CHARLESTON, W.Va. — Don Blankenship joined a small club of executives when he was indicted on federal charges in the 2010 West Virginia mine explosion that killed 29 people.

The former Massey Energy CEO is accused of conspiring to violate safety and health standards at Upper Big Branch Mine, site of the worst U.S. coal mining disaster in 40 years. The explosion and investigation led to the overhaul of the way the federal government oversees mine safety.

University of Virginia law professor Brandon Garrett has been tracking corporate prosecutions since 2001 and has written a book on the subject, “Too Big to Jail.” In that span, of the 280 companies, including Massey, that escaped prosecution by agreeing to pay a fine and change their operations, just 26 of their CEOs have been charged, he said.

Blankenship, who retired ahead of a $7.1 billion Massey buyout by Alpha Natural Resources in 2012, could face up to 31 years in prison if convicted.

His attorney, William Taylor III, said in a statement Thursday that Blankenship “is entirely innocent of these charges. He will fight them and he will be acquitted.”