Author: Madeleine R. Estryn-Béhar

Ergonomics is an applied science that deals with the adaptation of work and the workplace to the characteristics and capabilities of the worker so that he or she may perform the duties of the job effectively and safely. It addresses the worker’s physical capacities in relation to the physical requirements of the job (e.g., strength, endurance, dexterity, flexibility, ability to tolerate positions and postures, visual and auditory acuity) as well as his or her mental and emotional status in relation to the way the work is organized (e.g., work schedules, workload and work-related stress). Ideally, adaptations are made to the furniture, equipment and tools used by the worker and to the work environment to enable the worker to perform adequately without risk to himself/herself, co-workers and the public. Occasionally, it is necessary to improve the worker’s adaptation to the job through, for example, special training and the use of personal protective equipment.

Since the mid 1970s, the application of ergonomics to hospital workers has broadened. It is directed now at those involved in direct patient care (e.g., physicians and nurses), those involved in ancillary services (e.g., technicians, laboratory staff, pharmacists and social workers) and those providing support services (e.g., administrative and clerical personnel, food service staff, housekeeping staff, maintenance workers and security staff).

Extensive research has been conducted into the ergonomics of hospitalization, with most studies attempting to identify the extent to which hospital administrators should allow hospital personnel latitude in developing strategies to reconcile an acceptable workload with good quality of care. Participatory ergonomics has become increasingly widespread in hospitals in recent years. More specifically, wards have been reorganized on the basis of ergonomic analyses of activity undertaken in collaboration with medical and paramedical personnel, and participatory ergonomics has been used as the basis for the adaptation of equipment for use in health care.

In studies of hospital ergonomics, workstation analysis must extend at least to the departmental level—the distance between rooms and the amount and location of equipment are all crucial considerations.

Physical strain is one of the primary determinants of the health of HCWs and the quality of care that they dispense. This being said, the frequent interruptions that hinder care-giving and the effect of psychological factors associated with confrontations with serious illness, ageing and death must also be addressed. Accounting for all these factors is a difficult task, but approaches focusing only on single factors will fail to improve either working conditions or the quality of care. Similarly, patients’ perception of the quality of their hospital stay is determined by the effectiveness of the care they receive, their relationship with physicians and other personnel, the food and the architectural environment.

Basic to hospital ergonomics is study of the sum and interaction of personal factors (e.g., fatigue, fitness, age and training) and circumstantial factors (e.g., work organization, schedule, floor layout, furniture, equipment, communication and psychological support within the work team), which combine to affect the performance of work. Precise identification of the actual work performed by health care workers depends on ergonomic observation of entire workdays and collection of valid and objective information on the movements, postures, cognitive performance and emotional control called upon to satisfy work requirements. This helps to detect factors that may interfere with effective, safe, comfortable and healthy work. This approach also sheds light on the potential for workers’ suffering or taking pleasure in their work. Final recommendations must take the interdependence of the various professional and ancillary personnel attending the same patient into account.

These considerations lay the groundwork for further, specific research. Analysis of strain related to the use of basic equipment (e.g., beds, meal carts and mobile x-ray equipment) may help clarify the conditions of acceptable use. Measurements of lighting levels may be complemented by information on the size and contrast of medication labels, for example. Where alarms emitted by different intensive-care-unit equipment can be confused, analysis of their acoustic spectrum may prove useful. Computerization of patient charts should not be undertaken unless the formal and informal information-support structures have been analysed. The interdependence of the various elements of the work environment of any given caregiver should therefore always be borne in mind when analysing isolated factors.

Analysis of the interaction of different factors influencing care—physical strain, cognitive strain, affective strain, scheduling, ambience, architecture and hygiene protocols—is essential. It is important to adapt schedules and common work areas to the needs of the work team when attempting to improve overall patient management. Participatory ergonomics is a way of using specific information to bring about wide-ranging and relevant improvements to the quality of care and to working life. Involving all categories of personnel in key stages of the search for solution helps ensure that the modifications finally adopted will have their full support.

Working Postures

Epidemiological studies of joint and musculoskeletal disorders. Several epidemiological studies have indicated that inappropriate postures and handling techniques are associated with a doubling of the number of back, joint and muscle problems requiring treatment and time off the job. This phenomenon, discussed in greater detail elsewhere in this chapter and Encyclopaedia, is related to physical and cognitive strain.

Working conditions differ from country to country. Siegel et al. (1993) compared conditions in Germany and Norway and found that 51% of German nurses, but only 24% of Norwegian nurses, suffered lower-back pain on any given day. Working conditions in the two countries differed; however, in German hospitals, the patient-nurse ratio was twice as high and the number of adjustable-height beds half that in Norwegian hospitals, and fewer nurses had patient handling equipment (78% versus 87% in Norwegian hospitals).

Epidemiological studies of pregnancy and its outcome. Because the hospital workforce is usually predominantly female, the influence of work on pregnancy often becomes an important issue (see articles on pregnancy and work elsewhere in this Encyclopaedia). Saurel-Cubizolles et al. (1985) in France, for example, studied 621 women who returned to hospital work after giving birth and found that a higher rate of premature births were associated with heavy housekeeping chores (e.g., cleaning windows and floors), carrying heavy loads and long periods of standing. When these tasks were combined, the rate of premature births was increased: 6% when only one of these factors was involved and up to 21% when two or three were involved. These differences remained significant after adjustment for seniority, social and demographic characteristics and professional level. These factors were also associated with a higher frequency of contractions, more hospital admissions during pregnancy and, on average, longer sick leave.

In Sri Lanka, Senevirane and Fernando (1994) compared 130 pregnancies borne by 100 nursing officers and 126 by clerical workers whose jobs presumably were more sedentary; socio-economic backgrounds and use of prenatal care were similar for both groups. Odds-ratios for complications of pregnancy (2.18) and preterm delivery (5.64) were high among nursing officers.

Ergonomic Observation of Workdays

The effect of physical strain on health care workers has been demonstrated through continuous observation of workdays. Research in Belgium (Malchaire 1992), France (Estryn-Béhar and Fouillot 1990a) and Czechoslovakia (Hubacova, Borsky and Strelka 1992) has shown that health care workers spend 60 to 80% of their workday standing (see table 1). Belgian nurses were observed to spend approximately 10% of their workday bent over; Czechoslovakian nurses spent 11% of their workday positioning patients; and French nurses spent 16 to 24% of their workday in uncomfortable positions, such as stooping or squatting, or with their arms raised or loaded.

Table 1. Distribution of nurses’ time in three studies

Number of observations per shift:*   74 observations on 3 shifts. **  Morning: 10 observations (8 h); afternoon: 10 observations (8 h); night: 10 observations (11 h). *** Morning: 8 observations (8 h); afternoon: 10 observations (8 h); night: 9 observations (10-12 h).

In France, night-shift nurses spent somewhat more time sitting, but they end their shift by making beds and dispensing care, both of which involve work in uncomfortable positions. They are assisted in this by a nurses’ aide, but this should be contrasted with the situation during the morning shift, where these tasks are usually performed by two nurses’ aides. In general, nurses working day shifts spend less time in uncomfortable positions. Nurses’ aides were on their feet constantly, and uncomfortable positions, due largely to inadequate equipment, accounted for 31% (afternoon shift) to 46% (morning shift) of their time. Patient facilities in these French and Belgian teaching hospitals were spread out over large areas and consisted of rooms containing one to three beds. Nurses in these wards walked an average of 4 to 7 km per day.

Detailed ergonomic observation of entire workdays (Estryn-Béhar and Hakim-Serfaty 1990) is useful in revealing the interaction of the factors that determine quality of care and the manner in which work is performed. Consider the very different situations in a paediatric intensive care unit and a rheumatology ward. In paediatric resuscitation units, the nurse spends 71% of her time in patients’ rooms, and each patient’s equipment is kept on individual carts stocked by nurses’ aides. The nurses in this ward change location only 32 times per shift, walking a total of 2.5 km. They are able to communicate with physicians and other nurses in the adjoining lounge or nurses’ station through intercoms which have been installed in all the patients’ rooms.

By contrast, the nursing station in the rheumatology ward is very far from patients’ rooms, and care preparation is lengthy (38% of shift time). As a result, the nurses spend only 21% of their time in patients’ rooms and change location 128 times per shift, walking a total of 17 km. This clearly illustrates the interrelationship between physical strain, back problems and organizational and psychological factors. Because they need to move rapidly and get equipment and information, nurses only have time for hallway consultations—there is no time to sit while dispensing care, listen to patients and give patients personalized and integrated responses.

Continuous observation of 18 Dutch nurses in long-term-stay wards revealed that they spent 60% of their time performing physically demanding work with no direct contact with their patients (Engels, Senden and Hertog 1993). Housekeeping and preparation account for most of the 20% of the time described as spent in “slightly hazardous” activities. In all, 0.2% of shift time was spent in postures requiring immediate modification and 1.5% of shift time in postures requiring rapid modification. Contact with patients was the type of activity most frequently associated with these hazardous postures. The authors recommend modifying patient-handling practices and other less hazardous but more frequent tasks.

Given the physiological strain of the work of nurses’ aides, continuous measurement of heart rate is a useful complement to observation. Raffray (1994) used this technique to identify arduous housekeeping tasks and recommended not restricting personnel to this type of task for the whole day.

Electro-myographical (EMG) fatigue analysis is also interesting when body posture must remain more or less static—for example, during operations using an endoscope (Luttman et al. 1996).

Influence of architecture, equipment and organization

The inadequacy of nursing equipment, particularly beds, in 40 Japanese hospitals was demonstrated by Shindo (1992). In addition, patients’ rooms, both those lodging six to eight patients and single rooms reserved for the very ill, were poorly laid out and extremely small. Matsuda (1992) reported that these observations should lead to improvements in the comfort, safety and efficiency of nursing work.

In a French study (Saurel 1993), the size of patient rooms was problematic in 45 of 75 medium- and long-term-stay wards. The most common problems were:

• lack of space (30 wards)

• difficulty in manoeuvring patient-transfer gurneys (17)

• inadequate space for furniture (13)

• the need to take beds out of the room to transfer patients (12)

• difficult access and poor furniture layout (10)

• doors that were too small (8)

• difficulty moving between beds (8).

The mean available area per bed for patients and nurses is at the root of these problems and decreases as the number of beds per room increases: 12.98 m², 9.84 m², 9.60 m², 8.49 m² and 7.25 m² for rooms with one, two, three, four and more than four beds. A more accurate index of the useful area available to personnel is obtained by subtracting the area occupied by the beds themselves (1.8 to 2.0 m²) and by other equipment. The French Department of Health prescribes a useful surface area of 16 m² for single rooms and 22 m² for double rooms. The Quebec Department of Health recommends 17.8 m² and 36 m², respectively.

Turning to factors favouring the development of back problems, variable-height mechanisms were present on 55.1% of the 7,237 beds examined; of these, only 10.3% had electric controls. Patient-transfer systems, which reduce lifting, were rare. These systems were systematically used by 18.2% of the 55 responding wards, with over half the wards reporting using them “rarely” or “never”. “Poor” or “rather poor” manoeuvrability of meal carts was reported by 58.5% of 65 responding wards. There was no periodic maintenance of mobile equipment in 73.3% of 72 responding wards.

In almost half the responding wards, there were no rooms with seats that nurses could use. In many cases, this appears to have been due to the small size of the patient rooms. Sitting was usually possible only in the lounges—in 10 units, the nursing station itself had no seats. However, 13 units reported having no lounge and 4 units used the pantry for this purpose. In 30 wards, there were no seats in this room.

According to statistics for 1992 provided by the Confederation of Employees of the Health Services Employees of the United Kingdom (COHSE), 68.2% of nurses felt that there were not enough mechanical patient lifts and handling aides and 74.5% felt that they were expected to accept back problems as a normal part of their work.

In Quebec, the Joint Sectoral Association, Social Affairs Sector (Association pour la santé et la sécurité du travail, secteur afffaires sociales, ASSTAS) initiated its “Prevention-Planning-Renovation-Construction” project in 1993 (Villeneuve 1994). Over 18 months, funding for almost 100 bipartite projects, some costing several million dollars, was requested. This programme’s goal is to maximize investments in prevention by addressing health and safety concerns early in the design stage of planning, renovation and design projects.

The association completed the modification of the design specifications for patient rooms in long-term-care units in 1995. After noting that three-quarters of occupational accidents involving nurses occur in patient rooms, the association proposed new dimensions for patients’ rooms, and new rooms must now provide a minimum amount of free space around beds and accommodate patient lifts. Measuring 4.05 by 4.95 m, the rooms are more square than the older, rectangular rooms. To improve performance, ceiling-mounted patient lifts were installed, in collaboration with the manufacturer.

The association is also working on the modification of construction standards for washrooms, where many occupational accidents also occur, although to a lesser extent than in the rooms themselves. Finally, the feasibility of applying anti-skid coatings (with a coefficient of friction above the minimum standard of 0.50) on floors is being studied, since patient autonomy is best promoted by providing a non-skid surface on which neither they nor nurses can slip.

Evaluation of equipment that reduces physical strain

Proposals for improving beds (Teyssier-Cotte, Rocher and Mereau 1987) and meal carts (Bouhnik et al. 1989) have been formulated, but their impact is too limited. Tintori et al. (1994) studied adjustable-height beds with electric trunk-lifts and mechanical mattress-lifts. The trunk-lifts were judged satisfactory by the staff and patients, but the mattress-lifts were very unsatisfactory, since adjusting the beds required more than eight pedal strokes, each of which exceeded standards for foot force. Pushing a button located close to the patient’s head while talking to her or him is clearly preferable to pumping a pedal eight times from the foot of the bed (see figure 1).  Because of time constraints, the mattress lift was often simply not used.

Figure 1. Electronically-operated trunk-lifts on beds effectively reduce lifting accidents

B. Floret

Van der Star and Voogd (1992) studied health care workers caring for 30 patients in a new prototype of bed over a period of six weeks. Observations of the workers’ positions, the height of work surfaces, physical interaction between nurses and patients and the size of the work space were compared to data collected on the same ward over a seven-week period prior to the introduction of the prototype. Use of the prototypes reduced the total time spent in uncomfortable positions while washing patients from 40% to 20%; for bed-making the figures were 35% and 5%. Patients also enjoyed greater autonomy and often changed positions on their own, raising their trunks or legs by means of electric control buttons.

In Swedish hospitals, each double room is equipped with ceiling-mounted patient lifts (Ljungberg, Kilbom and Goran 1989). Rigorous programmes such as the April Project evaluate the interrelation of working conditions, work organization, the establishment of a back school and the improvement of physical fitness (Öhling and Estlund 1995).

In Quebec, ASSTAS developed a global approach to the analysis of working conditions causing back problems in hospitals (Villeneuve 1992). Between 1988 and 1991, this approach led to modifications of the work environment and equipment used in 120 wards and a 30% reduction in the frequency and severity of occupational injuries. In 1994, a cost-benefit analysis performed by the association demonstrated that the systematic implementation of ceiling-mounted patient lifts would reduce occupational accidents and increase productivity, compared to the continued use of mobile, ground-based lifts (see figure 2).

Figure 2. Using ceiling-mounted patient lifts to reduce lifting accidents

Accounting for individual variation and facilitating activity

The female population in France is generally not very physically active. Of 1,505 nurses studied by Estryn-Béhar et al. (1992), 68% participated in no athletic activity, with inactivity more pronounced among mothers and unskilled personnel. In Sweden, fitness programmes for hospital personnel have been reported to be useful (Wigaeus Hjelm, Hagberg and Hellstrom 1993), but are feasible only if potential participants do not end their work day too tired to participate.

The adoption of better work postures is also conditioned by the possibility of wearing appropriate clothing (Lempereur 1992). The quality of shoes is particularly important. Hard soles are to be avoided. Anti-skid soles prevent occupational accidents caused by slips and falls, which in many countries are the second-leading cause of accidents leading to work absence. Ill-fitting overshoes or boots worn by operating room personnel to minimize the build-up of static electricity may be a hazard for falls.

Slips on level floors can be prevented by using low-slip floor surfaces that require no waxing. The risk of slips, particularly at doorways, can also be reduced by using techniques that do not leave the floor wet for long. The use of one mop per room, recommended by hygiene departments, is one such technique and has the additional advantage of reducing the handling of buckets of water.

In Vasteras County (Sweden), the implementation of several practical measures reduced painful syndromes and absenteeism by at least 25% (Modig 1992). In the archives (e.g., record or file rooms), ground- and ceiling-level shelves were eliminated, and an adjustable sliding board on which personnel can take notes while consulting the archives was installed. A reception office equipped with movable filing units, a computer and a telephone was also constructed. The height of the filing units is adjustable, allowing employees to adjust them to their own needs and facilitating the transition from sitting to standing during work.

Importance of “anti-lifting”

Manual patient-handling techniques designed to prevent back injuries have been proposed in many countries. Given the poor results of these techniques that have been reported to date (Dehlin et al. 1981; Stubbs, Buckle and Hudson 1983), more work in this area is needed.

The department of kinesiology of the University of Groningen (Netherlands) has developed an integrated patient-handling programme (Landewe and Schröer 1993) consisting of:

• recognition of the relationship between patient-handling and back strain

• demonstration of the value of the “anti-lifting” approach

• sensitization of nursing students throughout their studies to the importance of avoiding back strain

• the use of problem-resolution techniques

• attention to implementation and evaluation.

In the “anti-lifting” approach, the resolution of problems associated with patient transfers is based on the systematic analysis of all aspects of transfers, especially those related to patients, nurses, transfer equipment, teamwork, general working conditions and environmental and psychological barriers to the use of patient lifts (Friele and Knibbe 1993).

The application of European standard EN 90/269 of 29 May 1990 on back problems is an example of an excellent starting point for this approach. Besides requiring employers to implement appropriate work organization structures or other appropriate means, particularly mechanical equipment, to avoid manual handling of loads by workers, it also emphasizes the importance of “no-risk” handling policies that incorporate training. In practice, the adoption of appropriate postures and handling practices depends on the amount of functional space, presence of appropriate furniture and equipment, good collaboration on work organization and quality of care, good physical fitness and comfortable work clothing. The net effect of these factors is improved prevention of back problems.

Back

Some text was adapted from the 3rd edition Encyclopaedia article “Aviation - ground personnel” authored by E. Evrard.

Commercial air transport involves the interaction of several groups including governments, airport operators, aircraft operators and aircraft manufacturers. Governments are generally involved in overall air transport regulation, oversight of aircraft operators (including maintenance and operations), manufacturing certification and oversight, air traffic control, airport facilities and security. Airport operators can either be local governments or commercial entities. They are usually responsible for the general operation of the airport. Types of aircraft operators include general airlines and commercial transport (either privately or publicly owned), cargo carriers, corporations and individual aircraft owners. Aircraft operators in general are responsible for operation and maintenance of the aircraft, training of personnel and operation of ticketing and boarding operations. Responsibility for security can vary; in some countries the aircraft operators are responsible, and in others the government or airport operators are responsible. Manufacturers are responsible for design, manufacturing and testing, and for aircraft support and improvement. There are also international agreements con- cerning international flights.

This article deals with the personnel involved with all aspects of flight control (i.e., those who control commercial aircraft from takeoff to landing and who maintain the radar towers and other facilities used for flight control) and with those airport personnel who perform maintenance on and load aircraft, handle baggage and air freight and provide passenger services. Such personnel are divided into the following categories:

• air traffic controllers

• airways facilities and radar towers maintenance personnel

• ground crews

• baggage handlers

• passenger service agents.

Flight Control Operations

Government aviation authorities such as the Federal Aviation Administration (FAA) in the United States maintain flight control over commercial aircraft from takeoff to landing. Their primary mission involves the handling of airplanes using radar and other surveillance equipment to keep aircraft separated and on course. Flight control personnel work at airports, terminal radar approach control facilities (Tracons) and regional long-distance centres, and consist of air traffic controllers and airways facilities maintenance personnel. Airways facilities maintenance personnel maintain the airport control towers, air traffic Tracons and regional centres, radio beacons, radar towers and radar equipment, and consist of electronics technicians, engineers, electricians and facilities maintenance workers. The guidance of planes using instruments is accomplished following instrument flight rules (IFR). Planes are tracked using the General National Air Space System (GNAS) by air traffic controllers working at airport control towers, Tracons and regional centres. Air traffic controllers keep planes separated and on course. As a plane moves from one jurisdiction to another, responsibility for the plane is handed from one type of controller to another.

Regional centres, terminal radar approach control and airport control towers

Regional centres direct planes after they have reached high altitudes. A centre is the largest of the aviation authority’s facilities. Regional centre controllers hand off and receive planes to and from Tracons or other regional control centres and use radio and radar to maintain communication with aircraft. A plane flying across a country will always be under surveillance by a regional centre and passed along from one regional centre to the next.

The regional centres all overlap each other in the surveillance range and receive radar information from long-range radar facilities. Radar information is sent to these facilities via microwave links and telephone lines, thus providing a redundancy of information so that if one form of communication is lost, the other is available. Oceanic air traffic, which cannot be seen by radar, is handled by the regional centres via radio. Technicians and engineers maintain the electronic surveillance equipment and the uninterrupted power systems, which includes emergency generators and large banks of back-up batteries.

Air traffic controllers at Tracons handle planes flying at low altitudes and within 80 km of airports, using radio and radar to maintain communication with aircraft. Tracons receive radar tracking information from the airport surveillance radar (ASR). The radar tracking system identifies the plane moving in space but also queries the plane beacon and identifies the plane and its flight information. Personnel and work tasks at Tracons are similar to those at the regional centres.

Regional and approach control systems exist in two variants: non-automated or manual systems and automated systems.

With manual air traffic control systems, radio communications between controller and pilot are supplemented by information from primary or secondary radar equipment. The trace of the aeroplane can be followed as a mobile echo on display screens formed by cathode-ray tubes (see figure 1). Manual systems have been replaced by automated systems in most countries.

Figure 1. Air traffic controller at a manual local control centre radar screen.

With automated air traffic control systems, information on the aeroplane is still based on the flight plan and primary and secondary radar, but computers make it possible to present in alphanumeric form on the display screen all data concerning each aeroplane and to follow its route. Computers are also used to anticipate conflict between two or more aircraft on identical or converging routes on the basis of the flight plans and standard separations. Automation relieves the controller of many of the activities he or she carries out in a manual system, leaving more time for taking decisions.

Conditions of work are different in manual and automated control centre systems. In the manual system the screen is horizontal or sloping, and the operator leans forward in an uncomfortable position with his or her face between 30 and 50 cm from it. The perception of mobile echoes in the form of spots depends on their brightness and their contrast with the illuminance of the screen. As some mobile echoes have a very low luminous intensity, the working environment must be very weakly illuminated to ensure the greatest possible visual sensitivity to contrast.

In the automated system the electronic data display screens are vertical or almost vertical, and the operator can work in a normal sitting position with a greater reading distance. The operator has horizontally arranged keyboards within reach to regulate the presentation of the characters and symbols conveying the various types of information and can alter the shape and brightness of the characters. The lighting of the room can approach the intensity of daylight, for contrast remains highly satisfactory at 160 lux. These features of the automated system place the operator in a much better position to increase efficiency and reduce visual and mental fatigue.

Work is carried out in a huge, artificially lighted room without windows, which is filled with display screens. This closed environment, often far from the airports, allows little social contact during the work, which calls for great concentration and powers of decision. The comparative isolation is mental as well as physical, and there is hardly any opportunity of diversion. All this has been held to produce stress.

Each airport has a control tower. Controllers at airport control towers direct planes in and out of the airport, using radar, radio and binoculars to maintain communication with aircraft both while taxiing and while taking off and landing. Airport tower controllers hand off to or receive planes from controllers at Tracons. Most of the radar and other surveillance systems are located at the airports. These systems are maintained by technicians and engineers.

The walls of the tower room are transparent, for there must be perfect visibility. The working environment is thus completely different from that of regional or approach control. The air traffic controllers have a direct view of aircraft movements and other activities. They meet some of the pilots and take part in the life of the airport. The atmosphere is no longer that of a closed environment, and it offers a greater variety of interest.

Airways facilities maintenance personnel

Airways facilities and radar towers maintenance personnel consist of radar technicians, navigational and communication technicians and environmental technicians.

Radar technicians maintain and operate the radar systems, including airport and long-range radar systems. The work involves electronic equipment maintenance, calibration and troubleshooting.

Navigational and communication technicians maintain and operate the radio communications equipment and other related navigational equipment used in controlling air traffic. The work involves electronic equipment maintenance, calibration and troubleshooting.

Environmental technicians maintain and operate the aviation authority buildings (regional centres, Tracons and airport facilities, including the control towers) and equipment. The work requires running heating, ventilation and air-conditioning equipment and maintaining emergency generators, airport lighting systems, large banks of batteries in uninterrupted power supply (UPS) equipment and related electrical power equipment.

The occupational hazards for all three jobs include: noise exposure; working on or near live electrical parts including exposure to high voltage, x-ray exposure from klystron and magnitron tubes, fall hazards while working on elevated radar towers or using climbing poles and ladders to access towers and radio antenna and possibly PCBs exposure when handling older capacitors and working on utility transformers. Workers may also be exposed to microwave and radio-frequency exposure. According to a study of a group of radar workers in Australia (Joyner and Bangay 1986), personnel are not generally exposed to levels of microwave radiation exceeding 10 W/m² unless they are working on open waveguides (microwave cables) and components utilizing waveguide slots, or working within transmitter cabinets when high-voltage arcing is occurring. The environmental technicians also work with chemicals related to building maintenance, including boiler and other related water treatment chemicals, asbestos, paints, diesel fuel and battery acid. Many of the electrical and utility cables at airports are underground. Inspection and repair work on these systems often involves confined space entry and exposure to confined space hazards—noxious or asphyxiating atmospheres, falls, electrocution and engulfment.

Airways facilities maintenance workers and other ground crews in the airport operating area are frequently exposed to jet exhaust. Several airport studies where sampling of jet engine exhaust has been conducted demonstrated similar results (Eisenhardt and Olmsted 1996; Miyamoto 1986; Decker 1994): the presence of aldehydes including butyraldehyde, acetaldehyde, acrolein, methacrolein, isobutyraldehyde, propionaldehyde, croton-aldehyde and formaldehyde. Formaldehyde was present at significantly higher concentrations then the other aldehydes, followed by acetaldehyde. The authors of these studies have concluded that the formaldehyde in the exhaust was probably the main causative factor in the eye and respiratory irritation reported by exposed persons. Depending on the study, nitrogen oxides either were not detected or were present in concentrations below 1 part per million (ppm) in the exhaust stream. They concluded that neither nitrogen oxides nor other oxides play a major role in the irritation. Jet exhaust was also found to contain 70 different hydrocarbon species with up to 13 consisting mostly of olefins (alkenes). Heavy-metal exposure from jet exhaust has been shown not to pose a health hazard for areas surrounding airports.

Radar towers should be equipped with standard railings around the stairs and platforms to prevent falls and with interlocks to prevent access to the radar dish while it is operating. Workers accessing towers and radio antennas should use approved devices for ladder climbing and personal fall protection.

Personnel work on both de-energized and energized electrical systems and equipment. Protection from electrical hazards should involve training in safe work practices, lockout/tagout procedures and the use of personal protective equipment (PPE).

The radar microwave is generated by high-voltage equipment using a klystron tube. The klystron tube generates x rays and can be a source of exposure when the panel is opened, allowing personnel to come in close proximity to it to work on it. The panel should always remain in place except when servicing the klystron tube, and work time should be kept to a minimum.

Personnel should wear the appropriate hearing protection (e.g., ear plugs and/or ear muffs) when working around noise sources such as jet planes and emergency generators.

Other controls involve training in materials handling, vehicle safety, emergency response equipment and evacuation procedures and confined space entry procedures equipment (including direct-reading air monitors, blowers and mechanical retrieval systems).

Air traffic controllers and flight services personnel

Air traffic controllers work in regional control centres, Tracons and airport control towers. This work generally involves working at a console tracking planes on radar scopes and communicating with pilots by radio. Flight services personnel provide weather information for pilots.

The hazards to air traffic controllers include possible visual problems, noise, stress and ergonomic problems. At one time there was concern about x-ray emissions from the radar screens. This, however, has not turned out to be a problem at the operating voltages used.

Standards of fitness for air traffic controllers have been recommended by the International Civil Aviation Organization (ICAO), and detailed standards are set out in national military and civil regulations, those relating to sight and hearing being particularly precise.

Visual problems

The broad, transparent surfaces of air traffic control towers at airports sometimes result in dazzling by the sun, and reflection from surrounding sand or concrete can increase the luminosity. This strain on the eyes may produce headaches, though often of a temporary nature. It may be prevented by surrounding the control tower with grass and avoiding concrete, asphalt or gravel and by giving a green tint to the transparent walls of the room. If the colour is not too strong, visual acuity and colour perception remain adequate while the excess radiation that causes dazzle is absorbed.

Until about 1960 there was a good deal of disagreement among authors on the frequency of eyestrain among controllers from viewing radar screens, but it does seem to have been high. Since then, attention given to visual refractive errors in the selection of radar controllers, their correction among serving controllers and the constant improvement of working conditions at the screen have helped to lower it considerably. Sometimes, however, eyestrain appears among controllers with excellent sight. This may be attributed to too low a level of lighting in the room, irregular illumination of the screen, the brightness of the echoes themselves and, in particular, flickering of the image. Progress in viewing conditions and insistence on higher technical specifications for new equipment are leading to a marked reduction in this source of eyestrain, or even its elimination. Strain in accommodation has also been considered until recently to be a possible cause of eyestrain among operators who have worked very close to the screen for an hour without interruption. Visual problems are becoming much less frequent and are likely to disappear or to occur only very occasionally in the automated radar system, for example, when there is a fault in a scope or where the rhythm of the images is badly adjusted.

A rational arrangement of the premises is mainly one that facilitates the adaptation of the scope readers to the intensity of the ambient lighting. In a non-automated radar station, adaptation to the semi-darkness of the scope room is achieved by spending 15 to 20 minutes in another dimly lighted room. The general lighting of the scope room, the luminous intensity of the scopes and the brightness of the spots must all be studied with care. In the automated system the signs and symbols are read under an ambient lighting of from 160 to 200 lux, and the disadvantages of the dark environment of the non-automated system are avoided. With regard to noise, despite modern sound-insulating techniques, the problem remains acute in control towers installed near the runways.

Readers of radar screens and electronic display screens are sensitive to changes in the ambient lighting. In the non-automated system the controllers must wear glasses absorbing 80% of the light for between 20 and 30 minutes before entering their workplace. In the automated system special glasses for adaptation are no longer essential, but persons particularly sensitive to the contrast between the lighting of the symbols on the display screen and that of the working environment find that glasses of medium absorptive power add to the comfort of their eyes. There is also a reduction in eyestrain. Runway controllers are well advised to wear glasses absorbing 80% of the light when they are exposed to strong sunlight.

Stress

The most serious occupational hazard for air traffic controllers is stress. The chief duty of the controller is to make decisions on the movements of aircraft in the sector he or she is responsible for: flight levels, routes, changes of course when there is conflict with the course of another aircraft or when congestion in one sector leads to delays, air traffic and so on. In non-automated systems the controller must also prepare, classify and organize the information his or her decision is based on. The data available are comparatively crude and must first be digested. In highly automated systems the instruments can help the controller in taking decisions, and he or she may then only have to analyse data produced by teamwork and presented in rational form by these instruments. Although the work may be greatly facilitated, the responsibility for approving the decision proposed to the controller remains the controller’s, and his or her activities still give rise to stress. The responsibilities of the job, pressure of work at certain hours of dense or complex traffic, increasingly crowded air space, sustained concentration, rotating shift work and awareness of the catastrophe that may result from an error all create a situation of continuous tension, which may lead to stress reactions. The fatigue of the controller may assume the three classic forms of acute fatigue, chronic fatigue or overstrain and nervous exhaustion. (See also the article “Case Studies of Air Traffic Controllers in the United States and Italy”.)

Air traffic control calls for an uninterrupted service 24 hours a day, all year long. The conditions of work of controllers thus include shift work, an irregular rhythm of work and rest and periods of work when most other people are enjoying holidays. Periods of concentration and of relaxation during working hours and days of rest during a week of work are indispensable to the avoidance of operational fatigue. Unfortunately, this principle cannot be embodied in general rules, for the arrangement of work in shifts is influenced by variables that may be legal (maximum number of consecutive hours of work authorized) or purely professional (workload depending on the hour of the day or the night), and by many other factors based on social or family considerations. With regard to the most suitable length for periods of sustained concentration during work, experiments show that there should be short breaks of at least a few minutes after periods of uninterrupted work of from half an hour to an hour-and-a-half, but that there is no need to be bound by rigid patterns to achieve the desired aim: the maintenance of the level of concentration and the prevention of operational fatigue. What is essential is to be able to interrupt the periods of work at the screen with periods of rest without interrupting the continuity of the shift work. Further study is necessary to establish the most suitable length of the periods of sustained concentration and of relaxation during work and the best rhythm for weekly and annual rest periods and holidays, with a view to drawing up more unified standards.

Other hazards

There are also ergonomic issues while working at the consoles similar to those of computer operators, and there may be indoor air quality problems. Air traffic controllers also experience tone incidents. Tone incidents are loud tones coming into the headsets. The tones are of short duration (a few seconds) and have sound levels up to 115 dBA.

In flight services work, there are hazards associated with lasers, which are used in ceilorometer equipment used to measure cloud ceiling height, as well as ergonomic and indoor air quality issues.

Other flight control services personnel

Other flight control services personnel include flight standards, security, airport facilities renovation and construction, administrative support and medical personnel.

Flight standards personnel are aviation inspectors who conduct airline maintenance and flight inspections. Flight standards personnel verify the airworthiness of the commercial airlines. They often inspect airplane maintenance hangers and other airport facilities, and they ride in the cockpits of commercial flights. They also investigate plane crashes, incidents or other aviation-related mishaps.

The hazards of the job include noise exposure from aircraft, jet fuel and jet exhaust while working in hangers and other airport areas, and potential exposure to hazardous materials and blood-borne pathogens while investigating aircraft crashes. Flight standards personnel face many of the same hazards as airport ground crews, and thus many of the same precautions apply.

Security personnel include sky marshals. Sky marshals provide internal security on airplanes and external security at airport ramps. They are essentially police and investigate criminal activities related to aircraft and airports.

Airport facilities renovation and construction personnel approve all plans for airport modifications or new construction. The personnel are usually engineers, and their work largely involves office work.

Administrative workers include personnel in accounting, management systems and logistics. Medical personnel in the flight surgeon’s office provide occupational medical services to aviation authority workers.

Air traffic controllers, flight services personnel and personnel who work in office environments should have ergonomic training on proper sitting postures and on emergency response equipment and evacuation procedures.

Airport Operations

Airport ground crews conduct maintenance on and load aircraft. Baggage handlers handle passenger baggage and air freight, whereas passenger service agents register passengers and check passenger baggage.

All loading operations (passengers, baggage, freight, fuel, supplies and so on) are controlled and integrated by a supervisor who prepares the loading plan. This plan is given to the pilot prior to take-off. When all operations have been completed and any checks or inspections considered necessary by the pilot have been made, the airport controller gives authorization for take-off.

Ground crews

Aircraft maintenance and servicing

Every aircraft is serviced every time it lands. Ground crews performing routine turnaround maintenance; conduct visual inspections, including checking the oils; perform equipment checks, minor repairs and internal and external cleaning; and refuel and restock the aircraft. As soon as the aircraft lands and arrives in the unloading bays, a team of mechanics begins a series of maintenance checks and operations which vary with the type of aircraft. These mechanics refuel the aircraft, check a number of safety systems which must be inspected after each landing, investigate the logbook for any reports or defects the flight crew may have noticed during the flight and, where necessary, make repairs. (See also the article “Aircraft Maintenance Operations” in this chapter.) In cold weather, the mechanics may have to perform additional tasks, such as de-icing of wings, landing gear, flaps and so on. In hot climates special attention is paid to the condition of the aircraft’s tyres. Once this work has been completed, the mechanics can declare the aircraft flightworthy.

More thorough maintenance inspections and aircraft overhauls are performed at specific intervals of flying hours for each aircraft.

Fuelling aircraft is one of the most potentially hazardous servicing operations. The amount of fuel to be loaded is determined on the basis of such factors as flight duration, take-off weight, flight path, weather and possible diversions.

A cleaning team cleans and services the aircraft cabins, replacing dirty or damaged material (cushions, blankets and so on), empties the toilets and refills the water tanks. This team may also disinfect or disinfest the aircraft under the supervision of public health authorities.

Another team stocks the aircraft with food and drink, emergency equipment and supplies needed for passenger comfort. Meals are prepared under high standards of hygiene to eliminate the risk of food poisoning, particularly among the flight crew. Certain meals are deep frozen to –40ºC, stored at –29ºC and reheated in flight.

Ground service work includes the use of motorized and non-motorized equipment.

Baggage and air cargo loading

Baggage and cargo handlers move passenger baggage and air freight. Freight can range from fresh fruits and vegetables and live animals to radioisotopes and machinery. Because baggage and cargo handling requires physical effort and the use of mechanized equipment, workers may be more at risk for injuries and ergonomic problems.

Ground crews and baggage and freight handlers are exposed to many of the same hazards. These hazards include working outdoors in all types of weather, exposure to potential airborne contaminants from jet fuel and jet engine exhaust and exposure to prop wash and jet blast. Prop wash and jet blast can slam doors shut, knock people or unsecured equipment over, cause turboprop propellers to rotate and blow debris into engines or onto people. Ground crews are also exposed to noise hazards. A study in China showed ground crews were exposed to noise at aircraft engine hatches that exceeds 115 dBA (Wu et al. 1989). Vehicle traffic on the airport ramps and apron is very heavy, and the risk of accidents and collision is high. Fuelling operations are very hazardous, and workers may be exposed to fuel spills, leaks, fires and explosions. Workers on lifting devices, aerial baskets, platforms or access stands are at risk of falling. Job hazards also include rotating shift work carried out under pressure of time.

Strict regulations must be implemented and enforced for vehicle movement and driver training. Driver training should emphasize complying with speed limits, obeying off-limit areas and ensuring that there is adequate room for planes to manoeuvre. There should be good maintenance of ramp surfaces and efficient control of ground traffic. All vehicles authorized to operate on the airfield should be conspicuously marked so they can be readily identified by air traffic controllers. All equipment used by the ground crews should be regularly inspected and maintained. Workers on lifting devices, aerial baskets, platforms or access stands must be protected from falls either through the use of guardrails or personal fall protection equipment. Hearing protection equipment (earplugs and earmuffs) must be used for protection against noise hazards. Other PPE includes suitable work clothing depending on the weather, non-slip reinforced-toe-cap foot protection and appropriate eye, face, glove and body protection when applying de-icing fluids. Rigorous fire prevention and protection measures including bonding and grounding and prevention of electric sparking, smoking, open flames and the presence of other vehicles within 15 m of aircraft, must be implemented for refuelling operations. Fire-fighting equipment should be maintained and located in the area. Training on procedures to follow in the event of a fuel spill or fire should be conducted regularly.

Baggage and freight handlers should store and stack cargo securely and should receive training on proper lifting techniques and back postures. Extreme care should be used when entering and leaving aircraft cargo areas from carts and tractors. Appropriate protective clothing should be worn, depending on the type of cargo or baggage (such as gloves when handling live animal cargo). Baggage and freight conveyors, carousels and dispensers should have emergency shut-offs and built-in guards.

Passenger service agents

Passenger service agents issue tickets, register and check in passengers and passenger baggage. These agents may also guide passengers when boarding. Passenger service agents who sell airline tickets and check in passengers may spend all day on their feet using a video display unit (VDU). Precautions against these ergonomic hazards include resilient floor mats and seats for relief from standing, work breaks and ergonomic and anti-glare measures for the VDUs. In addition, dealing with passengers can be a source of stress, particularly when there are delays in flights or problems with making flight connections and so on. Breakdowns in the computerized airline reservations systems can also be a major source of stress.

Baggage check-in and weigh-in facilities should minimize the need for employees and passengers to lift and handle bags, and baggage conveyors, carousels and dispensers should have emergency shut-offs and built-in guards. Agents should also receive training on proper lifting techniques and back postures.

Baggage inspection systems use fluoroscopic equipment to examine baggage and other carry-on items. Shielding protects workers and the public from x-ray emissions, and if the shielding is not properly positioned, interlocks prevent the system from operating. According to an early study by the US National Institute for Occupational Safety and Health (NIOSH) and the Air Transport Association at five US airports, maximum documented whole-body x-ray exposures were considerably lower than maximum levels set by the US Food and Drug Administration (FDA) and the Occupational Safety and Health Administration (OSHA) (NIOSH 1976). Workers should wear whole-body monitoring devices to measure radiation exposures. NIOSH recommended periodic maintenance programmes to check effectiveness of shielding.

Passenger service agents and other airport personnel must be thoroughly familiar with the airport emergency evacuation plan and procedures.

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Elementary and secondary schools employ many different types of personnel, including teachers, teachers’ aides, administrators, clerical personnel, maintenance personnel, cafeteria personnel, nurses and many others required to keep a school functioning. In general, school personnel face all the potential hazards found in normal indoor and office environments, including indoor air pollution, poor lighting, inadequate heating or cooling, use of office machines, slips and falls, ergonomics problems from poorly designed office furniture and fire hazards. Precautions are the standard ones developed for this type of indoor environment, although building and fire codes usually have specific requirements for schools because of the large number of children present. Other general concerns found in schools include asbestos (especially among custodial and maintenance workers), chipping lead paint, pesticides and herbicides, radon and electromagnetic fields (especially for schools built near high-voltage transmission power lines). Eye and respiratory complaints related to the painting of rooms and the tarring of school roofs while the building is occupied are also a common problem. Painting and tarring should be done when the building is not occupied.

Basic academic duties required of all teachers include: lesson preparation, which can include the development of learning strategies, copying of lecture notes and the making of visual aids such as illustrations, graphs and the like; lecturing, which requires presenting information in an organized fashion that arouses the attention and concentration of students, and can involve the use of blackboards, film projectors, overhead projectors and computers; writing, giving and grading examinations; and individual counselling of students. Most of this instruction takes place in classrooms. In addition, teachers with specialities in science, arts, vocational education, physical education and other areas will conduct much of their teaching in facilities such as laboratories, art studios, theatres, gymnasiums and the like. Teachers may also take students on class trips outside the school to locations such as museums and zoos.

Teachers also have special duties, which can include supervision of students in hallways and the cafeteria; attending meetings with administrators, parents and others; organization and supervision of after-school leisure and other activities; and other administrative duties. In addition, teachers attend conferences and other educational events in order to keep current with their field and advance their career.

There are specific hazards facing all teachers. Infectious diseases such as tuberculosis, measles and chicken pox can easily spread throughout a school. Vaccinations (both of students and teachers), tuberculosis testing and other standard public health measures are essential (see table 1). Overcrowded classrooms, classroom noise, overloaded schedules, inadequate facilities, career advancement questions, job security and general lack of control over working conditions contribute to major stress problems, absenteeism and burnout in teachers. Solutions include both institutional changes to improve working conditions and stress reduction programmes where possible. A growing problem, especially in urban environments, is violence against teachers by students and, sometimes, intruders. In the United States, many secondary-level students, especially in urban schools, carry weapons, including guns. In schools where violence is a problem, organized violence-prevention programmes are essential. Teachers’ aides face many of the same hazards.

Table 1.  Infectious diseases affecting day-care workers and teachers.

Teachers in specialized classes can have additional occupational hazards, including chemical exposures, machinery hazards, accidents, electrical hazards, excessive noise levels, radiation and fire, depending on the particular classroom. Figure 1 shows an industrial arts metal shop in a high school, and figure 2 shows a high school science lab with fume hoods and an emergency shower. Table 2 summarizes special precautions, particularly substitution of safer materials, for use in schools. Information on standard precautions can be found in the chapters relevant to the process (e.g., Entertainment and the arts and Safe handling of chemicals).

Figure 1. Industrial arts metal shop in a high school.

Michael McCann

Figure 2. High school science laboratory with fume hoods and an emergency shower.

Michael McCann

Table 2.  Hazards and precautions for particular classes.

Teachers in special education programmes can sometimes be at greater risk. Examples of hazards include violence from emotionally disturbed students and transmission of infections such as hepatitis A, B and C from institutionalized, developmentally disabled students (Clemens et al. 1992).

Preschool Programmes 

Child-care, which involves the physical care and often education of young children, takes many forms in different parts of the world. In many countries where extended families are common, grandparents and other female relatives care for young children when the mother has to work. In countries where the nuclear family and/or single parents predominate and the mother is working, the care of healthy children below school age often occurs in private or public day-care centres or nursery schools outside the home. In many countries - for example, Sweden - these child-care facilities are operated by municipalities. In the United States, most child-care facilities are private, although they are usually regulated by local health departments. An exception is the Head Start Program for preschool children, which is funded by the government. 

Staffing of child-care facilities usually depends on the number of children involved and the nature of the facility. For small numbers of children (usually less than 12), the child-care facility might be a home where the children include the preschool children of the caregiver. The staff can include one or more qualified adult assistants to meet staff-to-child ratio requirements. Larger, more formal child-care facilities include day-care centres and nursery schools. The staff members for these are usually required to have more education and can include a qualified director, trained teachers, nursing staff under the supervision of a physician, kitchen staff (nutrition specialists, food service managers and cooks) and other personnel, such as transportation staff and maintenance staff. The premises of the day-care centre should have such amenities as an outdoor play area, cloakroom, reception area, indoor classroom and play area, kitchen, sanitary facilities, administrative rooms, laundry room and so on.

Staff duties include supervision of children in all their activities, changing diapers of infants, emotional nurturing of the children, teaching, food preparation and service, recognition of signs of illness and/or safety hazards and many other functions. 

Day-care workers face many of the same hazards found in normal indoor environments, including indoor air pollution, poor lighting, inadequate temperature control, slips and falls and fire hazards. (See the article “Elementary and Secondary Schools”.) Stress (often resulting in burnout) and infections, however, are the major hazards for day-care workers. The lifting and carrying of children and exposure to possibly hazardous art supplies are other hazards.

Stress

Causes of stress in day-care workers include: high responsibility for the welfare of children without adequate pay and recognition; a perception of being unskilled even though many day-care workers have above-average education; image problems due to highly publicized incidents of day-care workers mistreating and abusing children, which have resulted in innocent day-care workers being fingerprinted and treated as potential criminals; and poor working conditions. The latter include low staff-to-child ratios, continual noise, lack of adequate time and facilities for meals and breaks separate from the children and inadequate mechanisms for parent-worker interaction, which can result in unnecessary and possibly unfair pressure and criticism from parents. 

Preventive measures to reduce stress in day-care workers include: higher wages and better benefits; higher staff-to-child ratios to allow job rotation, rest breaks, sick leave and better performance, with resulting increase in job satisfaction; establishing formal mechanisms for parent-worker communications and cooperation (possibly including a parent-workers health and safety committee); and improved working conditions, such as adult-size chairs, regular “quiet” times, a separate workers’ break area and so on.

Infections

Infectious diseases, such as diarrhoeal diseases, streptococcal and meningococcal infections, rubella, cytomegalovirus and respiratory infections, are major occupational hazards of day-care workers (see table 1). A study of day-care workers in Belgium found an increased risk of hepatitis A (Abdo and Chriske 1990). Up to 30% of the 25,000 cases of hepatitis A reported annually in the United States have been linked to day-care centres. Some organisms causing diarrhoeal diseases, such as Giardia lamblia, which causes giardiasis, are extremely infectious. Outbreaks can occur in day-care centres serving affluent populations as well as those serving poor areas (Polis et al. 1986). Some infections - for example, German measles and cytomegalovirus - can be especially hazardous for pregnant women, or women planning to have children, because of the risk of birth defects caused by the virus.

Sick children can spread diseases, as can children who have no overt symptoms but are carrying an illness. The most common routes of exposure are faecal-oral and respiratory. Young children usually have poor personal hygiene habits. Hand-to-mouth and toy-to-mouth contact are common. Handling contaminated toys and food is one type of entry route. Some organisms can live on inanimate objects for extended periods ranging from hours to weeks. Food can also be a vector if the food handler has contaminated hands or is ill. Inhalation of airborne respiratory droplets due to sneezing and coughing without protection such as tissues can result in transmission of infections. Such air-borne aerosols can remain suspended in the air for hours.

Day care employees working with children under the age of three years, especially if the children are not toilet-trained, are at greatest risk, particularly when changing and handling soiled diapers which are contaminated by disease-bearing organisms.

Precautions include: convenient facilities for handwashing; regular handwashing by children and staff members; changing diapers in designated areas which are regularly disinfected; disposal of soiled diapers in closed, plastic-lined receptacles which are emptied frequently; separating food preparation areas from other areas; frequent washing of toys, play areas, blankets and other items that could become contaminated; good ventilation; adequate staff-to-child ratios to allow proper implementation of a hygiene programme; a policy of excluding, isolating or restricting sick children, depending on the illness; and adequate sick-leave policies to allow sick day-care workers to stay home.

Adapted from Women’s Occupational Health Resource Center 1987

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Drawing involves making marks on a surface to express a feeling, experience or vision. The most commonly used surface is paper; drawing media include dry implements such as charcoal, coloured pencils, crayons, graphite, metalpoint and pastels, and liquids such as inks, markers and paints. Painting refers to processes that apply an aqueous or non-aqueous liquid medium (“paint”) to sized, primed or sealed surfaces such as canvas, paper or panel. Aqueous media include water-colours, tempera, acrylic polymers, latex and fresco; non-aqueous media include linseed or stand oils, dryers, varnish, alkyds, encaustic or molten wax, organic solvent-based acrylics, epoxy, enamels, stains and lacquers. Paints and inks typically consists of colouring agents (pigments and dyes), a liquid vehicle (organic solvent, oil or water), binders, bulking agents, antioxidants, preservatives and stabilizers.

Prints are works of art made by transferring a layer of ink from an image on a printing surface (such as woodblock, screen, metal plate or stone) onto paper, fabric or plastic. The printmaking process involves several steps: (1) preparation of the image; (2) printing; and (3) cleanup. Multiple copies of the image can be made by repeating the printing step. In monoprints, only one print is made.

Intaglio printing involves incising lines by mechanical means (e.g., engraving, drypoint) or etching the metal plate with acid to create depressed areas in the plate, which form the image. Various solvent-containing resists and other materials such as rosin or spray paint (aquatinting) can be used to protect the part of the plate not being etched. In printing, the ink (which is linseed oil based) is rolled onto the plate, and the excess wiped off, leaving ink in the depressed areas and lines. The print is made by placing the paper on the plate and applying pressure by a printing press to transfer the ink image to the paper.

Relief printing involves the cutting away of the parts of woodblocks or linoleum that are not to be printed, leaving a raised image. Water-or linseed oil–based inks are applied to the raised image and the ink image transferred to paper.

Stone lithography involves making an image with a greasy drawing crayon or other drawing materials that will make the image receptive to the linseed oil–based ink, and treating the plate with acids to make non-image areas water receptive and ink repellent. The image is washed out with mineral spirits or other solvents, inked with a roller and then printed. Metal plate lithography can involve a preliminary counteretch that often contains dichromate salts. Metal plates may be treated with vinyl lacquers containing ketone solvents for long print runs.

Screen printing is a stencil process where a negative image is made on the fabric screen by blocking out portions of the screen. For water-based inks, the blockout materials must be water insoluble; for solvent-based inks, the reverse. Cut plastic stencils are frequently used and adhered to the screen with solvents. The prints are made by scraping ink across the screen, forcing the ink through the unblocked parts of the screen onto paper located underneath the screen, thus creating the positive image. Large print runs using solvent-based inks involve the release of large amounts of solvent vapours into the air.

Collagraphs are made using either intaglio or relief printing techniques on a textured surface or collage, which can be made of many materials glued onto the plate.

Photoprintmaking processes can use either presensitized plates (often diazo) for lithography or intaglio, or the photoemulsion can be applied directly to the plate or stone. A mixture of gum arabic and dichromates have often been used on stones (gum printing). The photographic image is transferred to the plate, and then the plate exposed to ultraviolet light (e.g., carbon arcs, xenon lights, sunlight). When developed, the non-exposed portions of the photoemulsion are washed away, and the plate then printed. The coating and developing agents can often contain hazardous solvents and alkalis. In photo screen processes, the screen can be coated with dichromate or diazo photoemulsion directly, or an indirect process can be used, which involves adhering sensitized transfer films to the screen after exposure.

In printmaking techniques using oil-based inks, the ink is cleaned up with solvents or with vegetable oil and dishwashing liquid. Solvents also have to be used for cleaning lithography rollers. For water-based inks, water is used for cleanup. For solvent-based inks, large amounts of solvents are used for cleanup, making this one of the most hazardous processes in printmaking. Photoemulsions can be removed from screens using chlorine bleach or enzyme detergents.

Artists who draw, paint or make prints face significant health and safety hazards. The major sources of hazards for these artists include acids (in lithography and intaglio), alcohols (in paint, shellac, resin and varnish thinners and removers), alkalis (in paints, dye baths, photodevelopers and film cleaners), dusts (in chalks, charcoal and pastels), gases (in aerosols, etching, lithography and photoprocesses), metals (in pigments, photochemicals and emulsions), mists and sprays (in aerosols, air-brushing and aquatinting), pigments (in inks and paints), powders (in dry pigments and photochemicals, rosin, talc and whiting), preservatives (in paints, glues, hardeners and stabilizers) and solvents (such as aliphatic, aromatic and chlorinated hydrocarbons, glycol ethers and ketones). Common routes of exposure associated with these hazards include inhalation, ingestion and skin contact.

Among the well-documented health problems of painters, drawers and printmakers are: n-hexane-induced peripheral nerve damage in art students using rubber cement and spray adhesives; solvent-induced peripheral and central nervous system damage in silk-screen artists; bone marrow suppression related to solvents and glycol ethers in lithographers; onset or aggravation of asthma following exposure to sprays, mists, dusts, moulds and gases; abnormal heart rhythms following exposure to hydrocarbon solvents such as methylene chloride, freon, toluene and 1,1,1-trichloroethane found in glues or correction fluids; acid, alkali or phenol burns or irritation of the skin, eyes and mucous membranes; liver damage induced by organic solvents; and irritation, immune reaction, rashes and ulceration of the skin following exposure to nickel, dichromates and chromates, epoxy hardeners, turpentine or formaldehyde.

Although not well-documented, painting, drawing and printmaking may be associated with an increased risk of leukaemia, kidney tumours and bladder tumours. Suspected carcinogens to which painters, drawers and printmakers may be exposed include chromates and dichromates, polychlorinated biphenyls, trichloroethylene, tannic acid, methylene chloride, glycidol, formaldehyde, and cadmium and arsenic compounds.

The most important precautions in painting, drawing and printmaking include: substitution of water-based materials for materials based on organic solvents; proper use of general dilution ventilation and local exhaust ventilation (see figure 1); proper handling, labelling, storage and disposal of paints, flammable liquids and waste solvents; appropriate use of personal protective equipment such as aprons, gloves, goggles and respirators; and avoidance of products that contain toxic metals, especially lead, cadmium, mercury, arsenic, chromates and manganese. Solvents to be avoided include benzene, carbon tetrachloride, methyl n-butyl ketone, n-hexane and trichloroethylene.

Figure 1. Silk screen printing with slot exhaust hood.

Michael McCann

Additional efforts designed to reduce the risk of adverse health effects associated with painting, drawing and printmaking include early and continuous education of young artists concerning the hazards of art materials, and laws mandating labels on art materials that warn of both short-term and long-term health and safety hazards.

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