THE SCOURGE OF DEVELOPMENT: 25 Workers Killed in Sikkim Tunnel by Toxic Gas
On July 20 th, 25 workers were killed in the under-construction Head Race Tunnel( HRT) of NHPC’ s 500 MW Teesta Stage VI hydroelectric Project at Samardung in Sikkim’ s Namchi district. The NHPC authorities claim that the incident occurred due to sudden explosive release of suspected methane gas trapped / embedded in the rocks resulting in generation of dense smoke and toxic gasses; suggesting to the sudden release of suspected methane trapped in the rocks when the workers hit such rocks resulting in an unexpected explosion and partial damage to the tunnel and the workers killed.
With such a suggestion it is mooted to make believe that this disaster is an isolated misfortune, which was unexpected and unforeseen.
As usual with regards to such disasters and man-made calamities, the PM Modi expressing his surprise, called the Sikkim CM and enquired about the situation. The CM of Sikkim announced that the state government would constitute a high-level inquiry committee to ascertain the cause of the incident and the state government would provide exgratia to the families of the deceased workers. The National Hydro-electric Power Corporation too announced that a detailed investigation will be conducted to time out the cause of the incident.
The workers killed in this incident are from West Bengal, Sikkim, Uttarakhand and Assam states. However, their status employment, whether they are temporary workers, casual workers, out-sourcing workers supplied by private contractors is not known.
With announcement of conducting enquiry and payment of exgratia, the state government of Sikkim and NHPC washed out their hands and September-2026 absolved themselves, from their human sacrifice of workers at the altar of‘ development’. This became a continuous practice of both the private sector and public sector units, causing the death of workers due to their culpable negligence and carelessness towards workers’ lives without any compunction and accountability.
The State and Central governments under the pretext of development have been constructing a series of hydro-power projects along the 400-KM stretch of the Teesta that links Sikkim, West Bengal and Bangladesh in the fragile Himalayan belt which is environmentally vulnerable. This Himalayan region is highly prone to earthquakes. With heavy blasting and tunneling for highways, dams, and railways, the geological instability is increased in this region leading to frequent landslides and mudslides. Heavy tourism, unregulated urban expansion, poor waste management and deforestation have compounded the problems of vulnerability of this region.
Sikkim suffered from extreme weather events such as cloud bursts, rapidly melting glaciers and expanding glacial lakes due to climate change and the hydro power projects in the state have suffered of these factors. The glacial out-burst flood in October 2023 damaged NHPC’ s 510 MW Teesta-V hydro power project which was restored three years later.
This present incident of Toxic gas killing in the HRT tunnel cannot be treated as unexpected and unforeseen occurrence. It is an incident created by the culpable negligence of the NHPC administration, with utmost disregard to the lives of workers working in the HRT tunnel, despite many experiences in the past of the flammable gas encountered repeatedly and caught fire more than once inside HR tunnels of Stage-VI Teesta project in the year before this present incident of explosion.
A paper authored by five NHPC engineers and presented at EURDENGEO-2024, the 4 th regional Conference of the International Association at Croatia sets out the geological difficulties faced in completing the 500 MW projects two head race tunnels, each about 13.7 km long. It mentions about‘ flammable gas’ that was detected in November 2009, during excavation at a tunnel face where it“ burst in to flame”. Afterwards again gas was reported seeping from the tunnel roof at a separate face where a detector recorded readings of up to 30 % of the minimum concentration at which methane in the air can combust. Both‘ faces’( the working ends of a tunnel) reached the home access tunnel in which the present July 20 blast occurred killing 25 workers.
The paper attributes the gas to the rock itself noting that it was detected at the contact between hard quartzite and softer phyllite. The project’ s tunnels pass through young fractured Himalayan rock in Seismic Zone IV including carbonrich phyllite of the kind associated with trapped gas.
The paper also notes that several excavated stretches had collapsed, with cave-ins reaching the surface at some locations, while the access adits were flooded. The paper is titled,“ Planning and Methodology Adopted to Deal with Adverse Geological Problems Encountered during HRTS Excavation of Teesta-VI Hydroelectric Project( 500 MW), Sikkim, India.”
By this we can understand that the present explosion of methane gas killing 25 workers is not contd. in page 14 13