A boiler exploded at a Vlasic Foods plant in Omaha, Neb. on Wednesday, injuring at least five people.
Authorities said the explosion sprayed hot water and diesel fuel on the victims and started a fire that burned for an hour.
The most seriously injured person was burned on his face and arms.
Two victims were in fair condition, and three were treated at a hospital and released.
About 600 people are employed at the factory, which produces items in Vlasic's frozen food line.
The plant was evacuated.