Four people died whilst cleaning a manhole in Vehari district of south Punjab on Saturday.
The deceased were identified as Muhammad Aslam, Mohammad Nawaz, Muhammad Mushtaq and Muhammad Asghar.
Aslam got into a village manhole to clear the sewerage but fell unconscious.
The other three rushed to save him but toxic gases claimed their lives.
Rescuers reached the spot and retrieved the bodies.
A couple of days ago, three sanitary workers died in a well in Bhalwal area of Sargodha after inhaling toxic gas.
According to reports, four workers descended into the well in Satellite Town area of the city to clean it when they lost their consciousness and fell down due to the gas leakage.
They were taken to hospital where three of them died, while the fourth one had to be shifted to a hospital in Sargodha due to his critical condition.
A similar incident had taken place in the area a few days ago but the admin had not take notice.