In international legislation of antifouling biocides the adoption of the Antifouling Convention of the IMO (www.imo.org) exerted long-term and drastic effects in maritime industry.

In October 2001 the International Maritime Organization approved a treaty with the global prohibition for the application of organotins acting as biocides in antifouling paints on January 1, 2003 and a complete ban on the presence of organotins acting as biocides in antifouling paints by January 1, 2008.

The title of the convention points out that this treaty will cover more than organostannic biocides: International Convention on the Control of Harmful Effects of the Use of Anti-Fouling Systems on Ships.

This Convention shall enter into force twelve months after the date on which not less than twenty-five States, the combined merchant fleets of which constitute not less than twenty-five percent of the gross tonnage of the world's merchant shipping, have either signed it without reservation as to ratification, acceptance or approval, or have deposited the requisite instrument of ratification, acceptance, approval or accession. For the actual status of treaty ratification see:

AF Treaty Status (, 13 KB)

IMO Treaty Ratification 09-2007 (, 22 KB)

In a first step the following systems shall be banned:

Organotin compounds which act as biocides in anti-fouling systems shall not be applied or re-applied by January 1, 2003
Ships shall not bear such compounds on their hulls or external parts or surfaces,
Shall bear a coating that forms a barrier to such compounds leaching from the underlying noncompliant antifouling systems

Other antifouling systems than organotin-based can be proposed to be included in the Annex. The required elements for an initial proposal are clearly defined in the Annex 2 of the AFS-Convention.

It can be expected that antifouling systems banned after the implementation of the EU Biocidal Products Directive will be proposed to be included in the annex.

The Convention requires surveys and certification for anti-fouling systems for ships of 400 gross tonnage and above engaged in international voyages.

Technical guidelines for surveys were developed and implemented. A ship is issued with a Certificate after successful completion of a survey in accordance with regulations outlined in Annex 4. A model form of international anti-fouling system certificate is part of the convention as Appendix 1 to Annex 4. For details see:

AFS-Conf-26 (, 188 KB)

Despite the fact that the IMO Antifouling Convention is not yet valid, several classification societies started with separate procedures to certify TBT-free antifouling paints.

Lloyds Register publishes since 2002 a list with TBT-free antifouling paints which are certified according to its own procedure. This list is going to be regular updated. The PDF-document represents the status of April 2005. For details see:

Recognised TBT-free Antifouling Coatings LR, 04/2005 (, 244 KB)

The German classification society Germanischer Lloyd developed another certification system and is publishing a list of TBT-free paints recognised by the Germanischen Lloyd on their website. For details see:

List of Approved Anti-Fouling Systems GL, 06/2005 (20 KB)

Vom GL zugelassene Bewuchsschutzsysteme (Online-Anfrage bei gl-group.com)

Another worldwide operationg classification society Det Norske Veritas has certified a large number of professional antifouling paints. For details see:

List of Approved Anti-Fouling Systems DNV, 06/2005 (35 KB)