Braintree, Massachusetts - An explosion was reported at Wollaston Alloys, Inc. at about 11:40 a.m. Monday at 205 Wood Road.
The windows of the building were blown out and employees were seen stumbling out of the building covered in soot, Bob Bachman, who works across the street from the scene, told.
Bachman added that the employees who escaped from the building did not believe anyone was seriously hurt. Two people were taken to a hospital, one for chest pains and another for back injuries, a fire official said.
It was not immediately clear what exploded.
"It was such a large boom that the snow came flying off the roof of our building," said a witness, Martha Marsden, who works next door. "Once the smoke cleared we began to notice that windows had been blown out of the building and part of the roof may have imploded."
The company specializes in high-tech castings, according to Wollaston's Web site.