PETERBOROUGH, N.H. (AP) -- Investigators are trying to determine what caused an explosion in a New Hampshire ball bearings plant that blew out windows, shook walls and sent at least 15 people to the hospital.
In a statement posted on its website Tuesday, the corporate headquarters for New Hampshire Ball Bearings Inc. said the cause of Monday afternoon's blast remains undetermined. Investigators from the state fire marshal's office are at the site, along with federal Occupational Safety and Health Administration officials.
The plant manufactures parts for the aerospace industry and employs 700 people. Peterborough Fire Department spokesman Eric Bowman says all indications are that it was an industrial accident.
All but two of the injured workers have been released from the hospital.