A presentation on Ministry of Labour website: http://www.labour.gov.on.ca/english/hs/pdf/workbook.pdf, 参见9-10页 Rights of the worker: You also have a right to refuse to do unsafe work if you have reason to believe it puts you or a fellow worker in danger.
If you had thought that was a serious matter, why did you tolerant it , for two years? It's better to escalate to PM or Health and Safety Joint Meeting (If your company had). I agree with #6.