Remediating submerged marine munitions in European seas: Stakeholder priorities, requirements, perceived risks and constraints

European coastal waters contain hundreds of thousands to millions of submerged munitions following World Wars I and II. This war legacy poses critical ecological, human health, economic, and security risks through accidental detonations and leakage of toxic substances from corroding munitions, underscoring the urgent need for remediation. We conducted a structured survey of knowledgeable stakeholders to identify their needs, constraints, and priorities for remediating submerged marine munitions. The largest proportion of respondents (50%) were affiliated with Germany-based organizations. Stakeholders reported high concern about the environmental, economic, and security-related impacts of submerged munitions and largely agreed that remediation would provide benefits across these domains. However, they also identified key concerns and barriers to remediation, including unclear institutional responsibilities; permit issuance and bureaucracy; inadequate risk assessment; remediation costs; and safety and security threats. Notably, none of the respondents in the present study preferred Blast in Place (BiP) as a remediation method, despite its historical prevalence, likely reflecting growing awareness of BiP's ecological and security/safety risks. These stakeholder insights provide a timely snapshot that may inform ongoing European policy initiatives, especially the development of the EU Oceans Pact (adopted in 2025) and the drafting of the forthcoming EU Ocean Act. The findings may also guide ongoing EU co-funded projects and the frameworks of regional institutions, such as HELCOM and OSPAR, toward a comprehensive strategy for safe and sustainable remediation of submerged munitions in European coastal waters.