An estimated 40,000 litres still to be recovered during a planned follow-up operation next year."The professionalism and seamanship of the maritime authorities was of a very high standard. Every stage of the operation had been carefully planned and practised," said Commander Toni Joutsia.Yle News15:02The Finnish Environment Institute and the Finnish Navy have so far removed around 60,000 litres of fuel oil from the wreck of the coastal defence ship Ilmarinen during an operation carried out earlier this month, according to the Ministry of the Environment.The warship, which sank off the island of Utö after striking a sea mine in September 1941, is considered one of the most environmentally hazardous wrecks in the Baltic Sea. Authorities estimate that it originally contained around 100,000 litres of fuel oil.The operation, carried out between 14 and 24 July, was led by the Finnish Coastal Fleet in cooperation with the Finnish Environment Institute. Naval divers pumped oil directly from the ship's fuel tanks through holes drilled into the overturned wreck, as the multipurpose ship Louhi and oil recovery vessel Halli supported the work. The Finnish Border Guard were also on standby in case of environmental damage concerns.The Ilmarinen lies upside down on the seabed, its keel towards the surface. Image: RajavartiolaitosDuring the operation, crews recovered a significant amount of oil from the wreck. However, project manager Tommi Kontto of the Finnish Environment Institute said the rough sea conditions repeatedly interrupted work, forcing the operation to end about a day earlier than planned.An estimated 40,000 litres of fuel oil remain inside the wreck, and authorities plan to continue the removal operation next year.According to Coastal Fleet Chief of Staff Commander Toni Joutsia, the recovery was demanding because the wreck is upside down at a depth of 60–80 metres, requiring strict safety measures for both divers and surface crews.Minister of Climate and the Environment Sari Multala welcomed the progress, saying the operation had significantly reduced the environmental risk posed by the wreck while stressing that the remaining oil still needs to be removed.During the initial phase of the operation, a small amount of oil leaked into the sea from the wreck. In the aerial photo, a thin oil sheen can be seen alongside the multipurpose vessel Louhi. Image: Harri Mäkitalo / Sukelluslääketieteen keskusBefore the operation, the Finnish Environment Institute found the wreck was leaking fuel oil at a rate of one to two drops per minute through corroded riveted joints in the hull.The Ministry of the Environment is funding the project through the AHTI Programme (2023–2027), which aims to improve the condition of Finland's waters and marine areas.A total of 271 of the war vessel's crew members died when it struck a sea mine and sank during the Second World War.The wreck is regarded as their final resting place, and authorities said preserving the site's sanctity was an important part of the operation.