(CNN) -- Exhaust from diesel engines can cause cancer, a prominent global cancer group that's part of the World Health Organization said Tuesday.
While the International Agency For Research On Cancer (IARC) has no power to set or enforce rules, many governments look to it for guidance and the decision could put pressure on those governments to introduce stricter limits on emissions, especially to protect workers who are exposed to diesel exhaust while on the job.
The IARC has for more than two decades classified diesel engine exhaust as a "probable" carcinogen -- a cancer-causing agent -- but until recently there was no clear evidence linking it to higher cancer rates.
This winter, however, two studies were published based on research involving more than 12,000 mine workers done by the National Cancer Institute and the National Institute for Occupational Safety and Health, known as the Diesel Exhaust in Miners Study, or DEMS.
Together, the two new papers found an increase in lung cancer rates among workers exposed to diesel exhaust underground, with greater exposure linked to steadily higher cancer rates. In workers with the highest exposure, deaths from lung cancer tripled in one study, and increased five-fold in the other.
It's unclear whether the decision will affect rules in the United States. Since 2008, the Mine Safety and Health Administration has enforced a limit of 160 micrograms of total carbon per cubic meter for workers in U.S. mines. "Total carbon" is used as a marker for diesel fumes.
The IARC didn't specify a level at which diesel fumes are harmful, but data from DEMS suggests that cancer risks go up even at relatively modest levels -- the equivalent of air pollution in some major cities, including London, Mexico City and the Bronx section of New York City.
Hopefully this will result in greater support and subsidization of freight railroad capacity, intermodal freight, and otherwise getting trucks off the road. At the same time, there needs to be investment in clean trucks for short distance and yard duties as well as clean switcher locomotives. While the studies, focusing as they did on coal miners, do not necessarily prove a higher risk of cancer for those living in areas subjected to heavy amounts of diesel exhaust, I'm reasonably certain that application of the risk levels, especially with the DEMS study, will show an increased cancer risk resulting from truck traffic.