The exact cause of the initial blast is not yet known, official sources said, though prima facie, they cited lack of adequate safety measures as the cause behind the blast.
"Four people died on the spot, while four others suffered severe burn injuries," a fire department official said.
The deceased have been identified as Sachin Sawant, Narayan Parab, Sushil Sawant and Deepak Sawant.
Two severely injured workers were shifted to Mumbai, while the rest are recuperating at the Vinobha Bhave Hospital in the city.
In 2004, two people were burnt to death in a private company.
