St. Johns Fire Rescue says two men were flown to UF Health Jacksonville on Tuesday morning after a large tank at an industrial facility on Adams Acres Road exploded.
Authorities say workers were using a welding torch to dismantle the tank, but there was apparently some kind of combustible product inside and it ignited.
Charles Smith and Bradly Hartley were listed in fair condition Tuesday afternoon.
The accident occurred at Indianhead Biomass Services, a facility that accepts residential waste and converts it to biofuels. Fire-Rescue Lt. Jeremy Robshaw said the explosion was not very large, only damaging the cylinder that was being worked on at the time.
"It was quite loud, like almost like a cannon going off," resident Mary Varnedoe said. "I heard the fire trucks. Actually, my dogs heard the sirens not long afterwards. When I let him out, he was barking at the sirens."
Varnedoe said she had no idea the company was so close to her home and that she was somewhat concerned.
But some people aren't really worried.
"I don't think we're in any jeopardy or anything like that," resident Billy Angelus said. "I think it would have to be a pretty big explosion for, you know, any type of damage to occur a mile away, at least."
The State Fire Marshal's Office, Bureau of Alcohol, Tobacco, Firearms and Explosives, and Occupational Safety and Health Administration are all investigating.
The company would not comment. The managers went to the hospital where the two workers were taken.