Is there a legal requirement to conduct an explosive assessment?

There is no legal requirement to undertake an explosive assessment under ‘statute’ law.  However, under ‘tort’ law it is considered a civil wrong to cause harm knowingly or otherwise.  Therefore, if it is considered that reasonable actions were not taken i.e. following good practice, performing due diligence etc. then a legal liability may result. This is covered under the following acts:

  • Health and safety at Work Act 1974
  • Health and Safety at Work Regulations 1999
  • The Corporate Homicide and Manslaughter Act 2007
  • Construction design and Management Regulations 2015

Do I need a geophysical site survey?

Not necessarily, if the provenance of explosive ordnance is not discernable and or the site has been re-developed beyond the level of perceived explosive ordnance encounter then no further action is required.

What is the probability that all UXO is unstable and liable to explode?

NO, this is a myth.  If left alone, explosive ordnance will generally remain dormant and in due course it will erode.  Explosive ordnance comes in many shapes and sizes, including non-explosive training or exercise ammunition. However, it is prudent to assume all explosive stores are dangerous until proven otherwise by a suitably qualified experienced person (SQEP). Explosive Ordnance encounter is only one part of the function of probability, the other being probability of detonation. This will typically require force or energy being imparted on or near the device sufficient to make it function. 

Can UXO drift/migrate significant distances?

The term ‘drift’ implies ordnance moves to and fro with the tides, this is an exaggeration in part and may lead to poor decision making.  The process is far more complicated, and very difficult to model, much less predict. Migration is perhaps a better term as it covers other more feasible ways in which explosive ordnance moves, some of these include dredging and trawling. 

Do I need a risk assessment for investigation works?

You could argue that the probability of UXO encounter during geotechnical investigations is so low, that the risk is reduced ALARP.  However, a modified survey can still be achieved without exceeding the ‘De Minimis’ principle, in terms of rising costs with no risk reduction simply by subjecting the sample or borehole areas to a visual inspection, followed by an intrusive point focal survey vice a full area geophysical survey.

What generic guidance is available to project teams regarding the safe management of UXO?

The Construction Industry Research and Information Association (CIRIA) Is essentially an independent non-for-profit body that links organisations with common interests to improve the industry. They have produced guidance for developers and project managers with the help of subject matter experts. 

There are principally two guides available concerning the safe management of UXO through a project lifecycle:


  • The land publication ‘Unexploded Ordnance(UXO) A Guide for the Construction Industry’ C681 published 2009 provides the industry with clearly defined processes and frameworks for the safe management of explosive ordnance associated risks. 
  • The ‘Assessment and Management of Unexploded Ordnance (UXO) Risk in the Marine Environment C754, 2016.  This publication provided direction and guidance to organizations involved in the planning, design, delivery, operation, maintenance, decommissioning or regulation of projects in the marine environment regarding the risks associated with UXO.  It is worthy of note that these publications have wider application outside the territorial waters of the UK.