Unexploded Ordnances, or UXO’s, are a legacy of military activity affecting many parts of the UK, both rural and urban.1 Hundreds of thousands of bombs were dropped across Europe during WWI and WWII, of which at least 10% failed to explode and remain buried in land or underwater. UXO’s become more volatile with age and can easily be triggered by heat, shock or vibration. This makes them particularly hazardous for construction works involving any disruption of soil such as piling or earthworks.
A rare occurrence with severe consequences
In the UK, although the risk of discovering UXO’s on construction sites is low, the potential consequences on health, safety and environment (HSE) and project cost and schedule are significant. The key risks include:
- injury and material damage
- delays and unforeseen costs to projects due to standing time
- site evacuations
- road closures
- reputational damage.
To avoid serious issues down the line, a systematic preliminary risk assessment should be performed wherever the presence of a UXO is suspected on site.