Four firefighters were injured while battling a large fire at Latex International Foam Factory in Shelton, Connecticut.
Roads around the River Road factory were closed for part of the morning on Thursday, but have since reopened.
One firefighter broke his arm while fighting the fire and three others suffered heat exhaustion, according to Shelton Assistant Fire Chief Nick Verdicchio.
Fire broke out in the basement of the factory just after 1 a.m. while workers were inside. Everyone who was inside the building was able to escape unharmed when the fire alarms went off.
"When the first units came in, they found heavy fire load in the basement area, in the dryers," Verdicchio said.
Crews from several surrounding fire departments were called in to help and will remain at the scene to help put out hot spots.
Officials said there is heavy damage inside the factory, which produces latex bedding and mattresses.
The fire marshal has been called in to investigate. Crews from the state Department of Energy and Environmental Protection have also responded to test for hazardous chemicals.
Latex International moved to the 208-thousand square foot building in Shelton after a major fire destroyed its Ansonia factory in 2001, according to the Associated Press, and the company also survived an arson fire in 1975.
The parent company, Latex Foam International Holdings, filed for bankruptcy protection earlier this month.