Baltic Sea's deadly legacy: A looming ecological disaster

The depths of the sea, even in the relatively shallow Baltic, are inhospitable to humans. For this reason, people have long pointed to the dangers lurking within, such as sea serpents, the Kraken, mermaids, Leviathan, and Cthulhu. These were mythical creatures, often conjured to explain real but misunderstood threats.

Meanwhile, truly dangerous barrels containing deadly substances lie on the floor of the Baltic Sea. Recently, Professor Jacek Bełdowski from the Institute of Oceanology PAS highlighted this issue in his lecture "Sunk Munitions in the Baltic—a Forgotten Problem," delivered at the Museum of the Second World War in Gdańsk.

The scientist is involved in NATO and EU research programs related to monitoring the condition of chemical weapons stored at the bottom of the Baltic Sea. How did they end up there? These are remnants from World War II. During the war, the Third Reich produced chemical warfare agents on a massive scale, mainly gases. Although they did not use them extensively in combat, fearing Allied retaliation, the Germans employed them during the genocide against Poles, Jews, and others.

A large portion of the German stockpile of mustard gas, sarin, tabun, hydrogen cyanide, and other agents survived the war and was seized by the Allies. Like other German weapons, during the Potsdam Conference, the so-called Big Three decided to surrender or destroy these weapons to the victors. In the case of chemical weapons, two methods were considered: costly and difficult chemical disposal or deferring the problem over time. The latter method was chosen, explicitly sinking them in the Baltic.

Two main dump sites were selected: near the Gotland Deep (approximately 2,200 tons of chemical munitions) and the Bornholm Deep (approximately 42,000 tons). Another 165,000 tons of chemical warfare agents were sunk along with German ships in the Danish Straits, and 1,100 tons were sunk by the Germans themselves at the end of the war in Danish waters.

There are also much higher estimates: just in the central Baltic, there may be over 99,000 tons of chemical munitions. Most cargo was sunk in 1947 through the joint efforts of Britain, the USA, and the USSR. However, East Germany also carried out similar "disposals" in the Gulf of Gdańsk as late as 1954. Outside of the Baltic, chemical weapons were also sunk in the Bay of Biscay.

They were sunk in different ways: in the holds of sunken ships and, individually, in metal barrels. We are talking about agents where even the mildest is tear gas, and many are so potent that a minimal amount (in the case of sarin, micrograms are sufficient) can kill an adult human. According to various estimates, their total mass ranges from 13,200 to 28,600 tons. Not all have been located, as some were sunk outside official storage sites, according to the HELCOM CHEMU report, an expert group operating under the auspices of the Helsinki Commission.

The first incidents did not take long to appear. In 1955, a barrel of mustard gas washed ashore at Darłówko beach, injuring about 100 people, including children, some of whom suffered burns or lost their sight. Barrels and canisters continued to appear on beaches and fishing nets in subsequent years. In 1997, the crew of a fishing vessel was burned by mustard gas, and in 2012, white phosphorus contaminated a beach in the Czołpino area. Even small amounts of agents in these incidents caused serious injuries.

However, if larger quantities were released simultaneously, on the order of hundreds of tons, an ecological disaster would ensue. We do not honestly know how much time we have left. Chemical weapons lie on the sea floor, primarily inside various kinds of missiles or metal containers. Meanwhile, salty water and sea life activity promote corrosion.

According to Professor Bełdowski's lecture, two views prevail: according to the first, after a relatively short period (60-120 years from sinking), accelerated corrosion would occur, while other studies suggest it could take up to 500 years. We do not know whether this corrosion will breach the containers more or less simultaneously or gradually.

The second scenario is optimistic: only local contamination occurs occasionally, and in the long run, the impact on the Baltic ecosystem is nearly negligible. The first scenario, however, could lead to the cessation of life in the Baltic and possibly part of the North Sea. It is unnecessary to explain how this would affect human life around the Baltic, especially since we are part of the ecosystem.

The two scenarios may unfold somewhat simultaneously, as it is already known that containers of mustard gas or sarin are not airtight, and animals living near the dumping areas are noticeably less healthy than their counterparts living a bit farther away.

Efforts are being made to reduce the threat. One of the latest is the EU's MUNIMAP program, which, unfortunately, has a small budget. The international program aims to monitor and conduct research on the state of chemical weapons dumped at sea. Interestingly, this poses a legal problem: currently, it is treated as a military threat rather than an environmental one, and attempts to retrieve it must address the issue of acquiring possession of chemical weapons.

The military is expected to eventually contribute to the civilian initiative by providing specialized equipment for monitoring underwater objects. The Polish Navy regularly participates in neutralizing underwater hazardous objects. Nevertheless, no remedial measures are apparent so far. For example, Poland's Supreme Audit Office negatively assessed government actions in 2020 in the report "Combating Threats Arising from the Presence of Hazardous Materials on the Bottom of the Baltic Sea."

For now, only Germany has invested slightly more funds—112 million dollars (by comparison, efforts to combat the potential widespread leakage of chemical weapons could consume about 2.8 billion dollars annually)—in developing a system for the safe extraction and disposal of wartime deposits. However, as Professor Bełdowski points out, the problem has outgrown German experts because contemporary German law has proven to be a more significant threat than the creations of past German engineers, preventing the extraction of munitions from the sea floor unless they pose a direct threat to people.

In other words, we are monitoring the situation. Still, neither engineers nor lawyers are fully prepared to solve a problem that threatens the destruction of a key body of water for many countries.

Chemical weapons are just the tip of the iceberg. The Baltic was the scene of intense fighting during the Crimean War and both World Wars, as well as many maritime and aviation disasters were witnessed. Every sunken ship holds dozens, if not hundreds or even thousands, of tons of fuel (the tanker T/S Franken sunk at the bottom of the Gulf of Gdańsk contains about 3,300 tons of fuel), as well as artillery shells, torpedoes, and often dangerous cargo such as medicines and reagents.

Marine mines occasionally, sometimes freely floating in the Baltic waters, pose a threat to ships. The oldest passengers may no longer remember the war these mines are relics of. These factors further magnify the problem, and cleaning the Baltic of these lingering dangers is progressing ineffectively.