Anti-fouling Paint - Environmental Concerns

Environmental Concerns

In the 1960s and 1970s, commercial vessels commonly used bottom paints containing tributyltin (TBT), which has been banned by the International Maritime Organisation due to its serious toxic effects on marine life (such as the collapse of a French shellfish fishery). The Port of San Diego banned copper-based bottom paint on recreational boats in January, 2010 and Washington State did the same in May, 2011.

"Sloughing bottom paints", or "ablative" paints, are an older type of paint designed to create a hull coating which ablates (wears off) slowly, exposing a fresh layer of biocides. Scrubbing a hull with sloughing bottom paint while it is in the water releases its biocides into the environment. One way to minimize the environmental impact from hulls with sloughing bottom paint is to have them hauled out and cleaned at boatyards with a "closed loop" system.

Some innovative bottom paints that do not rely on copper or tin have been introduced. These products have been developed in response to the increasing scrutiny that copper-based ablative bottom paints have received as environmental pollutants. One brand, EPaint, which has been used by the US Coast Guard, works by producing hydrogen peroxide in the presence of light.

A possible future replacement for anti-fouling paint may be slime. A mesh would cover a ship's hull beneath which a series of pores would supply the slime compound. The compound would turn into a viscous slime on contact with water and coat the mesh. The slime would constantly slough off carrying away microorganisms and barnacle larvae.