Workers escape unscathed from L.A. tunnel cave-in

First responders saved all 31 people working in an underground tunnel Wednesday night after a portion of the structure collapsed. The cave-in occurred five or six miles from the tunnel’s only entrance in the city’s Wilmington neighborhood, according to statements from the Los Angeles Fire Department and county sanitation districts. The Los Angeles County Sanitation Districts are in charge of the $700 million project to build a new conduit for treated wastewater out to the ocean.

The collapse occurred while the crew was operating a tunnel boring machine about 400 feet below the surface, said Robert Ferrante, the chief engineer and general manager of the sanitation districts. He said the ground deformed and caused the incident. Work at the site will be stopped for an undetermined amount of time, he said. Trapped workers climbed over a big pile of loose soil—12 to 15 feet tall—to reach the rest of the crew on the other side of the collapse, according to the Los Angeles Fire Department. More than 100 firefighters responded to the scene and used cranes and rescue gages to hoist some workers out, Mayor Karen Bass said.

What tunnel were the workers building? The work is part of the city’s Clearwater Project that will replace aging infrastructure and construct a 7-mile tunnel underneath the city. Once complete, the tunnel will carry treated, clean wastewater from the Joint Water Pollution Control Plant to the ocean at Royal Palms Beach. Construction is expected to be completed in 2027. 

Dig deeper: Read Emma Freire’s report in WORLD Magazine about America’s aging wastewater treatment plants.