PATNA, India (AP) — An explosion at a privately-owned power plant in India ’s central Chhattisgarh state on Tuesday killed at least nine workers and injured 15 others, police said.

The blast occurred in a boiler tube at a power plant operated by Vedanta Limited, in Chhattisgarh state’s Sakti district, senior police officer Praful Thakur said. The cause of the explosion was not immediately clear.

Officials said rescue teams were searching the blast site for any trapped workers.

In a statement, the plant’s management said its immediate priority was to provide medical care to those affected and that it was working closely with local authorities. It added that an investigation had been opened into the cause of the blast.

Chhattisgarh state’s Chief Minister Vishnu Deo Sai described the incident as “extremely tragic” and said authorities were providing assistance to the families of those killed.

Industrial accidents are common in India and often blamed on people flouting safety norms, as well as lax inspections by government officials.