Two men were wounded Wednesday in an explosion that shook the ground in a Lula subdivision and was the result of an accident involving a blowtorch and an old gas tank from a logging truck, fire officials said.

Hall County Fire Chief David Kimbrell said at about 3:55 p.m. Wednesday, residents of Morgan Manor off Old Cornelia Highway reported hearing and feeling an explosion. Responding firefighters found evidence that a gas tank exploded outside a nearby Shockley Road residence.

Kimbrell said two men — a father and son — were cutting up old gas tanks for salvage when one exploded. The father had second- and third-degree burns over 20 percent of his body and the son had second- and third-degree burns over 10 percent of his body, Kimbrell said. They were driven by car to Northeast Georgia Medical Center’s Lanier Park campus before first responders arrived, he said.

The men later were flown to an Augusta burn center for treatment of respiratory burns, Kimbrell said. Their names and ages were not immediately available.

The gas tank had been sitting in nearby woods for some time and was not thought to contain gas vapors when the men began cutting it, Kimbrell said.