Federal prosecutors filed a motion Monday to dismiss charges against the final defendant in the criminal trial of W.R. Grace and Co.

A jury acquitted Grace and three individual defendants – Robert Bettacchi, Jack Wolter and Henry Eschenbach – last month of conspiracy charges related to asbestos exposure from a Libby vermiculite mine.

O. Mario Favorito, Grace’s in-house legal counsel, was scheduled to be tried individually this fall. 

“Due to adverse rulings during the previous trial and the verdict, the government has decided not to pursue pending charges against defendant O. Mario Favorito,” read a release from the U.S. Attorney’s Office and the Environmental Natural Resources Division of the Department of Justice in Missoula.

Grace and seven current and former executives were originally named in a 2005 indictment, but one defendant, former mine manager Alan Stringer, died.

Near the end of the three-month environmental crimes trial that began in February, charges were dropped against defendants William McCaig and Robert Walsh when it was determined that the prosecution did not have enough evidence to convict them.