'A big deal'

Recent classification of diesel exhaust as carcinogen could prompt changes in the workplace

On the heels of recent studies linking diesel exhaust exposure to cancer, the World Health Organization’s International Agency for Research on Cancer on June 12 declared diesel fumes carcinogenic and stressed that workers in the mining, trucking and vehicle maintenance industries could be most at risk.

Since 1988, diesel exhaust had been classified as “probably” carcinogenic to humans, which meant evidence of carcinogenicity was limited. The strongest evidence is for diesel fumes causing lung cancer, but a positive (albeit weaker) association also exists between the fumes and bladder cancer, according to IARC Director Christopher Wild. “The findings from this meeting send a very strong signal to governments and policymakers that diesel exhaust can cause cancer in people,” Wild said.

He stopped short of specifically calling for tighter regulations, but said individual governments and policymakers should take IARC’s recent reclassification into account. When these groups decide how to move forward, Wild said the decision should be balanced with a number of other factors, including the benefits of using newer technology, the levels of exposures, and known health effects such as respiratory disease or asthma attacks.

Growing evidence may prompt action

When announcing the new classification, IARC cited a recent NIOSH study on underground coal miners that found heavy exposure to diesel exhaust was linked to an increased risk of cancer.

Additionally, the Health and Safety Executive, Great Britain’s independent regulatory agency, released a discussion paper in May based on 2005 data estimating that in Great Britain, 652 lung and bladder cancer deaths were attributed to occupational diesel exposure, and more than 100,000 workers were exposed.

IARC’s reclassification of diesel exhaust is “going to be a big deal,” said Andrew Buchanan, a St. Louis-based attorney with Buchanan, Williams and Stilley. Buchanan, who represents injured truck drivers, believes that “as more and more truck drivers understand the connection to their health, they’ll start to demand more from their employers.”

The reclassification may not have an immediate effect on regulators, but it can make employers more conscientious over time about the hazards their employees face, Buchanan noted. He said some employers may begin investing in greater worker protections, but in his experience many changes are not implemented until employers are faced with the risk of financial responsibility for the injury or illness.

Although his firm has not taken on any cases from truckers alleging their cancer was caused by exhaust fumes, and he has heard of only a couple of cases occurring elsewhere, Buchanan speculates that more truckers may come forward as they learn about the fumes’ carcinogenic effects.


Employers have options to help mitigate the risk diesel exhaust has on workers. The best way to eliminate the exhaust, suggests the New York Committee for Occupational Safety and Health, is by replacing diesel engines with ones that use cleaner energy sources, such as natural gas or electricity. Aside from using alternative energy sources, employers can take other steps to reduce worker exposure. “A lot of the heavy exposure in places like garages and workshops can be easily prevented through ensuring that engines are always turned off when idle, installing proper exhaust ventilation, and by scheduling regular preventative maintenance,” a spokesperson for the Trade Union Congress, a United Kingdom union group, said in a statement.

Personal protective equipment such as respirators should be a last-resort control measure, as they are least effective at helping mitigate the risk, according to NYCOSH. If PPE is used, employers should ensure workers are trained in how to use respirators and fit-tested for the greatest effect.

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