Four people died after inhaling toxic gas of a septic tank in Naogaon this morning.

The dead are Roton, 32, Imtiaz, 28, Babu, 30, and Dilbor, 35.

Zakir Hossain, officer-in-charge of Naogaon Sadar Police Station, said Roton, a construction worker, went inside the newly built septic tank of a one-storey residential building at Goali village to fix a problem around 6:30am.

As he was not responding, Imtiaz, son of the building owner, entered the tank to check.

But Imtiaz also stopped responding after few minutes, prompting neighbours Babu and Dilbor to climb down the tank, the OC added.

Later, locals broke the septic tank and found Roton dead and the other three in unconscious state.

The trio was rushed to Naogaon Sadar Hospital where doctors pronounced them dead, the OC said.

All the bodies were sent to morgue for autopsy, OC Zakir added.