A report from India’s National Hydroelectric Power Corporation (NHPC) had documented gas fires in the tunnels of the Teesta-VI project before a fatal blast occurred on July 20, according to the company. The explosion took place in tunnel 4B of the hydropower project. NHPC stated that the incident likely resulted from an isolated gas patch near the tunnel’s face. The company described the event as sudden, giving no warning or time for workers inside to evacuate safely. The blast resulted in casualties, though the exact number has not been disclosed. The earlier report had flagged the presence of gas fires in the tunnels, indicating potential hazards. Investigations into the incident are underway. NHPC’s statement suggests that the patch was unexpected and could not have been anticipated despite prior warnings. The Teesta-VI project is located in Sikkim, India, and is part of a series of hydroelectric developments on the Teesta River. The incident raises questions about safety protocols in underground construction projects, where methane and other gases can accumulate. Authorities are expected to review procedures to prevent future occurrences.