First responders rescued 31 trapped workers from a collapsed tunnel in Los Angeles on July 9, officials said.

Tonight, we were lucky,” interim L.A. Fire Department Chief Ronnie Villanueva said of the improbable rescue of the workers, along with four others who ran into debris to help

Workers were 400 feet (121 meters) underground and as much as 6 miles (9.6 kilometers) inside from the only entrance when the cave-in Wednesday evening threatened to trap them on the far side of the tunnel’s boring machine,