AFS Convention

International Convention on the Control of Harmful Anti-Fouling Systems on Ships, adopted 2001 and effective 2008. The Convention initially banned organotin (tributyltin/TBT) compounds in anti-fouling paints because of their toxicity to non-target marine organisms. A 2021 amendment added cybutryne to the prohibited list effective 2023 with a transition period. Ships above 400 GT must carry an International Anti-fouling System Certificate; PSC inspectors verify compliance by reviewing the certificate and may require sampling of the underwater hull where toxicity is suspected.