Rochester firefighters say no one was hurt in a two-alarm fire at a commercial building on the city's west side.
The fire broke out in a machine shop in the rear of a three-story brick building on Murray Street.
The agent being used to put out the fire reacted with a material that was burning and caused an explosion.
A hazardous materials team arrived with special extinguishers. Crews were able to prevent the fire from spreading to other parts of the building.
The cause of the fire is under investigation.