At least 10 people have died after a suspected methane gas explosion trapped 25 personnel inside the under-construction Head Race Tunnel of NHPC’s 500-MW Teesta Stage-VI Hydroelectric Project in South Sikkim, as rescue teams battled toxic fumes and difficult tunnel conditions.
The incident occurred at 1.04 pm on July 20 at Samardung, NHPC said. A sudden burst of suspected methane gas trapped or embedded inside rock formations triggered the explosion, generating dense fumes and toxic gases.
“Immediately, the project team activated its emergency response protocols,” NHPC said in a statement. “All possible efforts are being made for evacuation of the trapped personnel.”
The state-owned company said its project team was coordinating with the district administration, National Disaster Response Force, State Disaster Response Force, local authorities and other emergency agencies. A specialised rescue team from the Directorate General of Mines Safety has also reached the site.
“Our site engineering teams are working round-the-clock alongside the authorities to assist in stabilizing the tunnel environment and ensuring rescue,” NHPC said. Its top management is at the site and coordinating with rescue teams and local officials.
Union Power Minister Manohar Lal Khattar said the Centre was closely monitoring the situation and extending all possible assistance. He said rescue and relief operations were underway on a war footing.
Prime Minister Narendra Modi spoke to Sikkim Chief Minister Prem Singh Tamang and announced ₹2 lakh for the family of each deceased and ₹50,000 for every injured person from the Prime Minister’s National Relief Fund. President Droupadi Murmu also expressed condolences.
Rescue operations continued amid heavy rainfall, waterlogging and concerns over possible gas accumulation inside the tunnel, officials said.
NHPC said a detailed investigation would be undertaken to ascertain the cause of the incident and reiterated its commitment to supporting rescue agencies and affected families.