Prosecutors say ex-Massey Energy CEO Don Blankenship may have to pay tens of millions of dollars after a conviction carrying up to one year in prison.

In U.S. District Court in Beckley Wednesday, prosecutors opposed Blankenship's plea to reduce his $5 million bond to $250,000 and drop travel restrictions. Prosecutors say restitution could ruin his wealth and make him a flight risk for sentencing in April.

Prosecutors say if it weren't for Blankenship's conspiracy, most of the 29 deaths from the Upper Big Branch Mine explosion in West Virginia in 2010 could've been avoided.

They say Massey, bought by Alpha Natural Resources, incurred significant fines and costs also subject to restitution.

Blankenship was convicted Dec. 3 of a misdemeanor conspiracy to willfully violate mine safety standards at Upper Big Branch.