Rescue efforts hampered as toxic gas blocks access to 13 trapped workers in India tunnel collapse

A methane gas explosion that tore through a hydropower tunnel in northeastern India on Monday has left 13 workers trapped and hampered ongoing rescue efforts. The blast occurred at the 500-megawatt Teesta Hydroelectric Project in Sikkim state’s Himalayan region, killing 12 workers whose bodies have since been recovered by authorities. Rescue teams continue to struggle Wednesday to access the remaining 13 trapped workers.

Specialized rescue crews equipped with breathing apparatus and night-vision technology face significant obstacles in penetrating the tunnel, according to administrative official Anupama Tamling. The hazardous conditions stem from both elevated toxic gas levels and substantial water accumulation within the structure, which lies approximately 40 kilometers south of the state capital Gangtok.

The Teesta River basin, where the hydroelectric facility is under construction, sits within a seismically active zone characterized by young, unstable rock formations containing numerous fractures and subsurface cavities capable of harboring ancient trapped gases. Experts point to the combination of fragile geology, seismic instability and unpredictable underground conditions as particularly dangerous factors for tunnel construction projects throughout the region.

The incident follows a February explosion at a coal mine in neighboring Meghalaya state that claimed 18 lives. In 2023, a tunnel section collapse in Uttarakhand state left 41 workers trapped for 17 days before their eventual rescue.