In 1989 the European Community introduced a directive to restrict the use of TBT-based (Tributyltin - a powerful biocide) antifouling paints on boats under 25m. This, in combination with other National and International legislation, has provoked paint manufacturers and chemical companies to develop and vend a range of agents for new antifouling paints for the "small boat" market and as an addition to TBT-based formulations to enhance efficacy for larger vessels.

Examples of the types of compounds being used or promoted include: 2,3,5,6-tetrachloro-4-(methyl sulphonyl) pyridine; 2-methylthio-4-tertiary-butylamino-6-cyclopropylamino-s-triazine (IRGAROL 1051); cuprous thiocyanate; 2,4,5,6-tetrachloro iso phthalo nitrile; 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (SeaNine 211); dichlorophenyl dimethylurea (Diuron); 2-(thiocyanomethyl thio)benzthiazole; zinc pyrithione; 4-chloro-meta-cresol; arsenic trioxide; cis 1-(3-chloroallyl)-3,5,7-triaza-1-azonia adamantane chloride; zineb; dichlofluanid; folpet; thiram; oxy tetracycline hydrochloride; ziram and maneb. This list includes compounds which are known to be highly toxic (e.g. cyanides, arsenicals) or to act as endocrine disrupters (e.g. maneb, ziram) but negligible data concerning contamination, (potential) effects and risks of these compounds in the coastal and marine environment are available.

Data are currently not available concerning the usage, distribution and effects of most of these biocides (IRGAROL 1051 being the only exception). Indeed, for most, suitably sensitive analytical protocols are not available.

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