Active Ingredient (Antifouling)

An antifouling active ingredient is the biocide in a hull coating that kills or repels settling organisms. Copper compounds, cuprous oxide and copper thiocyanate, are the primary biocides, supported by booster biocides such as zinc pyrithione, copper pyrithione, and historically the herbicide cybutryne (Irgarol 1051). Organotin biocides, mainly tributyltin (TBT), were the dominant actives until the AFS Convention banned organotin application from 2003 and prohibited cybutryne from 1 January 2023. Booster biocides leach into the water column and accumulate in marina sediments, driving the ecological risk assessments that set their use limits.