ELKHART — Four fire departments worked Tuesday afternoon to clear the site where there was a reported flash fire and release of chemical gas.

Osolo Township, Cleveland Township and Bristol Fire departments initially responded to a fire at Superior Fiberglass and Resin, part of Superior Oil Co., north of Elkhart around 1:51 p.m. There was no fire when the fire departments arrived, but there was a re-kindle, which they got under control shortly after, said Randy Stone, division chief at Osolo Township Fire Department.

The entire building was evacuated, and firefighters used foam to suppress the re-ignited fire.

Stone said people were working with flammable materials when a source of ignition prompted a flash fire. The fire department is still investigating the cause of the ignition.

David Pugh, an eyewitness, said he was making a delivery next door when he felt the explosion and saw smoke rolling out of the building.

“It just rocked the place. It was just boom,” Pugh said.

One worker was injured and taken to Parkview Hospital in Fort Wayne. The condition of the person was unknown, Stone said.

Elkhart Fire Department responded later to help measure air levels to make sure there were no vapors in the air that could ignite.

Stone said the vapors did not pose a threat to the nearby neighborhood.