WASHINGTON — A January home explosion in southeast Iowa that killed one person and injured another was caused when vapor from a gas leak was ignited when someone in the home lit a cigarette, officials report.

Washington County fire officials have determined a gas leak filled a confined space in the home on Jan. 4 before the cigarette was lit around 4 a.m., television station KCRG reported. The explosion injured 68-year-old George Carpenter and another person in the home. Carpenter died three days later at a hospital from his injuries.

Officials said they have not determined the source of the gas that led to the explosion.

Fire crews called to the scene of the explosion extinguished a resulting fire. The explosion severely damaged the home and blew out windows of nearby homes.

Washington is about 30 miles (48.28 kilometers) south of Iowa City.

.