The blast happened just before noon Wednesday, sparking a two-alarm fire at the Hibernia Road home in West Brandywine Township, fire officials said.
Three other people including four children and one adult had been released from the hospital, West Brandywine Police Chief Jeff Kimes said.
Over 260,000 gallons of water were used to fight the fire, and nearly two dozen fire and rescue companies responded to the scene from Berks, Chester, and Lehigh counties, officials said.
There were no reported injuries to any firefighters on the scene, police said.
Local, county, state, and federal investigators remain on the scene to determine the cause of the fire.
Click here to follow Daily Voice Lower Merion-Narberth and receive free news updates.