Indian government-run steel producer Rashtriya Ispat Nigam Limited has halted operations at its steel melt shop 1 (SMS 1) where an accident claimed the lives of nine workers and critically injured several others, according to company sources on Thursday, June 11.
The SMS-1 houses six casting machines, five of which typically run continuously. On the day of the accident, casting machines 1, 2, 3, and 4 had been operational. An explosion of molten steel at SMS-1 was followed by another explosion at casting machine 2 just 20 minutes later, leading to a crane becoming non-functional, apart from damaging cables and machinery throughout the section.
A preliminary investigation by the Department of Factories has indicated that the explosion at RINL might have been caused by the sudden release of entrapped gases in molten steel, triggering a powerful blast.
The report stated that a full ladle carrying molten steel had been rotated and positioned for casting. However, before the slide gate could be opened to transfer the molten metal, a sudden and severe explosion occurred.
The force of the blast was so intense that investigators were initially unable to determine whether the explosion originated from the ladle or the tundish. The report mentioned that a large fireball shot up to the roof of the shop floor, while an overhead crane operating in the area also caught fire.
“A worker stationed at Machine-4 reportedly witnessed flames reaching the ceiling immediately after the explosion. The workers positioned near Machine-2 bore the brunt of the impact,” the report noted.
The report identifies the “sudden release of entrapped gases in the liquid steel” as the anticipated cause of the incident. In steelmaking, gases such as oxygen, hydrogen and nitrogen can remain trapped within molten metal. If these gases accumulate and are suddenly released under certain conditions, they can create intense pressure, potentially leading to violent eruptions.
Employees alleged that a molten metal-related incident occurred at Steel SMS 2 barely 15 to 20 minutes before the fatal accident at SMS-1. While no injuries were reported in the earlier incident, a vehicle was damaged after molten material spilled during operations. Workers claimed a major accident was narrowly averted before the devastating explosion which occurred at SMS-1 later in the afternoon.