Police said the preliminary investigation revealed that the incident occurred due to the explosion inside the gas chamber of the structure.
Four labourers, between the age group of 25 to 35 years, were found dead, they said.
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Meanwhile, Chief Minister Amarinder Singh announced a compensation of Rs one lakh each to the families of the deceased and Rs 50,000 each to the injured.
He directed the officials to ensure strict implementation of rules in the operations of all businesses and industries using sensitive materials.
The Chief Minister asked the district officials to investigate the incident and pin the responsibility for the mishap.
Amarinder said units deploying such gases and other dangerous materials need to follow strict rules and regulations to prevent the recurrence of such incidents.