WEST BARNSTABLE, MA – An electrical failure at the Cape Cod Animal Hospital appears to be the cause of a gas explosion and fire that leveled the building and killed four pets Monday night.

Officials from the state Fire Marshal’s Office and the Centerville-Osterville-Marstons Mills Fire Department announced this afternoon that the electrical failure allowed natural gas to flow into the building, leading to an explosion and the fire that killed three cats and one dog.

Investigators haven’t determined yet what ignited the gas, leading to the explosion – it could have been several sources, including the furnace, the hot water heater, or the generator, State Fire Marshal Stephen D. Coan wrote in a written statement.

“This is one of several recent high profile incidents where natural gas has been involved. The circumstances of each of them are completely different,” he said.

Natural gas explosions have leveled several houses in recent weeks in Massachusetts and in New Hampshire.

Veterinarian Scott Munson and a neighbor rescued about 12 dogs from the fire. Most of the dogs have been reunited with their owners, though one – a young puggle, a pug and beagle mix, named Dutch – is still missing.