Los Angeles: A massive and complex rescue operation concluded successfully early Thursday morning in Wilmington, a suburb of Los Angeles, USA, after an industrial tunnel collapsed late Wednesday, trapping dozens of construction workers underground. All 31 workers initially feared isolated by the collapse have been safely brought to the surface, with no serious injuries reported.

The incident occurred around 8 PM local time on Wednesday within the Los Angeles Effluent Outfall Tunnel, a critical component of the $630.5 million "Clearwater Project" aimed at modernising the region's wastewater infrastructure. The tunnel, under construction by Flatiron Dragados, is designed to be 7 miles long and 18 feet in diameter, situated approximately 450 feet below ground. The collapse took place roughly six miles south of the only known access point at 1701 N Figueroa Street, significantly complicating rescue efforts.

The Los Angeles Fire Department (LAFD) swiftly mobilised over 100 personnel, including highly specialised Urban Search and Rescue teams trained for confined-space and tunnel rescues. Firefighters worked through the night, utilising a crane and an elevator system, often referred to as a "bird cage," to extricate the workers in groups.

Workers on site reported climbing over a 12-15-foot pile of loose soil to reach a safer area within the tunnel before being hoisted to safety. While all 31 individuals were rescued without life-threatening injuries, some received medical evaluations for minor ailments and fatigue.

Los Angeles Mayor Karen Bass commended the rapid and effective response of the first responders, stating on X, "LAFD has just reported that all workers who were trapped in the tunnel in Wilmington are now out and accounted for. I just spoke with many of the workers who were trapped. Thank you to all of our brave first responders who acted immediately. You are L.A.'s true heroes."

The Los Angeles Effluent Outfall Tunnel project is a crucial undertaking to replace ageing wastewater tunnels built in 1937 and 1958. It aims to ensure the safe transport of treated wastewater from the Hyperion Water Reclamation Plant to the Pacific Ocean, enhancing seismic resistance and preventing overflow concerns during heavy rains.

The exact cause of the collapse remains under investigation. Federal and state occupational safety agencies are expected to launch probes into the incident to determine the factors that led to the tunnel's partial failure. The successful rescue, however, stands as a testament to the dedication and expertise of Los Angeles's emergency services.