Thirty-one men working in a massive underground tunnel in Los Angeles were rescued Wednesday night after a portion of the structure collapsed, officials said.

None of the 31 construction workers rescued in the tunnel sustained visible injuries, according to LAFD. Firefighters said construction workers climbed over a roughly 12 to 15-foot pile of dirt to escape.

The Los Angeles Fire Department says 31 workers have been safely removed from an industrial tunnel after part of the structure collapsed.