SARTELL, Minn. — One person was killed Monday and five were injured in an explosion that caused a large fire at a paper mill in Sartell.

The explosion occurred shortly before noon at the Verso Paper Corp. mill.

The St. Cloud Times reported that a company official said an air compressor exploded. A full shift of 50 workers was on duty at the time; the company said all had been accounted for.

The name of the person killed and conditions of those hurt were not immediately released.

At least one firefighter was treated on the scene for heat exhaustion, according to Sartell City Manager Patti Gartland. In all, 14 area fire departments responded to the blaze.

Sartell is north of St. Cloud along the Mississippi River, and Gartland said the plant, located downtown, is a major local employer.

Authorities said no hazardous materials appeared to have been exposed to the fire, but they were warning residents downwind to stay indoors and close windows because of the smoke.

The building’s sprinkler system was damaged in the explosion, Gartland said, but firefighters had the blaze about 90 percent contained by Monday evening.

Matt Dahl, who lives nearby, said the explosion was huge and shook his house. He said he ran outside to see flames and smoke shooting from the mill.