After a week-long meeting of international experts, the International Agency for Research on Cancer (IARC), part of the World Health Organization (WHO), classified diesel engine exhaust as “carcinogenic to humans,” based on evidence that exposure is associated with an increased risk for lung cancer.

According to Dr. Christopher Portier, chairman of the IARC working Group, “The scientific evidence was compelling and the Working Group’s conclusion was unanimous: diesel engine exhaust causes lung cancer in humans.” This classification puts diesel exhaust into Group 1 of carcinogens, which includes chemicals such as asbestos, tobacco and formaldehyde.

Exposure to diesel exhaust occurs in everyday life, through motor vehicle exhausts as well as exhausts from other diesel engines, including from other modes of transport (e.g. diesel trains and ships) and from power generators.

“Given the additional health impacts from diesel particulates, exposure to this mixture of chemicals should be reduced worldwide,” Portier said.

Read the full announcement here.