A civic staffer died and four were injured after inhaling poisonous gases inside a manhole in Mumbai’s Grant Road early on Sunday, The Times Of India reported. The deceased was identified as Brihanmumbai Municipal Corporation employee Rakesh Nizab, 45.

The Gamdevi police have filed an accidental death report and are investigating the matter, the Mumbai Mirror reported.

The men had reportedly come to repair a pipeline inside the manhole near Girgaon’s Nana Chowk when they fell unconscious. Mumbai Fire Brigade Assistant Spokesperson Tanaji Kamble said all five men were extricated from the manhole and taken to BYL Nair Hospital, where Nizab was declared dead on arrival. The four injured – Balasaheb, Umesh Pawar, Suresh Pawar and Shantaram Bhakte – are out of danger, said hospital dean Ramesh Bharmal.

Bharmal confirmed that a postmortem examination was conducted and Nizab’s body was later handed over to his family.

Dr Shailesh Mohite, head of forensic medicine at the hospital, said the cause of the death is yet to be established. “We will be able to conclude only after the chemical analysis report from Forensic Science Laboratory in Kalina,” he said.

Milind Ranade, chief of workers’ union Kachra Vahtuk Shramik Sangh, claimed the Brihanmumbai Municipal Corporation had violated guidelines by not providing safety gear to the workers. “Senior civic officials should be held responsible for the death and for compromising the safety of conservancy workers,” he said. “Specific guidelines have been set to be followed before entering a manhole and workers should be provided safety equipment.”

Eleven such deaths were reported in the state last year. Three labourers had died of suffocation in an industrial drain in Dombivali East, and three firemen and two local residents died after entering a well in Kalyan’s Kolsewadi area. Three contract labourers cleaning a sewage line in Powai had died after the rope of the crane pulling them out of the manhole broke.

Similar incidents have been reported from New Delhi as well. In September last year, five men had died while cleaning a sewer at a residential complex in Moti Nagar. A preliminary investigation indicated that the workers were not wearing any safety equipment while cleaning the tank at the Phase 2 section of DLF Capital Greens.