Three contractual workers, who were injured in the mishap, later succumbed to injuries.
Three people were killed in a fire that broke out in a section of the rubber plant at the Reliance Industries' complex in Vadodara on Thursday.
The blaze erupted in the PBR2 (polybutadiene rubber) plant, the company said in a statement.
"In an unfortunate incident this morning, a fire broke out in PBR2 plant of the Vadodara complex. The fire was restricted to one section of the plant and timely action by Reliance fire-fighting team helped in quickly extinguishing the fire," it said.
Three contractual workers, who were injured in the mishap, later succumbed to injuries despite best efforts of the medical team, it said.
"Our prayers and sympathies are with their families in their time of grief and we will support the families to overcome their personal tragedy," the company said.
An investigation will be conducted to establish the cause of the fire, the statement said, adding that the rest of the complex continued with normal operations.