Introduction
Today, cargo ships sail every corner of the world’s oceans transporting goods from bananas to flatscreen TVs. But in the years following the Second World War, ships set sail from harbours carrying a very different, much more dangerous cargo: unexploded Chemical Warfare Munitions (CWM). Millions of tonnes of munitions including bombs, shells, torpedoes and grenades, some of which contained toxic chemicals such as sulphur mustard and sarin gas, were transported and piled high in munition depots at harbours across the Baltic states. Key areas were in Germany at the harbours of Flensburg, Kiel, Lübeck and Wolgast. What was to be done with all this dangerous material? The solution seemed obvious; dump it in the world’s largest waste disposal site… the oceans. After all, “out of sight, out of mind” … right?
A legacy of dumped munitions
The Second World War left emotional and physical scars across Europe. One consequence of the war is becoming a growing concern to many national authorities. Orchestrated by the German Navy during the final months of the war and later, on behalf of the British, American and Soviet forces in the Allied occupation zones, both the Baltic and the North Seas became a dumping ground for munitions including bombs, grenades, torpedoes and shells. It is estimated that 40,000 tonnes of Chemical Warfare Munitions (CWM) were sunk at designated dumping sites in the Baltic Sea and that a combined total of 1.6 million tonnes of Unexploded Ordnance (UXO) items still lie on the seabed of the North Sea and Baltic Sea. Despite efforts to salvage munitions from designated dumping grounds during the 1950s and 1960s, most of these munitions remain on the seabed. While many dumping grounds were precisely constrained in their location, many munition items were scattered in the region of the dumping grounds; bombs stored in wooden crates were reported to float and travel significant distances before they sank; diversions were taken from the prescribed vessel routes and unknown amounts of enroute dumping took place. Combining these uncertainties and the vast amount of unaccounted for munitions in the years following the end of the war creates a much larger and unclear picture of munition dumping activities than previously thought.
Now, more than 80 years since the end of the Second World War, the legacy of dumped munitions continues to reveal itself and pose new threats to human health, marine ecosystems, shipping, fisheries and marine infrastructure. Due to the uncertainty about the extent and rate of corrosion of munitions and their containers, and because most CWM contain highly toxic mustard gas agents, there are increasing concerns that leaking munitions will contaminate waters and marine organisms. In recent decades, a growing consensus that remediation will become inevitable has led to new efforts (such as NATO-led operation Open Spirit) to recover and safely dispose of the UXO items.
Munitions dumping in the Bay of Biscay
The main dumping sites in the Baltic Sea and North Sea, including Little Belt, Gotland, Bornholm and the Skagerrak, are well documented. They were used to dispose of munitions from harbours on the German-Baltic coast between 1945 and 1948. One dumping site, relatively less well-known, is off the northwest coast of Spain, in the Bay of Biscay. It is estimated that approx. 21,000 tonnes of CWM were sunk in the Bay of Biscay after the Second World War (BM 1/2391). While the details of many sinking operations, including the location of sinking sites, the loading ports and origin/type of the munitions, is largely unknown, the story of one particular ship and its dangerous voyages to the Bay of Biscay has been revealed thanks to recent archival research utilising historical documents including official letters, ship’s logs and maps from the Schleswig-Holstein State Archives. These documents have revealed the quantity and tonnage of munitions dumped, the origin of the munitions and the details of their transport from the loading harbours to the dumping sites. By rectifying historical maps and plotting coordinates, the routes taken and the exact dumping locations have been digitised into GIS software (see Figures 1, 4 and 6).
The story begins with the discovery of two vessels, a 1000-tonne ‘Rhine’ barge and 500-tonne ‘Lloyd’s Lighter’, which were both originally sunk in the Little Belt munition dumping site by the German Navy in haste just before the end of the Second World War in April 1945 (BM 1/2392). These wrecks were rediscovered in 1958, just off the Flensburg Fjord at the southern exit of Little Belt. However, like many military wrecks sunk during the war, the barges were not empty. They were sunk with thousands of tonnes of chemical weapons onboard.
During investigations of these wrecks, it was discovered that they contained live chemical warfare grenades filled with the deadly nerve gases tabun and sarin, which were partly fused and would be extremely dangerous were they to leak. The Schleswig-Holstein state government decided that the grenades posed an ever-increasing danger to fishermen and the population of the Schleswig-Holstein and Danish coastal areas. They believed that the dumped munitions would self-detonate over time through chemical decomposition. Because these munitions were deemed so dangerous to Baltic Sea mariners, the audacious plan was made to recover them from their post war seabed disposal sites and either destroy them or re-depose of them in the deeper water of the North Atlantic.
In May 1959, the smaller of the two wrecks, the 500-tonne Lloyd’s Lighter, was raised and moved to an ammunition sinking site just off the coast of Stein, a site known as Kolberge Heide. This salvage work on the smaller of the two barges was intended to determine whether the salvage and transport of the 1,000-tonne Rhine barge, fully loaded with chemical weapons grenades, was possible, what dangers this might pose and whether the plan for destroying the ammunition in the barges was even feasible (LASH Abt. 617 Nr. 165). Following the successful salvage of considerable quantities of grenades from the smaller barge, the 1000-tone Rhine barge was raised and transported to Gelting Bay in Flensburg Fjord in November of the same year. The salvage contract awarded on behalf the State Government of Schleswig-Holstein’s Munitions Clearance Group to the company “Bugsier-Reederie Hamburg” was based on a “No success, no payment” principle, highlighting the high confidence of the salvage operations being successful (LASH Abt. 617 Nr. 165). The Lloyd’s Lighter was then moved once more to Gelting Bay in May 1960 where it was considered a more favourable working position to salvage the remaining 300 tonnes of grenades, undisturbed by weather influences. By continuing the work in Gelting Bay, the overall operation was pushed forward quickly despite a period of bad weather. By the end of May 1960, both wrecks were stationed in Gelting Bay, the grenades were salvaged and ready for disposal.
Figure 1. Map showing the original sinking location of two barges in the Little Belt dumping site, and their approximate relocation sites in Gelting Bay and the Kolberge Heide dumping site just off the coast of Stein.
Divers salvaged a combined total of 1,200 tonnes of live chemical warfare grenades from onboard the two wrecks. The danger posed by the ammunition was thoroughly examined by the State Security Commission and the Bundeswehr’s Chemical Ordnance Investigation Centre. Originally, it was proposed to chemically destroy the munitions, but the quoted cost was an eye-watering 1.7 million Deutschmarks. However, they proposed that although such grenades pose a risk when surfaced and handled (by fishermen for example), in deep water, the risk was minimal. This is because the tungsten filling of the grenades is heavier than, and is dehydrated by, water and so the munition is rendered harmless, even in the event of a leak: the seawater would immediately hydrolyse and destroy the munitions. Because of this, it was decided that they would not be destroyed at the surface, but rather, be transported to and sunk in the deeper waters of the North Atlantic.
The 1,500 GRT steamer August Peters (shipowner H. Peters, Hamburg) under the command of Captain Nepperschmidt, was chartered by the Government of Schleswig-Holstein and commissioned with the audacious task of re-disposing of these high-riskchemical weapons far away from their original sinking sites in the Baltic Sea. After a decade and a half sitting at the bottom of the Baltic Sea, a total of 1,200 tonnes of live chemical warfare grenades were salvaged by divers and loaded onto the August Peters for re-disposal in the North Atlantic.
Figure 2. Captain Neppersschmidt of the August Peters, 1960. (Wikidata, 2023)
To ensure the ammunition was safe for transport and disposal, the grenades were cemented into iron barrels, rendering the contents inert. During the cementing tests to determine the most favourable concrete weight, including the packing container, it was determined, taking safety requirements into account, that three-quarters of the total weight of the grenades (1,200 tonnes) for concrete and sheet metal barrels had to be added, resulting in a total weight of approx. 2,100 tonnes for the sinking.
Despite the actions to render the munitions safe by encasing them in cement, the threat to the crew from the deadly chemicals was taken extremely seriously. The August Peters was equipped with gas masks; oxygen protection equipment and medication should a leak occur. In addition, the air in the hold was tested every thirty minutes using hydrogen cyanide tubes and three canaries and a family of stowaway white mice were kept as control animals.
The August Peters completed two successful voyages from Kiel to the Bay of Biscay in March and August of 1960, sinking the munitions in ~400
Figure 3. A basket filled with 10.5 cm Tabun shells is heaved on board from the wreck of the 1,000-tonne barge in 1959, which had been scuttled on behalf of the German Navy before the end of the war in 1945. (HELCOM, 2013)
0m water depth off the continental shelf, approx. 350 nautical miles off the northwest coast of Spain. The first voyage, in March 1960, comprised a cargo of approx. 28,000 grenades, which were salvaged from the Rhine barge and cemented into 1,600 iron barrels, giving a total sinking weight of 1,120 tonnes (LASH Abt. 617 Nr. 100(II)).
They were loaded onto the August Peters, which was equipped with special technical facilities for stowing the drums in the holds and for the sinking operation. The steamer was towed through the Kiel canal to Brunsbüttel lock by the tug Strande and then taken under tow by the deep-sea tug Wotan at Neuwerk near Cuxhaven (Figure 4). Once at the designated site, the grenades, in their iron barrels, were tipped, item-by-item over the side of the ship. Additionally, approx. 5,000 wooden crates used to store the barrels were also thrown overboard during the immediate return journey.
Figure 4. Map showing the route of the August Peters in March and August of 1960 from Kiel harbour, through the Kiel Canal, to the two dumping sites in the Bay of Biscay. The more northerly site was used in March, and the southerly site used later in August. The green points show other munition dumping sites collated from archival documents.
In August of the same year, the August Peters returned to the Bay of Biscay to sink a second load of ammunition at a site further south of the original dumping ground (see Figure 6). A total of 1,771 barrels of grenades, weighing 600kg each, were sunk, resulting in a total weight of 1,000 tonnes for sinking. The missions were successful – no leaks occurred, and all the crew and the control animals remained unharmed (LASH Abt. 617 Nr. 149). The crew were praised for their “exemplary personal and physical commitment”, with eight of the crew receiving bonuses for their hard work.
Figure 5. A closer view of the August Peters’ munition dumping sites in the Bay of Biscay.
Following the successful re-disposal operations carried out by the August Peters, salvage operations were continued by the Munitions Clearance Team in munition dumping areas around the German-Baltic coast. Except this time, ammunition was either detonated or transported to the Korügen ammunition dismantling plant (LASH Abt. 617 Nr. 134). What happened to the August Peters afterwards has not been revealed by the archival research yet.
What now?
In the present day, growing concerns about the contamination of chemical munitions into the water and marine ecosystems has led to greater efforts to salvage dumped munitions in the Baltic Sea. NATO-led operations have been active since the 1990s, but new research and emerging technologies are aiming to improve on the efficiency of these recovery operations. With a massive 40,000 tonnes of chemical warfare munitions dumped into the Baltic Sea, authorities might consider relocation a viable option for remediation of these chemical weapons. The story of the daring August Peters has revealed a dangerous and ambitious operation to re-dispose of munitions that had already been sunk for 15 years… some of these munitions have now been lying in wait in the Baltic Sea for over 80 years! Will history repeat itself? Will the story of the August Peters be retold as we attempt to manage today’s UXO risks?
References
Bundesarchiv. Abteilung Militärarchiv. BM 1/2392
Bundesarchiv. Abteilung Militärarchiv. BM 1/2391
HELCOM (2024) Thematic assessment on Hazardous Submerged Objects in the Baltic Sea (Submerged Assessment – Warfare Materials in the Baltic Sea). Helsinki. HELCOM.
HELCOM (2013) Chemical Munitions Dumped in the Baltic Sea. Report of the ad hoc Expert Group to Update and Review the Existing Information on Dumped Chemical Munitions in the Baltic Sea (HELCOM MUNI). Helsinki. HELCOM.
Landesarchiv Schleswig-Holstein. Abt. 617 Nr. 100 (II)
Landesarchiv Schleswig-Holstein. Abt. 617 Nr. 134
Landesarchiv Schleswig-Holstein. Abt. 617 Nr. 149
Landesarchiv Schleswig-Holstein. Abt. 617 Nr. 165
Landesarchiv Schleswig-Holstein. Abt. 617 Nr. 656
NATO (2021) Allied Maritime Command – NATO forces clear mines from the Baltic in Open Spirit operation
Wikidata (2023) H. Nepperschmidt – Wikidata
