Visakhapatnam: Four persons today died of asphyxiation and another hospitalised after inhaling poisonous gas in a septic tank, police said.

Police identified the deceased as Kandrakota Appa Rao (55), his son Rajasekhar (28) and Rao's nephews K Krishna (28) and Nageswara Rao (27). Krishna's brother Sattibabu has been admitted to hospital and his condition is said to be stable, police said.

According to police, Appa Rao has constructed a new septic tank around nine feet deep close to an old one of his house at Upamaka village in the district. Rao today entered the new tank to link it to the old one by drilling a hole with an iron rod.

Minutes later, poisonous gas drifted into the new septic tank from the old one and the man fell unconscious. His son tried to rescue him, but he too fainted, police said.

Noticing them in trouble, Rao's three nephews also attempted to rescue the duo but all were overcome by the gas, they said. Nakkapalle Sub-Inspector P Simhachalam said locals managed to bring them out.

However, four of them were found dead and Sattibabu, who was unconscious, admitted to hospital, police said. (PTI)