More than a decade after it was classified as probably carcinogenic to humans, the U.N. health agency Tuesday classified diesel engine exhaust as carcinogenic to humans.
The International Agency for Research on Cancer, which is part of the World Health Organization, announced the re-classification Tuesday, after a week-long meeting of international experts, and based its decision on sufficient evidence that exposure is associated with an increased risk for lung cancer.
“The scientific evidence was compelling and the working group’s conclusion was unanimous: diesel engine exhaust causes lung cancer in humans,” said the chairperson of the agency’s working group which reviewed the scientific evidence. He is Christopher Portier.
“Given the additional health impacts from diesel particulates, exposure to this mixture of chemicals should be reduced worldwide,” he added.
According to the agency, large populations are exposed to diesel exhaust in everyday life, whether through their occupation or through the ambient air. People are exposed not only to motor vehicle exhausts but also to exhausts from other diesel engines, including from other modes of transport, such as diesel trains and ships, and from power generators.
There had been mounting concern about the cancer-causing potential of diesel exhaust, particularly based on findings in epidemiological studies of workers exposed in various settings, the research agency noted.
The working group reviewed the evidence and, overall, it concluded that there was sufficient evidence in humans for the carcinogenicity of diesel exhaust. In particular, it found that there was sufficient evidence to determine that diesel exhaust is a cause of lung cancer, and noted that there is a positive association with an increased risk of bladder cancer.
The working group also concluded that gasoline exhaust was possibly carcinogenic to humans, a finding unchanged from a previous evaluation in 1989.
The agency said that governments and other decision-makers now have a valuable evidence-base on which to consider environmental standards for diesel exhaust emissions and to continue to work with the engine and fuel manufacturers towards those goals.
In 1988, the agency had classified diesel exhaust as probably carcinogenic to humans. An advisory group, which reviews and recommends future priorities for the agency, had recommended diesel exhaust as a high priority for re-evaluation since 1998.