Cause of Small Explosion at Sam Adams Brewery Still Under Investigation

A small explosion last week in a boiler at Sam Adams Brewery in Upper Macungie is still under investigation, and it could take weeks to determine the cause, Boston Beer Co. spokeswoman Michelle Sullivan said Tuesday.

Two men had been hurt slightly and were treated at the scene. One had smoke in his eyes, the other had a bump on his head.

The federal Occupational Safety and Health Administration (OSHA) and a state commission are on site to help determine what happened, Sullivan said, "so we understand exactly what did occur and if there's any learning there."

Sullivan confirmed Tuesday the small explosion was a natural gas ignition. At the time of the incident last week, it was still being determined whether it had been an explosion or boiler malfunction. 

The workers were getting ready to start the boiler around noon when the small explosion occurred. The brewery was shut down and the building evacuated. About 100 employees were on site at the time.

Sullivan said Sam Adams Brewery resumed shipping and packaging later on Thursday, and brewing resumed over the weekend.

The boiler room is a free-standing structure.

The brewery employs about 300 people and produces most styles of Samuel Adams beer, according to Lehigh Valley Marketplace. The Fogelsville brewery began as Schaefer Brewing Company in 1971 and was later sold to Stroh, then Pabst.

The facility changed hands again and produced Smirnoff Ice until June 2008, when The Boston Beer Company took ownership.