Finnish rescue services urge public to check if water surface film is pollen or oil

Emergency responders in South Savo have answered over ten false alarms on Saturday after pine pollen floating on water was mistaken for oil spills, Yle reports.

Calls came from across the region, with crews dispatched to investigate suspected oil slicks that turned out to be concentrated layers of pine pollen. The pollen collects in sheltered bays and along island shorelines, forming large rafts on the surface. A bluish film—resembling an oil sheen—can separate from the pollen, leading to confusion.

Authorities ask the public to verify the substance before reporting. A simple test with a stick can distinguish between the two: pollen rafts break into smaller patches when disturbed, whereas mineral oil reforms into a single slick when pressure is applied.

According to the University of Turku’s Norkko research group, spruce and pine trees are currently pollinating in southern and central Finland, with the season now beginning in southern Lapland. Heavy concentrations of conifer pollen appear as yellow deposits on surfaces.