One worker has died and more than 35 people have been hospitalised after an ammonia gas cylinder leaked at a dairy factory in Bihar’s Vaishali district on Saturday, ANI reported.

The gas leak happened between 10 pm to 10.30 pm at Raj Fresh Dairy in Hajipur. As workers rushed out of the factory, a stampede-like situation occurred and many of them were injured, according to PTI.

“One worker has died while trying to evacuate from the dairy,” said Rajiv Kumar, the manager of the factory. “Seven to eight workers came in the gas exposure but all recovered soon. The situation in the plant is under control and we are trying to revive it.”

A witness said the gas that leaked dissolved in the air and spread for about four kilometers, causing difficulty in breathing. It is not clear how many people were present in the factory at the time of the incident.

According to a preliminary inquiry, the gas leak happened due to negligence from the factory side, PTI reported. But a fire department official said that the authorities are still investigating the cause of the leak.