been sent a Notice of Intent to suspend their registrations because they 

 have not filed a timely response to the EPA's DCI requirements even though 

 they have indicated intent to comply. Of the 57 registered products that 

 provided acceptable data to EPA's DCI Notice, only 29 products meet the 

 proposed EPA release rate of 0.5 ug/cnr/d (U.S. EPA, 1987) . 



The aggregate effect of the voluntary requests for cancellation and the 

 Notice of Intent to Suspend registrations if carried out will be a reduc- 

 tion of 80% of the brand names available to the market place. However 

 these brand names which are candidates for cancellation account for only 

 half of the volume of antifouling paint production. Thus it is the less 

 popular products which are being dropped. An equivalent increase in 

 production can be anticipated by the more popular brands to capture the 

 segment of the market place abandoned by the canceled registrations. 

 Therefore, the cancellation of registrations may not have the effect of an 

 equivalent reduction in the amount of TBT reaching the environment. 



3.5 PATTERNS OF ANTTFOULANT PAINT USE AND RATES OF USE 



Antifouling paint use by individuals does represent a significant portion 

 of paint sold but is extremely difficult to assess with a survey method. 

 Industrial establishments are the other major user of antifouling paint. 

 The 1982 U.S. Census identified 2,500 to 2,600 non-military industrial 

 establishments in the contiguous States which are likely to be applicators 

 of antifouling paints. Of these nearly half build or repair ships or 

 boats. Lucas and Williams (1987) conducted for EPA a survey of these 

 shipyards and boatyards employing follow up procedures to increase the 

 accuracy of the survey results. The results of their studies are 

 summarized in the sections below. 



3.5.1 Paint Use by Vessel Hull Composition 



Table 3.5 presents the number of vessels painted, by the type of paint 

 used and by the composition of the hull. The first number in each category 

 is the probable number of vessels in the contiguous United States based on 

 the sample survey proportions. The primary hull composition material 

 painted with TBI containing bottom paints was found to be fiberglass or 

 glass reinforced plastic (GRP) . Fiberglass hulls comprise 77 . 3% of all the 

 hulls painted with paints containing TBT. Wood composition hulls comprise 

 13.5 % of the hulls painted with tributyltin containing paints. Copper 

 anti-fouling paints corrode aluminum hulls and outdrives rapidly and steel 

 structures somewhat more slowly. An epoxy type isolation primer is 

 normally used on metal hulls to prevent or control the effects of 

 electrolysis which is due to the action of antifouling paints containing 

 copper. Aluminum hulls (which have the most severe problem with 

 electrolysis (when painted with antifouling paints other than TBT) 

 represent only 2.3% of the hulls painted with Tributyltin antifouling 

 paints. 



Ill- 



