Police on Thursday evening sealed a chemical factory in Bin Qasim area of Karachi after four workers died of inhaling toxic fumes in an underground tank of the industrial unit, said Malir SSP Rao Anwar.

The bodies were shifted to the Jinnah Postgraduate Medical Centre (JPMC) for postmortem examination, whereas, another worker was rescued from the tank, he said.

Rao Anwar said that efforts were underway to detain the owner of the factory who lives in Gulshan-i-Iqbal. Some workers of the factory have been taken into custody for interrogation, he said, adding that no safety arrangements were visible at the underground chemical tank of the factory for prevention of loss of lives.

The victims were not provided with any protective gadgets, despite the fact that the provision of such gear is mandatory as per the rules, he maintained.

The latest incident, which came as a grim reminder of the last year's incident at a factory in Korangi area that had claimed five lives, indicates that gross violation of safety rules continues to exist.

Bin Qasim police SHO Dhani Bux told Dawn that the labourers died ostensibly because of inhaling fumes of chemicals inside a water tank in the Scada chemical factory near Ghaghar Phatak.

The official said that a labourer went inside the water tank purportedly to fix the fan when he slipped and fell down inside the tank, whereas, three other workers died while trying to save their colleague. Another worker was rescued and hospitalised, he said.

The deceased were identified as Zahoor Ahmed, Tanveer Ahmed, Faizan and Faisal while Ali Shah was rescued.

Later, Sindh Chief Minister Murad Ali Shah sought a detailed report on the issue from the secretary labour department.