Highlights of Noteworthy Decisions

Decision 975 23
2023-10-05
L. Petrykowski - D. Thomson - M. Tzaferis
  • Firefighter
  • Presumptions (firefighter)
  • Leukemia (chronic myelomonocytic)

The issue in this appeal brought by the worker's estate was whether the worker had initial entitlement for Chronic Myelomonocytic Leukemia (CMML) claimed to be related to his occupational exposure as a firefighter.

The appeal was denied.
The presumption that a prescribed condition is an occupational disease for firefighters is set out in section 4 of Ontario Regulation 253/07 made pursuant to the WSIA. CMML, a different form of leukemia, is not included and therefore the presumption did not apply in these circumstances. OPM Document No. 23-02-01, entitled "Cancers in Firefighters and Fire Investigators", similarly explains the potential application of the presumption, but again does not include CMML as a prescribed cancer. The claimed occupational disease in this case was therefore assessed on its own merits.
The Panel acknowledged that the worker was exposed to many substances in his firefighting career, which would have varied widely over the years, including composition, intensity and duration. However, there was no supportive evidence linking the nature of such exposures and CMML. There were two identified probable causes for CMML in the medical literature; however, there was an absence of evidence that work-related factors associated with radiation or chemotherapy were involved in the development of the worker's CMML.
While the Panel acknowledged that acute myeloid leukemia and CMML are both myelodysplastic conditions, it was noted that it would be incorrect for the Panel to accept CMML as being associated with firefighting on the basis of analogy. In addition, the circumstances did not support that work-related factors must have made a significant contribution to the development of CMML in the absence of other risk factors. It is not the responsibility of the Tribunal to determine the cause of a claimed condition in each case. The Panel determined there was insufficient evidence to conclude that the worker's exposure to any substance in his role as a firefighter played any identifiable role in the development of his CMML.