Two workers died on Wednesday while working inside a septic tank in Kaliakoir upazila of Gazipur.
The deceased were identified as Shahen and Mahbub Hasan, said Inspector Shahidul Islam of Mouchak Police Station.
According to eyewitnesses, the two went inside the septic tank of one Shamsul Haque's house in the Purbapara area of Safipur union around 4:00pm.
As they were not responding, another worker named Mohsin went inside the tank to try to rescue them and fell ill. Mohsin was later rescued and sent to hospital.
Police and witnesses said they believe the workers' deaths are linked to inhaling the poisonous gas accumulated inside the tank.
Police recovered the bodies and sent those for autopsy, said the inspector.
