Diesel exhausts are common both in occupational and non-occupational settings. They are considered as a cause of lung cancer, and International Agency for Research on Cancer (IARC) recently upgraded the evidence from probable to sufficient (http://www.iarc.fr). However, the opinions about the health effects are not consistent. A recent review concluded that the published studies lack consistency.1 A pooled analysis of case-control studies and a study of miners were interpreted as consistent with an increased risk but questioned by others.2 ,3 Some of the studies of lung cancer risk from diesel exhaust are evaluating the risk in drivers of vehicles like buses, trains or heavy equipment operators.1 ,2 ,4

The …