Workers Health & Safety Centre

Cancer burden of diesel exhaust steep for exposed workers

Almost five per cent of all lung cancers diagnosed in Canadian males each year are attributable to occupational exposure to diesel engine exhaust (DEE).
This burden was uncovered by Occupational Cancer Research Centre (OCRC) researchers as part of a wider project to estimate the current overall burden of occupational cancers suffered by Canadian workers.
The OCRC released preliminary data recently estimating the proportion of new DEE-related diagnosed lung cancers to be 4.92% for males, 0.29% for females and 2.70% overall. Considering it can take years, even decades, from initial exposure to carcinogens, including DEE and the development of cancer, these researchers looked at data for the risk exposure period between 1961 and 2001. 
“Historically, workers exposed to diesel exhaust were mostly male—it makes sense then to see the attributable male fraction to be higher than for women,” says OCRC researcher Joanne Kim. 
Specifically, this relates to male-dominated industries such as mining, trucking and the operation of other heavy equipment.
Using the OCRC estimates and those published by the Canadian Cancer Society (CCS), more than 230 men and women in Ontario will be diagnosed this year with lung cancer because of their prior exposures to DEE at work. This will be a death sentence for many. Lung cancer is the leading cause of cancer death with a five year survival rate of just 17 per cent.
Another study, published in February 2014, reported an estimated 4.8 per cent of lung cancer deaths in the United States and the United Kingdom were due to occupational exposure to DEE.
“With millions of workers currently exposed to such levels (of DEE), and likely higher levels in the past, the impact on current and future lung cancer burden could be substantial,” according to authors of the US/UK report.  
These same researchers pointed out a significant risk to public health from environmental exposure to DEE. This was most significant for those living in urban environments nearest to highways.
Just two years ago in 2012, the International Agency for Research on Cancer (IARC) reclassified DEE from a probable to a definite human carcinogen in light of what they explained was “compelling scientific evidence”. They specifically cited links with lung and bladder cancer. 
With cleaner diesel engines and retrofit emission control systems for older engines now available, some workplaces have already taken steps to reduce harmful exposures. Some Ontario and Canadian communities have also sought relief from harmful DEE through various initiatives such as idling control by-laws and purchasing policies for public transit and other fleet vehicles. 
The Workers Health & Safety Centre offers a diesel exhaust fact sheet highlighting these and other precautions designed to protect workers and the public. The fact sheet also outlines numerous additional risks to health posed by DEE. This information and more including employer legal obligations to address the risk to health are also explored in the WHSC Vehicle Emissions training program.   
The OCRC will be releasing further information regarding their study entitled Burden of cancer attributable to occupational diesel engine exhaust exposure in Canada later in 2014.
Want to read more?
OCRC DEE research
Canadian Cancer Society lung cancer statistics
United States/United Kingdom DEE research
Recent workers comp case in New York State linking DEE to lung cancer
Want to read more from the WHSC about related training and information?
WHSC Diesel Exhaust fact sheet
WHSC Vehicle Emissions training
Want additional information about how the WHSC can help your workplace comply with the extensive training obligations mandated by health and safety law?
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