Below are some of the more common misconceptions and myths we see in the industry.
The questions and answers below offer a realistic view of the potential risks that apply to most situations in the UK.
If you have more specific questions or details of a site, please feel free to contact us for advice.
You have to call the Police if you find a bomb.
Obviously call the emergency services if you find something in a busy public place.
But if you find something suspicious on site, call an EOD specialist first.
This will ensure you don’t unnecessarily use valuable emergency service resource.
Guidance issued by the Institute of Explosive Engineers, the MoD and the emergency services, advises that if you can reasonably foresee finding UXO, you can establish a mechanism for dealing with UXO finds. This will typically involve engaging the services of a UXO specialist such as Zetica.
Obviously use your common sense, but remember that most UXO that could be found in the UK is very unlikely to detonate on discovery, as long as you leave it alone. But its important to call a specialist as soon as possible.
If MagCone probes cannot penetrate the ground, would a bomb?
The dynamics of a bomb hitting the ground and a MagCone probe pushing into the ground are very different.
As an example, a bomb travelling at terminal velocity will penetrate several metres into medium dense gravel, whereas a MagCone probe might easily refuse, particularly where larger cobbles are encountered.
So refusal of a MagCone probe does not mean the location is also clear of bombs. You have to make an assessment on the likely bomb penetration based on the geology encountered. Then compare if the MagCone probe has reached that depth.
An alterative method (e.g. drilling based MagDrill) may be required to achieve the required depth of detection.
How does the risk of finding UXO in the UK compare with sites in Europe?
They are very similar in some respects, due to centuries of military activity. Activities such as military training will have resulted in areas of concentrated UXO hazards both in the UK and the rest of Europe.
In mainland Europe, the risk of finding UXO due to WWI and WWII can be greater. Former WWI battlefields in northern Europe cover significant areas that will have a greater likelihood to find UXO than the surrounding areas.
WWII also saw more than 2,000,000 tonnes of bombs dropped on northern Europe by the Allied forces, whilst an estimated 100,000 tonnes were dropped on Britain. So the risk of finding an unexploded bomb (UXB) in northern Europe is greater!
The hazard presented by WWII bombs dropped by Allied forces is also much greater. The fuze mechanisms are employed by the Allied forces mean that an accidental detonation is highly likely on encounter. This is in contrast to the UK where there has not been a significant incident leading to injury in the construction industry since at least the 1950s.
Non-intrusive surveys will detect bombs to 4m below ground level.
Only the big bombs. The more common smaller bombs (50kg) are typically detected to a maximum depth of 2.0m.
The actual depth of detection will depend on the site conditions. This can be verified by a geophysical specialist, by reviewing the data and assessing the levels of noise.
The effect of naturally occurring noise or noise from made ground or existing structures can be significant. This can detrimentally affect the levels of detection for a site and can mask the location of a bomb.
Arguably understanding where the detectability of a bomb is low, is most important.
Do intrusive UXB surveys have a constant radius of detection?
The radius of detection will depend on the site conditions. This can be verified by a geophysical specialist, by reviewing the data and assessing the levels of noise.
The effect of naturally occurring noise or noise from made ground, existing structures or the drilling rig can be significant. This can detrimentally affect the levels of detection for a site and can mask the location of a bomb.
If a clearance drawing for intrusive UXB survey has consistent radius of detection at each location, it probably indicates that a geophysical specialist has not been involved in assessing the data. There is a good chance that the clearance cannot be relied upon.
You need a home office licence to undertake Explosive Ordnance Disposal (EOD) in the UK
There is no such licence.
There are firearm licences which some people cite as a home Office licence for EOD, but it is not.
There is no legislation in the UK relating to managing UXO risk in the construction industry.
True, there isn’t anything specific for construction. But UK legislation such as the Health and Safety at Work Act and the Construction Design Regulations requires us to ensure a safe working environment.
So if you suspect UXO could be a reasonably foreseeable hazard you should address it. It could just be a low cost (or even free) assessment by a UXO specialist that confirms the hazard is unlikely.
Site redevelopment has removed the UXO hazard.
You can have some certainty where ground has been removed, or UXO clearance undertaken. Elsewhere on site, if a hazard has been identified and no development taken place, then the hazard will remain.
Outside of the heavily bombed cities like London, the UXO risk is low
Most UXO does not relate to WWI or WWII bombing, instead relating to other activity such as military training. These activities are typically in remote areas away from cities like London.
The potential to find unexploded bombs (UXB) is greater in cities like London. There is a potential to find UXB away from the cities due to bombing of strategically important targets like military airfields, or simply due to decoy sites designed to draw bombers away from their intended targets.
See our News feed for examples of where UXO has been found recently.
UXB become unstable and dangerous with age.
High Explosives within ordnance is typically very stable and does not significantly degrade or become more sensitive with age. Some primary explosives typically used in the fuzing mechanisms can more readily degrade to more sensitive compounds depending on conditions.
In practice, the degradation of such explosives is a process that will often mean they further degrade and become insensitive. So whilst some may cite finding sensitive explosives is common, in practice the potential for an accidental detonation when first discovery UXO is very unlikely. This is simply verified by the 1,000s of UXO found each year version injuries.
That said, we always treat any discovered UXO with utmost respect and ensure its dealt with appropriately once properly identified by a competent UXO specialist.
The main UXO risk in the UK today is from German bombs.
Ignoring small arms ammunition, the most commonly found UXO in the UK today is a British 2″ mortar.
Finding WWII UXB occasionally makes the news, but on a daily basis, companies like Zetica are detecting and clearing 1,000s of UXO of all different types reflecting the rich military history this country has