A powerful explosion hit the Brod oil refinery in northern Bosnia near the Croatian border on Tuesday and several workers were injured, police said.
Police and firefighters are trying to extinguish the blaze after the explosion at around 9.30 p.m. local time (1930 GMT), said police spokeswoman Dragana Kerkez.
"This was a strong explosion and the detonation could be heard in Slavonski Brod," Kerkez told Reuters, referring to the town just across the Sava river in Croatia.
Brod Mayor Ilija Jovicic said that some of injured workers were hospitalised, the Srna news agency reported.
Photos taken on mobile phones and published on Bosnian web sites showed a fire at the plant.
The Brod refinery is majority-owned by Russian state oil company Zarubezhneft.