Working in the marine environment is tough enough, but having the added complication of UXO hazards is something you’d rather not have to deal with.  There is a well-established UXO detection survey industry to help.  Less well established is the rigorous process to understand what the surveys really mean, how they reduce the risk and what they may have missed!


This is where we help.  Firstly we would ensure that any desk based risk assessment undertaken to understand the UXO hazard is based on good research providing robust conclusions based on thorough understanding.  If not, we would fill in the gaps.  Without this, you might design a detection survey targeting the wrong type of UXO.


Thereon we would either design a suitable survey for detecting the hazard or, more commonly, we are called in to review an existing survey dataset.  We would undertake a thorough review of the data and how it was collected in order to understand the survey’s effectiveness for detecting those hazards identified in the risk assessment.


Understanding the hazard and then the effectiveness of any survey to map the hazard is the only way to truly understand the potential risk to proposed works, such as pipeline laying or windfarm construction.


We have provided this service to some of the largest and most complex marine projects, including Nord Stream (gas pipelines across the Baltic Sea), the Perpetuus Tidal Energy project in the Solent and the FAB Link between Alderney and Devon.


Risk Assessment

As you might expect, if we undertake the risk assessment, it is conducted to the same rigorous standards as our land-based assessments. We endeavour to collate as much detailed site-specific information as possible in order to provide a confident, corroborative risk assessment with clear and reasonable recommendations.


Written in compliance with CIRIA’s C754 ‘Assessment and management of unexploded ordnance (UXO) risk in the marine environment’, our risk assessments at a minimum consider:-


  • WWI and WWII bombing.
  • Minefields.
  • Munitions disposal at sea.
  • Offshore firing ranges.
  • Aircraft crashes.
  • Shipwrecks.
  • Submarine activity (including torpedoes).


Further detail on these sources of UXO hazard are available on our free resources page.


As you would expect from us, we consult a wide range of data pools to provide corroborative information in order to make a confident evaluation of the potential hazard and risk.




Using a standard source-pathway-receptor model, we evaluate the location of hazards based on source location and pathways facilitated by tidal currents and sediment movements that can lead to UXO migration in the marine environment. This, coupled with an investigation of the likely burial setting for any potential UXO, allows us to formulate the most appropriate risk mitigation strategies for the identified risk in relation to proposed works.


Survey Design & Data Interpretation

Where a significant UXO hazard has been identified in the marine environment, Zetica can design an appropriate detection survey to optimise detection for the anticipated UXO.




Data Evaluation, Quality Control and Consultancy

Zetica’s involvement in marine UXO projects has typically been when the going gets tough.  As we have said, there is a well-established UXO detection survey industry out there.  Where there are difficult site conditions, poor quality survey data, or if a survey identifies 1,000s of UXO targets, clients tend to call on our help.  We have helped unravel the issues and provide the client with a clear understanding of the situation, enabling a way forward.


Typically, the primary requirement is to identify what a survey may have missed. As part of this process we can undertake:-


  • Review of initial risk assessment to confirm UXO hazard type.
  • Verification of the quality and positional accuracy of the survey data.
  • Characterization of noise sources within the data.
  • Assess whether the mapping of targets is consistent with modeled detectability.
  • Cross-checking of anomalies with survey results and other data.
  • Identify gaps in data coverage.
  • Forward model targets to understand detectability consequences of data quality.





Many have found Zetica’s input extremely useful in identifying the limitations of the survey data for UXO detection, and allowing the opportunity to solve this through additional surveys or a more comprehensive risk mitigation plan to address the potential UXO hazard.


Explosive Ordnance Disposal

Of course, Zetica also provides a comprehensive marine EOD service through its SiteSafe Alliance partners, using remote EOD systems which are purpose-built for marine operations.


Using highly trained and experienced EOD divers and technical specialists, we can ensure that any hazardous UXO or Explosive Remnants of War (ERW) that may provide a risk to pipelines, cables, platforms or any intended works are removed, ensuring safe development.