The fire broke out at Puja Fabrics factory in Manpada MIDC area of Dombivali around 3.30 AM, fire officials said.
Twelve fire tenders were rushed to the site and the fire-fighting operations went on for over six hours before the flames were finally put off, they said.
Around 18 workers were rescued from the site and 14 others, who received severe burns in the fire mishap have been admitted to the Shivam Hospital in Dombivali, officials said.
The deceased workers have been identified as Kuldeep Moholi (38), Matiuddin Garib Miya (54), Nandakumar Jha (50) and Ram Prakash Tiwari (40) all are from Jharkhand, UP and Bihar.
The fire may have been caused due to mechanical problems, the fire officials said, adding the exact reason is not yet known.