LOS ANGELES (TNND) — Thirty-one construction workers working inside an industrial tunnel in Los Angeles on Wednesday night miraculously reached safety after a portion of it collapsed.

The Los Angeles Fire Department said the incident was reported around 8 p.m. in the 1700 block of N. Figueroa Street in the Wilmington area of the city and involved at least 31 tunnel workers.

More than 100 LAFD personnel, including Urban Search and Rescue teams, responded to the scene, according to Mayor Karen Bass.

The workers were able to scramble over loose soil more than 12 feet high to reach the tunnel boring machine to be transported back to the opening, the fire department told media outlets. Video showed workers being brought out of the tunnel in a yellow cage hoisted up by a crane.

Robert Ferrante, chief engineer with the Los Angeles County Sanitation Districts, called it a "tense situation."

"Tonight, we were lucky," LAFD Interim Chief Ronnie Villanueva said during a news conference. "It was determined that a structure failure of the tunnel lining failed approximately five to six miles in."

Bass said she met with some of the workers after racing to the scene, expecting "to find tragedy."

“I know when we raced down here I was so concerned that we were going to find tragedy. Instead, what we found was victory," she said. "All of the men that were in that tunnel, rescued, up, safe.”

The tunnel is being constructed almost entirely underneath public right-of-way. The structure is 18 feet wide and will be 7 miles long to carry treated wastewater from across Los Angeles County to the Pacific Ocean.

Authorities said work will not resume until the project contractor assesses what happened and deems it safe.

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Editor's note: The Associated Press contributed to this article.