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INTRODUCTION 7 Application to ChIorobenzilate The preceding chapters have reviewed the methods currently used by the oPP in selecting pesticides for review and in analyzing the benefits and risks of alternative regulatory measures where they appear appropriate. A number of important recommendations for revising these procedures have also been made. But it is easier to recommend than to perform. Therefore, the Committee has felt responsible for applying its recom- mendations to an actual instance, to the extent that its resources permitted. This chapter reports on that application. It will also serve to help clarify the Con~mittee's recommendations by illustrating how they are implemented. Chlorobenzilate was selected as the pesticide for the test application. It was the first pesticide to complete the entire RPAR procedure and, consequently, all the data used in EPA'S evaluation were readily available for the Committee's use and appraisal. Because oPP has previously completed benefit and risk assessments for chlorobenzilate, including a comparison of benefits and risks associated with various regulatory options (U.S. EPA 1978a, 1979), the discussion in this chapter is to some extent framed in terms of a critique of the oPP analysis. The structure of the chapter basically follows the format of oPP's Chlorobenzilate: Position Document 3 (U.S. EPA 1978~. The first section reviews chemical and physical properties, registered uses, and environmental fate of the compound The second and third sections present the Committee's risk 154

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Application to Chlorobenzilate 155 and benefit assessments, respectively. Finally, in the last section, benefits and risks are compared and presented in a manner that reveals not only the Committee's assessment of the trade-o~s for the major regulatory options considered by oPP, but also the uncertainty in the scientific base and the extent to which value judgments enter into the decision. This chapter focuses on recommended departures from oPP's analytical methodology; it is not intended to stand as an independent document on chlorobenzilate. BACKGROUND Chlorobenzilate (ethyl 4,4'-dichlorobenzilate), a chlorinated hydrocar- bon acaricide, is manufactured by esterification of dichlorobenzilic acid and is formulated principally as emulsifiable concentrates and wettable powders (Severe 1978~. The formulation marketed in the United States contains 45.5 percent technical-grade chlorobenzilate. Approximately 93 percent of this amount is pure chlorobenzilate; the remaining 7 percent consists of several unidentified intermediates and other impurities (U.S. EPA 1978b). Chlorobenzilate is registered for use on almonds, walnuts, apples, melons, cherries, citrus fruit, cotton, pears, ornamentals, and trees (U.S. EPA 1978a). Approximately 90 percent of the total amount used in the United States is applied to citrus to control the citrus rust mite (U.S. EPA 1978a); the principal crops on which chlorobenzilate is applied are oranges, grapefruits, and lemons (Luttner 1977a). Limited use also occurs on limes, tangerines, and tangelos (Luster 1977a). The predomi- nant method of applying chlorobenzilate to citrus groves is with a speed sprayer pulled by a tractor. The illustrative analysis in this chapter concentrates on the principal uses of chlorobenzilate, namely, mite control on oranges, grapefruits, and lemons. PROPERTIES OF CHLOROBENZILATE, ETHION, Ad DICOFOL As noted earlier, to assess the risks and benefits of adopting any regulation restricting the use of a pesticide, it is necessary to compare the risks and benefits of using that pesticide with comparable risks and benefits of alternative pesticides to which users are likely to resort. Ethion and dicofol are two important alternatives to chlorobenzilate for control of rust mites on citrus fruits (U.S. EPA 1978a). Their physical properties are compared with those of chlorobenzilate in Table 7.1. Examination of these properties and calculation of other molecular parameters indicates some common behavioral characteristics in the

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156 REGULATING PESTICIDES environment. Each has a relatively low vapor pressure, which indicates that the rate of vapor loss from sprayed surfaces may not be high. The substantial polarity of ethion indicated by its molar refraction (100.1) probably indicates a strong adsorption on surfaces. Ethion may therefore persist as a surface residue allowing dermal exposure if reentry occurs before photochemical destruction or hydrolysis. Dicofol similarly shows low vapor loss, indicating ready adsorption. As with ethion, dicofol's physical and biological properties may afford exposure. Chlorobenzilate, while also having comparatively low vapor loss, is much more suscepti- ble to degradative chemical, biochemical, and photochemical reactions than dicofol. It should undergo metabolism more readily than dicofol and probably have less of a propensity for partitioning in lipid. Among the three compounds, ethion would probably be the least persistent and dicofol the most. In terms of biological activity, ethion is not as specific to rust mites as is chlorobenzilate, so that it is likely to have more extensive side ejects than chlorobenzilate on nontarget organisms. Dicofol is specific for mites, but is not as effective for rust mites as is chlorobenzilate. This cursory examination of physical and biological properties suggests that chlorobenzilate poses less of an environmental and human hazard in terms of persistence and the possibility of undesired exposure than its substitutes, dicofol or ethion. There are few actual data about the fate of chlorobenzilate in the environment. Several authors have studied its metabolism in plants and found that it is persistent in citrus and apple peels (Gunther et al. 1977, Severn 19781. When applied topically to soybean leaves, it translocates to the petioles unchanged after about 12 days (Hassan and Knowles 1969~. Miyazaki et al. (1970) found that chlorobenzilate can be metabolized by microorganisms, particularly yeast. A study of chlorobenzilate's persis- tence in Florida Lakeland and Leon fine sandy soils demonstrated a half-life of 1.5-5 weeks in Leon soil and 1.5-3 weeks in Lakeland soil (Wheeler et al. 1973~. This same study concluded that chlorobenzilate did not affect the microbiological activity in the soils. Finally, a study of environmental transport detected no chlorobenzilate in drainage water or in soil samples, following (1) the spraying of a citrus grove, (2) 39 hours of irrigation, and (3) a 2.41 cm rainfall a week later (U.S. EPA 1977). ANALYSIS AND ASSESSMENT OF THE RISKS The principal concern with the use of chlorobenzilate is the possibility that this chemical may increase the incidence of cancers in people exposed to it. The seriousness of this risk depends on three factors: (1)

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Application to Chlorobenzilate TABLE 7. ~ Physical Properties of Chlorobenzilate, Dicofol, and Ethion 157 Solubility Vapor Molecular In Water Pressurea Refractive Compound Weighta (temperature C) (mm Hg) Index ,a nD20 Chloroben- 325.2 - 2.2 x 10-6 (20) 1.5727 zilate (tech. prod.) Dicofol 370.5 1320,ug/1 (25)b 1.20 ppm (20)C 1.606 ppm (3)C Ethion 384 2ppm (22)4 1.5 x 10-6 (25) 1.5490 2 ppm (?)e 1.530 to 1.542 (tech. grade) a Source: Martin (1971) . b Source: Well et al. (1974). c Source: F. Parveen, Environmental Health Sciences Center, Oregon State University, Cor vallis, personal communication, 1975. Source: von Rumker and Horay (1972). e Source: Gunther et al. (1968). the number of people exposed, (2) the dosages to which each of them is exposed, and (3) the probable health risks from receiving these dosages. The next subsections present estimates of the extent of human exposure, followed by an assessment of that the consequences of the exposure. In a final subsection, risks posed by chlorobenzilate substitutes are evaluated and comparison compounds selected. HUMAN EXPOSURE TO CHLOROBENZILATE The use of chlorobenzilate on citrus fruit exposes different segments of the U.S. population to widely differing doses. The largest doses are received by citrus spray applicators and citrus fruit pickers. Much lower doses are received by people who eat foods that contain residues of the pesticide. Some of the meat consumed by residents of Florida ~y contain residues transmitted in the citrus pulp that is used as animal feed in the Florida livestock industry (U.S. EPA 1978a). In addition, the U.S population in general, including the residents of Florida, receives small quantitites through the ingestion of citrus fruits, some minor use crops, and products made from them. The daily doses of chlorobenzilate to these three population groups-workers, the Florida population, and the general U.S. population are presented in Table 7.2; the derivation of these estimates and estimates of total exposure are discussed below.

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159 o ~ ~ o _ ~ ~o~ ~o o o _ ~_ oo o - . _ ooo oo o o ~ o ~ ~o o o ~ ~o oo o ~ _ [_oo oo o o o ooo oo o _ _ o_o o . . ... . o o oo~ ~ C~ _ _ ~o :^ .a . ;~ _ _ r ~_ _ _ S o o o o V) ~o o o o o o o o o o C, C o ~ o . . . cr oo _ ~ 888 8 _ _ '_ _ _ o oo oooo ~X .. . . . . . o o _ o o ~ o o ~ - _ _ . . . . . o ~o o _ ~ ~ .~ ~ ~ ~ o ~ ~ ~ ~ ~ 3 ._ ~ _ _ O~D cn O [L, O C~ CL X X _ ~ CL ~ ~ UO, ~ ~ cn O 4., ~ U~ o _ o o tV V~ a) D ~ ~=.O V, O 4-= _ C ,C ~O C O O u pC ~ D ~ ~ C) ~ ~a.' ~ ~ ~_ =0 ~ ~ Ct ~ ~ O-m S-~m V, ~ O g . - ~ - ~ . u, o ~ m ~ ~ ~ . - D O U, S:: g O = U,~c-c', ~ ,C :m c ~ ;> ~ ~ ~ ~ ~ C X C ~ a X c ~ ~ ~ ~> 0 CtS C .0 C cI C) E ~ E ~ E ' ~ ~ ~ - o ,, E ~ ~ ~ o

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160 Occupational Exposures REGULATING PESTICIDES Citrus Spray Applicators The Committee basically accepts oPP's esti- mates of the worst-case exposure situation for spray applicators. Although these estimates are methodologically sound, they are only conjecture because there are no direct observations on the dosages received by chlorobenzilate applicators. The dosage received, therefore, had to be inferred from the experience of applicators of other pesticides believed to be analogous. Under the circumstances, the Committee sees no way to improve on the estimates. The estimated probable-case doses are similarly conjectural. A major modification of oPP's estimates, however, has to do with the number of years-a worker is expected to be exposed to chlorobenzilate. The Committee will use a value of 10 years as the additional expected economic life of chlorobenzilate for use on citrus, whereas oPP assumed that chlorobenzilate would continue to be used indefinitely (see Chapter 4~. If chlorobenzilate were only viable in the marketplace for an additional 10 years, the incremental exposure to citrus workers would occur only for those additional 10 years, not a full occupational lifetime. In a study of workers exposed to various pesticides, Wolfe et al. (1967) measured both dermal and respiratory (i.e., inhalation) exposure under a variety of ground spray application conditions (see Table 7.3~. All applications were to fruit orchards, using air-blast spray equipment. The technique for trapping residues of pesticides during application involved attaching absorbent pads to the body or clothing of the applicators to measure dermal exposure, and placing filter pads in respirators worn by the applicators to measure respiratory exposure. Trapped residues were extracted and chemical analysis of the various pesticides was carried out using a variety of analytical techniques. Measurements of residues derived from chemical analyses indicated that exposure from spray operations was greater for the dermal route than the inhalation route (see Table 7.3~. Data on dermal exposures were gathered under conditions in which applicators wore short-sleeved, open-necked shirts, with no hats or gloves (Wolfe et al. 19679. The investigators assumed that covered portions of the workers' bodies were completely protected. Since the data in Table 7.3 were obtained under conditions similar to those associated with the application of chloroben- zilate (i.e., similar type of crop, spray apparatus, and spray concentra- tion), oPP assumed that they provide a reasonable basis for estimating exposure of spray applicators to chlorobenzilate (Severe 19781. OPP'S estimates of the exposure of spray applicators are based on the

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Application to Chlorobenzilate 61 range of the mean values reported by Wolfe et al. (1967) for dermal exposures (rounded on to 15-50 mg/hour) and the maximum mean value reported for inhalation exposures (rounded off to 0.1 mg/hour) (see Table 7.3~. Assuming an 8-hour workday, oPP estimated the daily dermal dose to range from 120 to 400 mg and the daily inhalation dose to be approximately 1 mg (Severe 1978~. Data upon which to base an estimate of the rate of dermal absorption of chlorobenzilate were not available either (Severe 1978~. oPP therefore assumed that the chemical characteristics of chlorobenzilate are similar to those of DDT and other chlorinated hydrocarbon pesticides, and that chlorobenzilate would penetrate the skin at a rate comparable to that of DDT and other similar pesticides (Severe 1978~. Estimation of the amount of chlorobenzilate that penetrates the skin was based largely on a study by Feldmann and Maibach (1974), in which the authors studied the recovery from urine of radioactively labeled DDT, lindane, parathion, and malathion, following topical administration to the forearm in humans. They found that 5 percent of the applied dose was absorbed after the first day and that about 10.4 percent was absorbed after 5 days, although the subjects were allowed to wash the application site after the first day. The authors assumed that excretion and tissue distribution of the test compounds after dermal absorption are the same as after intravenous injection. Thus, oPP concluded that about 10 percent of the amount of chlorobenzilate that reaches the skin is absorbed (Severe 1978~. OPP estimated the daily dose of chlorobenzilate received by spray applicators based on the above data and assumptions. For dermal exposures without protective clothing or respirators, oPP considered 12 400 mg/day to be a reasonable estimate. Multiplying this range by a 10 percent absorption factor produced an estimate of 12-40 mg/day. oPP's daily inhalation exposure estimates assume 100 percent absorption by the lungs (Feldmann and Maibach 1974) and are estimated at 1 mg/day. Since protective clothing was not required, and climatic conditions where citrus is grown dictate against its use, oPP assumed, in the absence of other information, that spray applicators did not wear protective clothing (Severe 1978~. Thus, oPP estimated that daily occupational exposure per individual for spray applicators was 12 40 mg dermally and 1 mg by inhalation, or 13-41 mg total. Because the Committee has no new data with which to make better estimates, oPP's range is retained; the lower value is assumed to be a minimum-plausible and the higher value a maximum-plausible exposure estimate. To derive a probable-case estimate, as recommended in Chapter 4, the Committee has taken the

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162 o~ .~ ~ o ~_ g c Ct C~ o o . ~ U. Ct a, os .o .e _ ._ ao O X ~: Ct ~ o oo ~ ~ ~ oo _ _ _ _ _ ~ _ - _ o _ o _ o . . . . . o o o o o oo ~ ~ ~ ~ o ~ o ~ o . . . . . Ol O Ol Ol Ol ~ C~ ~ C~ _ o o o o o . . . . . o o o o o oo _ _ ~ ;: ~ o ~ _ . _ _ o oo V) _ - , _ - ~ ~ _ ~ oo _ 1 1 ~ 1 1 _ ~ ~ ~ ~ . . . . . _ ~ ~ ~ _ V) 1 1 1 o oo ~ ~ ~ ~ oo o o . . ol ol o o o o o o o o o o a, o ~ . - o o ;! a a ~ ~ ~L ._ a~ .` Ct S L U' - .s ~ U' ._ U] .~ a' ~ ~ ~ O o ~ 3 ~ ~ ~o U, ~ ~ .= ~ .c _ ~ ~ o ~ .~- a =s - ~ ~Z O ~0 cr -

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Application to Chlorobenzilate 163 mid-point between oPP's minimum- and maximum-plausible values (assuming that the dose-response curve is linear in this range) arriving at a probable exposure estimate for applicators of 27 mg/day (see Table 7.2~. Conversion of daily occupational exposures to total incremental exposure, were chlorobenzilate to continue in use, must take into account the duration of exposure. The USDA (1977c) estimates that the current use of chlorobenzilate in ground application to citrus is carried out by as few as 714 applicators for 30~0 days/year, or by as many as 1,375 applicators for 1~20 days/year (Severe 1978~. Again, oPP chose the worst-case exposure situation for an individual and assumed that the lesser number of applicators, 714, work for the greater number of days a year, 40, for approximately 40 years (U.S. EPA 1978a). Here the Con~n~ittee's estimates depart from oPP's by assuming that 10 years after a regulatory decision, chlorobenzilate will be gone from the marketplace. Instead of a 40-year exposure, then, the following calcula- tions assume 10 additional years of ground applicator exposure at 40 days/year to approximately 700 applicators. (These values 10 years, 40 daYs/vear. 700 applicators-are being treated as firm estimates for the , , , ~ ~ ~ . .. . .. .. ... . . ... .. . ... . sake of analytic simplicity, although In reality they should be presented as ranges.) Thus, the total incremental lifetime exposure of spray applicators to chlorobenzilate under assumed present conditions, i.e., no protective clothing, becomes: Probable case = 27 mg/dlay x 40 days/year x 10 years = 10,800 lag. Maximum-plausible case = 41 mg/day x 40 days/year x 10 years = 16,400 ma. OPP also considered occupational exposure of drivers of auxiliary vehicles and helicopter pilots. We adopt oPP's conclusions that (1) since the drivers only bring their trucks to the edges of the groves and are not generally in the immediate vicinity of the sprayer, the drivers' exposure is very much less than that of the applicators (Severe 1978), and (2) spraying by helicopters (in Florida) is sporadic and is unlikely to result in significant exposure to humans because of the small amount that is applied and because the pilot is protected by the enclosed helicopter cockpit (Luttner 1977b). The final regulatory action taken by oPP in concluding the chloroben

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164 REGULATING PESTICIDES zilate RPAR stipulates that ground applicators have to use either protective clothing and a respirator, or a suitably equipped enclosed cab. oPP derived exposure estimates for spray applicators using protective clothing and respirators. oPP,s estimate of the reduction in dermal exposure afforded by protective clothing (coveralls, a cloth cap, and gloves) was based on the assumption that covered skin areas are completely protected. According to Hayes (1975), the body surface areas of hands, arms, face, and neck make up approximately 16 percent of total body surface area. If all these areas except the face are covered, the remaining exposed surface would be 3.5 percent of total body surface, resulting in a reduction of dermal exposure by a factor of approximately 4.5 (Severe 1978~. Using this factor of 4.5, oPP derived a dermal exposure of 3-9 mg/day (12~0 mg/day . 4.5) with protective clothing. oPP also concluded that respirators would electively eliminate exposure by inhalation (estimated at 1 mg/day) and further reduce dermal exposure to the face by 1-3 mg/day. Thus, for applicators wearing both protective clothing and respirators, daily exposure could be reduced to between 2 and 6 mg/day, minimum-plausible and maximum-plausible exposure, respectively (U.S. EPA 1979~. Total incremental lifetime exposure of an applicator in full compliance with the new chlorobenzilate regulations-that is, with protective clothing and respirators would be: Probable case = 4 mg/day x 40 days/year x 10 years = 1,600 ma. Maximum-plausible case = 6 mg/day x 40 days/year x 10 years = 2,400 ma. However, these estimates of the ejects of the regulation cannot be confirmed until the required applicator exposure data are submitted and evaluated. In fact, when calculating risk to citrus spray applicators associated with the regulatory option that requires protective clothing and respirators, the Committee assumes only 50 percent compliance as the probable case and 20 percent in the maximum-plausible exposure case. These assumptions are based on the difficulty of enforcement and the Committee's direct experience with citrus growers and researchers in Texas, which indicated a disbelief that chlorobenzilate is hazardous. One of the major uncertainties in the forgoing analysis is the validity of the dermal absorption rate (i.e., 10 percent). Chlorobenzilate is relatively polar compared to other compounds of its general type, such

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228 - 0. 10 o E Al o C) LU ~ 0.003 he' - ~ 0.002 J ~ 0.001 a o . l _ i REGULATING PESTICIDES 0 20- Chlorobenzilate Equivalent of Hoptachlor, Mean U.S. Lifetime Dose (Nisbet 1976) _ _ , Chlorobenzilate Equivalent of Hoptachlor, M - n U.S. Lifetime Dose (CAG 1977) ~ - Florida Population (8 X 1 o6) 9. lC General U.S. Population (212 X 106) A \.,.~. E A \ C X>~ B K E OK 1 ' I 1 1 20 30 40 50 60 70 I I I ~ 0 10 DISCOUNTED COST {$ million) FIGURE 7.4 Equivalent maximum-plausible lifetime doses for the Florida and U.S. populations and ranges of discounted costs under five options for regulating chloroben~- late; heptachlor comparison shown (see text for discussion). Source: Table 7.26 and text. (based on an estimated lifetime exposure of 0.0081 m moles/kg [Nisbet 1976 and CAG 1977~. Recall that chlordane was also suspended and its major uses ultimately cancelled. Figures 7.2 and 7.3 present probable lifetime doses of Chlorobenzilate for each option, while Figures 7.4 and 7.5 show the maximum-plausible dose estimates. In each case, the first figure of the pair shows the general U.S. and the Florida populations while citrus applicators appear separately in the second. For the U.S. and Florida populations only the Chlorobenzilate equivalents of the mean heptachlor dose are graphed. This is because Chlorobenzilate doses under all five options are already below these values, making it unnecessary to add the higher chlorobenzi- late-equivalent of heptachlor lines. For the citrus applicators, both the mean and high-exposure level chlorobenzilate-equivalent doses of hetptachlor are shown. In the following discussion, the Committee has not attempted to

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Application to Chlorobenzilate 1 a8or en ~ 1.50 o ~.~ 1.20 oh o 0.90 It '~ 0.60 of us > 0.30 a Lo 229 ~ _ ~tit:~.,~t,)~t~,It.~t $. 'I .... , Chlorobenzilate Equivalent of Heptachlor, Highly Exposed 1% ... ... .~; of U.S. Population (Nisbet 1g76) ................... ....... ., .... ~ . ,, ,, ,. ; ......... .................................................................................................... ..... , , , , i, . .... ............................... ' " "a"'.' "" " " "' '' '1 '' "''"' "' "' '' "'X X" "' " ~ '''X "' '''X ' "''' ' " ' ' "X" '' "' ' " """" "'''" . ~ X '2.' ~ ' ~ ~ go ' 5'' 5' ~ ~ ~ X X '' ' ' . ~ ~ ~ ~ ~ ~ ~ ~ . ~ . ;~; ~,~, ..~; ;; ;~; j,` j,; A ;_, - ,,, . ~;~; ;,.;;;; . me, ..;~j;; ;; I, ^,,,~ ; I; i If,, A ~ ~.~... ~ ~- A Chlorobenzilate Equivalent of Heptachlor, Highly Exposed 1% Gil B ..~. of U.S. Population (CAG 1977) ..~. . _ ~2~ D , Chlorobenzilate Equivalent of Heptachlor, Mean U.S. Lifetime Dose (N'sbet 1976) Chlorobenzilate Equivalent of Heptachlor Mean U.S. Lifetime Dose (CAG 1977) , ~ , ~ O ~ 1 1 1 1 1 1 1 0 10 20 30 40 50 60 70 DISCOUNTED COST ($ million) FIGURE 7.5 Equivalent maximum-plausible lifetime doses for citrus ground applicators (700) and ranges of discounted costs under five options for regulating Chlorobenzilate Heptachlor comparison shown (see text for discussion). Source: Table 7.26 and text. analyze similarities or differences in the size or compositions of the populations exposed to Chlorobenzilate with those exposed to hepta- chlor. Such considerations may well be important. For example, is it more useful to compare a population of about 700 Chlorobenzilate applicators to a population of 212 x 106 average Americans exposed to Heptachlor or to a smaller population of breast-fed babies and young children receiving very high doses (from milk) for a short period of their life? This is a matter of judgment left to the Administrator. Furthermore, the economic impacts of the Heptachlor suspension are not discussed. Although EPA did conduct an economic impact assessment (U.S. EPA 1976a), the decisions to suspend and ultimately cancel most Heptachlor uses appear to have been based more on the risks involved than on the economic impacts, because alternative pesticides were predicted to be available and economic impacts were predicted to "be relatively minor in general and . . . (to) have no significant eject on production and

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230 REGULATING PESTICIDES prices of agricultural commodities, retail food prices, and otherwise on the agricultural economy" (U.S. EPA 1978c: 12375~. It is clear from Figure 7.2 that even without regulation, the intake of chlorobenzilate to which the U.S. population and Florida residents are exposed is orders of magnitude less than the equivalent intake of heptachlor corresponding to the mean levels at which its use was forbidden. The Committee recognizes that it is possible that heptachlor would have been suspended even if its dosage rate had been substantially smaller than the estimated levels. It is even possible that heptachlor would have been suspended at a dose level one thousandth as great as the estimated mean level being experienced at the time of the suspension in 1975, in which case its intake would be about equal to the intake of chlorobenzilate without regulation in terms of carcinogenic activity. That is a matter for the Administrator's judgment. The chart does make clear that the probable doses of chlorobenzilate received by food consumers are some 3 orders of magnitude below equivalent doses of heptachlor to which they had been exposed. The contrast is even greater for chlordane (not shown). On the other hand, if we turn to Figure 7.3, it can be seen that citrus ground applicators are expected to receive nearly 4 times the mean chlorobenzilate equivalent of heptachlor cutoff for the general U.S. population under our Options A and B. about twice as much under Option C, a comparable amount under Option D, and about half as much under Option E. If, however, the probable chlorobenzilate doses to applicators are compared to the chlorobenzilate equivalent of heptachlor for the 1 percent of the U.S. population most highly exposed to heptachlor, all the options are expected to expose applicators to less than the high-level chlorobenzilate equivalent of heptachlor, although Options A and B are so close to the high-level cut-off based on CAG data, that they may be questionable. The main implications of Figures 7.2 and 7.3 appear to be that Options A and B expose ground applicators to levels of risk that are nearly comparable to those being experienced by the populations that were highly exposed to heptachlor. Options D and E expose chlorobenzi- late applicators to levels of risk roughly comparable to those that were experienced by the average member of the U.S. population in the heptachlor situation. Exposure of applicators under Option C falls in between. At the same time, the risks to the U.S. and Florida populations associated with the probable dietary exposures to chlorobenzilate appear to be too small to be at issue. It would obviously be useful to compare the doses of chlorobenzilate being received by the U.S. and Florida populations to chlorobenzilate equivalents of a previously regulated

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Application to Chlorobenzilate comparison compound that were lower than the current chlorobenzilate exposure levels. In the case of chlorobenzilate, our bank of reference compounds (Table 4.3) was insufficient to supply such a comparison. We turn now to a consideration of the maximum-plausible dose levels of chlorobenzilate shown in Figures 7.4 and 7.5. Under all options, the highest doses that members of the U.S. population and Florida residents can plausibly be expected to receive by way of ingestion are of the order of 1 percent of the estimated chlorobenzilate-equivalent mean dose of heptachlor at the time that that pesticide was suspended (Figure 7.4~. Citrus ground applicators, on the other hand, may plausibly be exposed to doses greater than the mean chlorobenzilate equivalent of heptachlor under any of the options (Figure 7.5~. The excess is smallest under Option E, which requires immediate cancellation of chlorobenzilate use on citrus. Under Options A, B. and C, applicators may plausibly be exposed to doses comparable to the chlorobenzilate equivalent of heptachlor that the highly exposed members of the U.S. population were experiencing when heptachlor was cancelled. Options D and E may plausibly result in chlorobenzilate exposures to applicators that lie in between the mean chlorobenzilate-equivalent of heptachlor Put-on and the highly exposed. Ultimately, the choice among options depends upon a judgment as to whether the indicated reductions in the doses received by ground applicators of chlorobenzilate are sufficient to justify the extra costs associated with adopting the more stringent regulations. The critical figures to review are Figures 7.3 and 7.5 pertaining to the probable and maximum-plausible chlorobenzilate exposures to citrus ground applica- tors together with the cost information along the x-axes. For example, looking at the move from Option C to Option D, it can be seen from Figure 7.3 that the cost of reducing the lifetime exposure of about 700 applicators by about 0.1 m moles/kg/person is expected to be about $16 million. Recall that this would place applicators at a risk roughly comparable to that being experienced by the average member of the U.S. population when heptachlor was cancelled. Similar comparisons of incremental costs with incremental reductions in exposure and the concomitant risk implications as one moves form one regulatory option to the next will provide the scientific basis for making decisions about regulating pesticides. (It is interesting to note that had dicofol been submitted to RPAR together with chlorobenzilate, as would arise if the procedures recommended in Chapter 3 were adopted, the regulatory options would diner. For example, it is likely that they would include the option to cancel both chlorobenzilate and dicofol. This, in turn, might easily result in applicators' risks being reduced below those associated 231

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232 REGULATING PESTICIDES with the mean chlorobenzilate-equivalent of heptachlor cotton. Of course, without having considered that option explicitly, it is difficult to predict what risks or costs from other substitute pesticides might enter the picture.) NOTES 1. oPP assumes that about 19 percent of the Chlorobenzilate acre-treatments would be replaced by dicofol (Luttner 1977a). However, as the benefit analysis in a subsequent portion of this chapter demonstrates, this assumption seems to have no factual basis and is not rigorously defended in the oPP benefit analysis. The range (2-10 percent) adopted by the Committee is admittedly arbitrary, but nevertheless is consistent with the treatment levels implied by current usage levels (see the Doane Specialty Crops Survey included in Luttner 1977a). Presently, dicofol accounts for only about 5 percent of the treatments on lemons and grapefruits and about 2 percent of the treatments on orange trees. In contrast, Chlorobenzilate presently accounts for about 13 percent of the acre-treatments on lemons and about one third of the acre-treatments on oranges and grapefruits. 2. oPP estimates that cancellation of Chlorobenzilate would increase annual pesticide costs on noncitrus crops by $194,000, with cotton accounting for $125,000 and fruits, nuts, and other crops accounting for the remaining $69,000 (U.S. EPA 1978a:67). The Committee does not question these estimates, largely because their magnitudes are so small relative to the estimated impacts on citrus growers and consumers. 3. The benefit assessment for Chlorobenzilate was performed before the joint USDA/EPA assessment procedure was initiated. Therefore, the Preliminary Benefit Analysis of Chlorobenzilate (Luttner 1977a) was an EPA product to which the USDA reacted by producing a USDA assessment team report (USDA 1977b). EPA'S supplement to the PBA (Luttner 1977b) responded to the USDA report. 4. The USDA assessment team was formed after oPP had completed the PBA (see note 2); consequently, information from the assessment team is used only in the Supplement to the PBA of Chlorobenzilate (Luttner 1977b). 5. Prices for chlorobenzilate, oil, sulfur, ethion, and dicofol (and various combina- tions of these miticides) were obtained from the USDA-ATR (USDA 1977b) and the Anderson- Muraro production budgets (Luttner 1977a). Whenever these two sources reported different prices for the same product, we used the average of the reported prices in our analysis. 6. The documented costs in Table 7.26 and Figures 7.2 through 7.5 are based upon the following estimates of Anne forgone benefits (over a Midyear period). The noncitrus uses of chlorbenzilate are estimated to yield annual benefits of $194,000 (see note 2 to this chapter). The benefits from citrus uses range from $2.4 to $9.2 million annually, with the probable-case estimate being $5.8 million (see section on Changes in Pest Control Costs of this chapter for derivation of these estimates). Finally, the cost of providing applicators with protective clothing and respirators is assumed to be $ 10~$500 per applicator per year for a total annual cost of $70,000 $350,000. Neither oPP (U.S. EPA 1978a) nor the Committee developed actual empirical measures of the costs of protective clothing and respirators.

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Application to Chlorobenzilate REFERENCES 233 Allen, J.C. (1978) The Effect of Citrus Rust Mite Damage on Citrus Fruit Drop. University of Florida, Lake Alfred, Florida. (Unpublished) Allen, J.C. (1979) The effects of citrus rust mite damage on citrus fruit growth. Journal of Economic Entomology 72(V: 195-201. Allen, J.C. and J.H. Stamper (1979) The frequency distribution of citrus rust mite damage on citrus fruit. Journal of Economic Entomology 72(3):327-330. Bartsch, E., D. Eberle, K. Ramsteiner, A. Tomann, and M. Spindler (1971) The carbinole acaricides: chlorobenzilate and chloropropylate. Residue Reviews 39: 1-88. Brooks, R.F. (1977) Integrated control of Florida citrus pests. Citrus Industry 58(4):31, 34- 36. Brooks, R.F. and J.D. Whitney (1977) Citrus Snow Scale Control in Florida. Vol. 2, pages 427~31, Proceedings: I Congreso Mundial de Citricultura 1973. Murcia-Valencia, April 29-May 10, 1973. Murcia, Spain: Ministerio de Sciencia Consejo Superior des Investigaciones Scientifica, Centro de Adafologia y Biologia Aplicada del Segura. Burnam, W.L. (1977) First Draft of Chlorobenzilate Substitutes. Transmitted to J.B. Boyd, 6-22-79, Special Pesticide Review Division, Office of Pesticide Programs, U.S. Environmental Protection Agency, Washington, D.C. (Unpublished) Bushong, C. (1977) Chlorobenzilate risk analysis, fish and wildlife. Memorandum to J.B. Boyd, oPP. August 8, 1977, Special Pesticide Review Division, Office of Pesticide Programs, U.S. Environmental Protection Agency, Washington, D.C. (Unpublished) Carcinogen Assessment Group (1977) Risk Assessment of Chlordane and Heptachlor. Roy Albert, CAG Chairman, U.S. Environmental Protection Agency, Washington, D.C. 20460. (Unpublished) Carman, G.E., W.E. Westlake, and F.A. Gunther (1972) Potential residue problem associated with low volume sprays on citrus in California. Bulletin of Environmental Contamination and Toxicology 8:3845. Council on Environmental Quality (1976) Environmental Quality: The Seventh Annual Report of the Council on Environmental Quality. Stock no. 041-010-00031-2. Washing- ton, D.C.: U.S. Government Printing Offlce. C''mmings, J.G., M. Eidelman, V. Turner, D. Reed, K.T. Zee, and R.E. Cook (1967) Residues in poultry tissues from low level feeding of five chlorinated hydrocarbon insecticides to hens. Journal of the Association of Official Analytical Chemists 50(2):418-425. Dennis, J.D. (1977) Untitled, unpublished letter to F. Maxwell, University of Florida. August 15, 1977. (Available from Office of Pesticide Programs, U.S. Environmental Protection Agency, Washington, D.C.) Federal Working Group on Pest Management (1974) Occupational Exposure to Pesticides. Report of the Task Group on Occupational Exposure to Pesticides, T.H. Milby, Chairman, to Office of Pesticide Programs, U.S. Environmental Protection Agency, Washington, D.C. (Unpublished) Feldmann, R.J. and H.I. Maibach (1974) Percutaneous penetration of some pesticides and herbicides in man. Toxicology and Applied Pharmacology 28: 126-132. Fries, G.F. (1969) Comparative excretion and retention of DDT analogs by dai~y cows. Journal of Diary Science 52(11): 180~1805. George, P.S. and G.A. King (1971) Consumer Demand for Food Commodities in the United States With Projections for 1980. Monograph Series Number 26. Berkeley, Calif.: Giannini Foundation.

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234 REGULATING PESTICIDES Griffiths, J.T. ana W.L. Thompson (1953) Reduced spray program for citrus for Canning plants in Florida. Journal of Economic Entomology 46:930-936. Growers Administrative Committee (1977) 1976-77 Season Annual Statistical Record. Lal~eland, Florida. Gunther, F.A. (1969) Insecticide residues in California citrus fruits and products. Residue Reviews 28: 1-119. Gunther, F.A., W.E. Westlake, and P.S. Jaglan (1968) Reported solubilities of 738 chemicals in water. Residue Reviews 20: 1-148. Gunther, F.A., Y. Inata, G.E. Carman, and C.A. Smith (1977) The citrus reentry problem. Residue Reviews 67: 1-139. Hassan, T.K. and C.O. Knowles (1969) Behavior of three Ci4-labeled benzilate acaricides when applied topically to soybean leaves. Journal of Economic Entomology 62(3):618- 619. Hayes, W.J., Jr. (1975) Toxicology of Pesticides. Baltimore: Williams and Wilkins Company. Horn, H.J., R.B. Bruce, and O.K. Paynter (1955) Toxicology of chlorobenzilate. Jounce of Agricultural and Food Chemistry 3(9):752-756. Innes, J.R.M., B.M. Ulland, M.G. Valerio, L. Petrucelli, L. Fishbein, E.R. Hart, A.J. Pallotta, R.R. Bates, H.L. Falk, J.J. Gart, M. Klein, I. Mitchell, and J. Peters (1969) Bioassay of pesticides and industrial chemicals for tumorigenicity in mice: A preliminary note. Journal of the National Cancer Institute 42: 1101-1114. Jeppson, L.R., M.J. Jesser, and J.O. Complin (1955) Control of mites on citrus with chlorobenzilate. Journal of Economic Entomology 48: 37~377. Kesterson, J.W., R. Hendrickson, and R.J. Braddock (1971) Florida Citrus Oils. Bulletin 749 (technical), Agricultural Experiment Stations, Institute of Food and Agricultural Sciences. Gainesville, F1.: University of Florida. Luttner, M.A. (1977a) Preliminary Benefit Analysis of Chlorobenzilate. Criteria and Evaluation Division, Office of Pesticide Programs, U.S. Environmental Protection Agency, Washington, D.C. (Unpublished) Luttner, M.A. (1977b) Supplement to the Preliminary Benefit Analysis of Chlorobenzilate. Criteria and Evaluation Division, Office of Pesticide Programs, U.S. Environmental Protection Agency, Washington, D.C. (Unpublished) Martin, H., ed. (1971) Pesticide Manual. 2nd ed. British Crop Protection Council. (Copies can be obtained from Mr. A.W. Billitt, Clacks Farm, Boreley, Ombersley, Droitwich, Worcester, England.) Mattson, A.M. and M. Insler (1966) Chlorobenzilate Residues in Sheep and Cattle Tissues. Report submitted by Geigy Research Analytical Department to Office of Pesticide Programs, U.S. Environmental Protection Agency, Washington, D.C. (Unpublished) McCaskey, T.A., A.R. Stemp, B.J. Liska, and W.J. Stadelman (1968) Residues in egg yolks and raw and cooked tissues from laying hens administered selected chlorinated hydrocarbon insecticides. Poultry Science 47:564-569. McCoy, C.W. (1976) Leaf injury and defoliation caused by the virus rust mite, Phyllocoptruta oleivora. Florida Entomologist 59:40~410. McCoy, C.W. (1977) Resurgence of citrus rust mite populations following applications of methidathion. Journal of Economic Entomology 70:74~752. McCoy, C.W., A.G. Selhime, R.F. Kanavel, and A.J. Hill (1971) Supression of citrus rust mite populations with application of fragmented mycelia of Hirsutella thom~sonii. Journal of Invertebrate Pathology 17:27~276.

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Application to Chlorobenzilate 235 McCoy, C.W., R.F. Brooks, M.C. Allen, A.G. Selhime, and W.F. Wardowski (1976a) Effect of reduced pest control programs on yield and quality of 'Valencia' orange. Proceedings of the Florida State Horticulture Society 89:74-77. McCoy, C.W., P.L. Davis, and K.A. Munroe (1976b) Effect of late season fruit injury by the citrus rust mite, Phyllocoptruta oleivora (Prostigmata: Eriophyoidea) on the internal quality of Valencia orange. Florida Entomology 59:335-341. Miya7~ki, S., G.M. Boush, and F. Matsumura (1970) Microbial degradation of chloroben- zilate (ethyl 4,4'-dichlorobenzylate) and chloropropylate (isopropyl 4,4'-dichloroba~zy- late). Journal of Agricultural and Food Chemistry 18(1):87-91. National Cancer Institute (1978) Bioassay of Dicofol for Possible Carcinogenicity. cats No. 115-32-2, NCI-CG-TR-90. DHEW Publication No. (NOSH) 78-1340. Washington, D.C.: U.S. Government Printing Office. Nisbet, I.C.T. (1976) Human Exposure to Chlordane, Heptachlor, and Their Metabolites. Prepared for the Cancer Assessment Group, U.S. Environmental Protection Agency, under contract no. WA-7-1319-A, by Clement Associates, Inc., 1055 Thomas Jefferson Street, N.W., Washington, D.C. 20007. (Unpublished) Ol~nert, I. and R.G. Kenneth (1974) Sensitivity of entomopathogenic fungi, Beauveria bassiana, Verticillium lecor~ii and Verticillium sp. to fungicides and insecticides. Environmental Entomology 3:33-38. Quaife, M.L., J.S. Winbush, and O.G. Fitzhugh (1967) Survey of quantitative relationships between ingestion and storage of aldrin and dieldrin in animals and man. Food and Cosmetic Toxicology 5:39. Reinking, R.B. (1967) Evolution of some spray oils used on citrus in Texas. Proceedings of Rio Grande Horticulture Society 21 :28-34. Riggan, W.B. (1965) Demand for Florida Oranges. North Carolina State University at Raleigh. (Unpublished Ph.D. dissertation) Schmitt, R.D. (1977) Food Factors. Registration Division, Office of Pesticide Programs, U.S. Environmental Protection Agency, Washington, D.C. (Unpublished) Severn, D.J. (1978) Exposure Analysis for Chlorobenzilate. H~rd Evaluation Division, Office of Pesticide Programs, U.S. Environmental Protection Agency, Washington, D.C. (Unpublished) Simanton, W.A. (1962) Losses and production costs attributable to insects and related arthropods attacking citrus in Florida. U.S. Department of Agriculture Cooperative Economic Insect Report 12: 1182. Sinclair, W.B. (1972) The Grapefruit, Its Composition, Physiology, and Products. Division of Agricultural Sciences. University of California. Thomas, R.F. (1976) Chlorobenzilate Residues in Selected Citrus Products in the Washington Metropolitan Area, Fall 1966. Technical Services Division, Office of Pesticide Programs, U.S. Environmental Protection Agency, Washington, D.C. (Un- published) Tilley, D.S. (1977) A Retrospective Look at the 1976-1977 Season: Has a Structural Shift Occurred? Florida Department of Citrus, Tallahassee, Florida. (Unpublished) Tomek, W.G. and K.L. Robinson (1972) Agricultural Product Prices. Ithaca, N.Y.: Cornell University Press. Townsend, K.G. (1976) Two year summary of extension integrated pest management program. Proceedings of Florida State Horticulture Society 89:59-62. U.S. Department of Agriculture (1972) Household Food Con~sumption Survey, 196~1966, Report No. 12. Food Consumption of Households in the United States, Seasons and Years, 196~1966. USDA Agricultural Research Service. Washington, D.C.: U.S. Department of Agriculture.

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236 REGULATING PESTICIDES U.S. Department of Agriculture (1977a) Agricultural Statistics, 1977. Washington, D.C.: U.S. Department of Agriculture. U.S. Department of Agriculture (1977b) An Economic and Biotic Evaluation of Chlorobenzilate and Its Alternatives. (Note: This unpublished Final Report is available from Office of Pesticide Programs, U.S. Protection Agency, Washington, D.C.) U.S. Department of Agriculture (1977c) Comments on EPA Report on Estimates of Human Exposure to Chlorobenzilate Prepared by D.J. Severn, January 25, 1977. Submitted to U.S. Environmental Protection Agency on September 12, 1977. (Unpublished, available from Office of Pesticide Programs, U.S. EPA, Washington, D.C.) U.S. Department of Commerce (1978) 1974 Census of Agriculture-Statistics by Subject. Volume II, Part 6. Washington, D.C.: U.S. Department of Commerce. U.S. Environmental Protection Agency (1976a) EPA Actions to Cancel and Suspend Uses of Chlordane and Heptachlor as Pesticides: Economic and Social Implications. EPA- 540/4-76-004. Washington, D.C.: U.S. Environmental Protection Agency. U.S. Environmental Protection Agency (1976b) Pesticide Programs: Notice of Presumption Against Registration and Continued Registration of Pesticide Products Containing Chlorobenzilate. 41 Federal Register 21517-21519. U.S. Environmental Protection Agency (1977) Fertilizer and Pesticide Movement from Citrus Groves in Florida Flatwood Soils. Environmental Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Athens, Ga. EPA- 600/2-77-177. August 1977. U.S. Environmental Protection Agency (1978a) Chlorobenzilate: Position Document 3. Special Pesticide Review Division, Office of Pesticide Programs, U.S. ~PA, Washington, D.C. (Unpublished. Prepared under the general supervision of J.B. Boyd, oPP.) U.S. Environmental Protection Agency (1978b) Environmental Fate Profile: Chlorobenzi- late. Chemistry Branch, Criteria and Evaluation Division, Office of Pesticide Programs, U.S. BPA, Washington, D.C. (Unpublished) U.5. Environmental Protection Agency (1978c) Velsicol Chemical Co., et al., Consolidated Heptachlor/Chlordane Cancellation Proceedings. 43 Federal Register (58)12372-12375. U.S. Environmental Protection Agency (1979) Chlorobenzilate: Position Document 4. Special Pesticide Review Division, Office of Pesticide Programs, U.S. SPY, Washington, D.C. (Unpublished. Prepared under the general supervision of J.B. Boyd, oPP.) U.S. Environmental Protection Agency and U.S. Department of Agriculture (1978) Economic and Social Impacts of Cancelling Use of DBCP as a Pesticide for all Registered Use Sites with Known Current Usage. (Note: This unpublished Final Report is available from oPP' U.S. EPA, Washington, D.C.) U.S. Federal Energy Administration (1976) Energy and U.S. Agriculture: 1974 Data Base. Federal Energy Administration, Office of Energy Conservation and Environment. Vol. 1. FEA/D-76/459. Washington, D.C.: U.S. Federal Energy Administration. University of Florida (1977) Florida Citrus Spray and Dust Schedule 1977. Circular 393-C. Florida Cooperative Extension Service, Gainesville, Florida. van Brussel, E.W. (1975) Interrelations between citrus rust mite, Hirsutella thom~sonii and greasy spot on citrus in Surinam. Landbou~vproefstation Suliname/Agricultural Experiment Station Surinam. Bulletin 98. von Rumker, R. and F. Horay (1972) Pesticide Manual, Part II: Basic Information on Thirty-Five Pesticide Chem~cals. U.S. Agency for International Development. Berkeley, Calif.: University of California Press. Walker, A.I.T., D.E. Stevenson, J. Robinson, E. Thorpe, and M. Roberts (1969) The toxicology and pharmacodynamics of dieldrin (HBOD): Two year oral exposures of rats and dogs. Toxicology and Applied Pharmacology 15:345-373.

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Application to Chlorobenzilate Ward, R.W. and R.L. Kilmer (1978) The United States Citrus Subsector: Organization, Behavior and Performance. Department of Food and Resource Economics, University of Florida, Lake Alfred, Florida. (Unpublished) Well, Von L., G. Dure, and K.-E. Quentin (1974) Wasserloslichkeit van insektiziden chlorierten kohlenwasserstoffen und polychlorierten biphenylen im hinblick auf eine gewasserbelastung mit diesen stoffen. Zeitschrift fuer Wasser und Abwasser Forschung 7: 169-175. Wheeler, W.B., D.F. Rothwell, and D.H. Hubbell (1973) Persistence and microbiological efl-ects of Acarol~ and chlorobenzilate in two Florida soils. Journal of Environmental Quality 2(1):115-1 18. Wolfe, H.R., W.F. Durham, and J.F. Armstrong (1967) Exposure of workers to pesticides. Archives of Environmental Health 14:622-633. Woodard Research Corporation (1966) Chlorobenzilate Safety Evaluation by Dietary Feeding to Rats for 104 Weeks: Final Report. Geigy Chemical Corporation, Yonkers, New York. (Unpublished) Yothers, W.W. (1918) Some reasons for spraying to control insect and mite enemies of citrus trees in Florida. U.S. Department of Agriculture Bulletin 645. Washington, D.C.: U.S. Department of Agriculture. 237

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