Highlights of Noteworthy Decisions

Decision 905 21
08/11/2021
M. Crystal
  • Benefit of the doubt
  • Cancer (lung)
  • Exposure (herbicide)

The deceased worker was employed by the accident employer, a hydro company, from 1963, when he was about 23 years old, until he retired from his employment in 1993. He was diagnosed with lung cancer with metastases in April 2010. He passed away due to lung cancer and related factors on April 18, 2011, at age 70. The worker was employed by the accident employer as a "forestry journey person" and his employment involved the mixing and application of herbicide spray at roadsides and hydro rights of way. The Board accepted that the worker had exposure to the herbicide 2, 4, 5 T and its contaminant 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) in the course of his employment.

In this appeal the estate of the worker was seeking entitlement for the worker's cancer on the basis that the worker's herbicide exposure was causally related to his cancer diagnosis.
The Vice-Chair considered that the Board's Occupational Disease Policy and Research Branch (ODPRB) published an Adjudicative Support document entitled "Herbicide 2,4,5-T and its Contaminant TCDD" which was based on findings of a Panel chaired by Dr. Ritter and submitted on June 13, 2013 (Ritter report). The document went on to note that since the Board did not have a policy to guide the adjudication of claims associated with the herbicide, it stated that, accordingly, the decision is based on the merits and justice of the individual case and that to be entitled to compensation for a disease the evidence must show that workplace exposures contributed significantly to the development of a disease.
The Vice-Chair interpreted the Executive Summary of the Ritter report as meaning that information about the impact of exposure to 2,4,5-T or TCDD provided by that report did not provide scientific certainty in relation to the question of whether exposure to 2,4,5-T or TCDD would result in an adverse health effect.
The Vice-Chair found that the worker had exposure to the herbicide 2,4,5-T and its contaminant TCDD, that the worker's exposure was significant and that it was more than de minimus; accepting that the information provided to the Board by the worker's son concerning the worker's exposure which supported that worker's exposure during the relevant years from 1963 to 1970 was part of the worker's regular work processes. Based on the medical evidence before him, the Vice-Chair also concluded that the relative risk of the worker developing lung cancer as a result of his smoking history was approximately equal to the relative risk of his developing lung cancer as a result of his occupational exposures.
The Vice-Chair therefore concluded that: the worker's occupational exposure to 2,4,5-T and its contaminant TCDD was sufficient to support entitlement; the strength of association between exposure to 2,4,5-T and its contaminant TCDD and the development of lung cancer required for entitlement was satisfied in this appeal; applying section 124(2) the question of whether the worker's smoking history overwhelmed the significance of the worker's occupational exposures in the development of the worker's lung cancer should be resolved in favor of the claim of the worker's estate. The worker therefore granted initial entitlement for lung cancer.
The appeal was allowed.