NHPC reports 10 casualties in Teesta VI tunnel gas explosion
NHPC Limited reported an incident at its Teesta Stage VI Hydroelectric Project in Sikkim on July 20, 2026, resulting in casualties and personnel trapped inside the tunnel. A sudden burst of suspected methane gas trapped inside the rocks caused an explosion inside the under-construction Head Race Tunnel (HRT) at Samardung, South Sikkim. The incident occurred at 1.04 P.M., generating dense fumes and toxic gases.
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NHPC Limited reported a methane gas explosion at its Teesta Stage VI Hydroelectric Project in Sikkim on July 20, 2026, resulting in casualties and personnel trapped inside the tunnel. A sudden burst of suspected methane gas trapped inside the rocks caused an explosion inside the under-construction Head Race Tunnel (HRT) at Samardung, South Sikkim. The incident occurred at 1.04 P.M., generating dense fumes and toxic gases.
The project team activated emergency response protocols and is coordinating with the district administration, National Disaster Response Force (NDRF), State Disaster Response Force (SDRF), and local authorities. A special rescue team from DG Mines-Safety has also arrived at the site. NHPC's top management is present at the location, supervising rescue operations alongside site engineering teams working round-the-clock to stabilize the tunnel environment.
As per the latest information, 25 personnel were trapped inside the tunnel. The company reported that 10 casualties have been confirmed so far. Efforts are ongoing to evacuate the remaining trapped personnel.
Incident Details
| Parameter | Details |
|---|---|
| Project | Teesta Stage VI Hydroelectric Project (500 MW) |
| Location | Samardung, South Sikkim |
| Date & Time | July 20, 2026, at 1.04 P.M. |
| Affected Area | Under-construction Head Race Tunnel (HRT) |
| Cause | Suspected methane gas explosion |
| Personnel Trapped | 25 |
| Casualties Reported | 10 |
A detailed investigation will be undertaken to ascertain the exact cause of the incident. The company stated it is extending full support to the rescue agencies and the affected families.
Historical Stock Returns for NHPC
| 1 Day | 5 Days | 1 Month | 6 Months | 1 Year | 5 Years |
|---|---|---|---|---|---|
| +0.42% | +0.66% | +0.52% | +6.10% | -7.13% | +209.59% |
How will this incident impact the commissioning timeline and overall cost structure of the 500 MW Teesta Stage VI project?
What regulatory safety audits or operational suspensions can be expected for NHPC's other under-construction tunnel projects?
Will this event trigger a reassessment of geological risk premiums and insurance costs for future hydroelectric projects in the Himalayan region?
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