Lung Cancer Among Workers in the Uranium Mining Industry


Primary cancers of the trachea, bronchus and lung among workers previously employed in uranium mining in Ontario are recognized as occupational diseases under the Workplace Safety and Insurance Act. They are both characteristic of uranium mining and result from exposure to ionizing radiation relating to the uranium mining industry.


Among those who have sustained occupational radiation exposure in Ontario mines, the following can provide persuasive evidence that the worker's cancer of the trachea, bronchus or lung (ISCD9 162; ISCD10 C33, C34)* is work-related

  • a radiation index of at least 33 for workers diagnosed with these cancers before 55 years of age
  • a radiation index of at least 40 for workers diagnosed with these cancers between 55 and 64 years of age
  • a radiation index of at least 100 for workers diagnosed with these cancers at 65 years of age or older.

*International Statistical Classification of Diseases (Ninth and Tenth Revisions).

The radiation index is a time-weighted index of the worker's occupational radiation exposure measured in cumulative Working Level Months (WLM). In calculating the radiation index, all WLM sustained 5-14 years before diagnosis of the cancer and half of WLM sustained 15 or more years before the diagnosis of the cancer are cumulated. All WLM exposures sustained in Ontario employment exposures, be it in uranium mines and mills or in gold mines, are included in the calculation of the radiation index.

A worker's non-smoking status can provide evidence of work-relatedness in the weighing of evidence on the individual merits and justice of the case.

Application date

This policy applies to all claims with an accident date (the date of diagnosis) on or after 1947.

Document History

This document replaces 16-02-04.


Legislative Authority

Workplace Safety and Insurance Act, 1997, as amended
Sections 15(1) - (2)


Board of Directors
#8(XXXIV), June 10, 2004, Page 6622