PETERBOROUGH, N.H. — A factory explosion that blew out windows and injured more than a dozen people probably originated in a room where acid is used to treat the surface of ball bearings, but it could be weeks before the exact cause is determined, investigators said Tuesday.
The blast Monday afternoon at New Hampshire Ball Bearings Inc. shattered glass, dislodged ceiling tiles, and damaged walls.
The building, however, was stable enough for investigators to work inside Tuesday.
Deputy Fire Marshal Max Schultz said the on-site investigation was expected to end later in the day.
The building was then to be turned over to company officials for cleanup and repairs.
The plant makes parts for the aerospace industry and employs 700 people.
Company spokeswoman Kathy Gerrity said there would have been about 450 working at the time of the blast, which happened just after a 3:30 p.m. shift change.
No one was in close proximity to the explosion, Schultz said.