The blast took place in the 'Naphtha Cracker' plant of the oil major at around 2:30 PM, they said.
"One contractual employee of the IOCL died in the explosion," Panipat Superintendent of Police Rahul Sharma said over phone.
Of the five injured, the condition of two has been stated as critical, he said
The SP said technical teams were probing the incident and reasons that led to the blast could be clear by tomorrow.
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