A man has died from his injuries following a furnace explosion in Ayer, Massachusetts.
The furnace explosion at Advanced Vacuum Systems on Fitchburg Road Friday evening led to a 4-alarm industrial fire.
Two employees at Advance Vacuum Systems were taken to local hospitals as a result of the incident, where one, a man in his 50s, later died. His name has not been released. The other employee's condition is unclear at this time.
Two firefighters also suffered minor injuries in the fire.
A preliminary investigation indicates the explosion was caused by an apparent pressure vessel malfunction, according to the Middlesex district attorney's office.
The investigation into the furnace explosion is ongoing.