The shipwrecks at Måseskär
In an area west of the island of Måseskär in Skagerrak, 28 ships were scuttled after World War II. Over the years, low levels of chemical warfare agents have been detected in sediment and in fish, indicating that the ships contain dumped chemical warfare agents.
In 1992, low concentrations of sulphur mustard were detected in the sediments in the area, and in 2016 and 2017, low concentrations of the chemical warfare agent (CWA) Clark I was found in Norwegian lobster, flatfish and shrimps. Further studies are performed to investigate which wrecks contain chemical warfare agents, the extent of the contamination and their potential impact on the environment.
Questions and answers about the shipwrecks at Måseskär
All wrecks are located within an area of five square kilometres. The area is marked with a red ring on the map and is approximately 20 nautical miles west of Måseskär.
Thirteen wrecks have been found in the area, and another 15 close by.
Most of them were World War II warships. Some were relatively small vessels that did not take much cargo. Others were passenger- and merchant ships that were used for the transportation of materials.
After World War II, most of the ships were scuttled in 1946-1947.
The ships that were scuttled at Måseskär was damaged or worn out after the war and had no or low value. Full repairs was then not an option for the allies. The allies also had to get rid of several German war- and merchant ships seized after the war. Therefore, these ships were used in the dumping operations during 1946-1947 of conventional and chemical munitions.
The existing information regarding the content in the scuttled ships is contradictory but we know that at least 170 000 tons of chemical warfare agents were dumped in Skagerrak during this period. A large part of this was probably dumped at a greater depth in Arendalsdjupet, off the Norwegian coast, but there may also have been in the cargo of the ships that were scuttled outside of Måseskär. There is also a probability that there were conventional ammunition in the cargo, and smaller amounts of oil.
They are located at a depth of between 140 to 280 meters.
Chemical warfare agents can be found in metal containers, in bombs or in oil drums. When they were scuttled, the detonation caps had been removed from the bombs, so there was no risk of explosion during the journey.
We do not yet know how low concentrations of chemical warfare agents that have been found in the area might affect fish or other marine life.
In the Swedish Maritime Administration’s report Environmental hazards with sunken shipwrecks II (in Swedish).
During 2016 and 2017, an investigation was carried out close to the area outside of Måseskär. The study involved exploratory fishing and chemical analysis of fish and seafood from near the shipwrecks. The results were presented in the report Examination of biota in connection to scuttled vessels with chemical ammunition (in Swedish).