At least 11 workers were shifted to a hospital following a massive explosion at a chemical factory in the industrial development area in Bolarum on the outskirts of Hyderabad on Saturday, the Hindustan Times reported.

Several other workers are feared to be injured and trapped inside the factory. However, there is no confirmation yet.

The blast took place in a private firm, Vindhya Organics, according to the Deccan Herald. Furnaces and reactors in adjacent units have been shut down and workers too have been evacuated as a precaution.

“The fire erupted in the factory supposedly due to the explosion of a reactor,” Sangareddy Divisional Fire Officer V Srinivas told the Hindustan Times. “We are trying our best to prevent the fire from spreading to other areas.”

Reddy said four fire engines went to the spot as thick fumes were seen billowing after the explosion.