Tunnel Horror / Seven Workers Killed, 18 Trapped After Methane Explosion at NHPC Tunnel in Sikkim

Gangtok, Jul 21: At least seven workers were killed and 18 others remain trapped after a methane gas explosion inside an under-construction tunnel of the NHPC Teesta Stage-VI Hydroelectric Project in Sikkim's Namchi district, officials said on Tuesday.

Rescue teams continued operations for the second consecutive day amid hazardous conditions, including methane gas, low oxygen levels, poor visibility and a narrow tunnel passage.

Explosion Riggered Landslide Inside Tunnel
Officials said 25 workers, including National Hydroelectric Power Corporation (NHPC) personnel, were inside the tunnel when methane gas, which had accumulated about 1.5 km from the entrance, ignited during an attempt to vent it.

The explosion triggered a landslide that blocked the tunnel entrance, trapping workers inside. While some managed to escape immediately after the blast, 18 remain stranded.

The district administration has confirmed the deaths of seven workers.

Hazardous Conditions Hamper Rescue Efforts
The rescue operation has been severely affected by methane gas and depleted oxygen levels inside the tunnel.

An initial rescue attempt by the Fire and Emergency Services was abandoned after rescuers experienced breathing difficulties. Several personnel reportedly fell ill during the operation.

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

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Specialised Rescue Teams Deployed
To strengthen the operation, a specialised rescue 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 have also been deployed.

Multiple Agencies Involved In Rescue Operation
The district administration received information about the incident at around 3:40 pm on Monday, following which teams from the NDRF, State Disaster Response Force (SDRF), Sikkim Police, Fire and Emergency Services and other agencies rushed to the site.

The rescue operation is being carried out under the supervision of the Sikkim State Disaster Management Authority (SSDMA), with support from NHPC, the Health Department and other line departments.

Authorities said efforts are continuing to safely evacuate the trapped workers.