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Up to 8 kg of mercury discovered in a shipwreck located in Estonian waters

Projects implemented by EIC
Ohtlikke vrakkide uurimise projekti lõpuseminar 7. veebruaril 2024 Image: Tõnn Tuvikene

There are nearly 700 shipwrecks in Estonian waters, 55 of which have been identified as hazardous to the environment – i.e., they are a pollution risk, covered with ghost nets, or have various explosives on board. The Environmental Investment Centre and the Police and Border Guard Board worked together to carry out underwater inspections of the three most dangerous wrecks. The shipwrecks examined included destroyers S31 and T22, and minesweeper M37.

At a seminar held today at the Joint Building of Ministries, the people involved in the project gave an overview of the condition of the three examined hazardous wrecks, and made recommendations to prevent the wrecks from becoming a danger to the environment.

According to Kaupo Läänerand, Deputy Secretary General for Maritime and Water Affairs at the Ministry of Climate, the state, together with experts and divers, closely examines some wrecks every year to identify how environmentally hazardous the wrecks are. ‘Of the 55 hazardous wrecks, we have now been able to examine 25 in more detail. Several wrecks have been in such a state that they have either had to be pumped empty of fuel, or cleaned of hazardous oil waste,’ Läänerand explained. ‘The priority for the Ministry is to have an increasingly better situational awareness of the hazardousness of wrecks, so that wrecks in critical condition can systematically be made environmentally safe,’ he added.

Most of the wrecks that sunk during World War II still have heavy fuel oil on board, which the vessels used as fuel. However, we do not know the quantities of said oil, or whether it could start to leak out in the near future. It is highly likely that there are even more shipwrecks, which are also more likely to be discovered as the technology evolves.

According to Aivi Allikmets, Project Manager at the EIC, the most important result of the project was clarity regarding the three examined wrecks. ‘We know how critical their situation is, and how urgent it is to take the next steps. As prevention is always cheaper than cleaning up pollution later, we will definitely continue to work on finding ways to make the wrecks environmentally safe,’ Allikmets added.


The examined minesweeper M37


The underwater inspections revealed that, given the condition of the wrecks, it is unlikely that the destroyers S31 and T22 could still contain large amounts of fuel. To a lesser extent, there may be fuel in piping systems and elsewhere, but locating and retrieval of such fuel may not be possible. However, the wreck of the destroyer S31 has a large number of ghost nets, i.e., lost fishing nets, and removing these would be worth considering to avoid further threats to marine life.

The wreck of the minesweeper M37 has at least one paravane (a warship’s protection device against moored naval mines), probably containing up to 8 kg of mercury, that has been visually identified and should be removed. It is difficult to estimate the amount of fuel contained in the wreck, but the damage to the wreck suggests that fuel bunkers were not damaged at the time of sinking. As the vessel was based in Tallinn but sank in Narva Bay, and there was a fuel shortage at the time of the sinking, it is not plausible that the vessel would have set off with the maximum possible amount of fuel (143 tonnes). Pumping the wreck empty involves attaching taps to the wreck’s hull above the fuel bunkers (hot tapping), then pumping hot water or steam into the bunkers to liquefy the fuel, and then pumping it out. There are few ghost nets on the wreck, and these do not pose a threat to the marine environment.

Drawing of the minesweeper M37


Meanwhile, the Police and Border Guard Board continues to monitor the wrecks from the air. ‘The underwater inspections confirmed that all the wrecks investigated did indeed contain fuel oil, but also other hazardous substances. The Police and Border Guard Board Aviation Group performs routine check flights over potentially environmentally hazardous wrecks, so that we could detect fuel spills early,’ said Rene Hartõkainen, Head of the Maritime Security Group at the Police and Border Guard Board.

In the autumn of 2020, the EIC, together with the Police and Border Guard Board, submitted an application to the BSAP (Baltic Sea Action Plan) Fund, managed by NEFCO (Nordic Environment Finance Corporation) and NIB (Nordic Investment Bank), to apply for funding to inspect the most hazardous shipwrecks in Estonian territorial waters.

The total cost of the project ‘Environmental Risk Assessment of Potentially Hazardous Shipwrecks in the Estonian Maritime Area’ is 285,710 euros; 70% of which, or 199,997 euros, was provided by BSAP.

Nea Westerlund from NEFCO, talking about the financing opportunities of the BSAP Fund


In addition releasing the survey data at the final seminar of the project, the representatives of NEFCO, which funded the wreck investigations, presented the possible funding and cooperation opportunities in the field of marine environmental research. Also, Heli Haapsaari from the Finnish Boarder Guard talked about the work they have done with making wrecks environmentally safe.



Kaido Peremees (Tuukritööde OÜ) presenting the results of the inspection in the main picture


More information about the project