Worker Dies After Getting Trapped in Collapsed Trench with No Oxygen for Over 2 Hours

The worker was trapped underneath 6 to 8 feet of concrete and dirt on Thursday, the San Francisco Fire Department said

A contractor died on Thursday after he was trapped in a trench and buried under several feet of concrete and dirt in San Francisco.

The San Francisco Fire Department said the accident unfolded beneath the sidewalk at the intersection of Oak and Divisadero streets.

Several workers were performing utility work underground when the trench collapsed around 10 a.m. local time, according to CBS affiliate KPIX-TV. Five workers were able to get out, but one man was stuck.

"The San Francisco Fire Department responded and determined the need for Heavy Rescue units and accompanying support vehicles," the department said in a statement. "Over 50 Firefighters from both Heavy Rescue Squads, Light Rescue support vehicles and multiple Department rescue experts worked to gain access to the victim through the opening in the sidewalk and in the collapsed debris and dirt found in the space."

Related: 3 Workers Dead from 70-Ft. Fall as Scaffolding Collapses at Construction Site in Charlotte, N.C.

However, their efforts were unsuccessful and officials said the victim was found dead at 11:56 a.m. "This person was trapped under a lot of weight with no oxygen for over two hours," fire department spokesman Lt. Jonathan Baxter told ABC affiliate KGO-TV.

The San Francisco Medical Examiner was on scene, and the cause of the incident is under investigation, the department said. The California Division of Occupational Safety and Health is also investigating the incident, KGO-TV, KPIX-TV and The San Francisco Times reported.

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The worker, who has not been identified at this time, was employed by construction contractor D'Arcy & Harty Construction Inc., per KPIX-TV. It wasn't immediately clear what caused the trench to collapse.

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Rachel Gordon, San Francisco Public Works communications director, told The San Francisco Times that the agency is "inspecting to see what they were doing at the time of this trench collapse."

Related: 2 Men Killed After Being Struck by Truck and Falling into a Trench at Boston Construction Site

Gordon and the contracting company did not immediately respond to PEOPLE's requests for comment.

"Our deepest condolences go out to the family and loved ones of this worker, and our thoughts are with everyone affected by this situation," the fire department said in a statement.

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