Blog Post #683 – Cancer Risks Probed

Excerpt from the OH&S Canada magazine

A ground-breaking study has found evidence linking female workers exposed to toxic chemicals with a heightened risk of breast cancer.

Six-year study, published in November 2012, focuses on the automotive industry in Windsor, Ontario. It concludes that workers in the farming and manufacturing sectors – namely the automotive plastics, metalworking, agriculture and food canning industries – face exposure to carcinogenic chemicals and endocrine disruptors, with women at an especially high risk. Women in the industry were exposed to a “toxic soup” of hormone-mimicking chemicals known to cause cancer. These chemicals solvents, heavy metals and bisphenol A.

Although labour and safety code standardize restrictions on exposure levels, the cumulative effect of working with a combination of chemicals make this occupational exposure issue particularly challenging, suggests Sari Sairenan, health and safety Dir. at the Canadian Auto Workers union in Toronto.

“We have exposure limits on single chemicals, but not when they are in unison,” she says. “How do you control your exposure to these hazards when the threshold limit value tells you that you are within the norms, but then you have five other chemicals that you are exposed to and they have synergistic effects?”

The American Chemistry Council argues in a statement that the findings are inconsistent with other research and the study “should not be used to draw any conclusions about the cause of cancer patterns in workers.”

Sandy Knight, who worked in Windsor in the plastics industry for 20 years, was diagnosed with breast cancer in 2001 and had to undergo a mastectomy. Knight says she believes her workplace contributed to her cancer. “It takes more than a day or two to affect you – it takes years. I went to work healthy at 19, I should have left their healthy,” Knight says, adding that she has no family history of breast cancer.

My opinion

The hazardous substances covered by the regulations are quite often present in the workplace and some combination. The exposure values, on the other hand, are based only on the health effects of a single agent in isolation. When workers simultaneously exposed to a number of substances, there are several possible ways for the components to interact:

• The health effects may be Independent. This means that they have different effects on different body systems, and exposure to each substance can therefore be assessed independently.

• The health effects may be Additive. In this case, the total health effect of the mixture is the total of the individual effects of the components.

• The health effects may be Synergistic. This means that the total health effect of the mixture is greater than the sum of the individual hazards, but not additive.

• The health effects may be Antagonistic. This means that the components of the mixture diminish each other’s toxic effects.

Note – it is common practice to assume the health effects are additive, unless there is evidence to the contrary.

Please ensure that your company reviews all information concerning workplace chemicals. Any further information may be found in Ontario regulation 833, the MSDS for the chemical or the American Conference of Governmental Industrial Hygienists. (ACGIH)

Thank you.

Remember – In Ontario, “ALL Accidents are Preventable”

HRS Group Inc. has a great team that can help you with all your health and safety needs including ‘Due Diligence’, ‘Chemical Safety Awareness’, WHMIS’ and ‘Standard Operating Procedures’. Contact Deborah toll free at 1-877-907-7744 or locally at 705-749-1259.

We can also be reached at 

‘Work’ and ‘Play’ safe.

Daniel L. Beal
CHSEP – Advanced Level
VP & Senior Trainer
HRS Group Inc.