LOUISVILLE, Ky. (AP) — Eight former supervisors and safety officers at a Kentucky coal company were indicted Wednesday on federal charges that they rigged dust monitoring in underground mines, forcing miners to work in the kind of dirty conditions that can lead to black lung disease.

The eight officials who worked at the now-bankrupt Armstrong Coal in western Kentucky were charged with one count each of conspiracy to defraud the government by “deceit, trickery and dishonest means,” according to the indictment.

The indictment alleges company officials ordered workers to remove dust sampling equipment and place it in clean air portions of the mine to get desirable readings, or they moved workers without dust monitors into the dirtiest jobs. The indictment says the offenses happened at Armstrong’s Parkway and Kronos mines between 2013 and 2015.

“When companies and their senior officials are prepared to disregard the law and put miners at risk, they should also be prepared to face federal prosecutors,” Russell Coleman, the U.S. attorney for Kentucky’s western district, said in a release.

Company officials fabricated and submitted dust sampling test results on days the mine was shut down or not in operation, and one mine superintendent twice mandated a safety official take whatever action necessary to ensure that the company passed dust sampling tests, according to the indictment.

Miners who breathe dusty air over a period of years are at risk of contracting pneumoconiosis, or black lung disease. Recently, there has been a resurgence of severe cases of the disease in Appalachian mines, thought in part to be caused by thinner coal seams and more powerful equipment that kicks up more dust.

Mike Wilson, a veteran miner who worked at the Parkway mine, said dust conditions were so bad on the job that he couldn’t see his hand in front of his face.

“They’ve been doing this for years and years,” he said in a phone interview Wednesday.

Wilson, 63, said he has been diagnosed with black lung and has trouble sleeping at night because of fluid buildup in his lungs. He ran a coal digging machine at the mine and was told he had to manipulate his dust monitor to get low readings. He said he would routinely stuff the monitor in his pocket and clog its tube to restrict air flow.

“Every boss and every safety guy wanted you to do this,” he said.

Wilson said he went along with what his bosses told him for fear of losing a job that paid him about $27 an hour and offered routine bonuses. He retired in 2015 and said he now physically struggles to play with his grandchildren.

The eight indicted Wednesday are Charley Barber, the former superintendent of Parkway mine; Brian Keith Casebier, Parkway’s former safety director; Steven DeMoss; Billie Hearld; Ron Ivy, Kronos mine’s former safety director; John Ellis Scott; Dwight Fulkerson; and Jeremy Hackney. The maximum sentence on the conspiracy charge is five years in prison. It was not known Wednesday afternoon if the men had hired attorneys.

The Kronos mine has been purchased and is being run by another coal company. The Parkway mine has closed.