Brainerd, MN – By MATT ERICKSON, Staff Writer – A spark coming in contact with a propane leak is believed to have caused the explosion that injured two people on a converted school bus Friday.

The explosion happened about 5 p.m. after the bus, converted into a recreational vehicle, pulled onto Northwest Second Street off Washington Street, just west of the Mississippi River bridge.

Brainerd Fire Chief Kevin Mahle said the owners of the bus, Leon and Sanddra Renner, heard gas leaking from two, 100-pound propane cylinders on the bus as they crossed the Washington Street bridge.

The tanks, located in the back of the bus, fed a series of copper tubing, which sent propane throughout the bus, said Mahle. The tubing appeared to have broken, he said, and when Sanddra Renner went to close off the tanks with a wrench it caused a spark, igniting the propane and causing a flash explosion, the force of which extinguished the burning propane.

The force of the explosion blew the front window of the bus about 100 feet away, bowed the rear door and was heard several blocks away.

Though the fire caused by the initial explosion was put out by the force of the explosion itself, gas behind the propane tanks ignited and, aided by strong winds and flammable materials such as curtains and bedding on the bus, spread throughout the bus, turning it into a fireball, said Mahle.

“They’re extremely fortunate,” said Mahle of Leon Renner, 61, and Sanddra Renner, 51, both of Foley. “The initial blast did mostly thermal damage to their faces, necks and arms,” though Sanddra Renner suffered more severe burns because she was at the tanks as they exploded, said Mahle.

The Renners were transported to the Hennepin County Medical Center Burn Center, where on Saturday they were reported in satisfactory condition. On Monday a hospital spokesperson said the Renners were no longer patients at HCMC, but wouldn’t say if they had been discharged or transported to another hospital.

The Renners were towing behind their bus a livestock trailer carrying two horses and were able to push the trailer away from the fire, said Mahle.

Assisting at the scene of the explosion were the Brainerd Police Department and the Crow Wing County Sheriff’s Department. Deputy State Fire Marshal Mark Germain assisted with the investigation of the explosion and fire.

Mahle stressed that people who hear or smell any type of gas should leave the area immediately.

“Don’t turn the lights off or on, don’t use the phone, get out and call 911 from a remote area,” said Mahle.