Officials are breathing a sigh of relief after more than 30 construction workers in an industrial tunnel in Los Angeles reached safety after it partially collapsed. 

The cave-in occurred between the tunnel boring machine 5 miles from the entrance and the construction workers who were working 6 miles in. 

The workers, who were about 400 feet underground, scrambled over loose soil more than 12 feet high to reach the tunnel boring machine and then were transported back to the opening. Aerial footage showed workers being brought out of the tunnel in a yellow cage hoisted up by a crane.

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None of those rescued had major injuries, authorities said.

"Everyone is safe. Thank you to L.A.’s first responders and to the people throughout our city who work every day to make L.A. better," Los Angles Mayor Karen Bass wrote on X. 

Speaking at a news conference, Bass said she had met with some of the workers.

"All of the men that were in that tunnel: rescued up, safe. We had an opportunity to speak with them. We had an opportunity to make sure they were able to reach their family members," Bass said. "Their family members knew they were safe. There were many anxious family members who were here waiting to make sure that their relatives were okay. We spoke with the paramedics while the paramedics examined the men as they came up. And I just have to tell you that we’re all blessed today in Los Angeles." 

Bass praised first responders as Los Angeles' "true heroes." 

LA City Councilmember Tim McOsker praised the workers for keeping cool heads.

"This is a highly technical, difficult project. And they knew exactly what to do. They knew how to secure themselves," he said. "Thank goodness for the good people that were down in the tunnel."

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

The $700 million project is being overseen by the Los Angeles County Sanitation Districts.

The cause of the collapse is under investigation. Authorities said work will not resume until the project contractor assesses what happened and deems the site safe.

The Associated Press contributed to this report.