Achieving consensus on equitable and effective national and global regulation(s) for the use of organotins as biocides in antifouling boat bottom paints has proven to be very complex and difficult for a variety of reasons as discussed in this paper. There appears to be broad agreement among stakeholders about the effectiveness of tributyltin (TBT) in antifouling paints. A draft Assembly Resolution prepared by the Marine Environmental Protection Committee (MEPC) of the International Maritime Organization (IMO) to propose a global ban on the use of organotins in antifouling paints was approved by the IMO at its 21st regular session (November 1999). In approving the Resolution, the Assembly agreed that a legally binding instrument (global convention - an international treaty) be developed by the Marine Environmental Protection Committee that should ensure by 1 January 2003, a ban on the application of tributyltin (TBT)-based antifouling paints; and 1 January 2008 as the last date for having TBT-based antifouling paint on a vessel. The Assembly also agreed that a diplomatic conference be held in 2001 to consider adoption of the international legal instrument. Monitoring, policing, enforcement, fines and record-keeping are yet to be defined. In addition, the MEPC has also proposed that IMO promotes the use of environmentally-safe anti-fouling technologies to replace TBT. Existing national regulations in the US and Europe have: (1) restricted the use of TBT in antifouling boat bottom paints by vessel size (less than 25 m in length), thus eliminating TBT from the smaller and recreational vessels that exist in shallow coastal waters where the impacted oysters species grow; (2) restricted the release rates of TBT from co-polymer paints; and (3) eliminated the use of fret: TBT in paints. The present movement toward a global ban suggests that the above regulatory approach has not been sufficient in some countries. Advocates of the ban cite international findings of: (1) higher levels of TBT in surface waters of ports and open waters; (2) imposer still occurring and affecting a larger number of snail species; (3) TBT bioaccumulation in selected fisheries; and (4) the availability of 'comparable' alternatives (to TBT) with less environmental impact. The global ban has been absent of a policy debate on the: (1) lack of 'acceptable and approved' alternatives in many nations; (2) appreciation of market forces in nations without TBT regulations; (3) full consideration of the economic benefits from the use of TBT; (4) 'acceptance' of environmental impacts in marinas, ports and harbors; and (5) realization of the 'real' time period required by ships for antifoulant protection (is 5-7 years necessary or desirable?). Estimates of fuel savings range from $500 million to one billion. In assessing the environmental impact from TBT, then are hire sources: the shipyard painting vessels and the painted vessel itself. Today vessels can be painted with regulated or banned antifouling materials by boatyards in a country that does not ham TBT regulations and subsequently travel in international and regulated national waters and thus bringing the impact back to the country which was trying to prevent it. Worse, local and national regulations for TBT have proven to be the antithesis of the popular environmental cliche - 'Think Globally and Act Locally.' Legislative policies enacted by 'regulated' countries to regulate the use of TBT to protect (their) local marine resources have subsequently had far reaching environmental and economic impacts which have in essence transferred TBT contamination to those countries least able to deal with it. Market forces are selective for cheap labor and cheap environments. 'Unregulated' countries have unknowingly accepted the environmental and human health risks to gain the economic benefits from painting TBT on ships. Unfortunately, these countries may not have the funding or environmental expertise available for the monitoring, research and technology development essential to use these modern high technology compounds. Therefore, they end up with more contamination because they do not have the necessary regulatory structure to prevent it. In the US coastal zone, federal and state regulations have had a significant impact on reducing TBT levels, generally to well below the provisional water quality standard of 10 ng/l, and in bivalve tissues. Current environmental and marine and estuarine water concentrations are well below predicted acute TBT toxicity levels. Estimation or chronic toxicity effects using mean water TBT concentrations indicate that current levels would be protective of 95% of species. Analysis of allowable daily intake/oral reference dose values from market basket surveys and the NOAA National Status and Trends data suggest that there is no significant human health risk from consuming seafood contaminated with TBT. Most of the data that exceeded these values were from areas of high TBT input from ports, harbors and marinas (commercial shipping, shipyards and drydock facilities) and sites of previous contamination. In the US, at this time, TBT environmental data and lack of acceptable alternatives does not justify a global ban for TBT. Three significant aspects of the regulatory discussion should not be forgotten: (1) none of the available alternatives to TBT-based antifouling paints has been approved on a global basis or in the US by the USEPA, the VOC levels are above current regulatory levels and in the past such reviews have taken up to 54 months to complete; (2) studies in Ireland have found that the use of TBT has greatly reduced the threat and risk of introduction of invasive (exotic) marine species in foreign waters; and (3) a biofouled ship can transport on its bottom approximately 2 000 000 marine organisms which is significant when compared to the small numbers transported in ballast waters. Alternatives to TBT are available, but not proven and accepted on a global basis. Unfortunately in the less than 1000 days remaining before the proposed IMO ban, an international independent process is not available to expedite the IMO recommendation to evaluate and select alternatives to TBT. The cost (to shipowners) for this failure has been estimated to range from $500 million-$1 billion annually. A third party, neutral, independent, international Marine Coatings Board has been proposed to supplement the national regulatory process by providing the international standardized scientific data and information of the highest quality. The cost of the Marine Coating Board to evaluate available alternatives has been estimated to be $10 million/year or 1-2% of the estimated annual direct costs to shipowners of nor having comparable antifouling marine coating alternatives to TBT. In ship operating coasts, this is less than $1/day per vessel in global commerce with a total ROI in the first 37 days of 2008. (C) 2000 Elsevier Science B.V. All rights reserved.
