A suspected methane gas burst inside the under-construction Head Race Tunnel (HRT) of NHPC‘s Teesta Stage-VI Hydroelectric Project in South Sikkim triggered an explosion on July 20, 2026, trapping 25 workers. Ten fatalities have been confirmed, while rescue teams continue efforts to evacuate the remaining trapped personnel.
Key Highlights
- A suspected methane gas burst triggered an explosion inside NHPC’s Teesta Stage-VI Head Race Tunnel in South Sikkim.
- Twenty-five personnel were trapped, with 10 deaths confirmed so far.
- NDRF, SDRF, DGMS rescue teams and district authorities are conducting rescue operations.
- NHPC has ordered a detailed investigation and pledged full support to affected families.
Faridabad, July 21: A tragic accident occurred at 1:04 PM on July 20, 2026, inside the under-construction Head Race Tunnel (HRT) of the NHPC Teesta Stage-VI Hydroelectric Project at Samardung in South Sikkim, after a suspected methane gas pocket trapped within rock formations suddenly burst, causing an explosion that generated dense fumes and toxic gases inside the tunnel.
According to NHPC, the incident resulted in 25 personnel being trapped inside the tunnel. As per the latest information available from the project site, 10 fatalities have been confirmed, while efforts are continuing to rescue the remaining trapped workers.
Immediately after the incident, NHPC activated its emergency response protocols and launched coordinated rescue operations with the District Administration, National Disaster Response Force (NDRF), State Disaster Response Force (SDRF), local authorities and other emergency agencies. A special rescue team from the Directorate General of Mines Safety (DGMS) has also reached the site to assist in the operation.
NHPC said its site engineering teams are working round-the-clock with rescue agencies to stabilise conditions inside the tunnel, clear hazardous gases and facilitate the safe evacuation of trapped personnel. The company’s top management has reached the accident site and is closely monitoring rescue efforts in coordination with local authorities.
The public sector power major stated that a detailed investigation will be carried out to determine the exact cause of the accident. While initial information indicates a suspected methane gas burst embedded within the rock strata, authorities will conduct a comprehensive inquiry before establishing the cause of the explosion.
Expressing condolences, NHPC said it remains committed to extending full support to the rescue agencies and the affected families. “In this hour of grief, the prayers of the NHPC family are with the affected families during this difficult time,” the company said in its statement.
The accident at the NHPC Teesta Stage-VI Hydroelectric Project is one of the most serious industrial incidents reported in recent months. Rescue operations remain the top priority as authorities continue efforts to evacuate those trapped, while a detailed investigation will examine the circumstances that led to the suspected methane gas explosion.
