NEW YORK – Here's another one for the diesel-causes-cancer files.

Yet another health report has linked lifetime exposure to diesel exhaust to a heightened risk of lung cancer, according to Reuters.

The study, which combined the results from nearly a dozen reports from the U.S. Europe and Canada, suggests that workers such as truckers, miners and railway workers had a 31 percent higher risk of lung cancer than people with no such occupational exposure.

The study -- published in the American Journal of Respiratory and Critical Care Medicine -- does note, however, that the association between prolonged exposure and cancer is "small."

The study also states that chronic exposure to fine particles in diesel exhaust can worsen respiratory conditions like asthma.

Truck diesel engines built since 2002 have all but eliminated both particulate matter and NOx from emissions and the sulfur content in highway diesel fuel has also been reduced drastically. Diesel engines used in rail locomotives and marine vessels have been much slower to do so.

The analysis determined that miners, vehicle loaders, and diesel-engine mechanics are more at risk than over-the-road truck drivers, railway engineers and farmers.

That is consistent with other studies have found that highway drivers are at a much lower risk that vocational operators or drayage haulers because they're often on the road with their windows rolled up rather than idling around other trucks for long periods,

Most studies in the past that have examined the possible link between diesel exposure and cancer have not accounted for other factors such as the probable increase of smokers among those professions.