The International Agency for Research on Cancer has added diesel engine exhaust to its list of first-grade carcinogens, which also includes asbestos and arsenic.

The agency, an affiliate of the World Health Organization, classified diesel engine exhaust as a 2A-grade substance and a first-grade carcinogen.

The IARC cited its study as showing that diesel engine emissions cause lung cancer. The study advises people to limit their exposure to diesel engine exhaust, a move that has put the car industry on alert.