Oakland, CA- An Oakland man was severely burned in an apparent natural gas explosion that rocked his East Oakland home Monday night, authorities said.

Leon Spencer, 61, suffered burns to 80 percent of his body in the blast, which happened at about 8 p.m. at a duplex at 2317 and 2319 87th Ave., near Dowling Street, said Battalion Chief Melinda Drayton of the Oakland Fire Department.

Spencer was found outside the building. The upper unit, 2319, had collapsed onto the lower unit, 2317, where Spencer lived, Drayton said. He was listed in critical condition at Highland Hospital in Oakland.

Investigators say the explosion may have been caused by a natural gas line rupture, but the exact cause was not known Monday night, Drayton said. Neighbors across the street had been remodeling 2319 87th Ave. to prepare it as a rental property, authorities said.

The force of the blast also shattered the windows of a building at 2311 87th Ave., where three adults and a child were evacuated and were being assisted by the American Red Cross, Drayton said.