At least eight people were killed and several others remained trapped after a methane gas explosion triggered a landslide inside an under-construction tunnel of the NHPC Teesta Stage-VI hydropower project in Sikkim on Monday, July 20, officials said.
According to the latest official update issued by the district administration on July 21, eight bodies had been recovered and shifted to Singtam District Hospital, STNM Hospital in Gangtok and Namchi District Hospital.
The incident occurred around midday after methane gas reportedly accumulated in a section of the tunnel around 1.5 km from the entrance. The gas exploded during an attempt to release it, triggering a landslide that blocked the exit route and trapped workers inside.
Several workers managed to escape shortly after the blast. However, officials said at least 25 workers were believed to be trapped, although the exact number was still being verified.
Namchi Deputy Commissioner Anupa Tamling said the estimated number of trapped workers had been revised from an earlier figure of 17 following preliminary verification.
“The figure has been revised based on preliminary verification. The number may still change as authorities continue cross-checking details with company officials and verifying the attendance records of workers present at the site,” Tamling said.
Rescue operations were severely hampered by hazardous conditions inside the tunnel. Initial efforts by personnel from Rangpo Fire and Emergency Services were suspended after dangerously low oxygen levels and the presence of methane gas were detected. Some rescuers reportedly fell ill during the operation.
National Disaster Response Force (NDRF) teams later attempted to enter the tunnel but were also unable to proceed because of the high concentration of gas and unstable conditions caused by the landslide.
The Namchi district administration said rescue operations were being conducted jointly by the NHPC, State Disaster Response Force, NDRF, Sikkim Police, Fire and Emergency Services, the Health Department and other concerned departments.
Senior officials from the district administration, NHPC, police and disaster response agencies remained at the site as teams worked to improve ventilation inside the tunnel and identify the safest route to reach the trapped workers.
The Sikkim State Disaster Management Authority said it was closely monitoring the situation and that further updates would be issued as more information became available.
