While US authorities were warning of the potential cancer risk from exposures to methylene chloride (dichloromethane), the UK Health and Safety Executive (HSE) had nothing to say for itself. Pointing out at the US Environmental Protection Agency had declared methylene chloride a “probable human carcinogen”, Hazards magazine said HSE had “said nothing.” It added: “But we know the UK government ‘Expert Committee on Carcinogenicity’ where there are no trade union representatives have recently declared methylene chloride to be a human carcinogen.” Hazards said the new exposure limit of 100 parts per million introduced in January 1886 “must now be reduced” because of the emerging evidence of a cancer risk. In 1999 IARC said there was sufficient evidence to conclude the solvent was carcinogenic in animals and said it was “possibly carcinogenic to humans.” In 2014, the UK was the only European Union government to request a derogation for certain processes from the EU wide ban on methylene chloride’s use a paint stripper.
Toxic paint stripper: Methylene chloride, Hazards, number 10, September 1986.
The US Environmental Protection Agency (EPA) issued guidance to help motor mechanics avoid asbestos exposure from brake and clutch linings. In August 2003, the law firm of Morgan, Lewis & Bockius LLP filed a Data Quality Act (DQA) petition with EPA challenging the agency’s 1986 publication. The attorney from Morgan, Lewis & Bockius asked the EPA to either stop disseminating the asbestos disease prevention guide, and either alert the public that the booklet is scientifically outdated, or review the latest scientific literature and update the booklet. The company did not reveal the identity of its client, although it subsequently became clear these were firms defending asbestos cases compensation cases. EPA caved in, replacing the 15 page document with a pared back two page draft replacement. Industry backed scientists then pitched in, claiming a revision should acknowledge their findings that asbestos from brake linings was “innocuous.” According to David Michaels and Celeste Monforton “defendants in litigation involving asbestos-containing friction products have successfully modified an official EPA document which they viewed as “alarmist and inflammatory.”
Guidance for preventing asbestos disease among motor mechanics, US EPA, June 1986.
David Michaels and Celeste Monforton. How litigation shapes the scientific literature, Journal of Law and Policy, volume 15, issue 3, pages 1137-1169, 2007.
Following a lengthy union campaign, the Health and Safety Executive (HSE) in 1984 recognised that ‘mineral wool’ (glass, rock or slag insulation wools, made from mineral fibres) could no longer be regarded as ‘nuisance dusts’. In 1986, HSE issued a guidance note (EH46) tightening up working practices to reduce the risks, with exposures to be kept below a control limit of 5mg/m3. The precautions had been delayed for eight years at this point – they had been adopted by an HSE working party in 1979. In 1994, mineral fibres were added to the US government’s official list of recognised human carcinogens.
Exposure to mineral wood, guidance note EH40, June 1986.
Report in Hazards magazine, number 14, June 1987.
An International Agency for Research on Cancer (IARC) study of the health risks of man-made mineral fibres has concluded the findings do suggest a possible link with lung cancer. After over a decade of pressure from unions and mounting animal evidence of a cancer risk, the industry embarked on two studies, in Europe and the USA. IARC concluded that after reviewing the evidence including these two industry papers, they “support the inference that MMMF – as present in the environmental conditions of early slag-wool/rock-wool production – may have played a role in the causation of lung cancer.”
R Saracci. Contributions to the IARC (International Agency for Research on Cancer) study on mortality and cancer incidence among man-made mineral fiber production workers, Scandinavian Journal of work Environment and Health, volume 12, supplement 1, pages 5-93, 1986. See the mineral fibre themed supplement.
Lorry drivers and other workers exposed regularly to vehicle exhaust fumes are at greater risk of contracting bladder cancer, a US study found. Researchers investigated about 2,000 cases of bladder cancer in men and attempted to identify associations with their work. “Our findings indicated that males usually employed as truck drivers or deliverymen have a statistically significant, 50 per cent increase in risk of bladder cancer,” the study found. “Overall, a statistically significant trend in risk with increasing duration of truck driving was observed. This trend was particularly consistent for drivers first employed at least 50 years prior to diagnosis. Of these, truck drivers employed 25 years or more experienced a 120 per cent increase in risk. Elevations in risk were also suggested for taxicab and bus drivers.” In June 2012, IARC rated diesel exhaust fume as a group 1 human carcinogen.
DT Silverman and others. Motor exhaust related occupations and bladder cancer, Cancer Research, volume 46, number 4, part 2, pages 2113-2116, 1986.
A US study of over 7,000 women union members in the meat industry found that those working in supermarket meat departments had a 3-fold increased risk of death from myeloid leukaemia and non-Hodgkin’s lymphoma. These women, together with women employed in chicken slaughtering factories and meat-packing plants (slaughterhouses), also had a greater risk of lung cancer than those employed in non-meat work. The authors note: “The findings need to be confirmed, but the excess of lung cancer we observed is consistent with reports of an excess of lung cancer in butchers and meatcutters from the analysis of national statistics over different periods in England and Wales, Denmark and Sweden, and also from other studies.”
ES Johnson and others. Occurrence of cancer in women in the meat industry, British Journal of Industrial Medicine, volume 43, number 9, pages 597-604, 1986.
US researchers who investigated the increased risk of lung cancer in workers exposed to chromium VI found that those most at risk, with over three times the risk of dying from the disease, were those who had worked longer in the plants. The authors said this was probably due to their higher cumulative exposure. Because of this, they suggested exposure limits were insufficiently protective, as they didn’t take account of this cumulative effect, noting “these results suggest a potential excess risk of death from lung cancer among US workers exposed to the current permissible exposure limit (PEL) for hexavalent chromium.”
ER Braver and others. An analysis of lung cancer risk from exposure to hexavalent chromium, Teratogenesis, carcinogenesis and metagenesis, volume 5, issue 5, pages 365-378, 1985.
A German research paper described four case of the asbestos cancer mesothelioma in brake mechanics. The cancer had been caused by asbestos dust, a component of brake (and clutch) linings. In 2014, the asbestos industry was still disputing this link.
R Paur and others. Pleural mesothelioma after asbestos dust exposure in brake repair work in automobile repair workshops: case observation, Praxis und Klinik der Pneumologie, volume 39, number 10, pages 362-366, 1985.
Two studies have found excesses of cancers in people working with cadmium. Workers at a Colorado cadmium smelting plant were fund to have double the expected death rate from lung cancer. They noted: “A statistically significant dose-response relationship was observed between lung cancer mortality and cumulative exposure to cadmium.” This was despite a mandatory respirator programme and improvements in ventilation during the period covered by the study. A second study at a British cadmium-nickel battery plant showed increases in both lung and prostate cancers. While the findings were not statistically significant, the authors conclude there is a definite link between cadmium exposures and death from lung and prostate cancers. The paper notes: “A combination of all the available data from the most recent follow up of causes of death among cadmium workers in six different cohorts shows 28 cases of prostatic cancer (SMR = 162) and 195 cases of lung cancer (SMR = 121). This new analysis suggests that long term, high level exposure to cadmium is associated with an increased risk of cancer.”
MJ Thun and others. Mortality among a cohort of US cadmium production workers – an update. Journal of the National Cancer Institute, volume 74, pages 325-333, 1985.
CG Elinder and others. Cancer mortality of cadmium workers, British Journal of Industrial Medicine
A study of cause of death among 6,678 rubber production workers whose exposure to 25 solvents could be traced confirmed a cancer association. Exposure to carbon tetrachloride, xylene, carbon disulphide, ethyl acetate, acetone and hexane was related to increases in leukaemia and lymphosarcoma. Workers exposed to carbon tetrachloride had a 15 times greater risk and those exposed to carbon disulphide had a nine times greater risk of dying of leukaemia. In an earlier study the same group of workers were found to have increased deaths from stomach and prostate cancer, but these were not found to be related to solvent exposure.
TC Wilcosky and others. Cancer mortality and solvent exposures in the rubber industry, American Industrial Hygiene Association Journal, volume 45, number 12, page 809, 1984.