Detectors Were Disabled at Site of 4 Gas Deaths : Sepulveda: The carbon monoxide fumes might have been detected had the smoke alarms not been disconnected. No negligence was found on the part of the apartment owner.

Los Angeles city building inspectors said Monday that the buildup of carbon monoxide in a Sepulveda apartment that killed four people was not due to negligence by the building’s owner, confirming that the victims may have helped cause the tragedy by disabling their smoke detectors.

After a thorough examination of the 36-unit complex Monday morning, inspectors blamed the gas buildup, which also left one person in critical condition, on a blocked furnace exhaust vent on the roof that had been knocked out of position. They also said the blockage appeared to have existed for some time, but they were unable to determine exactly how or when the vent became dislodged.

Inspector Wayne Durand said the situation may have gone unnoticed because both smoke detectors in the apartment were inoperable. One was disconnected completely, and the sensor that detects the presence of smoke was covered with tape on the other.

He said the amount of soot on the walls and ceiling indicated that smoke backing up from the blocked vent “should have triggered the smoke detector.”

Durand and others interviewed Monday speculated that the residents of the apartment, all Vietnamese immigrants, may have disabled the smoke detectors to shut off the alarm sound, apparently unaware that the alarms signaled danger. They may also not have realized that the vent was not supposed to spew soot.

The five people were found in the apartment by a neighbor about noon Saturday. Preliminary coroner’s reports indicate that Tien Trinh, 35; Nga Bui, 30; Di V. Tran, 22, and Phuong Tran, 23, died from carbon monoxide poisoning. Ma Pham, 46, was in critical condition Monday at Panorama Community Hospital.

Southern California Gas Co. spokesman Ralph Cohen said the exhaust fumes accumulating in the apartment may have gone unnoticed because carbon monoxide has no odor. “They may not have smelled anything until it was too late,” Cohen said.

The gas causes drowsiness before eventual asphyxiation, according to Los Angeles County coroner’s spokesman Bob Dambacher.

Building owner Daniel L. Painter was ordered to replace the two smoke detectors, as well as make minor repairs to the furnaces in five apartments and obtain a permit for recent roofing work, Principal Inspector Donald Hubka said. None of the orders are intended to blame Painter for the deaths, Durand said.

“It doesn’t seem to be a negligent situation,” he said.

Painter could not be reached for comment.

Residents interviewed Monday about upkeep of the building, built in 1964, said repairs are made quickly. The only complaint about the complex filed with the city’s Department of Building and Safety was in 1988, when a resident complained that shower water alternated drastically in temperature between hot and cold. The inspector who investigated that complaint determined that there was no violation, Hubka said.

Following the deaths, other residents said they were nervous about the same thing happening to them. Inspectors said they examined every unit in the complex, but found no similar hazards.

Even so, several residents said Monday that they have turned off their heaters.

“I have an electric blanket,” assistant building manager Paula Primo said. “I’ll manage.”