A grand jury convened in Coos County, N.H., has indicted Craig Sanborn, owner of gunpowder manufacturer Black Mag LLC, for manslaughter and negligent homicide as a result of a deadly 2010 explosion that took the lives of two workers at the company's Colebrook, N.H., worksite.

The workers, Jesse Kennett and Donald Kendall -- who had been on the job for only a month -- were being required to hand feed explosive powder into operating equipment because the employer failed to implement essential protective controls. The multiple explosions that occurred when the powder detonated killed both men and blew out the walls and roof of the worksite. Four months earlier another worker had suffered serious burns from a flash fire at the facility.

OSHA issued 54 citations to Black Mag with penalties totaling $1,232,500 following an investigation that found the employer had shown willful indifference to protecting the safety and lives of his workers by failing to provide training, locate operators at safe locations while equipment was operating and separate workstations by distance or barriers. The employer also failed to provide fire resistant clothing, face shields and gloves; to safely store gun powder; and to identify explosion hazards in the company's operating procedures.