Entrapped Gas Pressure Suspected Behind Fatal VSP Explosion

A build-up of pressure caused by gas trapped inside molten steel is emerging as a key factor behind the June 8 explosion at the Rashtriya Ispat Nigam Limited (RINL)-Visakhapatnam Steel Plant (VSP) that has claimed nine lives, according to sources familiar with the ongoing investigation.

The suspected cause was reportedly shared by VSP officials with a three-member team of Central experts probing the accident. The victims include five permanent employees and four contract workers.

According to sources, the steelmaking process involves injecting high-pressure oxygen into molten iron heated to around 1,600°C to remove impurities such as carbon and silicon. However, if the process is expedited, some oxygen can remain trapped within the molten metal, creating pockets of high pressure.

Plant sources alleged that the batch of molten steel involved in the accident was moved to the next stage before adequate time was allowed for the trapped gases to dissipate.

The explosion is believed to have occurred when an overhead crane was transporting a ladle filled with molten steel. Sources said the pressure inside the ladle rose sharply, causing the slide-gate assembly at its base to fail and releasing tonnes of molten steel onto the shop floor where workers were present.

Investigators are also examining reports of another incident that occurred less than 30 minutes before the fatal blast. Sources claimed that at around 3.57 pm, a ladle in Steel Melt Shop-2 (SMS-2) exploded after a transport car malfunctioned, spilling nearly 60 tonnes of molten steel. Sixteen workers reportedly escaped unhurt.

Information about the incident was allegedly circulated among employees through WhatsApp groups, sources said.

At around 4.25 pm, just 28 minutes later, a second and far more devastating explosion occurred in Steel Melt Shop-1 (SMS-1), leaving workers with little time to react. Investigators are now examining whether the two incidents were linked and whether any warning signs were missed before the tragedy unfolded.