Elevated levels of diesel fumes seems to increase risk of lung cancer in non-metal miners, says a new study published in the Journal of the National Cancer Institute. Scientists from the National Institute for Occupational Safety and Health (NIOSH) and National Cancer Institute (NCI) worked together in what was a part of the “Diesel Exhausts in Miners” study.

The study basically intended to find the impact of elevated diesel exhaust levels on risk of developing cancer, particularly focusing on lung cancer. It involved around 13,000 miners from all over the US, including trona mines in Wyoming , a salt mine in Ohio and mines in New Mexico. A limestone mine in Missouri was also a part of the study.

The study found that diesel exhaust from heavy machineries that are operated in these mines tend to build up to higher levels in an underground setting. This exposes the miners to greater risk of lungs diseases than workers in any other settings suck as truck depots, open mines or dockyards.

Metal mines were ignored in the study since they tend to have higher levels of asbestos, silica and radon. These substances are known to increase cancer risks.

Scientists took historical information on exposure, measured constituting elements of diesel exhaust presence in the surroundings and combined the two data. They also measured the levels of carbon in the air that can be respired by the miners.

The study concluded that heavily exposed underground miners were three times more likely to develop lung cancer than those with less exposure.