After a week of considering the evidence, a working group of the World Health Organization determined that diesel exhaust is carcinogenic in human lungs. Underground miners, bus drivers and railroad workers are especially vulnerable, but the risks from traffic exhaust extend to the general population.
“Diesel exhaust is a cause of lung cancer in human beings,” Portier, director of the CDC’s National Center for Environmental Health and Agency for Toxic Substances and Disease Registry, told reporters in a telephone media briefing.
There is also more limited evidence that diesel exhaust may cause bladder cancer, said Portier.
The classification is a change—in 1989, IARC said diesel exhaust was “probably” a human carcinogen. Re-evaluating the status of diesel exhaust has been a priority for the agency since 1998.