Jaipur, Jan 8 (IANS) Three workers at an oil refining plant here died of suffocation when they climbed into a oil tank to clean it Sunday, police said.Police have arrested two officials of the plant, charging them with not following required safety norms leading to the workers’ death.

The three deceased, identified as Gopu, Gopal and Shyamraj, were workers at a private oil refining plant, where used industrial oil is refined and disposed of, in Vishwakarma Industrial Area here, said police.

“The three workers were cleaning an oil tank at the plant in the morning. First Gopu climbed into the plant. When he didn’t come out for a long time, Shyam went in to check if he was okay and then Gopal followed,” a senior police officer told IANS.

All three were taken out in unconscious state by a rescue team roped in by the police. “They were rushed to a hospital where they died while undergoing treatment,” said the officer.

The post-mortem examination has suggested that the workers died of suffocation. “We suspect that there were poisonous gases in the tank,” said the officer.

He said that the workers had not been provided with masks and other safety equipments.

“We booked plant’s two owners, Pankaj and Dipak, on charges of culpable homicide not amounting to murder,” said the officer.