Two workers suffered serious burns Tuesday morning while they were repairing an elevator in the Park Plaza Apartments building at 2865 Park Blvd. in Palo Alto, according to Palo Alto Deputy Fire Chief Kevin McNally.
The men were transported to Santa Clara Valley Medical Center with injuries that although "critical" are not deemed life-threatening, McNally said.
Palo Alto's fire inspector and a staff member from the state's Division of Occupational Safety and Health are investigating the incident.
The employees, who worked for American Industrial Coatings, were applying a fire-proofing material in an elevator pit and a fire ignited when a light bulb popped, Frank Polizzi, a spokesman for the California Department of Industrial Relations, Cal/OSHA, said on Wednesday.
The incident occurred at about 10:40 a.m. Tuesday, as the pair were repairing an elevator in the building. Witnesses reported hearing an explosion, although the fire department staff has not been able to confirm those reports.
Firefighters found the injured workers in the elevator shaft in the building's basement.
An active fire was not immediately visible, but fire crews decided to evacuate the buildings, which house both residents as well as companies. Fire crews from Palo Alto and Mountain View were called to assist, and the power to the building was turned off.
Crews did not find any fire, and no smoke or fire damage could be seen on the exterior of the distinctive multistory building, which features yellow and red panels interspersed with corrugated metal siding.
"It appears that whatever happened was confined to the elevator," McNally said.
Evacuees were allowed back into the building at about 12:10 p.m.
Park Boulevard was closed to traffic between Page Mill Road and Olive Avenue as fire personnel responded to the incident, but the road has reopened.