Three persons have died and 15 others injured in a powerful blast that was followed by a blaze which ripped through a government industrial estate late last night, an official said in Palghar on Friday.

The explosion reportedly took place in the Novaphene Specialities Pvt. Ltd (NSPL), a chemical company, around 11.15 p.m. on Thursday, Palghar Police Control official Pramod Pawar said.

The blast was so deafening that it was heard in a radius of 10 km. Houses and buildings were shaken, and glasses shattered in a vicinity of around three km radius, Pawar told.

Eyewitnesses said the explosion "sounded like a huge bomb" and it happened when many were preparing to retire for the night.

Scared and shaken many mistook it for an earthquake and hundreds rushed out on to the streets and sat there for hours.

"During the search operations this morning, three unidentified bodies were found inside one of the factories, Arti Industries, that was destroyed in the blaze.

"We fear there may be more casualties. Rescue and search operations are still underway. Although the fire still blazes, it is now under control," Palghar Superintendent of Police Manjunath Shinge told the media.

Even as firemen and disaster teams had rushed to the site, the blaze had quickly spread to at least five other chemical companies in the vicinity, Shinge said. There were multiple explosions and fires reported, he added.

The blaze spread to adjoining Aarti Drugs, Prachi Pharmaceuticals, Bharat Rasayan, Unimax chemicals and another unit.

The rescue teams are working with protective masks.

The cause of the blast is not yet clear. Preliminary investigations indicate that a boiler containing industrial solvents may have burst under high temperature or pressure.

Efforts were still on to douse the flames in the NSPL's factory precincts.

The victims have been identified as Pintu K. Gautam, Janu Adaria and Alok Nath. The injured have been admitted to hospitals, Shinge said.