The Risks of Ignoring UXO in Geotechnical Projects

Unexploded ordnance (UXO) may seem like a distant concern for many construction and geotechnical projects, but its presence can have serious consequences if not properly managed.

UXO can be buried for decades, often since the First or Second World War, remaining undetected until groundworks or geotechnical surveys disturb the area. Ignoring the risk of UXO can put lives, projects, and budgets at significant risk.

Understanding the UXO Threat

Across the UK, thousands of bombs, shells, and other explosive remnants of war remain buried underground. Many areas that were targeted during WWII or used for training and munitions testing are now being redeveloped for housing, infrastructure, and renewable energy projects. While these sites may appear harmless today, the risk of encountering UXO during intrusive ground activities remains real.

Geotechnical projects, such as site investigations, borehole drilling, and pile installation, are particularly vulnerable because they involve penetrating deeper ground layers where UXO may lie. Without the correct surveys and precautions in place, these operations can inadvertently disturb or detonate ordnance, endangering lives and disrupting entire projects.

Safety Risks to Personnel

The most immediate and obvious danger of UXO is the safety of site personnel. Even small items of buried ordnance can detonate if disturbed, posing a fatal risk to workers operating drilling rigs, excavators, or other ground investigation equipment.

In many cases, the ordnance may be corroded or partially degraded, making it unpredictable and highly sensitive to movement or vibration. Geotechnical activities such as soil sampling, dynamic probing, and trial pit excavations to obtain soil samples can easily trigger a device if its presence has not been identified.

Ensuring that potential UXO hazards are assessed and mitigated before any intrusive work begins is therefore essential. This not only protects on-site teams but also ensures compliance with health and safety legislation designed to safeguard workers in high-risk environments.

Project Delays and Increased Costs

Beyond the human risk, the discovery of UXO during active works can cause significant disruption. When ordnance is found, all operations must stop immediately until the site is declared safe. This can lead to unplanned downtime, the mobilisation of specialist UXO teams, and coordination with local authorities or the Ministry of Defence.

Even a short delay can create a domino effect, pushing back schedules, affecting subcontractors, and leading to increased costs for plant hire, staffing, and logistics. In some cases, projects face contractual penalties for missed deadlines or reputational damage due to the perceived lack of preparation.

Early UXO risk management helps to avoid these scenarios by ensuring that potential hazards are identified and dealt with before they can cause disruption.

Legal and Regulatory Implications

The Health and Safety at Work Act 1974 and the Construction (Design and Management) Regulations 2015 (CDM) place a legal duty on employers and project managers to assess and control all foreseeable risks to health and safety. UXO is considered one such risk.

Failure to take appropriate action, such as neglecting to commission a UXO risk assessment or ignoring known historical risks, can be deemed a breach of these regulations. This can result in investigations by the Health and Safety Executive (HSE), legal liability, and in serious cases, prosecution.

Developers, consultants, and contractors all share responsibility for ensuring that potential UXO hazards are identified and managed in accordance with best practice.

Best Practice: Early Risk Assessment

The most effective way to manage UXO risk is through proactive assessment and planning. A staged approach, beginning with a preliminary desk-based UXO risk assessment helps to determine whether a site is likely to contain unexploded ordnance.

If a potential risk is identified, further research and investigations can be carried out. Where intrusive works are necessary, borehole clearance and UXO engineer support ensure that deeper ground investigation can proceed safely.

Partnering with experienced UXO specialists provides peace of mind that all potential risks have been considered and mitigated. This collaborative approach not only protects people and assets but also allows geotechnical projects to progress efficiently and with minimal interruption.

A Risk Too Serious to Ignore

The presence of UXO in geotechnical projects is more than a theoretical concern, it is a real and potentially devastating hazard that must be taken seriously. By addressing UXO risk early in the planning and investigation stages, project teams can safeguard personnel, prevent costly delays, and maintain compliance with UK health and safety requirements.

Ignoring UXO is a gamble no construction or geotechnical project can afford to take.

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