Three members of a family and a sanitation worker died after inhaling poisonous gases inside a septic tank in Chhattisgarh’s Mungeli district on Tuesday, the police said. The incident took place at Marrakona village under Sargaon Nagar Panchayat area, a police official said.

Sanitation workers had been called to clean a septic tank at the house of Mansharam Kaushik, he said. A member of the Kaushik family was looking inside after the tank was cleaned when he fainted and fell in.

Two other family members climbed down into the tank to rescue him but did not come out. One of the sanitation workers went in but he too fell unconscious, the official said.

Villagers informed the police who retrieved the four bodies after considerable efforts. The victims were identified as Akhileshwar Kaushik (40), Gaurishankar Kaushik (28), Ramkhilawan Kaushik (45) and sanitation worker Subhash Dagaur (35).

“Prima facie it seems they died after inhaling poisonous gases inside the septic tank,” the police official said, adding that a case has been registered and further investigation is underway.

Chief Minister Bhupesh Baghel expressed grief over the incident and directed the district administration to provide all possible assistance to the family of the victims.