SHERMAN, Texas (KTEN) — An accidental propane gas leak is now confirmed to have led to the fatal explosion at a Sherman home on Sunday night.

The Grayson County Fire Marshal's Office said an investigation of the rubble at the residence in the 4300 block of Sistrunk Street revealed a "failure point" under the kitchen floor.

"This failure point allowed propane gas to escape and accumulate below the floor of the home," Fire Marshal John Weda said in a written statement. "This gas reached an unknown ignition source, which ignited, resulting in the explosion and fire."

Homeowner James Bateman died in the fire; his wife Sharon was hospitalized in critical condition.

Their residence was destroyed in the blast, and several neighboring properties were damaged by the pressure wave.