Deadly Mission District fire determined likely accidental

San Francisco Fire Department members fight blaze at 22nd and Mission Street in San Francisco, Calif., on Wednesday, January 28, 2015. San Francisco Fire Department members fight blaze at 22nd and Mission Street in San Francisco, Calif., on Wednesday, January 28, 2015. Photo: Scott Strazzante, The Chronicle Photo: Scott Strazzante, The Chronicle Image 1 of / 12 Caption Close Deadly Mission District fire determined likely accidental 1 / 12 Back to Gallery

An inferno that torched a three-story building in the Mission District in January, killing one man and leaving 58 others homeless, was likely accidental and possibly caused by an electrical short within a wall, city officials said Wednesday.

The blaze that tore through the mixed-use building at the corner of 22nd and Mission streets the night of Jan. 28 started in a wall in the southwest corner of the residential third floor, said Mindy Talmadge, a Fire Department spokeswoman.

The fire took off when it got to the attic, where it ran the length of the building and spread to the lower floors.

Because the fire started inside a wall, Talmadge said, it could have been caused by faulty wiring.

“Investigators could not rule out an unspecified electrical fault,” she said, reading from a soon-to-be-released preliminary report on the investigation.

The report states that hard-wired smoke detectors were present at the time of the fire but failed to sound, though it was unclear why, and that the building was not equipped with automatic sprinklers.

California began requiring sprinklers on new buildings in 1989. New buildings must also have sophisticated fire alarm systems loud enough to wake up sleeping people in every apartment.

Older buildings need only comply with whatever codes were in place when they were built, and the building at 22nd and Mission streets dates from either 1907 or 1910, according to city records.

Resident Elvis Rivera said shortly after the fire that he had painted each apartment but never saw smoke alarms inside.

Rivera’s roommate, 40-year-old Mauricio Orellana, died in the fire. Orellana was in his room in Apartment 300 wearing his headphones, said Rivera, who realized the building was burning only when his neighbor knocked frantically at his door, screaming, “Open up! I’m burning!”

Rivera helped his neighbor and a second roommate escape through a window.

Hawk Lou, whose family has owned the building since 1990, assumed full ownership in 2007 of the 18 apartments, 12 offices and 15 ground-floor restaurants and shops.

“I made sure everything was up to code. I did my part to maintain the building,” Lou said Wednesday. He declined to comment further, citing the advice of his lawyer and insurance adjuster.

Chronicle staff writer Nanette Asimov contributed to this report.

Kale Williams is a San Francisco Chronicle staff writer. E-mail: kwilliams@sfchronicle.com Twitter: @sfkale