The welding in a unit at a five-story Hollywood apartment building appears to be the source of the triggering of multiple carbon monoxide alarms that forced the evacuation of at least three units Thursday night.
“All of the affected units have been fully ventilated and all readings have returned to normal and the evacuated residents have returned to their units,” said Los Angeles Fire Department spokeswoman Margaret Stewart.
Firefighters dispatched at 7:49 p.m. to 7320 Hawthorn Ave., between Hollywood and Sunset boulevards, near La Brea Avenue, reported that a five-sensor gas monitor indicated the presence of hydrogen cyanide and carbon monoxide, predominately in one corner of the building's first occupied floor, the LAFD reported.