Six people died and 20 were hospitalised on Thursday in Gujarat’s Surat city after they inhaled toxic fumes at a chemical factory, The Indian Express reported. The gas leaked from a chemical tanker parked outside the factory.

Superintendent of Surat Civil Hospital Dr Omkar Chaudhary confirmed the deaths, while speaking to ANI.

The workers were inside the factory in Sachin industrial area when the gas leaked, said Surat Municipal Corporation’s Chief Fire Officer Basant Pareek said, PTI reported.

Sanjay Patel, production manager at one of the industrial units in the area said that a tanker was dumping chemicals in the nearby drain using a pipe, India Today reported. The workers fell unconscious after inhaling the fumes from the truck.

The fire department received a call about the incident at 4.25 am, PTI reported. The fire officials managed to prevent further leakage from the tanker.

Gujarat Chief Minister Bhupendra Patel expressed grief on the incident.

“Many people have unfortunately died due to gas leak in Surat,” he said in a tweet. “May the departed souls rest in peace and their kin get the strength to bear this. I also pray for the well-being of those who have fallen ill in this incident.”