Developers of offshore infrastructure projects have often overlooked the threat of unexploded ordnance (UXO) in the marine environment. Indeed, while the scale of marine construction has grown considerably with the development of the offshore energy industry, there is still insufficient clarity and awareness concerning the safe and cost-effective management of UXO hazards.
Project developers and operators are frequently under-informed about the true scale and nature of the UXO threat in European waters and, as a result, fail to properly protect their sites.
Yet large areas of the European shoreline and sea bed have, at one time or another, been subject to some form of military activity – leaving behind a potentially explosive legacy. The sources of these UXO hazards include explosive remnants of war (such as sea mines, beach land mines, aerially-delivered bombs, ship to ship projectiles and torpedoes), munitions dumps and wrecks of munitions-carrying vessels.
It’s important that, as offshore wind and cabling projects burgeon in UK and European waters, developers consider the threat posed by these munitions.
First, UXO presents a direct health and safety risk, threatening not only the safety of contractors and vessel operators working on site, but also crucial project equipment and infrastructure. Should an inadvertent detonation occur on site leading to injury of a worker, legal responsibility for any proven negligence will sit squarely with the project directors, in line with Construction Design and Management Regulations and the Corporate Manslaughter and Homicide Act.
Second, developers should take into account the potential environmental and financial costs of a UXO-related problem. Several high-profile offshore projects have experienced expensive delays and downtime resulting from UXO mismanagement – not only during construction, but also in the subsequent operational phases.
One of the main obstacles to developers understanding and resolving this threat has been the absence of any centralised formal guidance. Recognising this knowledge-gap, 6 Alpha has worked with Royal HaskoningDHV and the Construction Industry Research and Information Association (CIRIA) to provide definitive best-practice guidelines for the industry.
The end result is the CIRIA report Assessment and Management of Unexploded Ordnance (UXO) Risk in the Marine Environment, published this month.
This sets out a comprehensive guide for developers on the various steps that should be taken to ensure the safe management of UXO risk offshore. It provides guidance on identifying UXO threats, assessing site-specific risks, and managing those risks, including options for mitigation.
In the majority of cases, we find that a straightforward and cost-effective preliminary assessment is all that is required to render the UXO risk of a site as low as reasonably practicable (ALARP). However, this assessment does need to be performed at each stage of a project’s lifecycle. Human activities during the pre-construction, construction, operations and maintenance, and decommissioning phases of many nearshore and offshore developments, such as the drilling of boreholes or the installation of foundations or cables, disturb the seabed. As a result, UXO, which was initially buried, can emerge or in some cases migrate across the sea floor.
If a clear UXO threat is identified on site via preliminary assessment and substantiated by further surveys, the new CIRIA guidelines clearly explain the steps that should be taken by developers. Furthermore, we have identified the responsibilities and duties of different organisations under existing legislative and regulatory regimes, so developers know where to turn in the event of an UXO-related issue.
A balance must be struck between the costs of risk mitigation and its benefits. Developers will need to carefully weigh the costs of mitigation procedures against the likelihood of delays or damage to their sites. But the more awareness the industry has, and the more seriously we take it, the easier it will become to help developers properly assess the risks of their sites and propose cost-effective mitigation strategies.
Simon Cooke is managing director of 6 Alpha Associates