Kolkata, July 22 -- The death toll in the methane explosion inside the under-construction tunnel of the Teesta Stage-VI Hydel Project in Bengal's south Sikkim rose to 13 on Wednesday after another body was recovered, while 12 workers remained missing, officials said.

Rescue teams battled poisonous gases, mud and poor visibility to search for survivors. "Conditions are very bad inside. It is pitch-dark and hot inside. The tunnel is full of poisonous gases such as methane and carbon monoxide. The floor of the tunnel is full of mud and our legs were frequently getting stuck," said a member of the rescue team of Coal India Limited.

A total of 25 workers, who were working inside Adit-3 of the 15-km-long tunnel in Namchi district, connecting ...