Anti-Fouling System (AFS Convention)

The AFS Convention is the International Convention on the Control of Harmful Anti-fouling Systems on Ships, adopted by the IMO on 5 October 2001 and in force from 17 September 2008. It bans the use of organotin compounds acting as biocides in anti-fouling systems: tributyltin (TBT) paints could not be applied from 1 January 2003 and could not be present on hulls (unless sealed by an overcoat) from 1 January 2008. TBT was banned because it caused imposex in marine gastropods and shell deformation in oysters at very low concentrations. Amendments adding controls on cybutryne entered into force on 1 January 2023. Compliance is shown by an International Anti-fouling System Certificate.