is recommended to make possible the successive testing and validation of the purpose and scope of the LCA study versus the results obtained, in order to make                                                                                                                         corrections and set new assumptions.

Inventory analysis is an objective, data-based process of quantifying energy and raw material requirements, air emissions, waterborne effluents, solid waste and other environmental releases throughout the life cycle of a process, product, activity or service system (figure 3).

Figure 3. Stepwise elements in a life-cycle inventory analysis.

The calculation of inputs and outputs in the inventory analysis refers to the system defined. In many cases, processing operations yield more than one output, and it is important to break down such a complex system into a series of separate sub-processes, each of which produces a single product. During the production of a construction material, pollutant emissions occur in each sub-process, from raw material acquisition to the final product. The total production process may be illustrated by a “process tree” where the stem may be seen as the main chain of flow of materials and energy, whereas the branches may illustrate sub-processes and the leaves the specific figures on pollutant emissions and so on. When added together, these sub-processes have the total characteristics of                                                                                                                         the original single system of co-products.

To estimate the accuracy of the data gained in the inventory analysis, a sensitivity and error analysis is recommended. All data used should therefore be “labelled” with relevant information not only as to reliability but also source, origin and so on, to facilitate future updating and refinement of the data (so-called meta-data). The use of a sensitivity and error analysis will identify the key data of great importance for the outcome of the LCA study that may need further efforts to increase its reliability.

Impact assessment is a technical, qualitative and/or quantitative process to characterize and assess the effects of the environmental loading identified in the inventory component. The assessment should address both ecological and human health considerations, as well as other effects such as habitat modifications and noise pollution. The impact assessment component could be characterized as three consecutive steps—classification, characterization and valuation—all of which interpret the effects of environmental burdens identified in the inventory analysis, on different aggregated levels (figure 4). Classification is the step in which the inventory analyses are grouped together into a number of impact categories; characterization is the step in which analysis and quantification takes place, and, where possible, aggregation of the impacts within the given impact categories is carried out; valuation is the step in which the data of the different specific impact categories are weighted so that they can be compared amongst themselves to arrive at a further interpretation and aggregation of the data of the impact assessment.

Figure 4. Conceptual framework for the successive level of data aggregation in the impact assessment component

In the classification step, the impacts may be grouped in the general protection areas of resource depletion, ecological health and human health. These areas may be further divided into specific impact categories, preferably focusing on the environ-mental process involved, to allow a perspective consistent with current scientific knowledge about these processes.

There are various approaches to characterization—to relate data to no-observable-effect concentrations or to environmental standards, to model both exposure and effects and apply these models in a site-specific way, or to use equivalency factors for the different impact categories. A further approach is to normalize the aggregated data for each impact category to the                                                                                                                         actual magnitude of the impacts in some given area, to increase                                                                                                                     the comparability of the data from the different impact categories.

Valuation, with the aim of further aggregating the data of the impact assessment, is the LCA component that has probably generated the most heated debates. Some approaches, often referred to as decision theory techniques, are claimed to have the potential to make the valuation a rational, explicit method. Valuation principles may rest on scientific, political or societal judgements, and there are currently approaches available that cover all three perspectives. Of special importance is the use of sensitivity and error analysis. The sensitivity analysis enables the identification of those selected valuation criteria that may change the resultant priority between two process or product alternatives because of the uncertainties in the data. The error analysis may be used to indicate the likelihood of one alternative product being more environmentally benign than a competitor product.

Many are of the opinion that valuations have to be based largely on information about social values and preferences. However, no one has yet defined the specific requirements that a reliable and generally accepted valuation method should meet. Figure 5 lists some such specific requirements of potential value. However, it should be clearly emphasized that any valuation system for assessing the “seriousness” of environmental impacts of any human activity must be largely based on subjective value judgements. For such valuations it is probably not possible to establish criteria which are tenable in all situations worldwide.

Figure 5. List of suggested requirements to be met for a LCA valuation method

Interpretation of the results is a systematic evaluation of the needs and opportunities to reduce the environmental burden associated with energy and raw materials use and waste emissions throughout the whole life cycle of a product, process or activity. This assessment may include both quantitative and qualitative measures of improvements, such as changes in product design, raw material use, industrial processing, consumer demands and waste management.

Interpretation of the results is the component of an LCA in which options for reducing the environmental impacts or burdens of the processes or products under study are identified and evaluated. It deals with the identification, evaluation and selection of options for improvements in processes and product design, that is, technical redesign of a process or product to minimize the associated environmental burden while fulfilling the intended function and performance characteristics. It is important to guide the decision-maker regarding the effects of the existing uncertainties in the background data and the criteria used in achieving the results, to decrease the risk of making false conclusions regarding the processes and products under study. Again, a sensitivity and error analysis is needed to gain credibility for the LCA methodology as it provides the decision-maker with information on (1) key parameters and assumptions, which may need to be further considered and refined to strengthen the conclusions, and (2) the statistical significance of the calculated difference in total environmental burden between the process or product alternatives.

The interpretation component has been identified as the part of an LCA that is least documented. However, preliminary results from some large LCA studies carried out as comprehensive efforts by people from academia, consultancy firms and many companies all indicated that, from a general perspective, significant environmental burdens from products seem to be linked to the product use (figure 6). Hence, the potential seems to exist for industry-motivated initiatives to minimize environmental impacts through product development.

Figure 6. Outline of some general experiences of where in the life-cycles of  products the major environmental burdens occur

A study on international experiences of environmentally sound product development based on LCA (Ryding 1994) indicated that promising general applications of LCA seem to be (1) for internal use by corporations to form the basis for providing guidance in long-term strategic planning concerning product design, but also (2) to some extent for use by regulatory agencies and authorities to suit general purposes of societal planning and decision-making. By developing and using LCA information regarding environmental effects that are both “upstream” and “downstream” of the particular activity under scrutiny, a new paradigm may be created for basing decisions in both corporate management and regulatory policy-making.

Conclusion

Knowledge about human threats to the environment seems to grow faster than our ability to solve them. Therefore, decisions in the environmental arena must often be taken with greater uncertainties present than those in other areas. Furthermore, very small safety margins usually exist. Present ecological and technical knowledge is not always sufficient to offer a complete, fool-proof strategy to safeguard the environment. It is not possible to gain full understanding of all ecological responses to environmental stress before taking action. However, the absence of complete, irrefutable scientific evidence should not discourage making decisions about and implementation of pollution abatement programmes. It is not possible to wait until all ecological questions are scientifically substantiated before taking action—the damage that may result through such delays could be irreversible. Hence, the meaning and scope of most problems is already known to a sufficient extent to justify action, and there is, in many cases, sufficient knowledge at hand to initiate effective remedial measures for most environmental problems.

Life-cycle assessment offers a new concept to deal with the future complex environmental issues. However, there are no shortcuts or simple answers to all questions posed. The rapidly emerging adoption of a holistic approach to combat environmental problems will most likely identify a lot of gaps in our knowledge about new aspects that need to be dealt with. Also, available data that may be used are in many cases intended for other purposes. Despite all difficulties, there is no argument for waiting to use LCA until it gets better. It is by no means hard to find difficulties and uncertainties in the present LCA concept, if one wants to use such arguments to justify an unwillingness to conduct an LCA. One has to decide whether it is worthwhile to seek a holistic life-cycle approach to environmental aspects despite all difficulties. The more LCA is used, the more knowledge will be gained about its structure, function and applicability, which will be the best guarantee for a feedback to ensure its successive improvement.

To make use of LCA today may be more a question of will and ambition than of undisputed knowledge. The whole idea of LCA ought to be to make the best use of present scientific and technical knowledge and to make use of the result in an intelligent and humble way. Such an approach will most likely gain credibility.

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The term used as the title of this article, environmental impact assessments, has now been increasingly, but not universally, replaced with the term environmental assessments. A quick review of the reason for this change of name will help us define the essential nature of the activity described by these names, and one of the important factors behind opposition or reluctance to using the word impact.

In 1970, the National Environmental Policy Act (NEPA) became law in the United States, establishing environmental policy goals for the federal government, focusing on the need to take environmental factors into account in decision-making. It is, of course, easy to state a policy objective, but it is more difficult to achieve it. To ensure that the Act had “teeth”, legislators incorporated a provision requiring that the Federal government prepare an “Environmental Impact Statement” (EIS) for any proposed action “likely to significantly affect the quality of the human environment”. The content of this document was to be considered before a decision was made on whether the proposed action should be initiated. The work done to prepare the EIS became known as environmental impact assessment (EIA), because it involved the identification, prediction and evaluation of the impacts of the proposed federal action.

The word “impact”, in English, unfortunately is not a positive term. An impact is thought to be harmful (almost by definition). Therefore, as the practice of EIA spread beyond the United States to Canada, Europe, Southeast Asia and Australasia, many governments and their advisers wanted to move away from the negative aspects of impact, and so the term environmental assessment (EA) was born. EIA and EA are identical (except in the United States and those few countries which have adopted the US system, where EIA and EA have precise and different meanings). In this article only EIA will be referred to, although it should be remembered that all comments apply equally to EA, and both terms are in use internationally.

In addition to the use of the word impact, the context in which EIA was applied (particularly in the United States and Canada) was also influential on the perceptions of EIA which were (and in some cases still are) common amongst politicians, senior governmental officials and private and public-sector “developers”. In both the United States and Canada, land-use planning was weak and preparation of EISs or EIA reports were often “hijacked” by interested parties and almost became plan-making activities. This encouraged the production of large, multi-volume documents which were time-consuming and expensive to produce and, of course, virtually impossible to read and act upon! Sometimes projects were delayed while all this activity was in progress, causing irritation and financial costs to proponents and investors.

Also, in the first five to six years of its operation, NEPA gave rise to many court cases in which project opponents were able to challenge the adequacy of EISs on technical and sometimes procedural grounds. Again, this caused many delays to projects. However, as experience was gained and guidance was issued that was more clear and strict, the number of cases going to court declined significantly.

Unfortunately, the combined effect of these experiences was to give the distinct impression to many external observers that EIA was a well-intentioned activity which, unfortunately, had gone wrong and ended by being more of an obstacle than a help to development. To many people, it seemed an appropriate, if not entirely necessary, activity for self-indulgent developed countries, but for industrializing nations it was an expensive luxury they could not really afford.

Despite the adverse reaction in some places, globally the spread of EIA has proved irresistible. Starting in 1970 in the United States, EIA extended to Canada, Australia and to Europe. A number of developing countries—for example, the Philippines, Indonesia and Thailand—introduced EIA procedures before many Western European countries. Interestingly, the various development banks, such as the World Bank, were amongst the slowest organizations to introduce EIA into their decision-making systems. Indeed, it was only by the late 1980s and early 1990s that the banks and the bilateral aid agencies could be said to have caught up with the rest of the world. There is no sign that the rate at which EIA laws and regulations are being introduced into national decision-making systems is becoming slower. In fact, following the “Earth Summit” held in Rio de Janeiro in 1992, EIA has been used increasingly as international agencies and national governments attempt to meet the recommendations made in Rio regarding the need for sustainable development.

What is EIA?

How can we explain the ever-increasing popularity of EIA? What can it do for governments, private and public sector developers, workers, their families and the communities in which they live?

Before EIA, development projects such as highways, hydro-power dams, ports and industrial installations were assessed on technical, economic and, of course, political bases. Such projects have certain economic and social objectives to achieve, and decision-makers involved in issuing permits, licences or other types of authorization were interested in knowing whether the projects would achieve them (putting to one side those projects conceived and built for political purposes such as prestige). This required an economic study (usually cost-benefit analysis) and technical investigations. Unfortunately, these studies did not take account of environmental effects and, as time passed, more and more people became aware of the increasing damage caused to the environment by such development projects. In many cases, the unintended environmental and social impacts led to economic costs; for example, the Kariba Dam in Africa (on the border between Zambia and Zimbabwe) resulted in the resettlement of many villages into areas which were not suitable for the traditional agriculture practised by the people. In the resettled areas food became scarce and the government had to initiate emergency food supply operations. Other examples of unexpected “add-on” costs as well as environmental damage led to a growing realization that the traditional project appraisal techniques needed an additional dimension to reduce the chances of unexpected and unwelcome impacts.

The increasing awareness amongst governments, non-governmental organizations (NGOs) and members of the public of the unexpected economic penalties that could arise from major development projects coincided with a parallel growth in global understanding of the importance of the environment. In particular, concern focused on the implications of increasing population growth and the accompanying expansion in economic activities, and whether there might be environmental constraints to such growth. The importance of global biogeochemical and other processes for the maintenance of clean air and water as well as renewable resources such as food and timber were recognized increasingly. As a result, many were convinced that the environment could no longer be seen as a passive and never-ending deliverer of goods and a receiver of human wastes. It had to be seen as an active part of the development process which, if treated badly, could reduce the chances of achieving development objectives. This realization has led to the development and implementation of a number of procedures or practices to incorporate the environment into the development process by considering the extent to which it might be harmed or improved. One such procedure is EIA. The overall aim is to reduce the risk—for homo sapiens in general, and local groups in particular—that environmental damage will result in life-threatening consequences such as famines and floods.

Basically, EIA is a means of identifying, predicting and evaluating the environmental impacts of a proposed development action, and its alternatives, before a decision is made to implement it. The aim is to integrate EIA into the standard, pre-feasibility, feasibility, appraisal and design activities which are carried out to test whether a proposal will meet its objectives. By undertaking EIA work in parallel with these studies it should be possible to identify, early, the significant adverse impacts (and those which are beneficial) and to “design out”, as far as possible, the harmful impacts. Additionally, benefits can be enhanced. The outcome of any EIA should be a proposal which, in its location, design and method of construction or operation, is “environmentally friendly” in so far as its environmental implications are acceptable and any environmental deterioration is unlikely to cause difficulties. EIA is, therefore, a preventive tool, and medicine provides an appropriate analogy. In the field of community medicine it is better, and economically cheaper, to prevent illness rather than cure it. In the development process it is better to minimize environmental damage (while still achieving economic objectives) than to fund expensive clean-up or rehabilitation actions after damage has occurred.

Application of EIA

To what types of development activities does EIA apply? There is no standard or correct answer. Each country decides on the type and scale of activities to be subject to EIA; for example, a proposed 10 km road in a small tropical island may cause significant impacts, but a similar road in a large, semi-arid country with a low population density probably would be environmentally neutral. In all countries, EIA is applied to “physical” development projects according to national criteria; in some countries EIA is applied also to development plans, programmes and policies (such as sector development programmes for energy supply and national development plans) which might cause significant environmental impacts. Amongst the countries which apply EIA to these kinds of actions are the United States, the Netherlands and China. However, such countries are the exception to normal practice. Most EIAs are prepared for physical development projects, although there is no doubt that “strategic” EIAs will increase in importance in the future.

What kinds of impacts are analysed in EIAs? Again this varies from country to country, but to a lesser extent than in the case of the types of proposed activities subject to EIA. The usual answer given is “environmental” impacts, to which the inevitable response is likely to be, “Yes, but what is ‘environmental’?” Generally, most EIAs focus on the biophysical environment—that is, impacts on such factors as:

• water quality and quantity
• air quality
• ecosystems and ecological processes
• noise levels.

In some cases no other impacts are considered. However, the limitations of restricting EIA to biophysical impacts have been questioned and, increasingly, more and more EIAs are based on a broad concept of the environment and include, when appropriate, impacts on:

• local communities (“social” impacts)
• local economies
• health and safety
• landscapes
• cultural resources (archaeological or historical sites, environmental features with spiritual significance for local communities, etc.).

There are two reasons which help explain this wider definition of “environmental” impacts. First, it has been found to be socially and politically unacceptable to consider the impacts of a proposal on the biophysical environment and, at the same time, ignore the social, health and economic effects on local communities and inhabitants. This issue has been dominant in developed countries, especially those which have weak land-use planning systems into which social and economic objectives are incorporated.

In developing countries, this factor also exists and is joined by an additional, complementary explanation. The majority of the population in developing countries has a closer and, in many ways, more complex set of direct relationships with their environment than is the case in developed countries. This means that the way that local communities and their members interact with their environment can be changed by environmental, social and economic impacts. For example, in poor localities a major, new project such as a 2,400 MW power station will introduce a source of new labour opportunities and social infrastructure (schools, clinics) to provide for the large workforce needed. Basically, the income injected into the local economy makes the power station locality an island of prosperity in a sea of poverty. This attracts poor people to the area to try to improve their standard of living by trying to obtain a job and to use the new facilities. Not all will be successful. The unsuccessful will try to offer services to those employed, for example, by supplying firewood or charcoal. This will cause environmental stress, often at locations distant from the power station. Such impacts will occur in addition to the impacts caused by the influx of workers and their families who are directly employed at the station site. Thus, the main induced social effect of a project—in-migration—causes environmental impacts. If these socioeconomic implications were not analysed, then EISs would be in danger of failing to achieve one of their main objectives—that is, to identify, predict, evaluate and mitigate biophysical environmental impacts.

Virtually all project-related EIAs focus on the external environment, that is, the environment outside the site boundary. This reflects the history of EIA. As noted above it had its origins in the developed world. In these countries there is a strong legal framework for occupational health protection and it was inappropriate for EIA to focus on the internal, working environment as well as the external environment, as this would be a duplication of effort and misuse of scarce resources.

In many developing countries the opposite situation is often the reality. In such a context, it would seem appropriate for EIAs, particularly for industrial facilities, to consider the impacts on the internal environment. The main focus of considering such impacts as changes in internal air quality and noise levels is the health of workers. There are two other aspects which are important here. First, in poor countries the loss of a breadwinner through illness, injury or death can force the other members of a family to exploit natural resources to maintain income levels. If a number of families are affected then the cumulative impacts may be locally significant. Secondly, the health of family members can be affected, directly, by chemicals brought into the home on the clothes of workers. So there is a direct link between the internal and external environments. The inclusion of the internal environment in EIA has received little attention in the EIA literature and is conspicuous by its absence from EIA laws, regulations and guidelines. However, there is no logical or practical reason why, if local circumstances are appropriate, EIAs should not deal with the important issues of workers’ health and the possible external implications of a deterioration in the physical and mental well-being of workers.

Costs and Benefits of EIAs

Perhaps the most frequent issue raised by those who are either opposed to EIA or are neutral towards it concerns the cost. Preparation of EISs takes time and resources, and, in the end, this means money. It is important, therefore, to consider the economic aspects of EIA.

The main costs of introducing EIA procedures into a country fall on project investors or proponents, and central or local government (depending on the nature of the procedures). In virtually all countries, project investors or proponents pay for preparation of EIAs for their projects. Similarly, initiators (usually government agencies) of sectoral investment strategies and regional development plans pay for their EIAs. Evidence from developed and developing countries indicates that the cost of preparing EISs ranges from 0.1% to 1% of the capital cost of a project. This proportion can increase when mitigating measures recommended in the EISs are taken into account. The cost depends on the type of mitigation recommended. Obviously, resettling 5,000 families in such a way that their standard of living is maintained is a relatively costly exercise. In such cases the costs of the EIS and mitigation measures can rise to 15 to 20% of capital cost. In other cases it may be between 1 and 5%. Such figures may seem to be excessive and to indicate that EIA is a financial burden. There is no doubt that EIA costs money, but in the experience of the author no major projects have been halted because of the costs of EIA preparation, and in only a few cases have projects been made uneconomical because of the costs of necessary mitigating measures.

EIA procedures also impose costs to central or local governments which arise from the staff and other resources which need to be directed to managing the system and processing and reviewing the EISs. Again, the cost depends on the nature of the procedure and how many EISs are produced per year. The author is not aware of any calculations which attempt to provide an average figure for this cost.

To return to our medical analogy, prevention of illness requires a significant up-front investment to ensure future and possibly long-term dispersed benefits in terms of the health of the population, and EIA is no different. The financial benefits can be examined from the perspectives of the proponent as well as those of the government and the wider society. The proponent can benefit in a number of ways:

• prevention of delays in obtaining authorizations
• identification of mitigation measures involving recycling and recovery of components of waste streams
• creation of cleaner working environments
• identification of cheaper alternatives.

Not all of these will operate in all cases, but it is useful to consider the ways in which savings can accrue to the proponent.

In all countries various permits, permissions and authorizations are needed before a project can be implemented and operated. The authorization procedures take time, and this can be extended if there is opposition to a project and no formal mechanism exists by which concerns may be identified, considered and investigated. There seems little doubt that the days of passive populations welcoming all development as signs of inevitable economic and social progress are nearly over. All projects are subject to increasing local, national and international scrutiny—for example, the continuing opposition in India to the Sardar Sarovar (Narmada) complex of dams.

In this context, EIA provides a mechanism for public concerns to be addressed, if not eliminated. Studies in developed countries (such as the UK) have shown the potential for EIA to reduce the likelihood of delays in obtaining authorizations—and time is money! Indeed, a study by British Gas in the late 1970s showed that the average time taken to obtain authorization was shorter with EIA than for similar projects without EIA.

The add-on costs of mitigation have been mentioned, but it is worth considering the opposite situation. For facilities which produce one or more waste streams, the EIA may identify mitigation measures which reduce the waste load by use of recovery or recycling processes. In the former case recovery of a component from a waste stream might enable the proponent to sell it (if a market is available) and cover the costs of the recovery process or even make a profit. Recycling of an element such as water can reduce consumption, thus lowering expenditure on raw material inputs.

If an EIA has focused on the internal environment, then the working conditions should be better than would have been the case without the EIA. A cleaner, safer workplace reduces worker discontent, illness and absences. The overall effect is likely to be a more productive workforce, which again is a financial benefit to the proponent or operator.

Finally, the favoured option selected using solely technical and economic criteria may, in fact, not be the best alternative. In Botswana, a site had been selected for water to be stored before it was transported to Gaborone (the capital). An EIA was implemented and it was found, early in the EIA work, that the environmental impacts would be significantly adverse. During survey work, the EIA team identified an alternative site which they were given permission to include in the EIA. The alternative site comparison showed that the environmental impacts of the second option were much less severe. Technical and economic studies showed that the site met technical and economic criteria. In fact it was found that the second site could meet the original development objectives with less environmental damage and cost 50% less to build (IUCN and Government of the Republic of Botswana, undated). Unsurprisingly, the second option has been implemented, to the benefit not only to the proponent (a parastatal organization) but to the entire tax-paying population of Botswana. Such examples are likely to be uncommon, but do indicate the opportunity provided by EIA work to “test” various development options.

The main benefits of EIA procedures are dispersed amongst the component parts of society, such as government, communities and individuals. By preventing unacceptable environmental deterioration EIA helps to maintain the essential “life processes” upon which all human life and activities depend. This is a long-term and dispersed benefit. In specific instances, EIA can avoid localized environmental damage which would necessitate remedial measures (usually expensive) at a later date. The cost of remedial measures usually falls on local or central government and not the proponent or operator of the installation which caused the damage.

Recent events, especially since the Rio “Earth Summit”, are slowly changing the objectives of development activities. Until recently the objectives of development were to improve economic and social conditions in a specified area. Increasingly, the achievement of “sustainability” criteria or objectives is occupying a central place in the traditional hierarchy of objectives (which still remain relevant). The introduction of sustainability as an important, if not yet primary, objective in the development process will have a profound influence on the future existence of the sterile debate of “jobs versus environment” from which EIA has suffered. This debate had some meaning when environment was on the outside of the development process and looking in. Now the environment is becoming central and the debate is centred on mechanisms of having both jobs and a healthy environment linked in a sustainable manner. EIA still has a crucial and expanding contribution to make as one of the important mechanisms for moving towards, and achieving, sustainability.

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