The incident left one of the home's owners, Antony S. Khamala, with burns to his face, hands and a leg. Medics took Khamala to Duke University Medical Center. A neighborhood leader said he was later airlifted to the burn unit at UNC Hospitals.

Meanwhile, investigators began picking over the ruins of 1020 Ninth St., a 1,185-square-foot structure that, according to county property records, dates from 1919. The northern, larger portion of the roughly L-shaped house was knocked almost flat. The remains of the west wall drooped, bowed out, at an angle toward the street. A city fire station was only 300 feet away, but firefighters had no chance of saving the house. "When we got here, the house was on fire from front to back," Durham Fire Department Battalion Chief Andy Sannipoli said. "It was a matter of saving the houses on either side. That one was gone." Sannipoli and other officials at the scene wouldn't speculate about the incident's cause. As of about 12:30 p.m., fire marshals were still planning the investigation, Assistant Fire Marshal Edward Reid said.

The battalion chief did say, however, that the fact that the house's walls were knocked out was "indicative of some sort of explosion." The Fire Department's spokeswoman, Angelica Stroud, couldn't be reached for comment later in the afternoon.

Heat radiated by the fire did significant damage to the house just south of Khamala's, 1018 Ninth St. Its north wall was charred and fire penetrated its attic. James Amos was home inside 1018 Ninth St. when the fire broke out just after 9 a.m. He was watching television in a den on the north end of his house when he was startled by what he first thought was the impact of a tree falling against the structure.

But when he looked outside, the Khamala house was on fire. "In five minutes, the whole house was engulfed," Amos said, adding that Khamala "came out staggering" as it burned. Amos grabbed his dog -- a Yorky named Christina -- and ran out into the street in his pajamas. Given the damage to his home, he planned to spend the night with family members who live nearby.

The fire also damaged 1022 Ninth St., which belongs to the parents of Durham resident Susan Strickland. Heat melted the siding off the south wall of that house and damaged its electric meter, cutting its power, Sannipoli said.

Something also damaged its roof. Several shingles had been pushed up, and Strickland thought there might be a hole in it. All of the homes on the block, 1020 Ninth St. included, are heated by gas, said Strickland, who grew up in 1020 Ninth before her parents sold it in the late 1980s. Neighbors and friends said Khamala was alone in the house when the blaze occurred. His wife, Lori Khamala, was said to be visiting relatives elsewhere in North Carolina.

Lori Khamala is seven months pregnant and lost all the baby-related belongings she'd accumulated in recent weeks, family friend Marguerite Dingman said.

Old West Durham Neighborhood Association President John Schelp said Antony Khamala was a well-known figure in the Ninth Street area from having worked in a number of its restaurants. He now works as a field organizer for Democracy North Carolina, which has its headquarters nearby on Green Street. Schelp later passed along a report that Khamala, a native of Kenya, had been taken to UNC Hospitals. He also said Old West Durham residents were collecting clothing and other goods for the family at 1022 Rosehill Ave.