10 workers killed, several trapped after explosion in Sikkim tunnel, rescue ops on

A suspected build-up of methane gas about 1.5 km inside the tunnel is believed to have exploded during a venting attempt, triggering a landslide that sealed the entrance.

In Short

• Methane gas explosion causes landslide over Sikkim tunnel
• 10 killed, 15 workers still remain trapped inside tunnel
• Rescue efforts face challenges from toxic gas and low oxygen

Ten workers were killed and at least 16 remain trapped inside an under-construction tunnel in Sikkim after a methane gas explosion triggered a landslide, blocking the tunnel entrance and cutting off the escape route.

A total of 25 workers, including National Hydroelectric Power Corporation (NHPC) personnel, were trapped inside the tunnel. Of them, 10 have been confirmed dead by the district administration, while rescue operations are underway to evacuate the remaining 15 workers.

Rescue teams are continuing a massive operation for the second consecutive day inside the under-construction tunnel of the NHPC Teesta Stage-VI Hydroelectric Project in Namchi district, amid challenging conditions.

The operation has been severely hampered by hazardous methane gas, low oxygen levels, poor visibility and the narrow tunnel passage, making it difficult for rescue personnel to reach those trapped.

Officials said methane gas, believed to be naturally emanating from underground strata or rock formations, had reportedly accumulated around 1.5 kilometres inside the tunnel. An attempt to vent the trapped gas is believed to have triggered an explosion, causing a landslide that blocked a section of the tunnel. While some workers managed to escape immediately after the incident, dozens remained stranded deep inside.

The district administration received information about the incident at around 3.40 pm on Monday, following which teams from the NDRF, SDRF, district police and Fire and Emergency Services rushed to the site.

An initial rescue attempt by the Fire and Emergency Services had to be abandoned after rescuers experienced breathing difficulties due to the presence of methane gas and low oxygen levels inside the tunnel. Several rescue personnel reportedly fell ill during the operation.

A subsequent attempt by National Disaster Response Force (NDRF) teams also failed to make progress because of the hazardous conditions.

To strengthen the rescue effort, a specialised team equipped with gas-protective equipment was brought in from neighbouring West Bengal. Additional personnel from the NDRF's 2nd Battalion based in Pakyong and Siliguri, along with other emergency response agencies, have also been deployed.

Meanwhile, Prime Minister Narendra Modi on Tuesday spoke with Sikkim Chief Minister Prem Singh Tamang to enquire about the rescue operations following the tunnel collapse. The Chief Minister said the Prime Minister expressed concern for the affected workers and their families and assured all possible assistance from the Centre.

Out of the 10 victims, three were from West Bengal -- Bolo Oraon, Gora Oraon and Bikesar Oraon; two were from Assam -- Babul Borodalai and Lakpa Dorjee Tamang; one each from Punjab and Uttarakhand -- Yasohal and Vikey Rawat. The identities of the remaining three bodies are yet to be established.

The Namchi District Administration, NHPC officials, the NDRF, State Disaster Response Force (SDRF), Sikkim Police, Fire and Emergency Services, the Health Department and other line departments, continued rescue efforts overnight under the supervision of the Sikkim State Disaster Management Authority (SSDMA).

- Ends