Before the war in Bosnia and Herzegovina, a paper mill "Celpak" in Prijedor was draining wastewater into the Sana, just downstream from the town, so that the further flow of the river was considered polluted. From the outset of the war, and after the war to this day, the factory has been shut down and the discharge of wastewater is reduced to significantly smaller scale. At the center of Novi Grad the Sana reaches the Una river.