REMER, Minn. — Fire has caused extensive damage to a lumber mill in northern Minnesota.

The fire at Remer Cut-Stock Lumber was reported to the Cass County sheriff's office around 8:45 p.m. Tuesday. Firefighters arrived to find the mill engulfed in flames.

Remer Fire Chief Paul Swentkofske tells WDIO-TV (http://bit.ly/12OSKWQ ) that firefighters didn't leave the scene until 2 a.m. the next morning.

No one was hurt, but Swentkofske says 25 people worked at the business.

While he didn't call it a total loss, he says the fire warped the building's steel structural support.

The Remer Fire Department and the State Fire Marshal's office are investigating.