Since tributyltin compounds were first registered in the U.S., in the 

 early 1960 's, the number of EPA registered formulations has grown to 364. 

 Sixty-one manufacturers have one or more paint formulations registered for 

 use. 



The Navy estimates that, if the entire fleet were painted with TBT paint, 

 the reduction in fuel costs would exceed $110 million annually calculated 

 with fuel costing (also referred to as fuel avoidance costs) less than $16 

 per barrel, (U.S. NAVSEA, 1986) . In commercial shipping, fishing, and 

 private boating, this could add another $300 to $400 million in annual 

 fuel savings. Table 3.3 (from Iucas and Williams, 1987) presents an 

 estimate of the average area coverage (square feet) of paint coverage per 

 gallon of paint by paint type and application firm type. Copolymer, 

 ablative, and and self polishing paint designations have been combined due 

 to the fact that users surveyed were not always able to discriminate 

 whether the paint being applied was self polishing or not. Similarly if 

 the paint did not designate the manner of incorporation of the Tributyltin 

 as copolymer or self polishing, the paint was considered to be a free 

 association type. More square feet covered per gallon means that the 

 paint is usually applied in a thinner paint film. In most cases, free 

 association paints are generally applied with the thinnest paint film 

 possible because the spent paint film will have to be removed by 

 mechanical means. Copper base paints are usually applied as a thicker 

 film than free association TBT paints while self polishing copolymer 

 paints are applied in the thickest film. 



Another factor that affects quantity of TBT released from the paint to the 

 environment is the degree of drying. Table 3.4 presents the degree of 

 drying of the paint film in terms of the number of days between painting 

 and water contact with the new paint film. The Gulf and Southern Pacific 

 coasts have generally the shortest times between painting and launching. 

 This may possibly be due to external factors such as the prevalence of 

 good weather. However, the longer the paint film dries, the less 

 antifouling biocide is released from the film. 



III-5 



