Construction has resumed on the Twin Peaks Tunnel after a steel beam fell and killed a signal technician on Friday, according to transit officials.
The San Francisco Municipal Transportation Agency deemed the death accidental in a statement on Saturday night and said the area where the beam fell on the technician at around 4:30 p.m. is safe for workers to return.
Investigations by the California Occupational Safety and Health Administration and San Francisco Police Department halted construction on the 100-year-old tunnel Friday evening. The tunnel connects West Portal to Castro.
“We have taken extra precaution to ensure the tunnel is safe before returning workers to the project,” SFMTA Director of Transportation Ed Reiskin said in a statement. “We feel confident that the contractor, under the SFMTA’s oversight, has done everything possible to ensure construction can proceed safely.”
The SFMTA said the signal technician was pinned beneath a temporary steel beam that fell. Colleagues dialed 911 and the worker was rushed to Zuckerberg San Francisco General Hospital, where he died.
“Our sincerest condolences are with his family, friends and colleagues at this time,” Mayor London Breed said in a statement.
Construction on the tunnel began in June and is expected to continue through the end of August. The tunnel shuttles more than 80,000 passengers a day on the K-Ingleside, L-Taraval and M-OceanView lines.
An SFMTA spokesperson confirmed that the worker was a contractor for Shimmick Construction, an engineering company based in Oakland.
This story has been updated to include additional information.