U.S. Attorney Booth Goodwin said the UBB mine disaster investigation is “absolutely not” finished. A conviction on the federal fraud charge could result in fines and up to five years in prison. It’s a rare, if not unprecedented legal strategy that appears to be moving up the corporate ladder, according to the AP.

Goodwin urged a federal judge in Beckley to make an example of the only other person charged so far, former security chief Hughie Stover. Goodwin is demanding the maximum possible sentence of 25 years in prison for actions he says contributed to the disaster. Stover was sentenced February 29 for lying to federal investigators and attempting to destroy documents.

May began working at Upper Big Branch in February 2008 as a mine foreman and was promoted in October 2009 to superintendent. He held that post, overseeing three room-and-pillar mining sections and a longwall operation, until the day the mine exploded on April 5, 2010.

The information filed in U.S. District Court in Beckley accuses May of conspiring with others to conceal many dangers in the mine through an elaborate scheme that included code words to alert miners underground when inspectors were on the property, the deliberate alteration of approved ventilation plans, and the deliberate disabling of a methane gas monitor on the continuous mining machine.

The information, according to the AP, also says that when May knew the Mine Safety and Health Administration was about to sample the level of respirable coal dust in a section of the mine, he surreptitiously redirected additional air to that area to obscure the typical conditions. May is also accused of both falsifying safety inspection books and ordering someone not named in the information to leave out reports of deep water that would have made a section of the mine unsafe.