Highlights of Noteworthy Decisions

Decision 1229 24
2026-06-30
C. Huras - P. Greenside - Z. Agnidis
  • Exposure (benzene)
  • Lymphoma (non-Hodgkin's)

The worker's estate appealed a WSIB decision denying entitlement for Non-Hodgkin's lymphoma (NHL), specifically diffuse large B-cell lymphoma (DLBCL), linked to occupational exposures from 1978 to 2019, with the Panel revising the exposure period based on employment records and submissions. The hearing was conducted in writing, and the second employer did not participate.

The Panel denied the appeal.
The Panel issued an interim decision requesting an independent Medical Assessor's opinion on the worker's NHL/DLBCL and its relation to occupational and non-occupational factors, including exposures to chemicals, radiation, and personal health history.
Dr. Markus concluded that among occupational agents, only benzene had robust evidence linking it to DLBCL, but the worker's exposure pattern and latency did not support causation. Other exposures such as trichloroethylene, uranium dust, ionizing radiation, diesel exhaust, and PCBs were not found to have a medically likely association with the worker's NHL/DLBCL.
The assessor identified the worker's prior thyroid cancer and obese body habitus as significant non-occupational risk factors for DLBCL, with obesity notably increasing risk. Exposure to radiation from a meteor crash was deemed negligible. These non-occupational factors likely outweighed occupational exposures in contributing to the disease.
The Panel gave significant weight to Dr. Markus' independent medical opinion and found that the occupational exposures did not make a significant contribution to the worker's NHL/DLBCL. The Panel noted consistency with other medical opinions and found that the worker's non-occupational factors were predominant contributors to the disease.
The Panel reviewed the worker representative's submissions disputing the medical assessor's conclusions but found that Dr. Markus was aware of the extent and nature of occupational exposures, including diesel fumes, TCE, uranium dust, and PCBs, and had thoroughly considered these in his report. The Panel did not agree that occupational exposures cumulatively caused the NHL/DLBCL.