BCPL Managing Director Prabhu Nath Prasad said IOT Ltd, a firm engaged for constructing the gas cracker project at Lepetkata, sent a labourer in the tank to check if it was clean.
When the labourer did not come out, another one was sent in by IOT officials to find out what happened to the first one, followed by two others even when the second one, too, did not return.
Hiren Gogoi and Harish Cheleng died before reaching the hospital, while Gajen Gogoi and Hemanta Das died during treatment there, district SP Rana Hazarika said.
After the incident, labourers of the IOT set ablaze the construction company's office in the BPCL campus and damaged some vehicles.
The angry workers alleged the IOT authorities failed to ensure safety of the labourers by not checking whether the 20-feet-deep PP storage tank had oxygen.
The Chief Administrative Officer of the IOT Ltd has been summoned from Mumbai by the BCPL, he added.
The BCPL is implementing Assam Gas Cracker project, the first ever petrochemical project in the North East region, that came as a part of the historic Assam Accord of 1985 for overall socio-economic development of the region.
With its foundation stone laid by then Prime Minister Manmohan Singh on April 9, 2007, the project is expected to generate scope for substantial investment in setting up of downstream plastic processing industries, thereby generating both direct and indirect employment.
