Miners at increased risk of lung cancer
The US research involved almost 200 former mine workers who died from the disease up to 1997, and around 560 of their former co-workers matched for age and ethnicity.
Those in a group with the highest levels of diesel exhaust exposure had three times the risk of death from lung cancer, compared to those least exposed, the study found.
Increasing lung cancer risk was associated with increasing cumulative exposure, as well as average exposure, to exhaust fumes.
Miners who smoked had further elevated risk.