A portion of Deepak Nitrite's chemical manufacturing facility in Nandesari industrial area on the outskirts of Vadodara city in Gujarat was engulfed by a major fire on Thursday evening, said officials.

Seven workers have been hospitalised after inhaling smoke, while some 700 people living in the vicinity of the factory have been shifted to safer places, officials said.

"Efforts are on to douse the massive fire, in which no injury has been reported. Seven workers who had inhaled the smoke were shifted to a nearby hospital for treatment. As a precaution, nearly 700 people living in the rural areas adjoining the factory have been shifted to safer places," Vadodara Collector RB Barad said.

A Vadodara fire brigade official said a powerful explosion also occurred when the fire started spreading in the factory during the evening, adding that 10 fire tenders are at the spot to douse the blaze.

The district collector said the cause of the fire was not known as yet.