LOUISVILLE, Ky. (AP) – Federal regulators have announced that nearly all dust samples from the nation’s coal mines were in compliance with limits that were newly toughened to cut miners’ exposure to particles that can cause deadly black lung disease.

Citing a Monday announcement from Joseph Main, the head of the U.S. Mine Safety and Health Administration, the Lexington Herald-Leader  reports that about 99 percent of the 20,000 underground dust samples collected were in compliance. The samples were gathered from April through June.

The coal industry had challenged the new limits, arguing that the monitors had a high failure rate. Main says the results show the new rules are effective.

Main says 98 percent of the samples would have been in compliance with a new standard set to take effect Aug. 1.