The London Fire Brigade freed a woman from the debris, the Associated Press reported. She had been trapped for several hours when firefighters heard her calls for help.
Residents called the gas company to report an odor before duisaster struck, but utility crews "arrived two minutes after the blast," according to the BBC.
During the 36-hour search, a fire brigade safety officer alerted crews to a teetering chimney that collapsed seconds later in a hail of brick and mortar, the AP reported.
"It was a split second business," said Brian Clarke, a fire brigade spokesman, quoted by the AP. "We could have had a new disaster."
Government inspectors "concluded that the explosion was caused by gas leaking into the building from a crack in a cast-iron gas main," the BBC reported.
The BBC also said police chased looters from the site and "found a collection of plastic bags stuffed with £20 notes totalling thousands of pounds, among the debris."
