At least seven people were injured after a boiler explosion at a public-sector coal mining company in Tamil Nadu’s Cuddalore district on Thursday, India Today reported. Four of them are in a critical condition.

The explosion occurred in Neyveli Lignite Corporation plant. “The accident happened in the evening and the injured workers have been admitted to the hospital,” an unidentified police official told IANS.

The police and fire services are on the spot and monitoring the developments.

This came after the country witnessed two other industrial accidents on Thursday. At least 11 people died and thousands were exposed after the styrene gas leak in Andhra Pradesh’s Visakhapatnam city. Meanwhile, seven workers fell sick after inhaling a poisonous gas at a paper mill in Chhattisgarh’s Raigarh district.