What Are Unexploded Munitions?
Every year, construction workers, land developers, and the public encounter unexploded munitions buried beneath fields, beaches, and urban sites. These deadly remnants of past conflicts remain hidden for decades, and are still as dangerous as the day they were deployed.
But what exactly are unexploded munitions? Where do they come from, and why do they still pose a threat today? In this blog, we’ll explain the different types of UXO, their origins, and how they are safely managed.
What are unexploded munitions?
Unexploded munitions (also known as unexploded ordnance or UXO) refer to any explosive device that failed to detonate as intended. This includes:
- Bombs, rockets, and missiles fired or dropped during wartime.
- Landmines and grenades scattered across battlefields.
- Naval torpedoes and sea mines left in coastal waters.
- Mortars, artillery shells, and cluster munitions used in combat.
- Improvised explosive devices (IEDs), often found in post-conflict zones.
Despite being decades old, these devices can still contain live explosives or chemical agents, making them highly unstable and potentially lethal.
UXO vs. ERW: what’s the difference?
While UXO is the most commonly used term, you may also come across the phrase Explosive Remnants of War (ERW).
- UXO refers specifically to munitions that were fired, dropped, or deployed but failed to explode.
- ERW is a broader term that includes UXO, as well as abandoned munitions (e.g., stockpiled weapons left behind after a conflict).
Both UXO and ERW pose a significant hazard to construction and development projects, requiring specialist assessment and clearance.
Where do unexploded munitions come from?
World War I and II Bombing Campaigns
During WWI and WWII, Britain was heavily bombed, particularly during the Blitz (1940–1941), when the Luftwaffe dropped over 30,000 tonnes of bombs on London alone. It’s estimated that around 10% of these bombs failed to detonate, leaving a dangerous legacy beneath many British cities.
UXO from Allied bombing raids also remains scattered across Europe, with large quantities still found in Germany, France, Belgium, and the Netherlands.
Post-War Clearance and Disposal
After WWII, large quantities of captured munitions were disposed of in coastal waters, while some were abandoned in rural areas. In many cases, the disposal efforts were incomplete, leaving hazardous munitions behind.
Military Testing and Training Areas
Beyond wartime bombing, military training exercises left thousands of unexploded shells, mortars, and grenades on former practice ranges. In the UK, sites such as RAF Cowden in East Yorkshire remain contaminated by UXO decades after their use.
Naval Warfare and Coastal Contamination
Naval mines, depth charges, and torpedoes used during WWI and WWII still litter the seabed, making them a hazard for offshore construction, fishing vessels, and divers. Even today, UXO is regularly discovered in UK waters during marine infrastructure projects.
Types of unexploded munitions
Unexploded munitions are categorised based on their delivery method and intended purpose.
Air-Delivered Ordnance
Air-delivered munitions include:
- High-explosive (HE) bombs: Dropped by aircraft during wartime, often weighing 50kg to 1,000kg.
- Incendiary bombs: Designed to start fires, these bombs contain flammable agents such as thermite or phosphorus.
- Parachute mines: Massive air-dropped mines designed to detonate at roof level, creating a wide blast radius. Although they were intended for maritime use, they were also dropped on cities during the Blitz.
Ground-Deployed Ordnance
Military operations also left behind large quantities of ground-deployed munitions, including:
- Mortar shells and artillery rounds: These were heavily used in both world wars and remain buried in former battlefields.
- Landmines: Designed to detonate when disturbed, landmines still pose a serious risk in former conflict zones.
- Grenades and anti-tank weapons: Often found on former training ranges, these smaller munitions can still contain unstable explosives.
Naval and Marine UXO
Naval UXO includes:
- Sea mines: Large explosive devices used to destroy enemy ships. Many were moored in UK waters during WWII and remain active.
- Torpedoes and depth charges: Fired from submarines and ships, these munitions sometimes failed to detonate, sinking to the seabed intact.
Improvised Explosive Devices (IEDs)
While less common in the UK, IEDs are still encountered in areas where counter-terrorism training or bomb disposal exercises occurred. They can vary significantly in design and lethality.
The risks of unexploded munitions
Even decades after being deployed, UXO remains highly volatile. Factors that increase the danger include:
- Corrosion and degradation: Over time, casings may weaken, making the explosive material more unstable.
- Disturbance during excavation: Construction work, such as pile driving, trenching, or groundworks, can trigger UXO.
- Detonation risk: Although some UXO appears inert, internal components (such as fuses) may still be active.
Failing to properly assess and manage UXO risks can result in:
- Project delays and costly stoppages.
- Injury or loss of life from accidental detonation.
- Legal and financial liability for failing to mitigate known UXO risks.
How Brimstone UXO safely manages UXO risks
Brimstone UXO is the UK’s only government-assured UXO company, offering industry-leading services to identify, assess, and clear unexploded munitions.
Our services include:
- UXO Risk Assessments: We conduct detailed historical research to determine the likelihood of UXO contamination.
- Non-Intrusive Surveys: Using state-of-the-art detection equipment, we identify potential UXO without disturbing the ground.
- Intrusive UXO Surveys: For deeper investigations, we carry out intrusive surveys to locate buried ordnance.
- UXO Clearance and Disposal: If UXO is detected, our EOD engineers can safely dispose of it, minimising project disruption.
Why choose Brimstone UXO?
At Brimstone, our team of former military EOD specialists brings decades of experience to every project. We work with clients across the construction, infrastructure, and marine sectors to ensure projects are delivered safely and on time.
By partnering with Brimstone UXO, you can be confident that your project complies with industry standards and operates with minimal UXO-related risks. If you’re planning a project in a UXO-affected area, get in touch with our team today for expert support.
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