Highlights of Noteworthy Decisions

Decision 1642 21
M. Crystal
  • Causation (medical evidence) (standard of proof)
  • Evidence (epidemiological)
  • Exposure (chemicals)
  • Exposure (lead)
  • Exposure (polycyclic aromatic hydrocarbons)
  • Exposure (radiation)
  • Exposure (polyvinyl chloride)
  • Initial entitlement (eligibility)
  • Cancer (brain) (glioblastoma multiforme)

The worker, through his estate, sought entitlement to benefits for glioblastoma multiforme (GBM), a type of brain cancer.

The appeal was denied.
The Vice-Chair agreed with statements contained in the Demers Report, which noted that all cancers are likely to have multiple causes, and that in some cases, there may be synergy between causes and the joint effects can be much greater. The Vice-Chair noted that where the evidence does not disclose that it is probable that an occupational exposure made a significant contribution to the development of the cancer, and unless there is evidence about a particular synergy existing between the occupational exposure and another factor which is present, then it would be speculative to allow entitlement on the basis of a synergy between or among factors based on the general proposition that all cancers are likely to have multiple causes. The Vice-Chair determined that the medical and epidemiological evidence in this case did not indicate a synergistic effect that would support, on a balance of probabilities, that the worker's GBM was due to work-related factors.
In summary, the Vice-Chair concluded that the case materials did not provide information supporting the conclusion that the worker's occupational exposures or potential exposures made a significant contribution to the worker's GBM in relation to following agents: lead; polyvinyl chloride (PVC/PVMs); Polycyclic Aromatic Hydrocarbons (PAHs) including exposures to solvents, combustion products and other process emissions; mercury; arsenic; other environmental agents listed in the Advisory Committee Report, such as asbestos, copper, hydrogen cyanide, chromic acid, dicumyl peroxide, and other agents; exposures from TIG welding; and, ionizing radiation.
Furthermore, the estate's representative submitted that the evidence of the rate of incidence of brain cancer at the employer's production facility, around the period of the worker's employment there, should be considered. It was his submission that the rate of incidence of brain cancer of individuals employed at the facility from 1976 to 2018 greatly exceeded the expected rate of the incidence of brain cancer in the general population, and that this provided evidence that the worker's occupational exposures, while employed by the accident employer, made a significant contribution to his brain cancer.
From the information presented in the case materials, the Vice-Chair determined that he was unable to give weight to the submissions, as they did not appropriately take into account the number of persons to be studied or the duration of such a study, which would be necessary to capture the six claims relating to brain cancer arising from the employer's facility that were registered with the Board from 1976 to 2018.
The Vice-Chair noted that where there is a lack of evidence supporting the cause of the cancers, other evidence, such as the circumstantial evidence provided by the fact that the cancers occurred at the same employment location and at contemporaneous times, might nevertheless provide the basis of a finding that the cancers were occupationally related. However, the circumstances in this case differed. The submissions indicated that six brain cancer claims (which may have involved different histopathologic types of brain cancer) were registered to the employer's production facility over 42 years. The employer's production facility in this case encompassed a large physical area, apparently about the size of a city block, and included multiple buildings and departments. Many of the buildings presented diverse environments, including a nuclear facility in a corner of the area. The employer's facility also employed thousands of workers (the actual number was not available), over a period of 42 years. The Vice-Chair determined that this information did not provide significant circumstantial evidence to conclude, in the absence of stronger epidemiological or other scientific evidence related to causation of the brain cancer, that the worker's occupational exposures at the employer's facility made a significant contribution to the development of his GBM.
Lastly, the worker's claim to the Board was not related to his work as a voluntary firefighter, and it was exclusively related to his entitlement arising from his occupational exposures while employed by the accident employer, a company in the private sector. The Board had not provided a final decision on the question of whether the worker was entitled to benefits in relation to his service as a volunteer firefighter, and the Vice-Chair lacked jurisdiction to address the question. Therefore, the worker could not obtain the benefit of the statutory presumption included in the Act in favour of firefighters.