Governing flexitank safety and environmental risks in maritime transport: A multilevel gap analysis and policy options

Flexitanks are single-use bladders installed in dry containers to carry bulk liquids. Their use has grown faster than formal oversight. This study asks how safety and environmental risk should be governed in this trade. We combine risk-governance analysis with a review of international, national and industry rules, and we use evidence from more than 50 monitored coastal voyages and scaled bench tests. The analysis shows that flexitanks for non-dangerous liquids fall between mandatory regimes for ship safety, pollution prevention and dangerous goods, and that day-to-day control therefore depends mainly on voluntary guidance, carrier rules and insurer requirements. The empirical evidence is narrower than the policy problem. It shows that intact bags filled at or above 95% behaved as fixed loads under the monitored conditions, while a rupture scenario increased roll-induced stress amplitudes by 2.1% to 4.9%, demonstrating a plausible failure pathway under experimental conditions without establishing global fleet scalability. Consequently, proposed policy options are structured as precautionary risk control measures rather than empirical justifications for mandatory international intervention. The paper proposes International Maritime Organization guidance, clearer national disclosure and stowage rules, wider use of PAS 1008-based testing, crew and packer training, and emergency planning for large non-dangerous liquid releases. Its principal contribution is the integration of legal gaps, operational evidence and practical policy options within a single analytical framework.