Two firefighters were injured in St. Charles County this afternoon while fighting a fire that damaged a house owned by a church.

Central County Fire and Rescue Chief Russ Mason said the fire started about 1:30 p.m. at 420 Hemsath Road. The building used to be a house, he said, but it now is used as a retreat by Christian Fellowship Center. Church representatives could not be reached.

Mason said a church employee had burned papers behind the house. She cleaned up some of the debris this morning and put it in a trash can in the garage, he said. That’s where firefighters believe the blaze started.

Battalion Chief Mark Runge said a passer-by noticed the fire and called the church employee to tell her about it. He said the blaze destroyed the garage and a car inside it. The fire also spread into the second-floor attic, he said.

Damage was estimated at $200,000.

Runge said one firefighter was treated for heat exhaustion and released. A second firefighter was struck in the head by a falling floor joist as firefighters worked to overhaul the damage, Runge said. He was wearing a helmet.

The firefighter whose head was struck was expected to be OK, Runge said, but he was still at a local hospital as of about 6 p.m.