Three sanitation workers died in Pune while cleaning a sewage tank at a private society on Friday, ANI reported.

The deceased workers have been identified as Nitin Gaud, Ganesh Bhalerao and Satishkumar Chudahari, according to The Times of India.

According to an unidentified fire brigade official, the three persons had entered the septic chamber at 6 am and fainted after inhaling poisonous gases.

“The society members immediately alerted the fire brigade and the police,” the official said, according to The Times of India. “Our team reached the spot and brought them out of the chamber.”

They were then taken to a hospital where they were declared dead by the doctors, the official added.