KWTX is reporting the investigation into the explosion at a physical plant at Coryell Memorial Hospital in Gatesville is now closed.

The explosion that left 3 workers dead and 13 injured happen back on June 26th. The State Fire Marshal's Office reports the explosion was the result of a large pocket of natural gas that escaped from disconnected gas lines going into the building.

According to KWTX News 10, the report states that

Although the specific ignition source was not identified during the investigation, there was no evidence to suggest this was the result of an intentional act or of natural causes. The evidence tended to suggest this was a construction accident.

According to the report a mixture of gas and air ignited in the boiler room. That fire in the boiler room spread, lit the gas, and caused the explosion. In the aftermath, crews examined the three water heaters in the mechanical room and found "that the natural gas pipe supplying them had been disconnected at the coupling to the north and south units,” according to the study. Unfortunately, it seems the valves on the pipes were left open and that allowed the natural gas to flow into the mechanical room prior to the explosion.

What remains unsolved is the actual cause of ignition. Investigators have identified potential sources like two scissor lifts, fluorescent lights, HVAC units, cell phones, a BIC lighter, a striker for a welding torch, battery-powered tools, and water and chiller pumps as all possible causes of the spark that set off the explosion.

The Killeen Daily Herald reports the 3 individuals who died in the explosion were Michael Bruggman, 42, of Rogers, Filiberto Morales, 36, of Round Rock, and Wilber Dimas, 29.