The impact of unexploded ordnance in the marine environment: understanding the barriers affecting wind farm targets

Can UK offshore wind energy production quadruple by 2030?

In 2020, there was a significant increase in the tempo of working towards a green industrial revolution.  Greta Thunberg’s supporters, climate change deniers, and even fence-sitters joined conversations about the environment. 

Brands across all sectors are now looking to showcase environmentally friendly products and processes, and in the energy market, the Big Six are feeling the pressure of competition from the renewable sector.

In the UK, increasing offshore wind energy capacity is a particular focus for the next 10 years; the government has pledged to quadruple offshore wind energy generation by 2030. 

Clearly, clean wind powered energy is a great step towards a greener future - but explosive remnants of past conflict is currently hindering developments.

UXO in the marine environment

Unexploded ordnance (UXO), typically from WWI and WWII when talking specifically about UK waters, needs to be removed for the safe development of offshore wind farms. 

Just as conversations relating to the environment have increased in intensity of late, so too have concerns relating to the preservation of marine ecology and the protection of sea life when it comes to safely dealing with explosive devices in the murky depths of our seas.

Whether operational on land or in the marine environment, SafeLane is committed to the safe, sustainable clearance of munitions, utilising processes that protect the environment wherever possible.

Is explosive ordnance really still a risk?

Ordnance that has failed to explode as designed still contains high explosives and is a threat.   However, one of the biggest hurdles those operational in the explosive threat mitigation sector are consistently faced with is that if ordnance has lain dormant for decades, clients often fail to appreciate that it still poses a significant risk.

As the devices have been buried beneath the ground or lain below the water’s surface, they will have experienced significant degradation via erosion making them increasingly less stable. 

The risk of detonation is heightened if these old, unstable devices are disturbed - perhaps from vibrations during construction works or the sub-sea engineering processes essential for the development of wind farms.  When ordnance is exposed to heat, vibration or contact, it may explode.

In December last year, a fishing boat was severely damaged, and its crew seriously injured following an explosion off the English coast.  It is believed a WWII device got caught in the boat’s nets, resulting in detonation of the ordnance.

Stop Sea Blasts – a marine environmental campaign

Stop Sea Blasts is a campaign for low-order deflagration to dispose of subsea explosives; it’s a cause supported by actress and activist Joanna Lumley.

The campaign recognises that there are over 100,000 tonnes of UXO in waters around the UK, with contamination largely the result of WWI and WWII.  

This clearly shows the scale of the problem that ordnance poses for green initiatives such as offshore wind farms.  As evidenced above, this ordnance must be cleared to make way for the safe construction of wind farms, so we can move towards a future powered by clean energy.

The Stop Sea Blasts campaign focuses on concerns that blowing up unexploded ordnance at sea has a negative effect on marine ecology and sea life, particularly putting whale and dolphin populations at risk.

The deflagration process - why sometimes a detonation is unavoidable

What is low-order deflagration?

Deflagration is in itself a partial detonation; it may be a complete detonation at lower-than-normal velocity or an incomplete detonation.  In the case of an incomplete detonation, the initiation shockwave does not have enough energy to maintain the chain reaction detonation.  Therefore, the detonation wave dies away before all the explosive has detonated leaving some explosive remaining.

The cause of a partial detonation is usually either poor contact in the explosive train, deterioration of the explosive material or inadequate shock (velocity of detonation or VOD) applied by the initiating charge (detonator).

Why is the Stop Sea Blasts campaign calling for deflagration over detonation?

Utilising a low-order deflagration stops large vibrations that can cause harm to marine life.  In addition, it limits the release of harmful chemicals from ordnance. 

The deflagration, if it occurs, will not convert all the explosives into gas, heat and shock.  But some explosive will remain.  Therefore, the process decreases the effect of a full detonation, but deflagration is still a very violent event.

Why is detonation sometimes unavoidable?

At SafeLane, we fully recognise that this is the desired approach to neutralising munitions in the marine environment.  However, it must be taken into account that when dealing with unstable, explosive devices, this approach is sadly not always possible. 

When what is known as a low-order is attempted, the process uses explosive material to open up the container holding the explosives of the bomb.  By doing this we are seeking to:

1) Start an explosion (i.e., a rapid burn of explosive material but not a detonation)

2) To open the explosive material container so that the build-up of pressure within it is not realised.

The detonation wave relies on the ever-increasing gas pressure produced by the explosives to finally violently rupture the container and release the gases as a shock wave to the atmosphere.

The entry into the case by the low-order technique ensures pressure can be released and interrupts the detonation wave.

Low-order techniques include the use of shaped charges, sheet explosives and normal explosives placed at a certain location on a bomb, avoiding pistol and fuse positions. 

When one attempts a low-order technique one must always be prepared for a high-order detonation…

The biggest bomb ever found in Poland, a massive 5.4 tonne Tallboy or ‘earthquake’ bomb accidentally detonated during a low-order deflagration process last year. 

In the world of UXO you must plan for a variety of eventualities; your ultimate focus is preservation of human life. 

Innovating environmental protection processes since 2009

While the conversation relating to environmentally friendly UXO threat mitigation processes has only recently come to the media’s attention thanks to the likes of Joanna Lumley and the Stop Sea Blasts campaign, SafeLane has been proudly pioneering environmentally conscious processes since 2009. 

When SafeLane was working with a client to plan clearance of Finnish waters ahead of a subsea gas pipeline installation for a capital international project, environmental considerations were critical.

To gain the appropriate planning permission to even work in Finnish waters, the UXO threat mitigation plan had to have environmental damage limitation at its heart.  This is because Finland has stringent environmental measures in place, the contractor was required to come up with a methodology that mitigated the risk to the environment during UXO works.  The aim was to safely clear the area while protecting the fragile Baltic Sea eco system.

During the project, the marine team needed to dispose of 46 UXO targets.  For each target, an individual disposal plan and environmental assessment had to be completed.  These assessments would inform the overall impact assessment.

To be successful in this aim and to minimise impact when conducting disposal operations, SafeLane Global utilised the low-order techniques that are only now becoming common practice within the industry.  The use of shaped charges was selected as the primary disposal technique to significantly reduce the number of explosives used to minimise effects to the environment.  

To further help mitigate harm to the environment, but to also ensure the client’s project could go ahead safely, the team also developed and utilised a range of additional environmental mitigation techniques including:

• Acoustic deterrents (colloquially known as seal scarers),
• Remote passive acoustic monitors (PAMs),
• Hydrophones to measure peak pressure waves,
• Sonar fish surveys,
• Marine mammal observers,
• Seabed displacement pre and post disposal surveys,
• Turbidity & water quality pre- and post-detonation sampling.

Samples of the seabed and water surrounding the targets were taken to analyse changes pre- and post-any demolitions.  This was done as an ongoing monitoring exercise.

When dealing with explosive threats, in addition to protecting life and the environment it can also be essential to preserve building or historic artefacts, both on land and in water.  For example, the project was located near a Russian ship that was embedded in the seabed.  This needed to be constantly monitored to ensure it remained unaffected.

SafeLane’s Marine Director, Ryan Prophet says: “It was a complex project with a lot of crucial environmental considerations.  However, my team has the skills to overcome such challenges.  The learning from this project also enhanced our already strong environmental processes.  It’s great to see that the protection of the marine environment is now becoming a focus for others in our sector.”

The client was thrilled when the final reports confirmed that the environmental impact of the explosive threat mitigation work had been significantly less than expected.

A greener future

When dealing with explosives, there are many risks involved.  Utilising operational experience, gained over three decades, SafeLane implements rigorous environmental policies whether UXO is on land or in water.  With a quality management system that’s subject to external scrutiny and regulations, our processes evolve through lessons learned on projects.

We are proud to be ISO 14001 accredited and a supporter of the UN Sustainable Development Goals at SafeLane. 

As the world works towards a greener future, governments must consider the environmental impacts of achieving their goals to ensure we protect the planet and all its inhabitants. 

SafeLane will continue to use its skill and understanding to do everything it can to protect the planet, its communities, and the interests of its clients. 

As a company, we support the Stop Sea Blasts initiative.

How SafeLane can help you

SafeLane Global has been mitigating explosive threats, on land and in marine environments since 1989; our experience makes us an industry leader. 

Our marine team has an in-depth understanding of subsea engineering, oceanology, and marine physics.  This expert knowledge enables them to design appropriately considerate solutions to overcome challenges in all environments. 

Whether you’re planning operations onshore, offshore, nearshore or inshore, trust SafeLane to determine, manage and mitigate your exposure to explosive risk.