Interpreting the human health data in the printing, commercial photographic processing and reproduction industry is no simple matter, since the processes are complex and are continually evolving - sometimes dramatically. While the use of automation has substantially reduced manual work exposures in modernized versions of all three of the disciplines, work volume per employee has increased substantially. Furthermore, dermal exposure represents an important route of exposure for these industries, yet is less well characterized by available industrial hygiene data. Case reporting of the less serious, reversible effects (e.g., headaches, nose and eye irritation) is incomplete and under-reported in the published literature. Despite these challenges and limitations, epidemiological studies, health surveys and case reports provide a substantial amount of information regarding the health status of workers in these industries.

Printing Activities

Agents and exposures

Today there are five categories of printing processes: flexography, gravure, letterpress, lithography and screen printing. The type of exposure that can occur from each process is related to the types of printing inks that are used and to the likelihood of inhalation (mists, solvent fumes and so on) and penetrable skin contact from the process and cleaning activities employed. It should be noted that the inks are composed of organic or inorganic pigments, oil or solvent vehicles (i.e., carriers), and additives applied for special printing purposes. Table 1 outlines some characteristics of different printing processes.

Table 1. Some potential exposures in the printing industry

Mortality and chronic risks

Several epidemiological and case-report studies exist on printers. Exposure characterizations are not quantified in much of the older literature. However, respirable-size carbon black particles with potentially carcinogenic polycyclic aromatic hydrocarbons (benzo(a)pyrene) bound to the surface have been reported in rotary letterpress printing machine rooms of newspaper production. Animal studies find the benzo(a)pyrene tightly bound to the surface of the carbon black particle and not easily released to lung or other tissues. This lack of “bioavailability” makes it more difficult to determine whether cancer risks are feasible. Several, but not all, cohort (i.e., populations followed through time) epidemiological studies have found suggestions of increased lung cancer rates in printers (table 2). A more detailed assessment of over 100 lung cancer cases and 300 controls (case-control type study) from a group of over 9,000 printing workers in Manchester, England (Leon, Thomas and Hutchings 1994) found that the duration of work in a machine room was related to lung cancer occurrence in rotary letterpress workers. Since smoking patterns of the workers are not known, direct consideration of the role of occupation in the study is unknown. However, it is suggestive that rotary letterpress work may have presented a lung cancer risk in previous decades. In some areas of the world, however, older technologies, such as rotary letterpress work, may still exist and thus afford opportunities for preventive assessments, as well as installation of appropriate controls where needed.

* Standardized Mortality Ratios (SMR) = number of observed deaths divided by number of expected deaths, adjusted for age effects over the time periods in question. An SMR of 1 indicates no difference between observed and expected. Note: 95% confidence intervals are provided for the SMRs.

NGA = National Graphical Association, UK

NATSOPA = National Society of Operative Printers, Graphical and Media Personnel, UK.

Sources: Paganini-Hill et al. 1980; Bertazzi and Zoccheti 1980; Michaels, Zoloth and Stern 1991; Leon 1994; Svensson et al. 1990; Sinks et al. 1992.

Another group of workers that has been substantially studied are lithographers. Modern lithographers’ exposure to organic solvents (turpentine, toluene and so on), pigments, dyes, hydroquinone, chromates and cyanates has been markedly reduced in recent decades due to the use of computer technologies, automated processes and changes in materials. The International Agency for Research on Cancer (IARC) recently concluded that occupational exposures in printing process are possibly carcinogenic to humans (IARC 1996). At the same time, it may be important to point out that IARC’s conclusion is based on historical exposures which, in most cases, should be significantly different today. Reports of malignant melanoma have suggested risks about twice the expected rate (Dubrow 1986). While some postulate that skin contact with hydroquinone could be related to melanoma (Nielson, Henriksen and Olsen 1996), it has not been confirmed in a hydroquinone manufacturing plant where significant exposure to hydroquinone was reported (Pifer et al. 1995). However, practices which minimize skin contact with solvents, particularly in plate cleaning, should be emphasized.

Photographic Processing Activities

Exposures and agents

Photographic processing of black-and-white or colour film or paper can be done either manually or by essentially fully automated larger-scale processes. The selection of the process, chemicals, working conditions (including ventilation, hygiene and personal protective equipment) and workload can all influence the types of exposures and potential health issues of the occupational environment. The types of jobs (i.e., processor-related tasks) having the greatest potential for exposure to key photographic chemicals, such as formaldehyde, ammonia, hydroquinone, acetic acid and colour developers, are noted in table 3. The typical photographic processing and handling work flow is depicted in figure 1.

Table 3. Tasks in photographic processing with chemical exposure potential

Figure 1. Photographic processing operations

In more recently designed high-volume processing units, some of the steps in the workflow have been combined and automated, making inhalation and skin contact less likely. Formaldehyde, an agent that has been used for decades as a colour image stabilizer, is diminishing in concentration in photographic product. Depending on the specific process and site environmental conditions, its air concentration may range from non-detectable levels in the operator’s breathing zone up to about 0.2 ppm at machine dryer vents. Exposures can also occur during equipment cleaning, making or replenishing stabilizer fluid and unloading processors, as well as in spill situations.

It should be noted that while chemical exposures have been the primary focus of most health studies of photographic processors, other work environmental aspects, such as reduced light, materials handling and the postural demands of the job, are also of preventive health interest.

Mortality risks

The only published mortality surveillance of photographic processors suggests no increased risks of death for the occupation (Friedlander, Hearne and Newman 1982). The study covered nine processing laboratories in the United States, and was updated to cover 15 more years of follow-up (Pifer 1995). It should be noted that this is a study of over 2,000 employees who were actively working at the beginning of 1964, with over 70% of them having had at least 15 years of employment in their profession at that time. The group was followed for 31 years, through 1994. Many exposures relevant earlier in the careers of these employees, such as carbon tetrachloride, n-butylamine, and isopropylamine, were discontinued in the laboratories over thirty years ago. However, many of the key exposures in modern laboratories (i.e., acetic acid, formaldehyde and sulphur dioxide) were also present in previous decades, albeit at much higher concentrations. During the 31-year follow-up time period, the standardized mortality ratio was only 78% of that expected (SMR 0.78), with 677 deaths in the 2,061 workers. No individual causes of death were significantly increased.

The 464 processors in the study also had reduced mortality, whether compared to the general population (SMR 0.73) or to other hourly workers (SMR 0.83) and had no significant increases in any cause of death. Based on available epidemiological information, it does not appear that photographic processing presents an increased mortality risk, even at the higher concentrations of exposure likely to have been present in the 1950s and 1960s.

Pulmonary disease

The literature has very few reports of pulmonary disorders for photographic processors. Two articles, (Kipen and Lerman 1986; Hodgson and Parkinson 1986) describe a total of four potential pulmonary responses to processing workplace exposures; however, neither had quantitative environmental exposure data to assess the measured pulmonary findings. No increases in longer-term illness absence for pulmonary disorders was identified in the only epidemiological review of the subject (Friedlander, Hearne and Newman 1982); however, it is important to note that illness-absences of eight consecutive days were required in order to be captured in that study. It appears that respiratory symptoms can be aggravated or initiated in sensitive individuals by exposure to higher concentrations of acetic acid, sulphur dioxide and other agents in photographic processing, should ventilation be poorly controlled or errors occur during mixing, resulting in the release of undesired concentrations of these agents. However, work-related pulmonary cases have only rarely been reported in this occupation (Hodgson and Parkinson 1986).

Acute and subchronic effects

Contact irritative and allergic dermatitis has been reported in photographic processors for decades, starting with the initial use of colour chemicals in the late 1930s. Many of these cases occurred in the first few months of a processor’s exposure. The use of protective gloves and improved handling processes have substantially reduced photographic dermatitis. Eyesplashes with some photochemicals can present risks of corneal injury. Training on eyewash procedures (flushing eyes with cool water for at least 15 minutes followed by medical attention) and the use of protective eyewear is particularly important for photoprocessors, many of whom may work in isolation and/or in diminished light environments.

Some ergonomics concerns exist regarding the operation of rapid-turnaround, high-volume photographic processing units. The mounting and dismounting of large rolls of photographic paper can present a risk of upper back, shoulder and neck disorders. The rolls can weigh 13.6 to 22.7 kg (30 to 50 pounds), and may be awkward to handle, depending partly on access to the machine, which can be compromised in compact work sites.

Injuries and strains to the staff can be prevented by proper staff training, by provision of adequate access to the rolls and by considerations of human factors in the general design of the processing area.

Prevention and methods of early detection of effects

Protection from dermatitis, respiratory irritation, acute injury and ergonomic disorders starts with the recognition that such disorders can occur. With proper worker information (including labels, material safety data sheets, protective equipment and health protection training programmes), periodic health/safety reviews of the worksetting and informed supervision, prevention can be strongly emphasized. In addition, the early identification of disorders can be facilitated by having a medical resource for worker health reporting, coupled with targeted voluntary periodic health assessments, focusing on respiratory and upper extremity symptoms in questionnaires and direct observation of exposed skin areas for signs of work-related dermatitis.

Because formaldehyde is a potential respiratory sensitizer, a strong irritant and a possible carcinogen, it is important that each workplace be assessed to determine where formaldehyde is used (chemical inventory and material safety data sheet reviews), to assess air concentrations (if indicated by materials used), to identify where leaks or spills could occur and to estimate the quantity that could be spilled and the concentration generated in worst-case scenarios. An emergency response plan should be developed, conspicuously posted, communicated and periodically practised. A health and safety specialist should be consulted in the development of such an emergency plan.

Reproduction Activities

Agents and exposures

Modern photocopying machines emit very low levels of ultraviolet radiation through the glass cover (plenum), generate some noise and may emit low concentrations of ozone during the processing activity. These machines use a toner, primarily carbon black (for black-and-white printers), to produce a dark print on the paper or transparent film. Thus, potential routine exposures of health interest for photocopy operators can include ultraviolet radiation, noise, ozone and possibly toner. In older machines, toner could be an issue during replacement, although modern self-contained cartridges have substantially reduced potential respiratory and skin exposure.

The degree of ultraviolet radiation exposure that occurs through the copier machine platen glass is very low. The duration of a photocopier flash is approximately 250 microseconds, with continual copying making about 4,200 flashes per hour - a value that can vary depending upon the copier. With the glass platen in place, the emitted wavelength ranges from 380 to about 396 nm. UVB does not typically result from copier flashes. UVA measurements maximally recorded at the glass paten average about 1.65 microjoule/cm² per flash. Thus, the maximum 8-hour near-UV spectral exposure from a continuously run photocopier making about 33,000 copies per day is approximately 0.05 joules/cm² at the glass surface. This value is only a fraction of the threshold limit value recommended by the American Conference of Governmental Industrial Hygienists (ACGIH) and appears to present no measurable health risk, even in such exaggerated exposure conditions.

It should be noted that certain workers may be at higher risk for UV exposures, including those with photosensitive conditions, people using photosensitizing agents/medicines and people with impaired ocular pupils (aphakics). Such people are usually advised to minimize their UV exposures as a general precautionary measure.

Acute effects.

The literature does not reveal many acute effects meaningfully related to photocopying. Older, insufficiently maintained units could emit detectable ozone concentrations if run in poorly vented settings. While eye and upper respiratory irritation symptoms have been reported from workers in such environments, the minimum manufacturer specifications for space and ventilation, coupled with newer copier technology, have essentially eliminated ozone as an emission issue.

Mortality risks.

No studies were found that described mortality or chronic health risks from long-term photocopying.

Prevention and early detection

By simply following manufacturers’ recommended use, photocopying activity should not present a workplace risk. Individuals experiencing an aggravation of symptoms related to intense use of photocopiers should seek health and safety advice.

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