New Delhi - At least four workers died and two others fell ill after inhaling poisonous gas which leaked from a steel plant in India's eastern state of Orissa, news reports said Monday.

The incident occurred at a private steel plant in Sambhalpur district, 350 kilometres north-west of the state capital Bhubaneshwar, on Sunday night, the IANS news agency reported.

"Four people died and I saw their bodies. They had no injuries," Sambhalpur police chief Sanjay Kumar told IANS.

"They have died after inhaling some poisonous gas," he said, adding that police was investigating the incident although the company had not informed them about it.

The PTI news agency reported that the victims were workers of the steel unit and the gas had leaked from the plant's blast furnace.

Two other workers fell ill and were admitted to a hospital in the nearby town Burla.

Senior police and administrative officials went to the factory site to launch the investigation. (dpa)