The cause of a fire at the OmniSource recycling center in central Toledo is still under investigation.

Toledo fire Lt. Matthew Hertzfeld said the fire at 2453 Hill Ave. was first reported at 5:34 a.m. The first crews on scene found heavy fire at the rear of a “mixing unit,” Lieutenant Hertzfeld said.

A second alarm was issued at 5:43 a.m., the lieutenant said.

The fire was under control within an hour.

One firefighter, whose name was not released, was treated at Mercy St. Vincent Medical Center for a “minor burn,” Lieutenant Hertzfeld said.

The recycling center was evacuated. No employees were injured.

A damage estimate was not available this morning.

While crews were battling the fire, Hill Avenue was closed between North Westwood Avenue and Parkside Boulevard, Toledo police reported.

First Published August 23, 2012, 10:26 a.m.