Detected oil spills in the Baltic Sea reach all-time low (WK-intern) - Half of detections substance other than oil Link The number of oil spills in the Baltic Sea detected through daily aerial surveillance reached an all-time low again in 2015. According to the annual HELCOM report now available, also the size of spills spotted in the region continue to decline following long-term trends. Striking is that half (49%) of all spill detections were identified as substances other than oil or as unknown observations—highlighting the ongoing need to track various kinds of spills. Nonoil-based discharges, which only have been reported to HELCOM since 2014,