CASSELBERRY, Fla. -- Authorities in Casselberry are investigating a house fire at a home on Jericho Drive in Seminole County (see map) that turned deadly after a resident's oxygen tanks exploded from the heat and fueled the flames, trapping him inside.

Neighbors reported hearing a loud boom on Sunday, which they thought were leftover fireworks.

Seminole County Fire Rescue spokeswoman Lt. Alisa Keyes said crews found Paul D'Agostino dead in a back bedroom. His wife, Meryl, saved their 6-year-old grandson, but was unable to reach her husband.

D'Agostino had been recovering from a heart attack and coma. The state fire marshal said faulty wiring may have caused the blaze.