Orlen said the blaze broke out in one of the furnaces before firefighters extinguished it.
Polish officials say two people have died in a fire at a facility belonging to state-owned oil giant PKN Orlen.
The fire at the plant near the central town of Plock, which includes an oil refinery, was soon extinguished on Tuesday, the company said.
Iwona Śmigielska-Kowalska, a spokesperson for the prosecutors’ office in Plock, said two people had died and an investigation has been opened into the incident.
Orlen said the blaze broke out in one of the furnaces before plant firefighters put it out. The other installations were not affected, Orlen said.