Nord Stream probe: The known and unknowns of the bombing

It has been almost two weeks since Sweden officially confirmed that the Nord Stream gas pipeline system was damaged in an act of sabotage. Danish investigators have come to a similar conclusion. 

The subsea pipelines that carry Russian gas to Germany under the Baltic Sea were attacked in late September. The concrete-reinforced steel pipes were punctured at four different places within Denmark and Sweden’s exclusive economic zones. 

Along with the deadly missile strike in Poland on November 15, the sabotage targeting Nord Stream was the most nerve-wracking incident to have occurred outside the conflict zone in Ukraine which is under the Russian military attack since February.

Denmark is part of the North Atlantic Treaty Organization (NATO), which considers any aggression against one member as an affront to the entire security alliance. 

But since the pipelines were ruptured in the EEZ and not in territorial waters - which is basically considered part of international seas - it didn’t raise a very high level of alarm. 

Denmark, Sweden and as well as Germany, which is also located on the rim of the Baltic Sea, have all carried out their separate investigations. None of them has given any indication if the findings will be released any time soon. 

The attack on such a sensitive infrastructure has raised a host of questions: how was it attacked, what sort of explosives were used, can a simple fishing boat be deployed for the purpose, can the origins of the explosives be detected and, most importantly, is there a way to monitor dozens of undersea cables and pipelines? 

A diver could do it 

Terrance Long, the founder of the International Dialogue on Underwater Munitions (IDUM), says most of the navies in the region have the capacity and divers to carry out an attack on subsea pipelines. 

“You would undertake such a mission very quietly and during the night,” he tells TRT World. 

Nord Stream, a set of four pipelines majority owned by Russia’s state-run Gazprom, runs at a depth of 80 metres to 100 metres on the bottom of the Baltic Sea.

They were not transporting any gas at the time of the attack. Russia had blamed Western sanctions on delaying the acquisition of some critical components that Moscow needed to resume gas supplies through the Nord Stream network. 

But the pipelines had residual gas left. The bombing caused leaks that became visible on September 26. Aerial footage released by Swedish authorities around that time showed gas bubbling onto the sea’s surface. 

Long, a former Canadian military engineer, says the perpetrator or perpetrators of the attack must have relied on military-grade explosives such as TNT, DM-12 or RDX. 

“You are probably looking at linear charges set along the pipeline to actually destroy it. If authorities can recover pieces of the damaged pipe, they will most likely be able to tell what sort of explosives were used,” he says.

On October 17, a Swedish newspaper along with Blueye Robotics company, which sells undersea drones, recorded footage of the section of a mangled Nord Stream 1 pipe. 

Drone operator, Trond Larsen, told TRT World at the time that a 60 metres-long section of the pipe was damaged. 

Gazprom, the pipeline operator, which undertook its own inspection last month, said it found three-metre to five-metre-deep craters while pipe fragments were found 250 metres from the pipelines. 

Investigators would have been careful in navigating the floor of the Baltic Sea, which Long says is littered with unexploded munitions from World War II and those dumped by the navies. 

“Baltic has been a peaceful sea. But at the same time if you go to the seabed, all that you’d see are the remnants of war.” 

Rockets and artillery shells have toxic munitions such as mercury sulfate, which are deadly for marine life and ecology. 

“Once I spent a month studying the seabed off the coast of Poland. Everywhere we saw shipwrecks full of ammunition. During the time I was deployed there I saw only one cod fish. And it was dead.” 

How do you blow up a pipeline?

Within days after the apparent sabotage was detected on September 26 off the coast of the Danish island of Bornholm, officials from Denmark and Sweden were saying “hundreds of kilos” of explosives might have been used. 

That would have required a coordinated and organised operation. 

An explosive detonation works differently in water than on land. Shrapnels don’t travel far in water, so militaries prefer using explosive shockwaves to hit a target, says a retired US navy officer who specialises in explosive devices. 

He requested to remain anonymous because he’s not involved with the Nord Stream investigations.

While a shockwave travels four times faster in water than in air, ripping apart a 60-metre-long section of a steel pipe would have required the explosives to be attached to the pipeline. 

“If the explosives were off even by 10 feet, unless it was a very large charge, it would not have caused so much damage,” the officer says. 

The process of planting explosives on the pipeline is relatively easy and can be done by a submersible vehicle, he says. 

Determining the type of explosives wouldn’t be challenging for the investigators. But figuring out the origin of those explosives is much more difficult, he says. 

“Years ago, there was a programme in the US to add a material with explosives to keep track of where they are going. But not many countries adopted that, and the US eventually stopped doing it as well.”

Besides Denmark, Sweden, Germany and Poland, the Baltic Sea also touches the shores of Estonia, Latvia and Lithuania. All of them, except for Sweden, are part of NATO. But each country has vigorously backed Ukraine in the conflict with Russia, which also has access to the Baltic. 

Baltic Sea has been a theatre of military activity in recent years. In 2014, during the height of tensions with Russia after it illegally annexed Ukraine’s Crimea region, the Swedish military went on a high alert. 

Stockholm received a tip-off about a “foreign underwater activity”. That set off Sweden’s largest military mobilisation since the end of the Cold War as it sent ships to sweep across its territorial waters. 

Sweden’s navy is well equipped to deal with an underwater challenge. It has HMS Visby, a stealth corvette that has the capability to take on submarines. 

This has raised questions about the monitoring mechanism that Baltic Sea countries have put in place to ensure the safety of undersea telecommunication cables and energy pipelines. 

The International Association Oil and Gas Producers, which represents the interests of the energy firms, didn’t respond to a request for a comment. 

One analysis points out that the sabotage could be the result of the so-called grey zone activity where a group linked with a state might have taken the cover of a fishing vessel and planted explosives with the help of a submersible drone. 

In a story published last month, Wired cited satellite data to suggest that two ships with their tracking systems switched off were seen in the vicinity of blast sites. 

The tracking system is often turned off when illegal oil or other cargo changes hands on the high seas. 

Russia and the West have blamed each other for the attack. The Kremlin's spokesperson Dmitry Peskov pointed the finger at the UK last month, saying the Russian intelligence has evidence to show that the British military specialists supervised the attack. 

Washington had long opposed Europe’s reliance on Russian gas. But Germany went ahead with the multi-billion dollar Nord Stream 1 project in 2011, citing its energy needs. The Nord Stream 2, which was yet to start operation, also faced considerable US ire.  

Monitoring the entire sea – even with modern satellites and radar – is nearly impossible, experts say. 

Jens Wenzel Kristoffersen, an analyst at the Centre for Military Studies at the University of Copenhagen, told TRT World in October that navies have a fairly good idea about what goes on the sea surface. “But what happens under the sea is obviously hard to find out.” 

However, Terrance Long says it’s just a matter of time before the truth is known. 

“The technology is there. Navies monitor what goes on in the sea. They just haven’t released it to the public yet.”