Toxic gas slows efforts to rescue 13 workers trapped in India hydropower tunnel

GUWAHATI – Toxic gas prevented rescuers from reaching 13 workers trapped in a collapsed hydropower tunnel in India on Wednesday after a gas explosion two days earlier killed 12 workers.

The blast triggered by a buildup of methane gas tore through the tunnel Monday at the 500-megawatt Teesta Hydroelectric Project in northeastern Sikkim state in the Himalayas. Authorities have recovered the bodies of 12 workers who died inside the tunnel about 40 kilometers (25 miles) south of the state capital Gangtok.

Rescue teams equipped with specialized breathing equipment and night-vision gear were having difficulty entering the tunnel because of the gas and a buildup of water, administrative official Anupama Tamling said.

The Teesta River basin, where the hydropower project is being built, lies in a seismically active region marked by young, fragile rock formations riddled with fractures and underground pockets that can trap ancient gases. Fragile mountains, seismic activity and unpredictable underground conditions make tunnel projects especially risky in the region, according to experts.

A February explosion in a coal mine in neighboring Meghalaya state killed 18 workers. A tunnel section collapsed in 2023 in northern Uttarakhand state, trapping 41 workers for 17 days before they were rescued.