Residents of a duplex at 317 W. Fulton St. in Butler escaped without injuries from a fire that started on the back porch and spread to the attic late Friday afternoon and a city firefighter was taken to Butler Memorial Hospital with heat exhaustion.

The fire was reported just before 4 p.m. and the rear of the two-story brick building was fully involved in flames when fire fighters arrived.

“The first floor back porch was heavily involved. It ran up into the attic,” said Capt. Jim Kaufman of the Butler Fire Department.

One of the first floor tenants heard an explosion come from the rear of the home and saw a lot of flames, he said.

A state police fire marshal will investigate the cause of the fire on Monday, Kaufman said.