New Delhi, Mar 24 (IANS): Two employees suffocated to death, while two others were injured on Saturday after they entered a kitchen waste treatment plant of a restaurant here to clean it, a police officer said.

The incident occurred at 2 p.m when four employees belonged to housekeeping department were doing cleanliness work inside the waste treatment plant of 'Pirates of Grill' restaurant at Rajouri Garden area of west Delhi, the officer said.

"During the cleanliness work, two staffers, Rakesh, 45 and Ajay, 19 came in contact with toxic gas and fainted inside the plant. When they did not respond, two other employees, Pankaj and Raju, stepped inside to check them, but also fainted and were injured," DCP Monika Bhardwaj said.

All four were pulled by a local police team and taken to the nearby Deen Dayal Upadhyay hospital, where Rakesh and Ajay were declared dead, while Pankaj and Raju are undergoing treatment, she added.

A case of causing death by negligence has been registered in Rajouri Garden Police Station and investigations are on, the DCP said.

The family members of Rakesh and Ajay, both residents of Tagore Garden area, alleged that they were hired for the housekeeping department but the restaurant management assigned them cleanliness work in the treatment plant.