OAKBROOK TERRACE, Ill. — Several people are displaced after an apartment fire early Saturday morning in Oakbrook Terrace.

Ken Kovarik, the fire marshal for the York Center Fire Protection District, said the fire was believed to be caused by lightning from the storms overnight.

The DuPage County Arson Task Force is investigating.

While an official cause of the fire hasn’t been determined, Kovarik said the preliminary cause is believed to be the storms.

“It’s all wood construction, so you have wood truss ceiling and wood truss floors, so once the fire starts going, there’s really not much,” Kovarik said. “It can overrun the fire sprinkler system.”

No civilians were injured.

At least three firefighters were taken to a local hospital for heat exhaustion. They were treated and have since been released.