In 1988, IARC classified diesel exhaust as probably carcinogenic to humans (Group 2A). Since 1998, an advisory group that reviews and recommends future priorities for the IARC Monographs Program recommended that diesel exhaust be listed as a high priority for re-evaluation.
There has been mounting concern about the cancer-causing potential of diesel exhaust, and the publication in March 2012 of the results of a large U.S .National Cancer Institute/NIOSH study of occupational exposure of underground miners to diesel exhaust showed an increased risk of death from lung cancer in exposed workers.
The scientific evidence was reviewed thoroughly by the working group, which concluded that there was sufficient evidence in humans for the carcinogenicity of diesel exhaust. The working group determined that diesel exhaust is a cause of lung cancer (sufficient evidence) and also noted a positive association (limited evidence) with an increased risk of bladder cancer (Group 1).
The Working Group concluded that gasoline exhaust was possibly carcinogenic to humans (Group 2B), a finding unchanged from the previous evaluation in 1989.
The mission of the International Agency for Research on Cancer (IARC) is to coordinate and conduct research on the causes of human cancer and the mechanisms of carcinogenesis, and to develop scientific strategies for cancer control.
