Paint and Coatings Industry News

Main News Page

U.S. Joins IMO’s TBT Antifouling Ban

Monday, September 24, 2012

More items for Environmental Controls

Eleven years after it helped launch the measure, the United States is set to become the next “Contracting State” for the IMO Antifouling Systems Treaty, following President Obama’s recent approval of the treaty’s ratification package.

American Coatings Association

Marine coatings manufacturers and the Environmental Protection Agency have both endorsed the convention.

Adopted in 2001 by the International Maritime Organization, the International Convention on the Control of Harmful Anti-fouling Systems on Ships prohibits the use of tributyltin (TBT) antifouling coatings on ships and establishes a mechanism to prevent the potential future use of other harmful substances in antifouling systems.

The Convention will enter into force for the United States on Nov 21.
 
Coatings Industry Endorsement

Obama signed the treaty ratification package in August, to make the U.S. a “Contracting State,” and the U.S. Ambassador in London filed the documents with the IMO on Aug. 21.

The treaty has the rare support of both coatings manufacturers and the U.S. Environmental Protection Agency, which are frequently at odds on legislative and regulatory issues.

The American Coatings Association and its Marine Coatings Committee and Antifouling Workgroup have been actively pressing Congress and the Obama Administration since 2008 to ratify the treaty, saying that delayed ratification would exclude the U.S. as a party to future IMO decision making. Only parties to the treaty can participate in the vote at the IMO, a right that the United States will now be afforded, ACA said.

The marine coatings industry says the Convention “will provide a single regulatory program for all countries throughout the world, as well as a market for hull coatings that do not contain organotin biocides,” according to ACA, which represents coating manufacturers.

The treaty also levels the playing field for ship owners, by requiring all vessels in international trade to adhere to the same coating restrictions, ACA said.

The U.S. Coast Guard and the international maritime community have also endorsed the treaty.

U.S. shipyards already must comply with the organotin coating ban for vessels less than 25 meters in length and must meet stringent leaching standards that are unique to the United States.

Adoption and Ratification

The U.S. was a signatory when the IMO adopted the AFS treaty at the Diplomatic Conference on Oct. 5, 2001. The Convention did not take effect until Sept. 17, 2008, however, when the requisite number of flag states ratified it.

Environment Canada

Organotin coatings were effective and lasted twice as long as copper-based antifoulings, but they proved too toxic and were banned from use.

Some 61 signatories representing 80.22 percent of the world’s tonnage have now ratified the treaty, according to ACA.

“The treaty relies on rigorous scientific review as the basis for determining when controls are needed to limit the negative impacts of antifouling systems, and its implementation will uphold the standing of the United States as an environmental leader,” ACA reported.

Seeking Safer Antifouling

Antifouling coatings and systems are designed to minimize the marine growth that accumulates on a ship’s hull. Hull fouling can increase ship operating costs, fuel consumption, and gas emissions. Fouled ship hulls also transport damaging non-native species worldwide.

Organotin compounds made for powerful antifoulings and became a popular replacement for traditional copper-containing antifouling paints in the 1960s; TBT was the most commonly used organotin.

However, the highly toxic compound also proved deadly to organisms it was not meant to target. TBT coatings were banned in the most of the world in the 1980s, giving way to more environmentally benign cuprous oxide-based biocidal coatings and non-biocidal coatings.

Treaty Requirements

The IMO convention prohibits the new application of listed antifouling systems and requires the removal or overcoating of organotin biocides now in use on hulls. Currently, TBT is the only system listed. Any new additions to the banned so-called Annex 1 substances would also have to be removed or overcoated.

Survey, certification, and inspection mechanisms will ensure international compliance, according to ACA. The convention also “provides the appropriate means for addressing any other anti-fouling systems that might later be determined to pose a threat to the marine environment,” ACA adds.

ACA says the United States has been “among the chief advocates of the AFS; however, ratification of the treaty was slow coming.”