THOMASVILLE, Ala. (AP) -- Four employees were injured in an explosion and fire that damaged a building-products mill early Wednesday, company officials said.

The injured workers at Louisiana-Pacific Corp.'s Oriented Strand Board mill were taken to a Mobile hospital for treatment.

Mary Cohn, a spokeswoman at the company's headquarters in Nashville, Tenn., declined to discuss the extent of the worker's injuries, but said they remained hospitalized Wednesday.

The explosion and fire occurred just before 2 a.m. in the thermal oil room and was brought under control in just under two hours.

Cohn said it's unclear what caused the explosion and it remains under investigation.

Company CEO Rick Frost said he has sent a team of safety, human resource, operations and engineering managers to aid the injured workers and their families. The team also will begin an immediate investigation.

The mill manufactures sheathing used mainly in residential construction.