Highlights of Noteworthy Decisions

Decision 1372 19
02/01/2020
G. Dee
  • Cancer (lung)
  • Evidence (epidemiological)
  • Exposure (polycyclic aromatic hydrocarbons)
  • Smoking
  • Exposure (rubber)

The worker worked in the rubber industry from 1952 to 1984. He died of lung cancer in 2011, at age 76. The worker's estate appealed a decision of the Appeals Resolution Officer denying entitlement for the cancer.

The estate related the worker's lung cancer to workplace exposure to polycyclic aromatic hydrocarbons (PAHs) as well as asbestos.
A Board occupational hygienist found that the worker was exposed to low levels of rubber emissions and that exposure to asbestos was likely below the threshold limit value of 0.1 f/cc.
The estate raised concerns about the report of the hygienist, in that it reference a 1982 monograph from the International Agency of Research on Cancer (IARC), although there was no reference to a more recent 2012 monograph. The Vice-Chair accepted those concerns. The 2012 monograph concluded that there was an excess incidence of lung cancer among rubber manufacturing workers but that the evidence for a causal association with occupational exposure was limited. While the conclusions of the 2012 monograph were not specific to the worker's workplace, they more likely reflected the hazards to which the worker was exposed and the potential impact of those hazards at the time of the worker's employment. Between the 1982 monograph and the 2012 monograph, the 2012 monograph was likely more accurate and more reliable as it reflected studies of the rubber industry at the time of the worker's employment and, therefore, the worker's actual exposure.
Regarding asbestos exposure, the worker was not directly involved in production activities involving the use of asbestos. There was no reliable evidence to call into question the estimate of the Board's hygienist of exposure less than 0.1 f/cc.
The worker had a smoking history of 40-50 pack years.
Medical evidence indicated that the incidence of lung cancer in long-term smokers is roughly 20 times higher than in non-smokers, and that the incidence of lung cancer in rubber industry workers is roughly two time higher that people who are not rubber industry workers. It means that, if 20 people smoked in a manner similar to the worker and worked in the rubber industry and had lung cancer, 18 of those people would have lung cancer due to smoking, one person would have lung cancer due to workplace exposure and one person would have lung cancer as a result of other factors.
The worker's lung cancer was, therefore, considerably more likely to have been the result of his history of smoking than due to his employment in the rubber industry.
The appeal was dismissed.