DAVIE COUNTY, N.C. -- More than a dozen people remained hospitalized Tuesday, including four critically injured patients, after a fatal fire erupted at an adult care home.

Citing the oxygen tanks used by some residents of Davie Place Residential Care, officials said "an explosion could have happened" and ignited the blaze late Monday night. The home, about 25 miles southwest of Winston-Salem, housed about 50 people.

"Until the investigation is finished, we haven't ruled out anything," assistant Davie County manager Beth Dirks said at an afternoon news conference. "We are in the final stages of the investigation."

George Minor of Mocksville was killed in the blaze, Dirks said. Four patients were in critical condition at Wake Forest University Baptist Medical Center in Winston-Salem, and another 15 patients were in other hospitals but their conditions weren't released.

Two police officers also were treated for smoke inhalation. None of their names were released.

Dirks said inspection records at the home were up to date and she didn't know of any problems. She also said investigators don't believe arson was the cause.

The fire was reported as an explosion just after 10 p.m. Monday in an older wing of the house that didn't have sprinklers, said William Whaley, director of facilities management in Davie County. The wing was constructed before building codes required sprinklers and therefore didn't violate current codes, he said.

Fire scorched the front wing of the one-story brick home and left holes in the roof, exposing burned furniture and mangled metal. Residents who didn't need medical attention were taken to Hilltop Assisted Living in nearby Davidson County.

The facility's most recent annual fire and safety inspection was conducted in May and showed no violations, according to documents provided by the state Department of Health and Human Services. The agency licenses and inspects adult care homes statewide.

Records show the home was cited in November for not providing therapeutic diets, but that violation was corrected and no major violations have been reported, said health department spokesman Jim Jones.

The home's license was renewed in December, and at the time the facility housed 49 residents including five under age 50 and eight over age 85, Jones said.

The facility appeared to be built in the 1960s, and records showed a 17-bed wing with fire sprinklers and a fire wall was added in 2000, Jones said.

Adult care homes offer assisted living, but not the 24-hour care and services offered at nursing homes. Some residents have cars and can come and go, Jones said.

Daniel Tuttle, the home's owner, didn't return a telephone message left at his office, but in a written statement thanked emergency workers for responding quickly. He didn't address the cause of the blaze or provide details of its investigation.