Underwater Unexploded Ordnance in the Baltic and North Seas

Origins – Problems – Possible Solutions

A few years ago, a man was collecting amber on a beach on the island of Usedom . In the shallow water he saw something that looked exactly like amber. He picked up what he thought was a treasure and put it in his pocket. Shortly afterwards he had an unbearable burning sensation on his thigh and in his crotch and instinctively hit the object in his pocket with his hand. His reaction could not have been more wrong because what he had found was not amber but phosphorus, which ignites when it comes into contact with oxygen and which he just spread even more and rubbed deeper into his skin.

Another case: in 2005, three Dutch North Sea fishermen hauled up a bomb which exploded on the deck of their boat. All three were killed on the spot.

And yet another example: a diver found a 500 kg bomb off the island of Rügen . Only one solution to this problem occurred to the authorities: explode the bomb. A mountain of water 20 m high was the visible result. We can only guess what might have happened below the surface. Within a radius of more than one kilometer, not a single fish survived the shock wave. Marine mammals within four kilometers of the explosion had no chance of survival either. Even beyond the four-kilometer radius harbor porpoises, for instance, still suffer severe injury. In particular their hearing, which they use for orientation, is impaired. And less severe injury can occur in animals up to 33 kilometers from the explosion.

These three cases highlight a problem which has long been denied and which is now beginning to be thoroughly discussed – sixty years after the end of WW II.

At the end of WW II, piles of unused munitions were left in Europe . Nobody wanted what the Germans left behind. Some of the ordnance of the Allied troops had become useless and much of what remained could not be removed for lack of transport capacity. Somehow, however, all this stuff had to be done away with. So it was blown up, buried, or dumped at sea, in particular in the Baltic and North Seas .

Decommissioned warships were loaded with bombs, mines and shells, taken to sea and then flooded, blown up or bombarded until they sank. Some 300,000 tons of chemical agents (or, to put it less euphemistically, poison gas) were disposed of in this way. 300,000 tons are a lot, considering that trucks are allowed to transport a maximum of 40 tons on German Autobahns, or that a single drop of poison gas on a person’s skin can kill them.

Most of the dumping occurred in the following areas: German Bight, Skagerrak, Little Belt, Bornholm Basin and the waters off Gotland . In some cases, fishermen were paid to dump the munitions in specially designated areas. Many, however, tossed the stuff overboard as soon as they were out of sight. And there, close to the shore, it remains to this day, off Rügen for instance, or in the Kiel Bight.

It is safe to assume that currently there are still between 300,000 and 1.5 million tons of underwater unexploded ordnance (UWUXO) in the Baltic Sea . A similar amount is likely to rest on the bottom of the German Bight. The main areas where munitions were dumped are more or less known (or so we hope), and they are off limits to fisheries. Nonetheless, underwater photographs clearly show that nets have been dragged through these areas. Piles of bombs or mines are covered with old nets, and drag marks show that munitions containers were scattered across the Baltic seafloor by fishing nets.

Initially, and for several decades, munitions dumped at sea did not pose much of a threat. Water temperatures of 6.5°C limit chemical reactions. The only problem is that the containers are slowly rusting away. This is especially dangerous in the case of poison gas containers, the walls of which are sometimes no thicker than 2 – 2.5 mm – and losing 0.1 – 0.15 mm every year.

Chemical warfare agents were never used in their pure forms but always as compounds. 53 substances are involved and nobody knows how they will react if they leak and come into contact with other substances. What we do know, however, is this: most of these poisonous substances are highly toxic, carcinogenic and mutagenic even when diluted in water and the toxicity and longevity of their decomposition products is sometimes even higher than that of the substances making up the original compound.

The containers of conventional munitions are thicker, but they too corrode and allow highly toxic TNT, gun cotton or other explosive substances to escape. Water quality measurements related to the dumped munitions become known only sporadically.

One should think that in light of the enormous amounts of dumped munitions and the considerable number of accidents related to this stuff (off Bornholm alone, 443 incidents involving fishermen were recorded in the 20 years prior to 2005) alarm bells should be ringing in all competent government offices at the federal state and federal levels.

But far from it! Not even the most basic data are available. A special report published by the “Deutscher Umweltrat” (German Environmental Council) states: “We would like to point out that very little information about the current state of the ordnance is available and hence we do not know enough about the release of harmful substances to satisfactorily assess the situation.”

On the contrary! When it comes to UWUXO, government offices resort to all manner of tricks, deception and stonewalling. The marine biologist Sven Koschinski writes: “Only with luck is it possible to receive some information, but this information is frequently contradictory, out of context and distorted – or simply wrong.” Another commonly used trick is to use so-called scientific evidence, based on studies that are clearly designed NOT to produce certain results.

The current situation: it is only roughly known how much unexploded ordnance is left on the floors of the Baltic and North Seas . There could easily be twice as much as estimated today. Our idea of where the “hot spots” are is just as approximate. Nobody regularly checks on the condition of the bombs, mines and shells in those hot spots we do know of. For all we know, they may already be corroded. Nor do we have the slightest idea of the long-term eco-toxicological effects on marine habitats. The effects of these horrific amounts of poisonous substances on the water and marine flora and fauna have only been examined sporadically.

Government authorities – i.e. the competent authorities – are clueless as to how to solve this problem. They do not have any sort of overview of new approaches to recovering and destroying UWUXO. The German armed forces do have two installations for the destruction of ammunition found on land, including poison gas. But nobody knows how to get a 500 kg bomb out of the water and transport it to these installations. Taking a ship to the place where it was found and trying to lift the bomb out of the water is extremely dangerous.

And anyway, what do we do with it once it has been recovered? Take it to a busy port and transport it by truck through cities and villages teeming with people? Hardly! Actually, the real problems only start once the munitions reach the surface. A poison gas shell on the seafloor is relatively unproblematic. But take it up to the surface, where the pressure is lower and the temperature higher, and the poison will start seeping out through every opening, such as holes due to corrosion or leaky fittings.

Theoretically, there are four possible approaches to handling UWUXO:

1. Leave everything as it is (“permanent disposal scenario “).

2. Partial rehabilitation of affected areas (“by the way scenario”). In practice this means taking action only when a problem – such as a bomb or a mine found in a shipping lane or a shell that is washed ashore – occurs.

3. Rehabilitation of strongly affected areas (“hot spot scenario”). In places where entire shiploads are piled up, munitions are removed and disposed of.

4. Full rehabilitation of all areas known to be affected (“full clean-up scenario”)

In the long run, a hot spot approach will be unavoidable. The first two scenarios are not viable since the toxic waste cannot be left in the water indefinitely or removed only in case of immediate danger. The fourth scenario, i.e. a full clean-up, would generate such immense costs as to appear illusory. Moreover, there are still technological limits to our ability to detect all the munitions, including those covered by silt.

So far, the competent ministries in Kiel and Schwerin have opted for a mixture of the first two scenarios. Whenever possible, they try not to touch anything and if a problem does occur, such as a bomb in a shipping lane, they usually go for what appears to be the simplest solution: blow it up.

But blowing the stuff up is a method that GSM and other environmental organizations decidedly disapprove of. The risks this method poses to water and marine life are too high. As explained above, the explosion of a 500 kg bomb would presumably cause devastation for miles around.

None of these explosions manage to destroy all of the explosives. Divers working for the Federal State of Schleswig Holstein report that after every detonation they collect chunks of undestroyed explosives in baskets and blow them up again.

And there is another risk: the explosion can damage other munitions, which may lead to an uncontrolled release of poison into the environment. Or there might be other bombs, mines and shells underneath the ones being blown up, which could lead to an uncontrolled explosion.

But above all: what chemical reactions will occur in the water when 500 kg of explosives suddenly explode? As a rule, nobody knows exactly what explosives a bomb may contain and how these substances and their decomposition products will react to each other.

For this reason, GSM, NABU and GRD have repeatedly demanded that blowing up of UWUXO should only be considered as a last resort.

It was left to a congress co-organized by GSM that took place in Kiel on 19 October 2007, to look for new approaches to munitions disposal. For the first time ever, this symposium enabled discussions between nearly all stakeholders: representatives of the ministries concerned, civil protection experts, nature conservation agencies, environmental NGOs, armed forces and industry.

The main aim of the symposium was to allow the relevant industries to present new processes for munitions recovery.

One method that is not entirely new and known even to the authorities of the federal state of Schleswig-Holstein is the bubble curtain. The method consists of closely surrounding the center of the explosion with a ring or, effectively, a curtain of air bubbles, which mitigates the shock waves and the sound waves. Sven Koschinski estimates that, in a best-case scenario, this can lead to a 90 percent reduction.

Recovery by means of freezing is a promising method. Using liquid nitrogen and super cooling equipment, the object is completely encased in 20 cm of ice while still under water. Freezing practically neutralizes the explosive content. It is then safe to deposit it in a cooling container and relatively safe to tow it away, still under water. The disadvantage is that this method has not been employed in practice, but the northern-German company involved offers public demonstrations of this method of recovery.

Another method that is still in the trial phase uses a water abrasive suspension cutting process (water jet cutting) to separate detonators from bombs or mines without vibrations. The content of the munitions can then be liquefied and processed. This method too has thus far not progressed beyond the laboratory phase.

It has also been suggested to use water jet cutting to drill holes into large bombs or mines in order to flush out their content, which could then be destroyed by means of ultraviolet light.

Combinations of these various methods can possibly be used. Above all, however, robotic technology will be needed in applying them.

We hear that the civil protection experts were not terribly impressed by any of these alternatives to blasting. In principle they would like to stick to the violent method they are used to. “Always dunnit that way, who are they to tell us not to?” But: civil servants take their instructions from the government and that is the road we will have to continue to go down.

For numerous reasons, government and society will have to think about ways to solve the problem of what may be some one million tons of dumped munitions. For reasons of civil protection, animal welfare and environmental protection we cannot continue to turn a blind eye. Currently the German armed forces are disposing of approximately one thousand tons of munitions per annum. Most of these were found on land. If one wanted to use the same installations to dispose of the explosive trash from the sea, it would take approximately one thousand years to get rid of all of it.

Walter Karpf/translation Rüdiger Strempel/GSM