Thirty-one people working in a massive underground tunnel in Los Angeles were rescued Wednesday night after a portion of the structure collapsed, officials said. Those rescued didn’t have any visible injuries,

A portion of a huge industrial tunnel under construction in Los Angeles collapsed Wednesday and up to 15 workers may have been trapped, the Los Angeles Fire Department said.

More than 100 LAFD rescuers were on the scene, working for nearly two hours to pull the workers out of the tunnel.