This commentary addresses questions about asbestos-related cancer recognition. According to Andrew Watterson (2014): “It has much wider importance in terms of
the interrelationship between scientific knowledge and the different disciples relevant to occupational cancer research. Challenges the view that asbestos cancers were recognized epidemiologically only in the 1960s and not the 1940s. Notes pathology studies between the 1930s and the 1950s often carried greater weight than epidemiological ones.”
David Egilman. Public health and epistemology, American Journal of Industrial Medicine, volume 22.3, pages 457-459, 1992.
The Industrial Injuries Advisory Council (IIAC) recommend that the government “prescribe lung cancer where there is silicosis in certain jobs”. The recommendation was accepted by the government and implemented in April 1993.
Lung Cancer in relation to occupational exposure to silica, Cm 2043, IIAC, September 1992.
On 1 January 1992, the Health and Safety Executive (HSE) introduced a weaker permissible exposure standard for crystalline silica. The new maximum exposure limit for respirable quartz was 0.4mg/m3 (up from a recommended limit of 0.1mg/m3) and with the same standard applying to cristabolite and tridymite (0.05 mg/m3). According to Hazards magazine: “It has become clear that the quarry industry demanded an weakening of exposure standards because it claimed that it could not meet the existing standards. Rather than stand firm, the HSE has caved in and accepted the weaker standard, claiming that its new guidance notes would ensure that where better standards had already been achieved they would be maintained.” At the time IARC said there was limited evidence crystalline silica caused cancer in humans (IARC, 1987); it was subsequently upgraded by IARC to a group 1 proven cause of cancer in humans. HSE research in 2009 found HSE had dramatically over-estimated levels of industry compliance with silica exposure standards and under-estimated the numbers of workers over-exposed. At this point the exposure standard had reverted to 0.1mg/m3.
Reported in Hazards, number 38, 1992.
Work can be a major contributor to cancer mortality on certain occupational groups. This study found 40 per cent of the lung and bladder cancer cases in certain industrial groups can be caused by occupational exposures.
Vineis P and Simonato L. Proportion of lung and bladder cancers in males resulting from occupation: a systematic approach, Archives of Environmental Health, volume 46, pages 6-15, 1991.
The UK Control of Substances Hazardous to Health Regulations 1988, which took effect in January 1990, put a new emphasis on substitution of dangerous chemicals and processes with less dangerous ones. This mirrored the approach promoted by unions for years, including campaigns to rid workplaces of asbestos, carcinogenic dyes, the weedkiller 2,4,5-T, wood preservatives, organic solvents and isocyanates. It also brought UK legislation closer to that in in many developed nations in Europe and better practice in North America. But Hazards magazine warns to secure real improvements requires information, organisation and union vigilance.
Safer alternatives, Hazards, number 31, December 1990.
An investigation conducted in the Swedish glass industry found workers in the industry may be at an increased risk of death from lung or colon cancer. The study, which was based at the largest glassworks in Sweden, traced the cause of death of over 600 past employees. Lung cancer deaths were 1.4 to 2.4 times higher than the national or county figures. Colon cancer deaths were at approximately 2.5 times the level in the general population. The findings support those of several other reports.
G Wingren and V Englander. Mortality and cancer morbidity in a cohort of Swedish glassworkers, International Archives of Occupational and Environmental Health, volume 62, pages 253-257, 1990.
Two US studies reported increased incidence of certain cancers among male firefighters. An investigation of cancer cases in the US state of Massachussetts between 1982 and 1986 found the incidence of melanoma was three times greater in firefighters than in other occupations. Bladder cancer and non-Hodgkin’s lymphoma were also more frequent among firefighters, with an incidence that was 1.6 times that of other occupations. A second study looked only at cases of cancer that resulted in death. One 2,000 Seattle firefighters employed between 1945 and 1983 were investigated. Compared to other occupations, the researchers found increases in deaths among firefighters from the blood cancers leukaemia and myeloma. For firefighters with at least 30 years service, death from leukaemia was increases five times and myeloma nine times. The authors of both studies identified benzene, polycyclic aromatic hydrocarbons (PAHs) and asbestos as key carcinogen exposures. A third report looking at birth defects in the offspring of firefighers identified about 50 chemical exposures faced by firefighters, many of the substances linked to cancer. Many jurisdictions, notably in the US, Canada and Australia, have since introduced presumptive legislation, granting compensation automatically to many firefighters suffering a number of named cancers. In 2015, no such compensation was available to firefighters in the UK.
SR Sama and others. Cancer incidence among Massachussetts firefighters, 1982-86, American Journal of Industrial Medicine, volume 18, issue 1, pages 47-54, 1990.
N Heyer and others. Cohort mortality study of Seattle firefighters: 1945-1983, American Journal of Industrial Medicine, volume 17, issue 4, pages 493-504, 1990.
AF Olshan and others. Birth defects among offspring of firemen, American Journal of Epidemiology, volume 131, pages 312-321, 1990.
The association between employment in motor exhaust-related occupations and the risk for lung cancer was examined in 2,291 male cases of lung cancer and 2,570 controls in data pooled from three US case control studies carried out by the National Cancer Institute between 1976 and 1983. The researchers concluded that workers in motor-exhaust related occupations had a 50 per cent higher rate of lung cancer than in other occupations, after accounting for smoking. The authors note: “The 50 per cent excess risk for lung cancer associated with employment in motor exhaust-related occupations could not be explained by greater use of cigarettes or by other occupational exposures among these workers.”
R Hayes and others. Lung cancer in motor exhaust-related occupations, American Journal of Industrial Medicine, volume 16, number 6, pages 685-695, 1989.
Researchers in the US identified a link between paternal exposure to low frequency electromagnetic fields (EMFs) at work and higher rates of nervous system cancers in their offspring. The study investigated 499 childhood nervous system cancers occurring in Texas over a 17 year period, comparing them to 998 randomly selected controls. Children who had died of these cancers were 1.6 times more likely to have had fathers whose work involved exposure to low frequency EMFs. Highlighted occupations were electricians, where the odds ratio was 3.5, and those involved in electronic component manufacture and assembly. The authors noted: “The additional presence of chemical exposures in these diverse occupations and industries must also be considered.”
CC Johnson and MR Splitz. Childhood nervous system tumours: An Assessment of Risk Associated with Paternal Occupations Involving Use, Repair or Manufacture of Electrical and Electronic Equipment, International Journal of Epidemiology, volume 18, number 4, pages 756-762, 1989.
Petroleum refinery workers have an excess of skin cancer and leukaemia, with this work rated by the International Agency for Research on Cancer as probably carcinogenic in humans (group 2A). Petrol, heavy fuel oil and marine diesel were classified as possibly carcinogenic to humans (group 2B), with some evidence of excess of cancer of the stomach and pancreas (petrol) and lung and prostate (diesel). IARC found there was insufficient evidence to categorise jet fuels, light fuel oils and crude oil as human carcinogens, despite supportive animal evidence.
Occupational exposure in petroleum refining: Crude oil and major petroleum fuels, Monograph volume 45, IARC, 1989.