Battling toxic gas, low oxygen levels and narrow underground passages, rescue teams from the NDRF, SDRF, police and fire services carried out a high-risk operation lasting several hours to bring the workers to safety.
BY PC Bureau
July 20: All 16 workers trapped inside an under-construction tunnel at the NHPC Teesta Stage-VI Hydroelectric Project in Sikkim’s Namchi district were rescued safely on Monday after an arduous operation involving multiple rescue agencies. The workers were taken to a Primary Health Centre in Rangpo for medical examination and are reported to be in stable condition.
The workers had been trapped after a suspected methane gas explosion inside the tunnel triggered a landslide, sealing a section of the underground passage and cutting off their escape route. Authorities confirmed that no fatalities or serious injuries were reported.
Methane Explosion Triggers Tunnel Collapse
The incident occurred inside the Jholungey (also known as Samardung) adit tunnel, where construction work is being carried out by Patel Engineering for NHPC’s Teesta Stage-VI Hydroelectric Project.
According to officials, methane gas had accumulated nearly 1.5 kilometres inside the tunnel. Preliminary findings suggest that efforts to vent the trapped gas may have triggered an explosion, causing a landslide that blocked the tunnel and trapped workers inside.
While some workers managed to escape immediately after the blast, 16 others remained stranded deep inside the tunnel.
Rescue Teams Battle Toxic Gas
The district administration was alerted at around 3.40 pm, following which rescue teams from the National Disaster Response Force (NDRF), State Disaster Response Force (SDRF), Sikkim Police, Fire and Emergency Services and district administration rushed to the site.
The operation proved exceptionally challenging due to the presence of methane gas, dangerously low oxygen levels, poor visibility and narrow tunnel passages.
The first rescue attempt by the Rangpo Fire and Emergency Services had to be suspended after several rescuers experienced breathing difficulties and symptoms of gas exposure. A subsequent effort by NDRF personnel also encountered hazardous conditions, prompting authorities to deploy a specialised rescue team equipped with breathing apparatus and gas-protection equipment from neighbouring West Bengal.
After several hours of painstaking efforts, rescue personnel succeeded in reaching the trapped workers and bringing all 16 to safety.
🚨 BREAKING: Workers feared trapped inside the under-construction Samardung, Mamring tunnel after a landslide reportedly caused a gas leak and blocked part of the tunnel.
Rescue operations underway; some rescuers reportedly affected by gas exposure. Sikkim Police & emergency… pic.twitter.com/ixnQ1xGcp1— Sikkim Media (@SikkimMedia) July 20, 2026
Exclusive Footage Captures High-Risk Operation
Videos recorded by senior police officers, including the Additional Superintendent of Police, Pakyong, the Sub-Divisional Police Officer, Rangpo, and personnel from the Rangpo Fire Station, captured the difficult rescue operation inside the tunnel.
The footage showed responders navigating confined spaces, poor visibility and hazardous conditions while evacuating the trapped workers to safety.
Officials praised the coordinated efforts of the police, fire services, disaster response teams and district administration, describing the operation as a successful example of inter-agency coordination under extremely challenging circumstances.
Workers Stable, Probe Ordered
All rescued workers were shifted to the Primary Health Centre at Rangpo, where they underwent medical examinations. Officials said their condition was stable, and no deaths or major injuries had been reported.
Earlier, Namchi District Collector Anupa Tamling had said rescue operations were complicated by methane gas exposure and difficult working conditions inside the tunnel. She noted that the gas may have originated from disturbed underground geological formations, although the exact cause remains under investigation.
Ambulances and medical teams remained stationed at the site throughout the operation as a precautionary measure.
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Safety Under Scrutiny
With the rescue operation now complete, authorities have launched an investigation into the cause of the methane buildup and the circumstances leading to the explosion.
The incident has once again highlighted the significant risks associated with tunnelling projects in the geologically fragile Himalayan region, where unstable rock formations and naturally occurring gas pockets pose major challenges to infrastructure development.
Officials said safety protocols at the project site would be reviewed as part of the investigation to prevent similar incidents in the future.
