In 2025, approximately 5.9 million liters of substances hazardous to water were unintentionally released into the environment in Germany, according to statistics released by the Federal Statistical Office (Destatis) on Monday. This figure represents an 8.9 percent decrease compared to the previous year, 2024, when 6.5 million liters were released.
Furthermore, 2.4 million liters (41.1 percent) of the leaked substances could not be recovered and remained permanently in the environment. This is an increase from the roughly 2.0 million liters that remained in 2024. While fluctuations in these figures are not unusual-as the amount of released and residual pollutants depends on the nature and severity of accidents-the overall number of accidents involving water-hazardous substances decreased by 5.3 percent from the prior year to reach 1,461. This represents the lowest level since 2010 and confirms the downward trend in accident rates that has been ongoing since 2017.
Water-hazardous substances are classified based on their contamination potential as either “generally water-hazardous” or into one of three Water Hazard Classes (WGK). Among the 2.4 million liters that remained in the environment in 2025, the largest proportion, 1.7 million liters (69.9 percent), belonged to the “generally water-hazardous” category. This group included 805,300 liters of slurry, manure, and silage effluent (JGS), and 882,200 liters of fermentation substrates and remains.
Other substances included 76,800 liters (3.2 percent) of “weakly water-hazardous” materials (WGK 1), such as ethanol or soda lye. An additional 198,900 liters (8.2 percent) were classified as “clearly water-hazardous” (WGK 2), which includes mineral oil products like heating oil or diesel fuel. The most dangerous substances are the “strongly water-hazardous” materials (WGK 3), such as mercury or gasoline. In 2025, 43,500 liters (1.8 percent) of these were released and remained in the environment, causing potential damage. The remaining portion (16.9 percent) could not be classified.
Analyzing the 1,461 accidents, 741 (50.7 percent) were attributed to human behavior. Accidents are broadly differentiated between those occurring during handling and those during transport. In 2025, 477 accidents happened during handling, 214 of which resulted from faulty behavior, such as operational or assembly errors. In total, 984 accidents occurred during transport, 741 of which were linked to human error, including single-vehicle accidents or collisions with other vehicles.
Regarding environmental impact, the released substances entered a surface water body, such as a river or lake, in 432 cases. Canal systems were affected in 370 instances. Groundwater was polluted in 46 cases, and the immediate water supply was affected in two of those incidents. Overall, in 708 accidents in 2025, at least one water body was directly contaminated 850 times by released pollutants, with 135 accidents involving the pollution of two or more water bodies.
