Federal Register / Vol. 73, No. 210 / Wednesday, October 29, 2008 / Rules and Regulations 64229 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 180 

[EPA–HQ–OPP–2008–0347; FRL–8388–1] 

Carbaryl; Order Denying NRDC’s 

Petition to Revoke Tolerances 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Order. 

SUMMARY: In this Order, EPA denies a 

petition requesting that EPA revoke all 

pesticide tolerances for carbaryl under 

section 408(d) of the Federal Food, 

Drug, and Cosmetic Act (FFDCA). The 

petition was filed on January 10, 2005, 

by the Natural Resources Defense 

Council (NRDC). 

DATES: This Order is effective October 

29, 2008. Objections and requests for 

hearings must be received on or before 

December 29, 2008, and must be filed in 

accordance with the instructions 

provided in 40 CFR part 178 (see also 

Unit I.C. of the SUPPLEMENTARY

INFORMATION). 

ADDRESSES: EPA has established a 

docket for this action under docket 

identification (ID) number EPA–HQ– 

OPP–2008–0347. To access the 

electronic docket, go to http:// 

www.regulations.gov, select ‘‘Advanced 

Search,’’ then ‘‘Docket Search.’’ Insert 

the docket ID number where indicated 

and select the ‘‘Submit’’ button. Follow 

the instructions on the regulations.gov 

website to view the docket index or 

access available documents. All 

documents in the docket are listed in 

the docket index available in 

regulations.gov. Although listed in the 

index, some information is not publicly 

available, e.g., Confidential Business 

Information (CBI) or other information 

whose disclosure is restricted by statute. 

Certain other material, such as 

copyrighted material, is not placed on 

the Internet and will be publicly 

available only in hard copy form. 

Publicly available docket materials are 

available in the electronic docket at 

http://www.regulations.gov, or, if only 

available in hard copy, at the OPP 

Regulatory Public Docket in Rm. S– 

4400, One Potomac Yard (South Bldg.), 

2777 S. Crystal Dr., Arlington, VA. The 

Docket Facility is open from 8:30 a.m. 

to 4 p.m., Monday through Friday, 

excluding legal holidays. The Docket 

Facility telephone number is (703) 305– 

5805. 

FOR FURTHER INFORMATION CONTACT: 

Christina Scheltema, Special Review 

and Reregistration Division (7508P), 

Office of Pesticide Programs, 

Environmental Protection Agency, 1200 

Pennsylvania Ave., NW., Washington, 

DC 20460–0001; telephone number: 

703–308–2201; e-mail address: 

scheltema.christina@epa.gov. 

SUPPLEMENTARY INFORMATION: 

I. General Information 

A. Does this Action Apply to Me? 

In this document, EPA denies a 

petition by the NRDC to revoke 

pesticide tolerances. This action may be 

of interest to agricultural producers, 

food manufacturers, or pesticide 

manufacturers. Potentially affected 

entities may include, but are not limited 

to those engaged in the following 

activities: 

• Crop production (NAICS code 111), 

e.g., agricultural workers; greenhouse, 

nursery, and floriculture workers; 

farmers. 

• Animal production (NAICS code 

112), e.g., cattle ranchers and farmers, 

dairy cattle farmers, livestock farmers. 

• Food manufacturing (NAICS code 

311), e.g., agricultural workers; farmers; 

greenhouse, nursery, and floriculture 

workers; ranchers; pesticide applicators. 

• Pesticide manufacturing (NAICS 

code 32532), e.g., agricultural workers; 

commercial applicators; farmers; 

greenhouse, nursery, and floriculture 

workers; residential users. 

This listing is not intended to be 

exhaustive, but rather to provide a guide 

for readers regarding entities likely to be 

affected by this action. Other types of 

entities not listed in this unit could also 

be affected. The North American 

Industrial Classification System 

(NAICS) codes have been provided to 

assist you and others in determining 

whether this action might apply to 

certain entities. If you have any 

questions regarding the applicability of 

this action to a particular entity, consult 

the person listed under FOR FURTHER

INFORMATION CONTACT. 

B. How Can I Access Electronic Copies 

of this Document? 

In addition to accessing an electronic 

copy of this Federal Register document 

through the electronic docket at http:// 

www.regulations.gov, you may access 

this Federal Register document 

electronically through the EPA Internet 

under the ‘‘Federal Register’’ listings at 

http://www.epa.gov/fedrgstr. You may 

also access a frequently updated 

electronic version of EPA’s tolerance 

regulations at 40 CFR part 180 through 

the Government Printing Office’s pilot 

e-CFR site at http://www.gpoaccess.gov/ 

ecfr. 

C. Can I File an Objection or Hearing 

Request? 

Under section 408(g) of FFDCA, any 

person may file an objection to any 

aspect of this regulation and may also 

request a hearing on those objections. 

You must file your objection or request 

a hearing on this regulation in 

accordance with the instructions 

provided in 40 CFR part 178. To ensure 

proper receipt by EPA, you must 

identify docket ID number EPA–HQ– 

OPP–2008–0347 in the subject line on 

the first page of your submission. All 

requests must be in writing, and must be 

mailed or delivered to the Hearing Clerk 

as required by 40 CFR part 178 on or 

before December 29, 2008. 

In addition to filing an objection or 

hearing request with the Hearing Clerk 

as described in 40 CFR part 178, please 

submit a copy of the filing that does not 

contain any CBI for inclusion in the 

public docket that is described in 

ADDRESSES. Information not marked 

confidential pursuant to 40 CFR part 2 

may be disclosed publicly by EPA 

without prior notice. Submit this copy, 

identified by docket ID number EPA– 

HQ–OPP–2008–0347, by one of the 

following methods: 

• Federal eRulemaking Portal: http:// 

www.regulations.gov. Follow the on-line 

instructions for submitting comments. 

• Mail: Office of Pesticide Programs 

(OPP) Regulatory Public Docket (7502P), 

Environmental Protection Agency, 1200 

Pennsylvania Ave., NW., Washington, 

DC 20460–0001. 

• Delivery: OPP Regulatory Public 

Docket (7502P), Environmental 

Protection Agency, Rm. S–4400, One 

Potomac Yard (South Bldg.), 2777 S. 

Crystal Dr., Arlington, VA. Deliveries 

are only accepted during the Docket’s 

normal hours of operation (8:30 a.m. to 

4 p.m., Monday through Friday, 

excluding legal holidays). Special 

arrangements should be made for 

deliveries of boxed information. The 

Docket Facility telephone number is 

(703) 305–5805. 

II. Introduction 

A. What Action Is the Agency Taking? 

The NRDC filed a petition dated 

January 10, 2005 with EPA which, 

among other things, requested that EPA 

revoke all tolerances for the pesticide 

carbaryl established under section 408 

of the FFDCA, 21 U.S.C. 346a (Ref. 1) 

This Order denies that aspect of the 

petition that sought the revocation of 

the carbaryl tolerances. This Order also 

denies NRDC’s petition to cancel 

carbaryl pet collar registrations 

submitted as part of NRDC’s comments 

on the N-methyl carbamate (NMC) 

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64230 Federal Register / Vol. 73, No. 210 / Wednesday, October 29, 2008 / Rules and Regulations 

cumulative assessment and dated 

November 26, 2007, because NRDC is 

arguing that exposure to carbaryl pet 

collars makes the cumulative risks 

presented by carbaryl unsafe (Ref. 2). 

B. What Is the Agency’s Authority for 

Taking This Action? 

Under section 408(d)(4) of the 

FFDCA, EPA is authorized to respond to 

a section 408(d) petition to revoke 

tolerances either by issuing a final rule 

revoking the tolerances, issuing a 

proposed rule, or issuing an order 

denying the petition. (21 U.S.C. 

346a(d)(4)). 

III. Statutory and Regulatory 

Background 

A. FFDCA/FIFRA and Applicable 

Regulations 

1. In general. EPA establishes 

maximum residue limits, or 

‘‘tolerances,’’ for pesticide residues in 

food and feed commodities under 

section 408 of the FFDCA. (21 U.S.C. 

346a). Without such a tolerance or an 

exemption from the requirement of a 

tolerance, a food containing a pesticide 

residue is ‘‘adulterated’’ under section 

402 of the FFDCA and may not be 

legally moved in interstate commerce. 

(21 U.S.C. 331, 342). Monitoring and 

enforcement of pesticide tolerances are 

carried out by the U.S. Food and Drug 

Administration (FDA) and the U.S. 

Department of Agriculture (USDA). 

Section 408 was substantially rewritten 

by the Food Quality Protection Act of 

1996 (FQPA), which added the 

provisions discussed below establishing 

a detailed safety standard for pesticides, 

additional protections for infants and 

children, and the estrogenic substances 

screening program. (Public Law 104– 

170, 110 Stat. 1489 (1996)). 

EPA also regulates pesticides under 

the Federal Insecticide, Fungicide, and 

Rodenticide Act (FIFRA), (7 U.S.C. 136 

et seq). While the FFDCA authorizes the 

establishment of legal limits for 

pesticide residues in food, FIFRA 

requires the approval of pesticides prior 

to their sale and distribution, (7 U.S.C. 

136a(a)), and establishes a registration 

regime for regulating the use of 

pesticides. FIFRA regulates pesticide 

use in conjunction with its registration 

scheme by requiring EPA review and 

approval of pesticide labels and 

specifying that use of a pesticide 

inconsistent with its label is a violation 

of federal law. (7 U.S.C. 136j(a)(2)(G)). 

In the FQPA, Congress integrated action 

under the two statutes by requiring that 

the safety standard under the FFDCA be 

used as a criterion in FIFRA registration 

actions as to pesticide uses which result 

in dietary risk from residues in or on 

food, (7 U.S.C. 136(bb)), and directing 

that EPA coordinate, to the extent 

practicable, revocations of tolerances 

with pesticide cancellations under 

FIFRA. (21 U.S.C. 346a(l)(1)). 

2. Safety standard for pesticide 

tolerances. A pesticide tolerance may 

only be promulgated or left in effect by 

EPA if the tolerance is ‘‘safe.’’ (21 U.S.C. 

346a(b)(2)(A)(i)). This standard applies 

both to petitions to establish and 

petitions to revoke tolerances. ‘‘Safe’’ is 

defined by the statute to mean that 

‘‘there is a reasonable certainty that no 

harm will result from aggregate 

exposure to the pesticide chemical 

residue, including all anticipated 

dietary exposures and all other 

exposures for which there is reliable 

information.’’ (21 U.S.C. 

346a(b)(2)(A)(ii)). Section 408(b)(2)(D) 

directs EPA, in making a safety 

determination, to: 

consider, among other relevant 

factors—... 

(v) available information concerning the 

cumulative effects of such residues and other 

substances that have a common mechanism 

of toxicity; and 

(vi) available information concerning the 

aggregate exposure levels of consumers (and 

major identifiable subgroups of consumers) 

to the pesticide chemical residue and to other 

related substances, including dietary 

exposure under the tolerance and all other 

tolerances in effect for the pesticide chemical 

residue, and exposure from other nonoccupational sources; 

(21 U.S.C. 346a(b)(2)(D)(v), (vi) and 

(viii)). 

EPA must also consider, in evaluating 

the safety of tolerances, ‘‘safety factors 

which . . . are generally recognized as 

appropriate for the use of animal 

experimentation data.’’ (21 U.S.C. 

346a(b)(2)(D)(ix). 

Risks to infants and children are given 

special consideration. Specifically, 

section 408(b)(2)(C) states that EPA: 

shall assess the risk of the pesticide 

chemical based on— 

(II) available information concerning the 

special susceptibility of infants and children 

to the pesticide chemical residues, including 

neurological differences between infants and 

children and adults, and effects of in utero 

exposure to pesticide chemicals; and 

(III) available information concerning the 

cumulative effects on infants and children of 

such residues and other substances that have 

a common mechanism of toxicity. ... 

(21 U.S.C. 346a(b)(2)(C)(i)(II) and (III)). 

This provision also creates a 

presumptive additional safety factor for 

the protection of infants and children. 

Specifically, it directs that ‘‘[i]n the case 

of threshold effects, ... an additional 

tenfold margin of safety for the pesticide 

chemical residue and other sources of 

exposure shall be applied for infants 

and children to take into account 

potential pre- and post-natal toxicity 

and completeness of the data with 

respect to exposure and toxicity to 

infants and children.’’ (21 U.S.C. 

346a(b)(2)(C)). EPA is permitted to ‘‘use 

a different margin of safety for the 

pesticide chemical residue only if, on 

the basis of reliable data, such margin 

will be safe for infants and children.’’ 

(Id.). The additional safety margin for 

infants and children is referred to 

throughout this Order as the ‘‘FQPA 

Safety Factor.’’ 

3. Procedures for establishing, 

amending, or revoking tolerances. 

Tolerances are established, amended, or 

revoked by rulemaking under the 

unique procedural framework set forth 

in the FFDCA. Generally, a tolerance 

rulemaking is initiated by the party 

seeking to establish, amend, or revoke a 

tolerance by means of filing a petition 

with EPA. (See 21 U.S.C. 346a(d)(1)). 

EPA publishes in the Federal Register a 

notice of the petition filing and requests 

public comment. (21 U.S.C. 346a(d)(3)). 

After reviewing the petition, and any 

comments received on it, EPA may issue 

a final rule establishing, amending, or 

revoking the tolerance, issue a proposed 

rule to do the same, or deny the 

petition. (21 U.S.C. 346a(d)(4)). 

Once EPA takes final action on the 

petition by establishing, amending, or 

revoking the tolerance or denying the 

petition, any party may file objections 

with EPA and seek an evidentiary 

hearing on those objections. (21 U.S.C. 

346a(g)(2)). Objections and hearing 

requests must be filed within 60 days. 

(Id.). The statute provides that EPA shall 

‘‘hold a public evidentiary hearing if 

and to the extent the Administrator 

determines that such a public hearing is 

necessary to receive factual evidence 

relevant to material issues of fact raised 

by the objections.’’ (21 U.S.C. 

346a(g)(2)(B). EPA regulations make 

clear that hearings will only be granted 

where it is shown that there is ‘‘a 

genuine and substantial issue of fact,’’ 

the requestor has identified evidence 

‘‘which, if established, resolve one or 

more of such issues in favor of the 

requestor,’’ and the issue is 

‘‘determinative’’ with regard to the relief 

requested. (40 CFR 178.32(b)). EPA’s 

final order on the objections is subject 

to judicial review. (21 U.S.C. 

346a(h)(1)). 

4. Tolerance reassessment and FIFRA 

reregistration. The FQPA required that 

EPA reassess the safety of all pesticide 

tolerances existing at the time of its 

enactment. (21 U.S.C. 346a(q)). EPA was 

given 10 years to reassess the 

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Federal Register / Vol. 73, No. 210 / Wednesday, October 29, 2008 / Rules and Regulations 64231 

approximately 10,000 tolerances in 

existence in 1996. In this reassessment, 

EPA was required to review existing 

pesticide tolerances under the new 

‘‘reasonable certainty that no harm will 

result’’ standard set forth in section 

408(b)(2)(A)(i). (21 U.S.C. 

346a(b)(2)(A)(i)). This reassessment was 

substantially completed by the August 

3, 2006 deadline. Tolerance 

reassessment was generally handled in 

conjunction with a similar program 

involving reregistration of pesticides 

under FIFRA. (7 U.S.C. 136a–1). 

Reassessment and reregistration 

decisions were generally combined in a 

document labeled a Reregistration 

Eligibility Decision (‘‘RED’’). 

B. EPA’s Approach to Dietary Risk 

Assessment 

EPA performs a number of analyses to 

determine the risks from aggregate 

exposure to pesticide residues. A short 

summary is provided below to aid the 

reader. For further discussion of the 

regulatory requirements of section 408 

of the FFDCA and a complete 

description of the risk assessment 

process, see http://www.epa.gov/ 

fedrgstr/EPA–PEST/1999/January/Day– 

04/p34736.htm.(64 FR 162) 

To assess the risk of a pesticide 

tolerance, EPA combines information on 

pesticide toxicity with information 

regarding the route, magnitude, and 

duration of exposure to the pesticide. 

The risk assessment process involves 

three distinct steps: (1) identification of 

the toxicological hazards posed by a 

pesticide and determination of the 

exposure ‘‘level of concern’’ for humans; 

(2) estimation of human exposure; and 

(3) characterization of human risk based 

on comparison of human exposure to 

the level of concern. 

1. Hazard identification and 

determination of the level of concern. 

Any risk assessment begins with an 

evaluation of a chemical’s inherent 

properties, and whether those properties 

have the potential to cause adverse 

effects (i.e., hazard identification). EPA 

then evaluates the hazards to determine 

the most sensitive and appropriate 

adverse effect of concern, based on 

factors such as the effect’s relevance to 

humans and the likely routes of 

exposure. Once a pesticide’s potential 

hazards are identified, EPA determines 

a toxicological level of concern for 

evaluating the risk posed by human 

exposure to the pesticide. In this step of 

the risk assessment process, EPA 

essentially evaluates the levels of 

exposure to the pesticide at which 

effects might occur. An important aspect 

of this determination is assessing the 

relationship between exposure (dose) 

and response (often referred to as the 

dose-response analysis). Another aspect 

is the determination of whether the 

effect is associated with a threshold 

dose (i.e., the effect is seen only at or 

above a certain dose) or whether the 

effect can occur at any dose (such as 

some tumors). 

In evaluating a chemical’s dietary 

risks for threshold effects, EPA uses a 

reference dose (RfD) approach, which 

involves a number of considerations 

including: 

• A ’point of departure’(PoD) - the 

value from a dose-response curve that is 

at the low end of the observable data 

(the no observed adverse effect level, or 

NOAEL, the lowest-observed adverse 

effect level or LOAEL, or an 

extrapolated benchmark dose) and that 

is the dose serving as the ’starting point’ 

in extrapolating a risk to the human 

population; 

• An uncertainty factor to address the 

potential for a difference in toxic 

response between humans and animals 

used in toxicity tests (i.e., interspecies 

extrapolation); 

• An uncertainty factor to address the 

potential for differences in sensitivity in 

the toxic response across the human 

population (for intraspecies 

extrapolation); and 

• The need for an additional safety 

factor to protect infants and children, as 

specified in FFDCA section 408(b)(2)(C). 

EPA uses the chosen PoD to calculate 

a safe dose or RfD. The RfD is calculated 

by dividing the chosen PoD by all 

applicable safety or uncertainty factors. 

Typically in EPA risk assessments, a 

combination of safety or uncertainty 

factors providing at least a hundredfold 

(100X) margin of safety is used: 10X to 

account for interspecies extrapolation 

and 10X to account for intraspecies 

extrapolation. Further, in evaluating the 

dietary risks for pesticide chemicals, an 

additional safety factor of 10X is 

presumptively applied to protect infants 

and children, unless reliable data 

support selection of a different factor. In 

implementing FFDCA section 408, EPA 

also calculates a variant of the RfD 

referred to as a population adjusted dose 

(PAD). The PAD is the RfD divided by 

any portion of the children’s safety 

factor that does not correspond to one 

of the traditional additional uncertainty/ 

safety factors used in general Agency 

risk assessment. The reason for 

calculating PADs is so that other parts 

of the Agency, which are not governed 

by FFDCA section 408, can, when 

evaluating the same or similar 

substances, easily identify which 

aspects of a pesticide risk assessment 

are a function of the particular statutory 

commands in FFDCA section 408. For 

acute assessments, the risk is expressed 

as a percentage of a maximum 

acceptable dose or the acute PAD (i.e., 

the acute dose which EPA has 

concluded will be ‘‘safe’’). As discussed 

below in Unit V.C., dietary exposures 

greater than 100 percent of the acute 

PAD are generally cause for concern and 

would be considered ‘‘unsafe’’ within 

the meaning of FFDCA section 

408(b)(2)(B). Throughout this document 

general references to EPA’s calculated 

safe dose are denoted as an acute PAD, 

or aPAD, because the relevant point of 

departure for carbaryl is based on an 

acute risk endpoint. 

In evaluating a chemical’s dietary risk 

for non-threshold effects, such as 

cancer; EPA’s default approach is to 

extrapolate a Q1* from the doseresponse curve as a measure of cancer 

potency, and then to use this Q1* value 

in conjunction with estimated dietary 

exposure to estimate the probability of 

occurrence of additional adverse effects. 

The Q1*is the 95th percentile upper 

confidence limit from a tumor dose 

response curve extrapolated using a 

linear low-dose model. For nonthreshold dietary cancer risks, EPA 

generally considers cancer risk to be 

negligible if the probability of increased 

cancer cases falls within the range of 1 

in 1 million. 

Animal studies show that carbaryl, 

like other NMC pesticides, causes 

transient, reversible inhibition of 

cholinesterase activity in brain, red 

blood cells, and plasma across all tested 

routes of exposure. Developmental 

toxicity was seen in rats and rabbits 

treated with carbaryl during gestation; 

effects included decreased fetal weight 

and incomplete ossification (bone 

formation). A carbaryl rat reproductive 

toxicity study showed decreased pup 

survival, and a rat developmental 

neurotoxicity study showed changes in 

fetal brain morphometry. In addition, a 

comparative cholinesterase study shows 

that young animals had increased 

sensitivity, compared with adults, to 

inhibition of brain cholinesterase from 

carbaryl. EPA used endpoints from the 

comparative cholinesterase study to 

assess human health risk in both the 

single chemical risk assessment for 

carbaryl and in the cumulative risk 

assessment for the NMC pesticides. 

Carbaryl is considered to be ‘‘likely to 

be carcinogenic in humans’’ based on 

tumors in male mice and EPA utilized 

the Agency default low-dose linear 

extrapolation (Q1*) approach to 

quantify cancer risk. 

2. Estimating human exposure levels. 

Pursuant to section 408(b) of the 

FFDCA, EPA has evaluated carbaryl 

dietary risks based on ‘‘aggregate 

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64232 Federal Register / Vol. 73, No. 210 / Wednesday, October 29, 2008 / Rules and Regulations 

exposure’’ to carbaryl. By ‘‘aggregate 

exposure,’’ EPA is referring to exposure 

to carbaryl alone by multiple pathways 

of exposure, including residues in food 

and water and exposure from use of 

carbaryl products in residential settings. 

EPA uses available data, together with 

assumptions designed to be protective 

of public health and standard analytical 

methods, to produce separate estimates 

of exposure for a highly exposed 

subgroup of the general population, for 

each potential pathway and route of 

exposure. For acute risks, EPA then 

calculates potential aggregate exposure 

and risk by using probabilistic 

techniques to combine distributions of 

potential exposures in the population 

for the dietary pathway, and uses single 

point estimates for the residential 

component in calculating aggregate 

exposure. For dietary analyses, the 

relevant sources of potential exposure to 

carbaryl are from the ingestion of 

residues in food and drinking water. 

The Agency uses a combination of 

monitoring data and predictive models 

to evaluate environmental exposure of 

humans to carbaryl, which may occur 

from ingesting carbaryl residues in food 

or drinking water, or from using 

products containing carbaryl in 

residential settings. These are described 

below. 

a. Exposure from food. Data on the 

residues of carbaryl in foods are 

available from a variety of sources. One 

of the primary sources of the data comes 

from federally-conducted surveys, 

including the Pesticide Data Program 

(PDP) conducted by the USDA. Further, 

market basket studies, which are 

typically performed by registrants, can 

provide additional residue data. These 

data generally provide a 

characterization of pesticide residues in 

or on foods consumed by the U.S. 

population that closely approximates 

real world exposures because they are 

sampled closer to the point of 

consumption in the chain of commerce 

than field trial data, which are generated 

to establish the maximum level of legal 

residues that could result from 

maximum permissible use of the 

pesticide. In certain circumstances, EPA 

will rely on field trial data, as it can 

provide more accurate exposure 

estimates. EPA estimated dietary 

exposure to carbaryl using residue data 

from a variety of sources, including 

USDA and FDA monitoring and crop 

field trial studies. These residue data 

were refined based on relevant 

processing factors. EPA also took into 

account information on the extent to 

which crops which may be treated with 

carbaryl are actually so treated. 

EPA uses a computer program, the 

Dietary Exposure Evaluation Model 

(DEEM), and the USDA Food 

Commodity Intake database (FCID), to 

estimate exposure by combining data on 

human consumption amounts with 

residue values in food commodities. 

DEEM-FCIDTM also compares exposure 

estimates to appropriate RfD or PAD 

values to estimate risk. EPA uses DEEMFCIDTM to estimate exposure for the 

general U.S. population as well as for 32 

subgroups based on age, sex, ethnicity, 

and region. DEEM-FCIDTM allows EPA 

to process extensive volumes of data on 

human consumption amounts and 

residue levels in making risk estimates. 

Matching consumption and residue 

data, as well as managing the thousands 

of repeated analyses of the consumption 

database conducted under probabilistic 

risk assessment techniques, requires the 

use of a computer. 

DEEM-FCIDTM contains consumption 

and demographic information on the 

individuals who participated in the 

USDA’s Combined Survey of Food 

Intake by Individuals (CSFII) in 1994– 

1996 and 1998. The 1998 survey was a 

special survey required by the FQPA to 

supplement the number of children 

survey participants. DEEM-FCIDTM also 

contains ‘‘recipes’’ that convert foods as 

consumed (e.g., pizza) back into their 

component raw agricultural 

commodities (e.g., wheat from flour, or 

tomatoes from sauce, etc.). This is 

necessary because residue data are 

generally gathered on raw agricultural 

commodities rather than on finished 

ready-to-eat food. Data on residue 

values for a particular pesticide and the 

RfD or PADs for that pesticide are 

inputs to the DEEM-FCIDTM program to 

estimate exposure and risk. 

For carbaryl’s assessment, EPA used 

DEEM-FCIDTM to calculate risk 

estimates based on a probabilistic 

distribution. DEEM-FCIDTM combines 

the full range of residue values for each 

food with the full range of data on 

individual consumption amounts to 

create a distribution of exposure and 

risk levels. More specifically, DEEMFCIDTM creates this distribution by 

calculating an exposure value for each 

reported day of consumption per person 

(‘‘person/day’’) in USDA’s CSFII, 

assuming that all foods potentially 

bearing the pesticide residue contain 

such residue at the chosen value. The 

exposure amounts for the thousands of 

person/days in the CSFII are then 

collected in a frequency distribution. 

EPA also uses DEEM-FCIDTM to 

compute a distribution taking into 

account both the full range of data on 

consumption levels and the full range of 

data on potential residue levels in food. 

Combining consumption and residue 

levels into a distribution of potential 

exposures and risk requires use of 

probabilistic techniques. 

Probabilistic analysis is used to 

predict the frequency with which 

variations of a given event will occur. 

By taking into account the actual 

distribution of possible consumption 

and pesticide residue values, 

probabilistic analysis for pesticide 

exposure assessments ‘‘provides more 

accurate information on the range and 

probability of possible exposure and 

their associated risk values’’ (Ref. 3). In 

capsule, a probabilistic pesticide 

exposure analysis constructs a 

distribution of potential exposures 

based on data on consumption patterns 

and residue levels and provides a 

ranking of the probability that each 

potential exposure will occur. People 

consume differing amounts of the same 

foods, including none at all, and a food 

will contain differing amounts of a 

pesticide residue, including none at all. 

The probabilistic technique that 

DEEM-FCIDTM uses to combine differing 

levels of consumption and residues 

involves the following steps: 

(1) Identification of any food(s) that 

could bear the residue in question for 

each person/day in the CSFII; 

(2) Calculation of an exposure level 

for each of the thousands of person/days 

in the CSFII database, based on the 

foods identified in Step #1 by randomly 

selecting residue values for the foods 

from the residue database; 

(3) Repetition of Step #2 up to one 

thousand times for each person/day; 

and 

(4) Collection of all of the hundreds 

of thousands of potential exposures 

estimated in Steps # 2 and 3 in a 

frequency distribution. 

The resulting probabilistic assessment 

presents a range of exposure/risk 

estimates. 

b. Exposure from water. EPA may use 

field monitoring data and/or simulation 

water exposure models to generate 

pesticide concentration estimates in 

drinking water. Monitoring and 

modeling are both important tools for 

estimating pesticide concentrations in 

water and can provide different types of 

information. Monitoring data can 

provide estimates of pesticide 

concentrations in water that are 

representative of the specific 

agricultural or residential pesticide 

practices in specific locations, under the 

environmental conditions associated 

with a sampling design (i.e., the 

locations of sampling, the times of the 

year samples were taken, and the 

frequency by which samples were 

collected). Although monitoring data 

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1Because carbaryl is a member of the NMC group 

of pesticides, which share a common mechanism of 

toxicity, EPA was unable to complete the carbaryl 

Reregistration Eligibility Decision (RED) before 

completion of the NMC cumulative risk assessment 

in September 2007. 

can provide a direct measure of the 

concentration of a pesticide in water, it 

does not always provide a reliable basis 

for estimating spatial and temporal 

variability in exposures because 

sampling may not occur in areas with 

the highest pesticide use, and/or when 

the pesticides are being used and/or at 

an appropriate sampling frequency to 

detect high concentrations of a pesticide 

that occur over the period of a day to 

several days. 

Because of the limitations in most 

monitoring studies, EPA’s standard 

approach is to use simulation water 

exposure models as the primary means 

to estimate pesticide exposure levels in 

drinking water. EPA’s computer models 

use detailed information on soil 

properties, crop characteristics, and 

weather patterns to estimate water 

concentrations in vulnerable locations 

where the pesticide could be used 

according to its label. (69 FR 30042, 

May 26, 2004). These models calculate 

estimated water concentrations of 

pesticides using laboratory data that 

describe how fast the pesticide breaks 

down to other chemicals and how it 

moves in the environment at these 

vulnerable locations. The modeling 

provides an estimate of pesticide 

concentrations in ground and surface 

water. Daily concentrations can be 

estimated continuously over long 

periods of time, and for places that are 

of most interest for any particular 

pesticide. 

EPA relies on models it has developed 

for estimating pesticide concentrations 

in both surface water and ground water. 

Typically EPA uses a two-tiered 

approach to modeling pesticide 

concentrations in surface and ground 

water. If the first tier model suggests 

that pesticide levels in water may be 

unacceptably high, a more ined model 

is used as a second tier assessment. For 

surface water assessments, the second 

tier model is actually a combination of 

two models: The Pesticide Root Zone 

Model (PRZM) and the Exposure 

Analysis Model System (EXAMS). 

A detailed description of the models 

routinely used for exposure assessment 

is available from the EPA web site: 

http://www.epa.gov/oppefed1/models/ 

water/index.htm. These models provide 

a means for EPA to estimate daily 

pesticide concentrations in surface 

water sources of drinking water (a 

reservoir) using local soil, site, 

hydrology, and weather characteristics 

along with pesticide application and 

agricultural management practices, and 

pesticide environmental fate and 

transport properties. Consistent with the 

recommendations of the FIFRA Science 

Advisory Panel (SAP), EPA also 

considers percent cropped area factors 

(PCA) which takes into account the 

potential extent of cropped areas that 

could be treated with pesticides in a 

particular area. The PRZM and EXAMS 

models used by EPA were developed by 

EPA’s Office of Research and 

Development (ORD), and are used by 

many international pesticide regulatory 

agencies to estimate pesticide exposure 

in surface water. EPA’s use of the 

percent cropped area factors and the 

Index Reservoir scenario was reviewed 

by the FIFRA SAP in 1999 and 1998, 

respectively (Refs. 4 and 5). 

In modeling potential surface water 

concentrations, EPA attempts to model 

areas of the country that are highly 

vulnerable to surface water 

contamination rather than simply model 

‘‘typical’’ locations occurring across the 

nation. Consequently, EPA models 

exposures occurring in small highly 

agricultural watersheds in different 

growing areas throughout the country. 

The scenarios are designed to capture 

residue levels in drinking water from 

reservoirs with small watersheds with a 

large percentage of land use in 

agricultural production. EPA believes 

these assessments are likely reflective of 

a small subset of the watersheds across 

the country that maintain drinking 

water reservoirs, representing a drinking 

water source generally considered to be 

more vulnerable to frequent high 

concentrations of pesticides than most 

locations that could be used for crop 

production. 

When EPA completed the carbaryl 

Interim Reregistration Eligibility 

Decision (IRED)1 in June 2003, EPA 

compared the estimated drinking water 

concentrations (EDWCs) of pesticides, 

from the PRZM/EXAMS model, with a 

drinking water level of concern 

(DWLOC), a value representing the 

concentration of a pesticide in drinking 

water that would represent the upper 

limit in light of total aggregate exposure 

to that pesticide from food, water, and 

residential uses of that pesticide. The 

DWLOC approach was developed in the 

mid 1990s as part of EPA’s review of 

pesticides under FQPA, before the 

current risk assessment methodologies 

became available. EPA now uses the 

output of daily concentration values 

from tier two modeling as an input to 

DEEM-FCIDTM, which combines water 

concentrations with drinking water 

consumption information in the daily 

diet to generate a distribution of 

exposures from consumption of 

drinking water containing pesticide 

residues. These results are then used to 

calculate a probabilistic assessment of 

the aggregate human exposure and risk 

from residues in food and drinking 

water. 

EPA also considers available surface 

water monitoring data, including data 

from the US Geological Survey (USGS) 

National Water Quality Assessment 

Program (NAWQA), in conducting 

drinking water assessments. For the 

2007 carbaryl RED, EPA considered data 

from a variety of sources, including 

NAWQA, the joint USGS-EPA Mini 

Pilot Monitoring Program, Washington 

and California state monitoring data, 

and registrant voluntary water 

monitoring study measuring carbaryl in 

targeted community water systems 

associated with watersheds having high 

carbaryl use. 

c. Residential exposures. Generally, in 

assessing residential exposure to 

pesticides EPA relies on its Standard 

Operating Procedures (SOPs) for 

Residential Exposure Assessment and 

subsequent amendments (Refs. 6, 7, and 

8). The Residential SOPs establish the 

approaches used for estimating 

application and post-application 

exposures in a residential setting. SOPs 

have been developed for many common 

exposure scenarios including pesticide 

treatment of lawns, garden plants, trees, 

swimming pools, pets, and indoor 

surfaces including crack and crevice 

treatments. The SOPs are based on 

existing monitoring and survey data 

including information on activity 

patterns, particularly for children. 

Where available, EPA relies on 

pesticide-specific data in estimating 

residential exposures. Although limited 

carbaryl specific data were available at 

the time the carbaryl IRED was 

completed, additional data were 

submitted in response to the 2005 Data 

Call-In (DCI) for carbaryl. These data 

were reviewed and incorporated into 

the revised residential risk assessment 

used to support the final carbaryl RED. 

Residential exposure from carbaryl was 

estimated using EPA’s Residential SOPs 

(as amended) as well as a turf 

dissipation study for carbaryl which 

quantified turf transferable residues 

after carbaryl application to turf and 

other monitoring data available to the 

Agency (e.g., residue decline studies on 

garden crops). 

3. Risk characterization. The final 

step in the risk assessment is risk 

characterization. In this step, EPA 

combines information from the first 

three steps (hazard identification, level 

of concern/dose-response analysis, and 

human exposure assessment) to 

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quantitatively estimate the risks posed 

by a pesticide. Separate 

characterizations of risk are conducted 

for different durations of exposure. 

Additionally, separate and, where 

appropriate, aggregate characterizations 

of risk are conducted for the different 

routes of exposure (dietary and nondietary). 

For threshold risks, EPA estimates 

risk in one of two ways. Where EPA has 

calculated an RfD/PAD, risk is estimated 

by expressing human exposure as a 

percentage of the RfD/PAD. Exposures 

lower than 100 percent of the RfD/PAD 

are generally not of concern. 

Alternatively, EPA may express risk by 

dividing the estimated human exposure 

into the PoD to derive a margin of 

exposure (MOE). The MOE is compared 

with a level of concern, which is the 

product of all applicable uncertainty/ 

safety factors. In contrast to the RfD/ 

PAD approach, the higher the MOE, the 

lower the risk concern for the pesticide. 

Accordingly, if the level of concern is 

100, MOEs equal to or exceeding 100 

would generally not be of concern. 

As a conceptual matter, the RfD/PAD 

and MOE approaches are fundamentally 

equivalent. For a given risk and given 

exposure of a pesticide, if exposure to 

a pesticide were found to be acceptable 

under an RfD/PAD analysis it would 

also pass under the MOE approach, and 

vice-versa. However, for any specific 

pesticide, risk assessments for different 

exposure durations or routes may yield 

different results. This is a function not 

of the choice of the RfD/PAD or MOE 

approach but of the fact that the levels 

of concern and the levels of exposure 

may differ depending on the duration 

and route of exposure. 

For non-threshold risks (generally, 

cancer risks), EPA uses the slope of the 

dose-response curve for a pesticide in 

conjunction with an estimation of 

human exposure to that pesticide to 

estimate the probability of occurrence of 

additional adverse effects. For nonthreshold cancer risks, EPA generally 

considers cancer risk to be negligible if 

the probability of increased cancer cases 

falls within the range of 1 in 1 million. 

Risks exceeding values within that 

range would raise a risk concern. 

C. Science Policy Considerations 

1. EPA policy on the children’s safety 

factor. As the above brief summary of 

EPA’s risk assessment practice 

indicates, the use of safety factors plays 

a critical role in the process. This is true 

for traditional 10X safety factors to 

account for potential differences 

between animals and humans when 

relying on studies in animals (interspecies safety factor) and potential 

differences among humans (intraspecies safety factor) as well as the 

FQPA’s additional 10X children’s safety 

factor. 

In general, Section 408 of FFDCA 

provides that EPA shall apply an 

additional tenfold margin of safety for 

infants and children in the case of 

threshold effects to account for prenatal 

and postnatal toxicity and the 

completeness of the data base on 

toxicity and exposure unless EPA 

determines that a different margin of 

safety will be safe for infants and 

children. Margins of safety are 

incorporated into EPA assessments 

either directly through use of a margin 

of exposure analysis or through using 

uncertainty (safety) factors in 

calculating a dose level that poses 

acceptable risk to humans. 

In applying the children’s safety 

factor provision, EPA has interpreted 

the statutory language as imposing a 

presumption in favor of applying an 

additional 10X safety factor (Ref. 9). 

Thus, EPA generally refers to the 

additional 10X factor as a presumptive 

or default 10X factor. EPA has also 

made clear, however, that the 

presumption can be overcome if reliable 

data demonstrate that a different factor 

is safe for children (Id.). In determining 

whether a different factor is safe for 

children, EPA focuses on the three 

factors listed in section 408(b)(2)(C) - 

the completeness of the toxicity 

database, the completeness of the 

exposure database, and potential preand post-natal toxicity. In examining 

these factors, EPA strives to make sure 

that its choice of a safety factor, based 

on a weight-of-the-evidence evaluation, 

does not understate the risk to children. 

(Id.). 

When EPA evaluated the carbaryl 

toxicological database in 2003 to 

determine the appropriate FQPA Safety 

Factor for use in the IRED, available 

studies included rat and rabbit 

teratology (developmental toxicity) 

studies, a rat developmental 

neurotoxicity study, a rat reproductive 

toxicity study, a 4–week dermal rat 

study, acute and subchronic 

neurotoxicity screening studies, and a 

chronic oral dog study (Ref. 10). Based 

on the weight of the evidence as 

evaluated in 2003, the FQPA Safety 

Factor was determined to be 3X due to 

the lack of a NOAEL in the chronic dog 

study. This was what the weight of the 

evidence showed in 2003. 

The science has advanced since 2003; 

additional information on 

pharmacokinetics as well as additional 

acute cholinesterase data have become 

available for carbaryl and other NMCs. 

Due to the rapid recovery of 

cholinesterase activity, chronic 

exposure is no longer considered to be 

a concern for carbaryl. As the science 

has advanced, science policy has also 

evolved. As EPA acquired 

developmental neurotoxicity and 

comparative cholinesterase data on the 

NMCs, it became apparent that 

comparative cholinesterase studies 

measuring red blood cell (RBC) and 

brain cholinesterase inhibition in both 

maternal and young animals (postnatal 

day 11 (PND11) and postnatal day 17 

(PND17)) were a more accurate 

predictor of age-related sensitivity than 

developmental neurotoxicity studies 

measuring behavioral and 

histopathological changes. Therefore, 

EPA informed registrants that, in the 

absence of comparative cholinesterase 

data for each pesticide, a 10X FQPA 

Safety Factor would be applied to that 

pesticide in the NMC cumulative risk 

assessment. If comparative 

cholinesterase data were available, EPA 

used a data derived approach for the 

FQPA Safety Factor by comparing the 

benchmark dose (BMD) at the 10% 

inhibition level for either brain or RBC 

acetyl cholinesterase inhibition between 

maternal animals and the juvenile 

animals (typically PND11). 

2. EPA Policy on cholinesterase 

inhibition as a regulatory endpoint. 

Cholinesterase inhibition is a disruption 

of the normal process in the body by 

which the nervous system chemically 

communicates with muscles and glands. 

Communication between nerve cells 

and a target cell (i.e., another nerve cell, 

a muscle fiber, or a gland) is facilitated 

by the chemical, acetylcholine. When a 

nerve cell is stimulated it releases 

acetylcholine into the synapse (or space) 

between the nerve cell and the target 

cell. The released acetylcholine binds to 

receptors in the target cell, stimulating 

the target cell in turn. As EPA has 

explained, ‘‘the end result of the 

stimulation of cholinergic pathway(s) 

includes, for example, the contraction of 

smooth (e.g., in the gastrointestinal 

tract) or skeletal muscle, changes in 

heart rate or glandular secretion (e.g., 

sweat glands) or communication 

between nerve cells in the brain or in 

the autonomic ganglia of the peripheral 

nervous system.’’ (Ref. 11 at 10). 

Acetylcholinesterase (AChE) is an 

enzyme that breaks down acetylcholine 

and terminates its stimulating action in 

the synapse between nerve cells and 

target cells. When AChE is inhibited, 

acetylcholine builds up prolonging the 

stimulation of the target cell. This 

excessive stimulation potentially results 

in a broad range of adverse effects on 

many bodily functions. Depending on 

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the degree of inhibition these effects can 

be serious, even fatal. 

EPA’s cholinesterase inhibition policy 

statement explains EPA’s approach to 

evaluating the risks posed by 

cholinesterase-inhibiting pesticides 

such as carbaryl. (Id). The policy 

focuses on three types of effects 

associated with cholinesteraseinhibiting pesticides that may be 

assessed in animal and human 

toxicological studies: (1) physiological 

and behavioral/functional effects; (2) 

cholinesterase inhibition in the central 

and peripheral nervous system; and (3) 

cholinesterase inhibition in red blood 

cells and blood plasma. The policy 

discusses how such data should be 

integrated in deriving an acceptable 

dose (RfD/PAD) for a cholinesteraseinhibiting pesticide. 

Clinical signs or symptoms of 

cholinesterase inhibition in humans, the 

policy concludes, provide the most 

direct evidence of the adverse 

consequences of exposure to 

cholinesterase-inhibiting pesticides. 

Nonetheless, as the policy notes, due to 

strict ethical limitations, studies in 

humans are ‘‘quite limited.’’ (Id. at 19). 

Although animal studies can also 

provide direct evidence of 

cholinesterase inhibition effects, animal 

studies cannot easily measure cognitive 

effects of cholinesterase inhibition such 

as effects on perception, learning, and 

memory. For these reasons, the policy 

recommends that ‘‘functional data 

obtained from human and animal 

studies should not be relied on solely, 

to the exclusion of other kinds of 

pertinent information, when weighing 

the evidence for selection of the critical 

effect(s) that will be used as the basis of 

the RfD or RfC.’’ (Id. at 20). 

After clinical signs or symptoms, 

cholinesterase inhibition in the nervous 

system provides the next most 

important endpoint for evaluating 

cholinesterase-inhibiting pesticides. 

Although cholinesterase inhibition in 

the nervous system is not itself regarded 

as a direct adverse effect, it is ‘‘generally 

accepted as a key component of the 

mechanism of toxicity leading to 

adverse cholinergic effects.’’ (Id. at 25). 

As such, the policy states that it should 

be treated as ‘‘direct evidence of 

potential adverse effects’’ and ‘‘data 

showing this response provide valuable 

information in assessing potential 

hazards posed by anticholinesterase 

pesticides.’’ (Id.). AChE inhibition in 

brain and the peripheral nervous system 

is the initial adverse biological event 

which results from exposure to NMC 

pesticides, such as carbaryl, and with 

sufficient levels of inhibition leads to 

other effects. Thus, AChE inhibition 

provides the most appropriate effect to 

use in risk extrapolation for derivation 

of RfDs and PADs. Protecting against 

AChE inhibition ensures that the other 

adverse effects mentioned above do not 

occur. 

In summary, EPA uses a weight of 

evidence approach to determine the 

toxic effect that will serve as the 

appropriate PoD for a risk assessment 

for AChE inhibiting pesticides, such as 

carbaryl (Id). The neurotoxicity that is 

associated with these pesticides can 

occur in both the central (brain) and the 

peripheral nervous system. In its weight 

of the evidence analysis, EPA reviews 

data, such as AChE inhibition data from 

the brain, peripheral tissues and blood 

(e.g., RBC or plasma), in addition to data 

on clinical signs and other functional 

effects related to AChE inhibition. Based 

on these data, EPA selects the most 

appropriate effect on which to regulate; 

such effects can include clinical signs of 

AChE inhibition, central or peripheral 

nervous tissue measurements of AChE 

inhibition or RBC AChE measures (Id). 

Although RBC AChE inhibition is not 

adverse in itself, it is a surrogate for 

inhibition in peripheral tissues when 

peripheral data are not available. As 

such, RBC AChE inhibition provides an 

indirect indication of adverse effects on 

the nervous system (Id.). Due to 

technical difficulties regarding 

dissection of peripheral nerves and the 

rapid nature of carbaryl toxicity, 

measures of AChE inhibition in the 

peripheral nervous system are very rare 

for NMC pesticides. For these reasons, 

other state and national agencies such as 

California, Washington, Canada, the 

European Union, as well as the World 

Health Organization (WHO), all use 

blood measures in human health risk 

assessment and/or worker safety 

monitoring programs. 

3. Benchmark dose. EPA has relied on 

a benchmark dose approach for deriving 

the PoD from the available rat toxicity 

studies (Ref. 12). A benchmark dose, or 

BMD, is a point estimate along a doseresponse curve that corresponds to a 

specific response level. For example, a 

BMD10 represents a 10% change from 

the background or typical value for the 

response of concern. Generically, the 

direction of change from background 

can be an increase or a decrease 

depending on the biological parameter 

and the chemical of interest. In the case 

of carbaryl, inhibition of AChE is the 

toxic effect of concern. Following 

exposure to carbaryl, the normal 

biological activity of the AChE enzyme 

is decreased (i.e., the enzyme is 

inhibited). Thus, when evaluating BMDs 

for carbaryl, the Agency is interested in 

a decrease in AChE activity compared to 

normal activity levels, which are also 

termed ‘‘background’’ levels. 

Measurements of ‘‘background’’ AChE 

activity levels are usually obtained from 

animals in experimental studies that are 

not treated with the pesticide of interest 

(i.e., ‘‘negative control’’ animals). 

In addition to the BMD, a ‘‘confidence 

limit’’ was also calculated. Confidence 

limits express the uncertainty in a BMD 

that may be due to sampling and/or 

experimental error. The lower 

confidence limit on the dose used as the 

BMD is termed the BMDL, which the 

Agency uses as the PoD. Use of the 

BMDL for deriving the PoD rewards 

better experimental design and 

procedures that provide more precise 

estimates of the BMD, resulting in 

tighter confidence intervals. Use of the 

BMDL also helps ensure with high 

confidence (e.g., 95% confidence) that 

the selected percentage of AChE 

inhibition is not exceeded. From the 

PoD, EPA calculates the RfD and aPAD. 

Numerous scientific peer review 

panels over the last decade have 

supported the Agency’s application of 

the BMD approach as a scientifically 

supportable method for deriving PoDs 

in human health risk assessment, and as 

an improvement over the historically 

applied approach of using NOAELs or 

LOAELs. The NOAEL/LOAEL approach 

does not account for the variability and 

uncertainty in the experimental results, 

which are due to characteristics of the 

study design, such as dose selection, 

dose spacing, and sample size. With the 

BMD approach, all the dose response 

data are used to derive a PoD. Moreover, 

the response level used for setting 

regulatory limits can vary based on the 

chemical and/or type of toxic effect 

(Refs. 12, 13, 14, and 15). Specific to 

carbaryl and other NMCs, the FIFRA 

SAP has reviewed and supported the 

statistical methods used by the Agency 

to derive BMDs and BMDLs on two 

occasions, February 2005 and August 

2005 (Refs. 14 and 15). 

IV. Carbaryl Tolerances 

A. Regulatory Background 

Carbaryl is a carbamate insecticide 

and molluscide that was first registered 

in 1959 for use on cotton. Carbaryl has 

many trade names, but is most 

commonly known as Sevin. In 1980, 

the Agency published a position 

document summarizing its conclusions 

from a Special Review of carbaryl, and 

concluded that risk concerns, 

particularly those related to 

teratogenicity, did not warrant 

cancellation of the registration for 

carbaryl. A Registration Standard, 

issued for carbaryl in 1984 and revised 

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64236 Federal Register / Vol. 73, No. 210 / Wednesday, October 29, 2008 / Rules and Regulations 

in 1988, described the terms and 

conditions for continued registration of 

carbaryl. At the time carbaryl was 

assessed for purposes of reregistration, 

carbaryl was registered for use on over 

400 agricultural and non–agricultural 

use sites, and there were more than 140 

tolerances for carbaryl in the Code of 

Federal Regulations (40 CFR 180.169). 

For example, carbaryl was registered for 

domestic outdoor uses on lawns and 

gardens, and indoors in kennels and on 

pet sleeping quarters. It was also 

registered for direct application to cats 

and dogs (collar, powder, and dip) to 

control fleas and ticks. 

EPA completed an IRED for carbaryl 

on June 30, 2003 (2003 IRED). The 

Agency amended the IRED on October 

22, 2004 (2004 Amended IRED), and 

published a formal Notice of 

Availability for the document, which 

provided for a 60–day public comment 

period (Ref. 16). EPA received 

numerous comments on the carbaryl 

IRED, including the NRDC petition 

requesting that EPA cancel all carbaryl 

registrations and revoke all tolerances. 

The Agency published a Notice of 

Receipt for the petition in the Federal 

Register, which provided a public 

comment period. Petition to Revoke or 

Modify Tolerances Established for 

Carbaryl; Notice of Availability, 70 FR 

16281 (March 30, 2005). The mitigation 

detailed in the 2004 Amended IRED for 

residential uses included: canceling 

liquid broadcast applications to home 

lawns pending EPA review of 

pharmacokinetic data to refine postapplication risk estimates; home garden/ 

ornamental dust products must be 

packaged in ready-to-use shaker can 

containers, with no more than 0.05 lbs. 

active ingredient per container; 

cancellation of the following uses and 

application methods: all pet uses (dusts 

and liquids) except collars, aerosol 

products for various uses, belly grinder 

applications of granular and bait 

products for lawns, hand applications of 

granular and bait products for 

ornamentals and gardens. 

On March 9, 2005, EPA issued a 

cancellation order for the liquid 

broadcast use of carbaryl on residential 

turf to address post-application risk to 

toddlers (Ref. 17). In March 2005, EPA 

also issued generic and product-specific 

DCIs for carbaryl. The carbaryl generic 

DCI required several studies of the 

active ingredient carbaryl, including 

additional toxicology, worker exposure 

monitoring, and environmental fate 

data. The product-specific DCI required 

acute toxicity and product chemistry 

data for all pesticide products 

containing carbaryl; these data are being 

used for product labeling. EPA has 

received numerous studies in response 

to these DCIs, and, where appropriate, 

these studies were considered in the 

tolerance reassessment. 

In response to the DCIs, many 

carbaryl registrants chose to voluntarily 

cancel their carbaryl products, rather 

than revise their labels or conduct 

studies to support these products. EPA 

published a notice of receipt of this 

request in the Federal Register on 

October 28, 2005 (70 FR 62112), 

followed by a cancellation order issued 

on July 3, 2006. One technical 

registrant, Burlington Scientific, chose 

to cancel their technical product, 

leaving Bayer CropScience (Bayer) as 

the sole technical registrant for carbaryl. 

Approximately two-thirds of all of the 

carbaryl products registered at the time 

of the 2003 IRED have been canceled 

through this process. 

In addition, Bayer, the sole remaining 

technical registrant responsible for 

developing data, requested waivers of 

required exposure monitoring or residue 

studies because these use scenarios are 

not on any Bayer technical or product 

labels or were to be deleted from Bayer 

labels: carbaryl use in or on pea and 

bean, succulent shelled (subgroup 6B); 

millet; wheat; pre-plant root dip for 

sweet potato; pre-plant root dip/drench 

fpr nursery stocks, vegetable 

transplants, bedding plants, and foliage 

plants; use of granular formulations on 

leafy vegetables (except Brassica); ultra 

low volume (ULV) application for adult 

mosquito control; and dust applications 

in agriculture. 

Bayer subsequently requested that all 

of their carbaryl registrations bearing 

any of these uses be amended to delete 

these uses; EPA published a Notice of 

receipt of this request in the Federal 

Register on August 20, 2008 (73 FR 

49184), and plans to approve Bayer’s 

request and issue a final order amending 

these registrations at the end of the 

comment period for the Notice. As a 

consequence, EPA has notified all 

affected registrants that these uses and 

application methods must be deleted 

from their carbaryl product labels. EPA 

has identified thirty four (34) product 

labels from 14 registrants (other than 

Bayer) bearing these end uses. All of 

these registrants have requested that 

their affected carbaryl product 

registrations be amended to delete these 

uses. EPA published a Notice of receipt 

of these requests in the Federal Register 

on August 20, 2008 and will publish a 

second Notice of Receipt of these 

requests on or about October 8, 2008. 

In June 2006, EPA determined that the 

uses associated with 120 of the existing 

carbaryl tolerances are not significant 

contributors to the overall NMC 

cumulative risk and as a result these 

tolerances will have no effect on the 

retention or revocation of other NMC 

tolerances. Therefore, EPA considered 

these 120 tolerances for carbaryl as 

reassessed on June 29, 2006, and posted 

this decision on the internet site. (See 

http://www.epa.gov/pesticides/ 

cumulative/ 

carbamates_commodity.pdf). 

Carbaryl is a member of the NMC 

class of pesticides which share a 

common mechanism of toxicity by 

affecting the nervous system via 

cholinesterase inhibition. Specifically, 

carbaryl is a reversible inhibitor of 

AChE. A cumulative risk assessment, 

which evaluates exposures based on a 

common mechanism of toxicity, was 

conducted to evaluate risk from food, 

drinking water, residential use, and 

other non-occupational exposures 

resulting from registered uses of NMC 

pesticides, including carbaryl. 

In late November 2006, EPA received 

data from a carbaryl comparative 

cholinesterase study, conducted to 

determine the comparative sensitivity of 

adults and offspring to cholinesterase 

inhibition by carbaryl. These data were 

used to revise the FQPA Safety Factor 

for carbaryl for the NMC cumulative risk 

assessment and to select new toxicology 

endpoints (PoDs) for the risk 

assessment. The Agency determined 

that it was appropriate to use the new 

FQPA Safety Factor and revised PoDs in 

both the NMC cumulative risk 

assessment and the carbaryl-specific 

human health risk assessment. Because 

this necessitated a revision of the 

carbaryl human health aggregate risk 

assessment, EPA also considered 

additional new data generated in 

response to the DCI, new 

methodologies, and other new 

information in performing its most 

recent assessment of carbaryl and in 

responding to this Petition. EPA has 

thus, in effect, revised the carbaryl 

single chemical assessment in response 

to the issues raised during the public 

comment process as well as based upon 

more recent data and analytical 

methods. 

On September 26, 2007, EPA issued 

the NMC cumulative risk assessment. 

EPA concluded that the cumulative 

risks associated with the NMC 

pesticides meet the safety standard set 

forth in section 408(b)(2) of the FFDCA, 

provided that the mitigation specified in 

the NMC cumulative risk assessment is 

implemented, such as cancellation of all 

uses of carbofuran, termination of 

methomyl use on grapes, etc. EPA has 

therefore terminated the tolerance 

reassessment process under 408(q) of 

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the FFDCA. (See Ref. 18 for additional 

information). 

In conjunction with the NMC 

cumulative risk assessment, EPA 

completed a RED for carbaryl on 

September 24, 2007 and issued this RED 

on October 17, 2007 with a formal 

Notice of Availability in the Federal 

Register (72 FR 58844). In addition to 

relying on the NMC cumulative risk 

assessment to determine that the 

cumulative effects from exposure to all 

NMC residues, including carbaryl, was 

safe, the carbaryl RED relied upon the 

revised assessments and the mitigation 

that had already been implemented 

(e.g., cancellation of pet uses except for 

collars). In addition, the RED included 

additional mitigation with respect to 

granular turf products for residential 

use; namely, that product labels direct 

users to water the product in 

immediately after application. 

Subsequently, on August 25, 2008, EPA 

completed an addendum to the Carbaryl 

RED incorporating the results of a 

revised occupational risk assessment 

and modified mitigation measures for 

the protection of workers. Elsewhere in 

this issue of the Federal Register EPA 

is announcing the availability of the 

amendments to the Carbaryl RED. 

B. FFDCA Tolerance Reassessment and 

FIFRA Pesticide Reregistration 

As required by the Food Quality 

Protection Act of 1996, EPA reassessed 

the safety of the carbaryl tolerances 

under the safety standard established in 

the FQPA. In the September 2007 RED 

for carbaryl, EPA evaluated the human 

health risks associated with all currently 

registered uses of carbaryl and 

determined that there is a reasonable 

certainty that no harm will result from 

aggregate non-occupational exposure to 

the pesticide chemical residue. In 

making this determination, EPA 

considered dietary exposure from food 

and drinking water and all other nonoccupational sources of pesticide 

exposure for which there is reliable 

information (Ref. 18). The Agency has 

concluded that with the adoption of the 

risk mitigation measures identified in 

the NMC cumulative risk assessment, all 

of the tolerances for carbaryl meet the 

safety standard as set forth in section 

408(b)(2)(D) of the FFDCA. Therefore, 

the tolerances established for residues of 

carbaryl in/on raw agricultural 

commodities were considered 

reassessed as safe under section 408(q) 

of FFDCA, as amended by FQPA, in 

September 2007. These findings 

satisfied EPA’s obligation to review the 

carbaryl tolerances under the FQPA 

safety standard. 

To implement the carbaryl tolerance 

reassessment, EPA commenced with 

rulemaking in 2008. The Agency 

published a Notice of proposed 

tolerance actions in the May 21, 2008 

Federal Register (73 FR 29456). This 

proposed rule provided for a 60 day 

public comment period. No comments 

relevant to carbaryl tolerances were 

received and EPA published a Notice of 

final tolerance actions in the September 

10, 2008 Federal Register (73 FR 

52607). This rule codifies the carbaryl 

tolerances in 40 CFR 180.169. 

V. The Petition to Revoke Tolerances 

NRDC filed a petition dated January 

10, 2005 (Petition), requesting, among 

other things, that EPA cancel all 

carbaryl registrations and revoke all 

carbaryl tolerances (Ref. 1). In response 

to EPA’s publication of the Petition 

pursuant to section 408(d) of the 

FFDCA, NRDC resubmitted its Petition 

and earlier comments in support of its 

Petition. (See Docket ID EPA–HQ–OPP– 

2005–0077–0066). 

It should be noted that NRDC’s 

January 10, 2005 submission is in the 

form of comments on and requests for 

changes to the Carbaryl Interim 

Reregistration Eligibility Decision 

published in the Federal Register on 

October 27, 2004, 70 FR 62663; (Ref. 

16). Nonetheless, in the introduction to 

the comments, NRDC included a 

statement that NRDC is also petitioning 

the Agency to revoke all carbaryl 

tolerances. Among other things, NRDC 

raises issues with the dietary assessment 

and in particular its drinking water 

assessment that supported the 2004 

IRED decision. NRDC also raises 

concerns about the data surrounding 

EPA’s selection of a children’s safety 

factor. NRDC’s petition also includes 

some generic disagreements with how 

EPA conducts its assessments. 

VI. Public Comment 

In response to that portion of NRDC’s 

petition seeking revocation of the 

carbaryl tolerances, EPA published 

notice of the Petition for comment on 

March 30, 2005 (70 FR 16281). EPA 

received approximately 5,230 comments 

in support of the Petition. The vast 

majority of these comments followed an 

identical or similar format expressing 

the commenters support for the Petition 

in general terms. These commenters 

uniformly protested the Agency’s 

decision to continue allowing the use of 

carbaryl ‘‘a chemical [EPA] consider[s] 

likely to cause cancer.’’ As a 

preliminary note, although the Agency 

considers carbaryl to have the potential 

to cause cancer, exposure to carbaryl 

residues is so low that the actual risk of 

cancer from carbaryl is negligible. EPA 

is generally not concerned about cancer 

risks at or below the range of 1 x 10-6, 

or 1 in a million. For carbaryl, the 

dietary cancer risk from residues in food 

and drinking water is estimated to be 3 

x 10-8, or 3 in 10 million. The estimated 

cancer risk from exposure to carbaryl in 

products used in a residential setting 

range from 1 x 10-8 to 10-13 (from 1 in 

10 million to 1 in 10 trillion). Because 

EPA considers carbaryl to be a nonthreshold carcinogen, the Agency uses 

the conservative, default linear low-dose 

linear method to quantify cancer risk. 

Even using this conservative approach 

to evaluate potential cancer risk from 

food, drinking water, and residential 

uses of carbaryl, EPA has not identified 

any cancer risks of concern. 

Of the subset of comments not based 

upon a form letter, most related to 

ecological issues and in particular 

toxicity to bees and apple thinning uses. 

These comments are not relevant to the 

requested revocation of pesticide 

tolerances. EPA is responding to the 

Petition insofar as it seeks the 

cancellation of all carbaryl registrations 

separately and, therefore, these 

comments are not directly relevant here. 

One commenter, Bayer, the sole 

technical product registrant, submitted 

comments that purport to address all of 

the issues raised by NRDC (Ref. 19). In 

any event, these comments as a whole 

did not add any new information 

pertaining to whether the tolerances 

were in compliance with the FFDCA. 

Comments on the specific claims by 

NRDC are summarized in Unit VII 

immediately following the summary of 

NRDC’s claim but prior to EPA’s 

response to the claim. 

VII. Ruling on Petition 

This Order addresses NRDC’s petition 

to revoke carbaryl tolerances. As noted 

above, this ‘‘Petition’’ was included as 

part of NRDC’s comments on the 

carbaryl IRED. Thus, the Petition 

contains a number of comments that are 

just that, comments, and that do not 

provide a basis upon which to either 

cancel all carbaryl registrations or 

revoke all carbaryl tolerances. Where 

those comments are directly related to 

suggestions that the carbaryl tolerances 

do not meet the safety standard in 

section 408 of the FFDCA, the Agency 

has tried to address those comments in 

this petition response. However, EPA 

has not attempted to respond to every 

comment or suggestion for improvement 

made in NRDC’s filing. 

EPA has, to the extent possible, 

construed NRDC’s comments as 

asserting various grounds as to why the 

carbaryl tolerances do not meet the 

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FQPA safety standard and should be 

revoked. EPA has divided NRDC’s 

grounds for revocation into four 

categories - toxicology; dietary 

exposure; residential exposure; and risk 

characterization - and addressed 

separately each claim under these 

categories. Each specific claim of NRDC 

is summarized in Unit VII immediately 

prior to EPA’s response to the claim. 

This Order also constitutes a response 

to a petition dated November 26, 2007, 

to cancel carbaryl pet collar registrations 

submitted as part of NRDC’s comments 

on the NMC cumulative assessment 

(NMC Petition) (Ref. 2). EPA’s response 

to NRDC’s petition to cancel pet collar 

registrations is addressed here because 

the basis for the petition to cancel pet 

collars rests on issues related to EPA’s 

assessment of cumulative effects under 

the FFDCA. 

EPA has not addressed claims that 

concern carbaryl uses that have been 

canceled, or application methods that 

have been discontinued since the time 

of the Petition. Nor is EPA addressing 

claims that concern carbaryl uses for 

which the registrant(s) has requested 

that the use be deleted or registration 

cancelled pursuant to section 6(f) of 

FIFRA. These include the liquid 

broadcast use of carbaryl on residential 

lawns and turf, cancelled in March 2005 

(Ref. 17), and several other uses and 

application methods which have been 

or are in the process of cancellation 

because the registrants are not 

supporting these uses and application 

methods with the necessary data (73 FR 

49184, August 20, 2008). The following 

carbaryl uses are in the process of being 

cancelled: wheat, millet, and fresh/ 

succulent beans and peas (crop 

subgroup 6B); use of carbaryl drench or 

dip treatments of seedlings or seed 

pieces, dust formulations in agricultural 

crops, granular applications to leafy 

vegetables (except Brassica), direct 

applications of carbaryl (except for flea 

collars) to domestic animals (including 

dogs, cats, and other pets), and all 

indoor applications. Carbaryl 

registrations are also being amended to 

discontinue the following application 

methods: drenching dipping, hand held 

fogger, mosquito adulticide ULV, power 

backpack sprayer, and tree injection. 

A. Dietary Exposure Issues 

1. Revised dietary exposure and risk 

assessment. NRDC’s petition challenges 

some aspects of EPA’s 2003 proposed 

dietary exposure and risk assessment of 

carbaryl (Ref. 1 at 16-20). EPA has since 

updated its dietary exposure and risk 

assessment. These revisions were 

incorporated in and provided the basis 

for the RED. The main changes in the 

revised assessment include: (1) Use of 

the half-life value for carbaryl from a 

study that measures how quickly 

carbaryl degrades in an aerobic aquatic 

environment; (2) inclusion of updated 

percent crop treated data for evaluation 

of dietary exposure from residues in 

food; (3) inclusion of a comprehensive 

review of recent surface water 

monitoring data, including an 

investigation into the high carbaryl 

detection in groundwater reported in 

the 2003 IRED; (4) incorporation of the 

most recent food residue data from 

USDA’s PDP; and (5) inclusion of 

drinking water exposure modeling and 

monitoring data for agricultural and 

nonagricultural uses of carbaryl. In 

addition, in a change from the 2003 

assessment, the revised risk assessment 

did not evaluate dietary risk for long 

term (> 6 months) and chronic exposure 

to carbaryl due to the rapid reversibility 

of cholinesterase inhibition, the 

toxicological endpoint of concern. 

Specifically, recent data for carbaryl and 

the other NMCs show that 

cholinesterase inhibition is reversible, 

with recovery in less than 24 hours. 

Because the acute exposure from 

carbaryl is the main duration of 

concern, EPA determined that a chronic 

assessment is not appropriate for 

carbaryl. 

These revisions effectively address 

NRDC’s concerns and EPA is not 

reopening the issues here. Nonetheless, 

EPA is providing more specific 

information concerning the revised risk 

assessment in the context of the specific 

issues raised by NRDC. 

2. Drinking water assessment—a. 

NRDC’s claims. NRDC criticizes the 

Agency’s drinking water assessment 

because it only considered agricultural 

sources. NRDC urged EPA to include all 

available information in its surface 

water assessment, including nonagricultural sources (Ref. 1 at 16). NRDC 

further notes that the drinking water 

levels of comparison (DWLOCs) 

‘‘exceeds acceptable levels.’’ (Ref. 1 at 

16). NRDC disagrees with EPA’s 

conclusion that the DWLOC was 

nonetheless acceptable because the 

modeling is overly conservative and that 

actual concentrations of carbaryl in 

drinking water are likely to be ‘‘much 

lower.’’ NRDC faults the Agency for not 

defining the magnitude of ‘‘much 

lower’’ and not providing any support 

for this contention. In particular, NRDC 

argues that the modeling estimates are 

actually in agreement with some of the 

monitoring data, and therefore EPA 

should accept the modeling estimates as 

an accurate indicator of exposure. 

Specifically, NRDC argues that peak 

modeling estimates from Florida citrus 

use (646 ppb) match monitoring data 

from a well in New York (610 ppb), and 

therefore EPA should accept the 

modeling estimates as an accurate 

indicator of exposure. NRDC further 

argues that the Agency’s rationale for 

concluding that the models overestimate 

actual concentrations in surface water is 

faulty. 

b. Public comments. In its comments, 

Bayer took issue with NRDC’s 

characterization that the monitoring 

data are in agreement with the model 

calculations, based upon a detection of 

610 ppb in a well in New York and a 

maximum concentration value of 6.5 

ppb in the USGS NAWQA data. Bayer 

argues that comparing an isolated 

ground water finding with predicted 

concentrations in surface water is 

scientifically inappropriate because of 

the different transport processes in 

ground water as compared to surface 

water. Bayer characterizes the ground 

water detection in NY as anomalous and 

notes that it has not been investigated or 

confirmed, and argues that it is not 

likely to be the result of normal 

movement though the soil. 

Further, Bayer submitted a voluntary 

drinking water monitoring study for 

carbaryl, Surface Water Monitoring for 

Residue of Carbaryl in High Use Areas 

in the United States: Final Report (MRID 

45788101). Bayer defends its drinking 

water study, stating that it was targeted 

to community water systems having 

watersheds with high carbaryl use and 

that showed lower concentrations than 

the NAWQA data. Bayer further argues 

that NRDC’s assertion that monitoring 

can be spotty and is not designed to 

coincide with high use sites, seasonal 

application times, watershed 

characteristics, and urban and 

agricultural methods is misplaced. 

Bayer asserts that the monitoring 

program was targeted and did focus on 

high use sites, with a sampling program 

tailored to the application times, and 

covered both agricultural and nonagricultural uses. 

Bayer also argues that the modeling is 

a worst case scenario and gives several 

reasons why EPA’s model can 

overestimate movement of surface 

water, including assumptions regarding 

use intensity (100% of field treated at 

maximum rates for the maximum 

number of times). Bayer then asserts 

that the worst-case predictions are not 

confirmed by monitoring data 

‘‘specifically designed to capture high 

use areas and application times.’’ (Ref. 

19 at 5). 

Another commenter from the 

Department of Entomology, Virginia 

Tech, notes that while NRDC complains 

that EPA makes assumptions in its risk 

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2Large watershed having an 8 digit hydrologic 

unit code (HUC-8). 

models, NRDC makes questionable 

assumptions of its own; namely, that 

EPA’s model is more reliable than actual 

monitoring data. Similarly, NRDC 

emphasizes that most acreage is treated, 

implying that most acres received the 

full allowable rate. However, although 

carbaryl is allowed to be applied to 

apples during the growing season, apple 

growers use carbaryl mainly as a 

chemical thinner, which occurs early in 

the season and is much less likely to 

cause harvest residues. Other 

commenters (apple growers) submitted 

similar comments regarding the actual 

use and that the use of carbaryl for 

thinning is not likely to result in 

residues at harvest time as well as the 

importance of carbaryl for chemical 

thinning. 

Another commenter from the 

University of Florida asserts that the 

acute drinking water concern is driven 

by Florida modeling, based upon a 38% 

crop treated assumption. According to 

the commenter, actual use in Florida is 

‘‘probably closer’’ to one tenth of that 

amount. Again, according to the 

commenter, the National Agricultural 

Statistics Service (NASS) 2003 fruit data 

report percent crop treated amounts of 

3% for Florida and 5% for grapefruit 

nationally. The commenter takes issue 

with NRDC’s claim that the greater than 

600 ppb spike in New York ‘‘conforms’’ 

to the results from the modeling. In so 

doing, the commenter asserts that 

carbaryl in New York degrades much 

slower than in Florida. The commenter 

then implies that it is significant that 

there are no Florida monitoring values 

that were in the hundred parts per 

billion concentration range. 

c. EPA’s response. EPA has addressed 

NRDC’s concerns in the revised 

drinking water assessments supporting 

the carbaryl RED, which includes all 

available information including surface 

water monitoring data, new 

environmental fate data, and other new 

information and methodologies. EPA 

incorporated new half-life data from an 

aerobic aquatic metabolism study, 

regional percent cropped area factors, 

and the mitigation required in the 

carbaryl IRED into modeled estimates of 

carbaryl levels in surface water. In 

addition, the Agency used the PRZMEXAMS model to generate a distribution 

of approximately 11,000 values, 

representing daily peak values over 30 

years. This data set was used to create 

water residue data files for use in 

DEEM-FCIDTM. The range of annual 

peak water values was 13 to 108 parts 

per billion (ppb) over 30 years (Ref. 20 

for further details of EPA’s refined 

drinking water modeling). EPA 

incorporated this distribution of 

drinking water values directly into the 

exposure component of the dietary 

assessment, using the DEEM-FCIDTM

model. EPA also incorporated drinking 

water consumption data and reported 

body weights from the CSFII into the 

exposure assessment. 

As mentioned above, the carbaryl 

drinking water assessment is no longer 

based upon the DWLOC approach. EPA 

officially withdrew the science policy 

paper describing the DWLOC approach 

on August 1, 2007 (72 FR 42082). In 

addition, EPA believes that the new 

approach is more protective of sensitive 

population subgroups, including infants 

and children, than the DWLOC 

approach used in the carbaryl IRED. 

Although EPA did not model 

nonagricultural use of carbaryl, the 

Agency considered these uses in the 

process of evaluating all available water 

monitoring data for carbaryl for the 2007 

carbaryl RED. EPA reviewed the most 

recent surface water monitoring data for 

carbaryl in urban and suburban areas for 

both the carbaryl IRED and the RED. 

Specifically, EPA considered data from 

NAWQA, the joint USGS-EPA Mini 

Pilot Monitoring Program, Washington 

and California state monitoring data, 

and a registrant voluntary water 

monitoring study measuring carbaryl in 

targeted community water systems 

associated with watersheds having high 

carbaryl use. The Agency also 

considered California monitoring data 

targeted to urban use of pesticides (Ref. 

21). 

EPA has also obtained additional 

information on the groundwater 

monitoring value of 610 micrograms/ 

liter (μg/L) from Suffolk County New 

York reported in the carbaryl IRED. 

Because this value was significantly 

higher than any other monitoring values 

from ground or surface water, EPA 

contacted the Suffolk County 

government for more information about 

this particular groundwater sample. The 

sample associated with that 

concentration (the actual concentration 

was 61,000 μg/L, not 610 μg/L) was 

taken from a sump at a pesticide mixer/ 

loader site as part of a pesticide spill 

investigation, not from a groundwater 

monitoring well. Therefore, this value 

should not have been reported in the 

Suffolk County water quality database 

(Suffolk County Department of Health 

2007, personal communication); EPA 

has removed it from the carbaryl 

drinking water assessment. There were 

a small number of detections of carbaryl 

reported to OPP as a result of a quality 

control check of the Suffolk County 

database, ranging from 0.1 to 13 μg/L. 

These values are more in line with other 

monitoring data for carbaryl reported in 

the EPA assessment. 

Finally, both the commenter from the 

University of Florida and NRDC are 

mistaken in their statements that that 

EPA’s drinking water assessment relied 

on default percent crop treated 

assumptions. In particular, NRDC 

appears to have confused percent crop 

treated (PCT) data for the percentage of 

a food commodity treated with carbaryl 

with EPA’s use of percent crop area 

(PCA) in the carbaryl drinking water 

assessment. The default PCA (87%) 

represents the largest fraction of a 

watershed that can be planted to any 

crop. This default PCA, which is based 

on Geographic Information Systems 

(GIS) analysis of fairly large 

watersheds2, is used in drinking water 

assessments to account for the fact that 

not all land in a watershed is 

agricultural land (planted with crops). 

Regional PCAs reflect the greatest 

fraction of a watershed used in 

agriculture in each of the major drainage 

basins in the United States. In either 

case, the drinking water assessment 

assumes that carbaryl is applied to 

100% of the agricultural land in the 

watershed, regardless of the fraction of 

the watershed that is used in 

agriculture. 

In sum, the revised dietary risk 

assessment for food shows that acute 

dietary exposure and risk are below the 

Agency’s level of concern for the general 

U.S. population and all population 

subgroups. The revised drinking water 

assessment also does not rely on the old 

methodology, using DWLOCs. The 

drinking water assessment was not 

limited to agriculture uses; EPA 

included the most recent available 

monitoring data for carbaryl in urban 

and suburban areas in the revised 

assessment. Last, estimated pesticide 

residues in drinking water were 

incorporated directly into the exposure 

component of the dietary assessment. 

3. CARES dietary exposure model—a. 

NRDC’s claims. NRDC asserts that EPA 

improperly relied upon Cumulative and 

Aggregate Risk Evaluation System 

(CARES), a ‘‘confidential’’ industry 

model to assess human health risks. 

While NRDC acknowledges that EPA 

may rely on a proprietary model, it 

insists that EPA has not provided 

sufficient detail about the model’s 

‘‘built-in assumptions and calculation 

methodologies.’’ (Ref. 1 at 19). 

b. Public comments. Bayer asserts that 

during its development by industry, 

with input from EPA and USDA, CARES 

was ‘‘freely’’ available from CropLife 

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America by request. Bayer also notes 

that the model was reviewed at two 

FIFRA SAP meetings in 2002 and 2004 

(US EPA, SAP April 30 to May 1, 2002. 

CARES Model Review http:// 

www.epa.gov/scipoly/sap; USEPA, SAP 

April 29 to 30, 2004. A Model 

Comparison: Dietary and Aggregate 

Exposure in Calendex, CARES and 

Lifeline. http://www.epa.gov/scipoly/ 

sap). On completion of the model, it 

was donated to The International Life 

Sciences Institute (ILSI). CARES is now 

freely available from the ILSI web site 

(http://www.ilsi.org). 

c. EPA’s Response. In the 2003 IRED, 

EPA used the DEEM- FCIDTM model to 

estimate dietary risks from carbaryl. The 

carbaryl registrant submitted an 

assessment derived from CARES, which 

EPA reviewed and compared with the 

Agency’s results. However, the Agency 

did not rely upon the CARES model in 

the Carbaryl IRED. EPA relied upon the 

DEEM-FCIDTM model for both the 2003 

human health risk assessment 

supporting the IRED and the revised 

2007 dietary assessment supporting the 

carbaryl RED. Thus, any concerns 

regarding the public availability of the 

CARES model are irrelevant to EPA’s 

risk assessment for the 2003 IRED. 

Nonetheless, it is worth noting that 

the CARES model has been transferred 

to the ILSI Research Foundation and the 

CARES program and source code is 

publicly available at no charge. In 

addition, in 2002, the FIFRA SAP 

reviewed the underlying science, 

computational approaches and ease of 

use of the CARES model. The FIFRA 

SAP’s June 13, 2002 report (Ref. 22) 

provides results of the panel’s 

deliberations. The FIFRA SAP provided 

a series of recommendations designed to 

improve the technical basis of the model 

and software system. In any case, 

CARES meets OPP’s criteria for use in 

regulatory decision making with respect 

to public availability, transparency, and 

compliance with Agency policy 

guidelines and NRDC’s objection in this 

regard are without merit. 

4. Farmers’ markets and roadside 

produce stands—a. NRDC’s claims. 

NRDC asserts that EPA did not 

explicitly consider food purchased at 

farmer’s markets, farm stands, ‘‘U-PIK’’ 

farms, or eaten from household gardens 

(Ref. 1 at 19-20). NRDC suggests that, in 

the absence of data to support EPA’s 

belief that its exposure assessment 

adequately accounts for food purchased 

at such locals, EPA include an 

uncertainty factor to account for 

children who consume this source of 

food (Ref. 1 at 20). 

b. Public comments. Bayer noted that 

EPA adequately responded to this issue 

in its October 26, 2004 Response to 

Comments on Phase 5 Risk Assessment 

(Docket ID No. EPA–HQ–OPP–2003– 

0376–00008). 

c. EPA’s response. In an Order 

responding to NRDC objections to 

tolerances for different pesticides, EPA 

has addressed NRDC’s claims regarding 

pesticide exposure to persons who 

purchase food at roadside stands or 

farmers’ markets. (70 FR 733; 72 FR 662, 

December 5, 2007). This is equally 

applicable to ‘‘U-PIK’’ farms and 

household gardens. As EPA explained 

there, whether EPA relies on data from 

crop field trials or monitoring data in 

estimating pesticide exposure, given the 

sampling methods in field trials and 

food monitoring residue levels 

identified from these sources are 

unlikely to understate residue levels at 

farm stands. Moreover, EPA does not 

believe it is reasonable to assume that 

farm stands sell food containing a 

significantly different residue profile 

than found in PDP monitoring data. 

Therefore, this factor introduces little to 

no uncertainty concerning the 

possibility of underestimation of 

residues into EPA’s analysis. In any 

case, EPA hereby incorporates its prior 

response to these issues EPA relies on 

its prior response to this issue and finds 

NRDC’s contentions without merit. 

5. Tolerances for cancelled uses—a. 

NRDC’s claims. NRDC is concerned that 

EPA proposed to increase tolerances for 

20 commodities and establish new 

tolerances for 7 commodities (Ref. 1 at 

14-15). Specifically, NRDC urges EPA 

not to make any tolerance reassessment 

determination prior to completion of the 

carbamate cumulative risk assessment. 

NRDC also insists that EPA revoke 

tolerances for all uses of carbaryl that 

have been voluntarily cancelled. NRDC 

is particularly concerned about 

imported food and products entering the 

United States with carbaryl residues 

without triggering action by the FDA. 

NRDC is also concerned about the effect 

that the failure to ‘‘ban’’ products will 

have on the international community 

and in particular developing countries. 

Specifically, NRDC asserts that 

manufacturers voluntarily cancel the 

registration of high risk products to 

avoid Prior Informed Consent (PIC) 

listings. 

b. Public comments. Bayer asserts in 

its comments that in the carbaryl IRED 

EPA addressed NRDC’s concern 

regarding the reassessment of tolerances 

prior to the completion of the NMC 

cumulative risk assessment. Bayer 

notes, however, that the IRED 

specifically provides that the 

establishment of new tolerances or 

raising tolerances will be deferred 

pending consideration of cumulative 

risk for the NMCs. The IRED further 

provides that, for purposes of that 

document, the term ‘‘reassessed’’ does 

not imply that all of the tolerances for 

carbaryl have been reassessed as 

required by FQPA, since these 

tolerances may only be reassessed once 

the cumulative risk assessment of all 

carbamate pesticides is considered. 

Rather, the IRED provided reassessed 

tolerances for carbaryl in/on various 

commodities, supported by all of the 

submitted residue data, only for the 

single carbamate chemical carbaryl (Ref. 

16 at 67). 

Bayer further expressed its belief that 

EPA’s practice of revoking tolerances 

after a sufficient period of time that 

allows existing stocks bearing the use 

being cancelled to clear the channels of 

trade is in compliance with the 

requirements of the FQPA. Finally, 

Bayer argues that NRDC’s concern about 

potential risk from new or increased 

tolerances being established for carbaryl 

are not justified because the tolerance 

reassessment process is not associated 

with labeling changes that increase the 

maximum application rates or frequency 

of application allowed by current labels. 

Bayer further notes that many of the 

labeling amendments required by the 

IRED serve to reduce potential human 

health and environmental risks. Bayer 

also notes that the pursuant to the IRED 

most tolerances will be either reduced, 

revoked, or left unchanged. 

c. EPA’s response. Notwithstanding 

NRDC’s insistence that EPA revoke 

tolerances for uses that have been 

voluntarily canceled, NRDC has not 

provided any basis for determining that 

tolerances for uses that have been 

voluntarily cancelled do not meet the 

FFDCA standard such that the tolerance 

must be revoked. Be that as it may, EPA 

has now completed and released the 

cumulative risk assessment for the 

NMCs and, therefore, all carbaryl 

tolerances are considered reassessed at 

this time. With respect to tolerances 

associated with uses that have been 

cancelled and/or deleted pursuant to 

section 6(f)(1) of FIFRA, EPA has 

revoked the associated tolerances, 

except for the wheat tolerance, which is 

still needed to cover imported wheat 

and any domestic wheat that may 

receive inadvertent residues of carbaryl 

resulting from carbaryl use to control 

grasshoppers and/or Mormon crickets 

on pasture and rangeland. The Agency 

included carbaryl residues on wheat in 

the cumulative risk assessment for the 

NMCs. 

The Agency has completed 

rulemaking proceedings to revoke and 

modify the existing carbaryl tolerances, 

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and correct commodity definitions. EPA 

published a proposed tolerance rule for 

carbaryl on May 21, 2008 (73 FR 29456) 

and a final tolerance rule on September 

10, 2008 (73 FR 52607). The final 

carbaryl tolerance rule revokes 

tolerances associated with uses that 

have been cancelled and/or deleted to 

date pursuant to section 6(f)(1) of 

FIFRA, allowing sufficient time for 

existing stock to clear channels of trade, 

with the exception of the tolerance for 

wheat. As a result of the final tolerance 

rule, many existing carbaryl tolerances 

have been reassigned to crop groups, 

and old commodity specific tolerances 

have been revoked as new tolerances 

have been established for residues in/on 

various crop groups and subgroups. 

New tolerances were also established for 

carbaryl residues in/on the following 

raw agricultural commodities: aspirated 

grain fractions, proso millet hay, 

sorghum stover, and sugar beet roots. At 

the present time, sufficient data are 

available to determine an appropriate 

tolerance for residues in/on aspirated 

grain fractions (70 ppm), sugar beet 

roots (0.5 ppm), and sorghum stover 

(30.0 ppm). Separate tolerances have 

been established for residues in the 

following processed food/feed items: 

wet apple pomace (15.0 ppm), citrus 

fruit oil (20.0 ppm), raisins (12.0 ppm), 

and rice hulls (30.0 ppm). 

Finally, to the extent that NRDC 

argues that tolerances must be revoked 

simply because an active ingredient or 

use is not registered in the United 

States, EPA disagrees. Nothing in the 

FFDCA requires that tolerances be 

limited to pesticides that have a U.S. 

registration. In fact, FIFRA explicitly 

recognizes that EPA may set import 

tolerances under the FFDCA. See 

Section 33 of FIFRA (establishing fees 

and decision review times for import 

tolerance applications). While EPA 

often proposes to revoke tolerances after 

the cancellation of associated uses 

because EPA believes the tolerances 

may no longer be necessary, EPA has 

always recognized that a revocation can 

not proceed on such grounds if foreign 

growers wish to rely on the tolerance. In 

such circumstances, a tolerance can 

only be revoked if necessary data to 

support the tolerance are not provided 

or if EPA determines that the tolerance 

does not meet the safety standard. 

B. Risk Characterization 

1. New data. In keeping with science 

policy developments for the NMCs, EPA 

used data from a comparative 

cholinesterase study comparing 

carbaryl-induced cholinesterase 

inhibition in adult and juvenile rats to 

calculate a revised FQPA Safety Factor 

for carbaryl and to derive the toxicology 

points of departure for risk assessment. 

Specifically, this study was conducted 

to determine whether young animals are 

more susceptible to the effects of 

carbaryl than adults. This oral study 

showed that juvenile 11–day-old 

(PND11) pups were more sensitive to 

inhibition of brain cholinesterase from 

carbaryl than adult rats. 

EPA conducted a benchmark dose 

analysis for the carbaryl comparative 

cholinesterase study, using the same 

modeling methodology used in the NMC 

cumulative risk assessment. A 

benchmark dose analysis models the 

dose-response relationship with a doseresponse curve, which allows selection 

of doses corresponding to a specified 

level of response, called a benchmark 

response. This analysis allows EPA to 

determine a more appropriate point of 

departure from a toxicology study rather 

than using the study NOAEL or LOAEL. 

(See Refs. 12, 23, and 24 for more 

information on benchmark dose 

modeling). 

The Agency estimated the 10% 

benchmark dose response (BMD10) and 

the BMDL10, or lower 95% confidence 

limit of the benchmark dose, for this 

study. The Agency also conducted a full 

benchmark dose analysis of all rat oral 

toxicity studies for adults; this analysis 

showed that the BMDL10 for pups is 

also protective for adults. Because the 

brain is the target tissue for carbaryl, 

and the brain BMDL10 of 1.1 milligrams/ 

kilogram (mg/kg) is also protective of 

cholinesterase inhibition in blood, then 

the brain BMDL10 is the appropriate 

point of departure for both children and 

adults in the revised carbaryl risk 

assessment. (See Ref. 23 and Ref. 24 for 

additional details regarding the 

comparative cholinesterase study). 

2. Revised FQPA safety factor. To 

complete the carbaryl IRED in 2003, 

EPA evaluated the potential for special 

sensitivity of infants and children to 

carbaryl and the need for an additional 

FQPA Safety Factor. After evaluating 

the entire toxicity database available for 

carbaryl at that time, the FQPA Safety 

Factor, to account for special 

susceptibility of infants and children, 

was reduced from 10X to 1X for all 

scenarios, except for the chronic dietary 

endpoint where a 3X FQPA SF was used 

to account for the lack of a NOAEL. This 

decision and rationale is described in 

detail in the technical support 

documents for the carbaryl IRED. 

As previously mentioned in Unit 

III.C.1. of this document, EPA has 

revised the FQPA Safety Factor for 

carbaryl using the most recent data on 

carbaryl age sensitivity. The new 

comparative cholinesterase study data 

was used to derive a new FQPA Safety 

Factor by comparing the BMD10 for 

brain cholinesterase inhibition between 

adults and pups at postnatal day 11. 

Pups were 1.8x more sensitive to brain 

cholinesterase inhibition than the 

adults; therefore, a 1.8X FQPA Safety 

Factor was applied to both the NMC 

cumulative and the carbaryl-specific 

risk assessments. This safety factor of 

1.8X is applied to the dermal endpoint 

because there are no comparative 

cholinesterase data in offspring from 

dermal exposure, and because juvenile 

rats are 1.8X more sensitive than adults 

based on the oral comparative 

cholinesterase study in rats. The FQPA 

Safety Factor is 1X for oral and 

inhalation endpoints because these 

endpoints are selected from the 

comparative cholinesterase data for the 

most sensitive population (PND11 

pups). 

3. Issues raised by NRDC concerning 

the FQPA safety factor—a. NRDC’s 

claims. NRDC objects to EPA’s decision 

to reduce the FQPA Safety Factor to 1X 

in the IRED and repeats earlier 

arguments that a developmental 

neurotoxicity study (DNT) used by EPA 

in the 2004 IRED does not provide a 

basis for removing the FQPA Safety 

Factor because pups had effects at doses 

that did not produce effects in adults in 

the DNT study. (Ref. 1 at 17, 18) In 

addition, NRDC maintains that EPA 

should have applied an additional 3X 

uncertainty factor to account for the 

failure to identify a No Observable 

Adverse Effect Level (NOAEL) for brain 

morphometric changes in pups in the 

DNT study. Specifically, NRDC argues 

that the low and mid-dose samples were 

‘‘damaged and uninterpretable’’ and 

thus this test did not produce a ‘‘no 

observed adverse effect level.’’ (Ref. 1 at 

17-19). 

b. Public comments. Bayer noted that 

EPA adequately responded to this issue 

in its October 26, 2004 Response to 

Comments on Phase 5 Risk Assessment 

(Docket ID No. 2003–0376–00008). 

c. EPA’s response. Since the 2004 

IRED, EPA has incorporated new data 

into its assessment of carbaryl. In the 

process of completing the carbaryl RED 

and the cumulative risk assessment for 

the NMCs, EPA re-evaluated the 

toxicology database for carbaryl, which 

includes studies submitted since the 

completion of the IRED. EPA received 

pharmacokinetic data on the rapid 

reversibility of carbaryl effects (Ref. 25), 

a comparative cholinesterase study to 

inform age-related sensitivity to carbaryl 

(Ref. 23), and a dermal penetration 

study for carbaryl (Ref. 26). As a result, 

the Agency revised the FQPA Safety 

Factor in 2007 and selected new points 

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of departure using the new comparative 

cholinesterase data and benchmark dose 

modeling. 

The comparative cholinesterase study 

was conducted specifically to provide 

age-related sensitivity data for carbaryl 

to be used in the NMC cumulative risk 

assessment. Experience with other 

NMCs has shown that comparative 

cholinesterase studies provide a more 

accurate indication of comparative adult 

and offspring sensitivity than the 

behavioral and histopathological 

changes evaluated in the DNT study. 

The carbaryl comparative cholinesterase 

study involved oral dosing of three age 

groups of rats, adults (97 days old) and 

juveniles 11 or 17 days old (postnatal 

day, PND, 11 or 17), followed by 

measurement of both brain and blood 

cholinesterase. Based on a benchmark 

dose analysis of the results of this study, 

EPA identified a clear point of departure 

(the equivalent of a NOAEL) for brain 

cholinesterase effects in the young and 

thus the sensitivity in the young is wellcharacterized. In these circumstances, 

EPA finds that it has reliable data on 

pre- and post-natal toxicity to remove 

(oral and inhalation) or reduce (dermal) 

the 10X FQPA Safety Factor. 

Based on the results of the benchmark 

dose analysis from the comparative 

cholinesterase study, which provide the 

most sensitive data available to date on 

age related sensitivity to carbaryl, 

juvenile animals are 1.8X more sensitive 

to carbaryl induced cholinesterase 

inhibition than adults. EPA has thus 

derived an FQPA Safety Factor of 1.8X. 

This safety factor of 1.8X is applied to 

the dermal endpoint because there are 

no comparative cholinesterase data in 

offspring from dermal exposure, and 

because juvenile rats are 1.8X more 

sensitive than adults based on the oral 

comparative cholinesterase study in 

rats. The FQPA Safety Factor is 1X for 

oral and inhalation endpoints because 

these endpoints are selected from the 

comparative cholinesterase data for the 

most sensitive population (PND11 

pups). 

Moreover, NRDC’s concern that EPA 

failed to apply an additional 3X 

uncertainty factor to account for the 

failure to detect a NOAEL in the DNT 

study is no longer relevant. Specifically, 

brain cholinesterase inhibition in the 

PND 11 animals in the comparative 

cholinesterase study was the most 

sensitive endpoint in this study; 

therefore, this endpoint of 1.1 mg/kg/ 

day was used as the point of departure 

for the 2007 carbaryl risk assessment. 

This new endpoint occurs at a lower 

dose than NRDC’s suggested 

extrapolated NOAEL (i.e., including a 

3X uncertainty factor) of 3.3 mg/kg/day 

for brain morphometry from the DNT 

study. Because EPA’s assessment is now 

based upon a lower endpoint, NRDC’s 

contention that EPA failed to apply an 

additional 3X uncertainty factor to the 

point of departure derived from the 

DNT study is no longer relevant. 

C. Residential Exposure 

1. Aggregating exposures. The safety 

standard in FFDCA section 408 for 

tolerances requires that there be a 

reasonable certainty of no harm from 

‘‘aggregate exposure to the pesticide 

chemical residue, including all dietary 

exposures and all other exposure for 

which there is reliable information.’’ (21 

U.S.C. 346a(b)(2)(A)(ii)). Further, in 

evaluating the safety of tolerances EPA 

is directed to ‘‘consider . . . available 

information concerning the aggregate 

exposures of consumers . . . to the 

pesticide chemical residue . . . including 

dietary exposure under [all] tolerance[s] 

. . . in effect for the pesticide chemical 

residue and exposure from other nonoccupational sources.’’ (21 U.S.C. 

346a(b)(2)(D)(vi)). 

Unit VII.B. discusses EPA’s 

assessment of aggregate dietary 

exposure to carbaryl from residues in 

foods and water. That assessment 

showed that the dietary exposure and 

risk are below the Agency’s level of 

concern for the general U.S. population 

and all population subgroups; exposure 

to carbaryl residues in food comprises 

<100% of the aPAD at the 99.9th 

percentile of exposure. Estimated 

dietary exposure for the general U.S. 

population is 29% of the aPAD; 

exposure to children age 1 to 2 years, 

the most highly exposed population 

subgroup, comprises 60% of the aPAD. 

Although refined, these exposure 

estimates still are likely to overstate 

exposure and risk. 

Pesticide residues to which humans 

are exposed from residential uses of 

pesticides must be considered as part of 

section 408’s aggregate exposure 

calculus. The concern, of course, is that 

pesticide tolerances should not be 

established or left in effect if dietary 

exposures when combined with other 

sources of exposure exceed safe levels. 

2. Residential exposure and risk 

assessment. Since the 2004 Amended 

IRED, the Agency has revised the 

residential risk assessment for carbaryl 

to incorporate the revised toxicology 

endpoints and FQPA Safety Factor, the 

mitigation specified in the IRED (as well 

as the mitigation specified in the RED 

for residential use of granular 

formulations; namely, that granular 

formulations must be watered in 

immediately), and confirmatory data 

received as a result of the generic DCI 

for carbaryl. EPA received turf 

transferable residue (TTR) data for 

granular formulations of carbaryl, as 

well as additional data to support the 

use of carbaryl in pet collars. The 

granular TTR data were incorporated 

into the revised risk assessment; 

however, the pet collar data were 

considered but not incorporated because 

of data quality issues. In addition, the 

Agency incorporated data from several 

studies for pesticides applied to turf to 

estimate the percent of carbaryl 

transferred from turf to a person’s hand. 

(See Ref. 27 for details of the revised 

carbaryl residential risk assessment). 

3. Pet collars—a. NRDC’s claims. In 

its Petition, NRDC expressed concern 

that EPA’s assessment of pet collars 

significantly underestimates exposure. 

(Ref. 1 at 4). NRDC therefore requested 

that EPA provide information on the 

assumptions used to calculate flea collar 

exposures. In particular, NRDC is 

concerned that EPA’s calculations do 

not take into account the possibility that 

pet sleep with children, share intimate 

spaces or share hugs/kisses with 

children. NRDC also contends that there 

are safer ‘‘non-pesticide’’ alternatives 

available. 

In addition, in a November 2007 

petition to cancel all carbaryl pet collar 

registrations, NRDC asserts that changes 

in this algorithm made from the 

preliminary NMC cumulative 

assessment result in a repeated and 

additive bias towards reducing the 

exposure estimate so that it ‘‘appears’’ 

that the pet collar uses do not exceed 

the Agency’s level of concern. (Ref. 2 at 

5-7). Specifically, NRDC takes issue 

with the following modifications made 

in the probabilistic assessment for 

carbaryl as part of the NMC cumulative 

risk assessment: 

• Assuming a child mouths only one 

hand at a time, thereby dividing the 

hand-loading residues by 2X. 

• Assuming the hand is fully 

replenished with residues from a 

contaminated surface on an hourly basis 

rather than assuming (as done 

previously with flea collar assessments) 

full replenishment between each 

mouthing event, which NRDC contends 

is a more likely scenario for children 

actively engaged with their pets. 

• Assuming that the maximum time 

spent with a pet is 1.03 hrs./day. NRDC 

contends that EPA’s assumption in 

previous assessments of 2 hrs./day is a 

much more likely scenario for preschoolers who are home all day with 

their pets and for school age children 

lying with their pets watching TV. 

• Assuming that only 1% of the 

surface area of a single hand is 

mouthed, which is approximately 1/75 

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3NRDC asserts that a MOE of 1 million relates to 

residential postapplication exposures associated 

with pet collars. This is incorrect. The MOE 

referred to relates to residential handler (applicator) 

exposure as assessed in the 2003 carbaryl IRED. 

cm2 surface area. NRDC contends that 

EPA’s assumption in previous 

assessments of 20 cm2 is a more 

reasonable and realistic estimate of the 

surface area likely to contact a child’s 

mouth repeatedly. 

• Assuming that only 20 to 50% of 

the pesticide is removed per mouthing 

event (saliva extraction factor). NRDC 

contends that EPA’s assumption in 

previous assessments that all of the 

pesticide is removed is more reasonable 

and realistic. 

NRDC also criticizes the Agency for not 

including inhalation as an exposure 

route for residential post-application of 

flea collars. NRDC also points out that 

inhalation was the only route of 

exposure that EPA estimated in an 

earlier RED decision on another 

pesticide used in flea collars. 

NRDC argues that all of these 

modifications in the Agency’s algorithm 

for calculating non-dietary hand-tomouth exposures for children bias 

towards reducing the exposure estimate. 

NRDC also criticizes the Agency for 

stating that the modifications result 

from the recommendations from the 

August 2005 FIFRA SAP. To the 

contrary, NRDC contends that these 

modifications were never reviewed or 

recommended by the FIFRA SAP. NRDC 

therefore asserts that EPA cannot use 

this new method presented in the NMC 

cumulative assessment to ‘‘reduce 

protections for children from pet uses of 

[carbamate] pesticides’’. (Ref. 2 at 7). 

b. Public comments. Bayer contends 

that NRDC is misinformed regarding 

‘‘non-pesticide’’ alternatives. In 

particular, Bayer takes issue with 

NRDC’s statement that ‘‘[p]et products 

containing non-pesticide growth 

regulators also can stop fleas from 

reproducing successfully’’. (Ref. 19 at 7, 

citing Ref. 1 at 4). Bayer points out that 

by definition any product that controls 

pest growth is a pesticide and that 

making pesticidal claims without 

registration is a violation of federal law. 

Bayer further asserts that unspecified 

‘‘non-pesticide’’ alternatives have not 

been rigorously tested for efficacy or 

safety. Thus, Bayer asserts that NRDC 

offers no real alternative to the use of 

carbaryl-containing flea collars. 

c. EPA’s response. NRDC is concerned 

that while EPA has determined that pet 

collar uses are safe (with MOEs of 

greater than 1 million), EPA’s 

calculations significantly underestimate 

exposure3. NRDC therefore requested 

that EPA provide information on the 

assumptions used to calculate flea collar 

exposures. In particular, NRDC is 

concerned that EPA’s calculations do 

not take into account the possibility that 

pets sleep with children, share intimate 

spaces or share hugs/kisses with 

children. 

As a preliminary matter, it is 

important to note that EPA assessed pet 

collars both in the individual chemical 

assessment and as part of the NMC 

cumulative risk assessment. The single 

chemical assessment done for carbaryl 

was a deterministic assessment. For the 

NMC cumulative risk assessment, EPA 

performed a probabilistic assessment. 

With respect to the single chemical, 

deterministic assessment, the 

assumptions used are based upon 

Agency standard values for estimating 

exposure to pets as defined in the 1997 

Draft SOPs for Residential Exposure 

Assessments and amendments. (Refs. 6, 

7, and 8). Specifically, SOPs 9.2.1— 

Postapplication Dermal Dose from 

Pesticide Residues on Pets and 9.2.2 - 

Postapplication Potential Dose Among 

Toddlers from Incidental Nondietary 

Ingestion of Pesticide Residues on Pets 

from Hand-to-Mouth Transfer describe 

the algorithms that provided the basis 

for EPA’s assessment. In addition, to the 

extent that EPA had chemical specific 

data (e.g., transferable residue data) or 

made chemical specific adjustments to 

the algorithms, they are explained in the 

Revised Phase 5, Occupational and 

Residential Exposure Assessment and 

Recommendations for the Reregistration 

Eligibility Decision Document (RED), 

dated February 20, 2003. 

In sum, for the single chemical 

assessment, exposures to children after 

contact with treated pets were 

addressed using the latest EPA 

methodology, as described below: 

• Only toddlers are considered 

because their exposures are considered 

to be the most highly exposed 

population by the Agency; 

• An equilibrium approach based on 

a single child ‘‘hug’’ of the treated 

animal is used to assess dermal 

exposure (i.e., the skin loads after a 

single contact with the treated animal 

and additional contacts don’t 

proportionally add exposures) as 

described in the amendments to the 

residential SOPs (Ref. 6), the surface 

area of the dermal hug is based on a 

toddler’s skin surface area and typical 

clothing; 

• The Agency default for 

transferability of residues from fur is 

20%; however, a pet collar transferable 

residue study (MRID 45792201) was 

submitted and used in the assessment 

for comparative purposes with the 

Agency’s standard approach. The data 

from this study were used to develop an 

alternative transferability factor of 2.6% 

for dusts and liquid applications; 

• The active lifetime of a collar is 

expected to be 120 days based on label 

statements which were used by the 

Agency, a daily emission term from the 

collar of 0.000290 mg/cm/gram ai/day2

is also based on measured data from 

Mississippi State University for a pet 

collar. Additionally, data from a pet 

collar transferable residue study (MRID 

45792201) was submitted and used in 

the assessment for comparative 

purposes with the Agency’s standard 

approach the data from this study were 

used to complete risk calculations using 

direct measurements of transferable 

residue concentration on dogs; 

• Risks are based on an even loading 

of residues across the entire surface of 

a 30 lb dog which has been chosen as 

a representative animal. The animal 

surface area was calculated using (12.3 

* Body Weight (g) 0.65) from the 

Agency’s 1993 Wildlife Exposure 

Factors Handbook (i.e., dog surface area 

of 5986 cm2); 

• The approach used to address the 

hand-to-mouth exposure pathway has 

been modified since the previous risk 

assessment. In the previous assessment, 

contact with dogs was based on 40 

events per day, in each event, the 

palmar surface of the hands (i.e., 20 

cm2/event) is placed in the mouth of the 

child contributing to nondietary 

ingestion exposure. In the revised 

approach, the frequency term has been 

modified to an equilibrium approach 

analogous to the dermal exposure 

component (i.e., the frequency = 1) 

because the transferable residue 

concentrations are from measured 

concentrations on the hands following 

heavy rubbing/petting of a dog for 5 

minutes. This would result in 

significantly higher concentrations on 

the hands than would be expected from 

a single contact. 

With respect to the single chemical 

assessment, NRDC asserts that the 

Agency failed to properly take into 

account children hugging and sleeping 

with pets. To the contrary, EPA’s 

assessment is in fact based upon toddler 

exposure through hugging and petting. 

Indeed, for maximum exposure, EPA’s 

assessment is based upon assumptions 

of hugging and petting followed by 

mouthing activity. Thus, NRDC’s 

concerns about EPA’s assessment not 

taking hugging into account are 

misplaced. 

The estimation of risk from dermal 

and oral exposures related to pet collars 

is best described by means of combining 

both routes of exposure. The Agency 

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combines risks resulting from total 

exposures to individual chemicals when 

it is likely that they can occur 

simultaneously based on the use pattern 

and the behavior associated with the 

exposure population. For carbaryl, the 

Agency combined risk values (i.e., 

MOEs) for different kinds of exposures 

associated with the pet collar scenario 

(dermal and hand-to-mouth). These 

represent the standard set of exposures 

that are typically added together when 

chemicals are used on pets because it is 

logical that they can co-occur. It should 

be noted that the dermal and hand-tomouth assessments are considered 

conservative and that combining the 

assessments is expected to provide a 

highly conservative assessment of 

children’s incidental oral exposure. 

EPA did not, however, separately 

assess exposure to toddlers while 

sleeping with (near or next to) pets 

wearing a pet collar impregnated with 

carbaryl. This is because EPA assumes 

that the ‘‘hug’’ or equilibrium approach 

is adequately protective for all activities 

in which a child engages that result in 

dermal exposure. EPA presented the 

concept of a pet hug to assess dermal 

exposure to the FIFRA SAP on 

September 21, 1999 (64 FR 48394, Ref. 

28); this was considered to be a 

reasonable approach. (Ref. 26). As 

described in the 1999 Overview 

document presented to the SAP (Ref. 

21), the residential pet SOP ‘‘assumes a 

one to one transfer to the skin of surface 

area representing both hands. This 

assumption suggests equilibrium is 

established between the transferable 

residues on the pet and the residues on 

the hand after contact. The concept of 

equilibrium ... has utility in 

constructing scenarios such as a child 

hugging a dog or a child sleeping with 

a dog. This is possible by assuming 

direct transfer or transferable residue 

estimates to human surface area 

values.’’ (Ref. 22 at 38 to 39). 

NRDC also criticizes the Agency for 

not including inhalation as an exposure 

route for residential post-application of 

flea collars. In so doing, NRDC points 

out that inhalation was the only route of 

exposure that EPA estimated in an 

earlier RED decision on another 

pesticide used in flea collars. 

EPA did not assess inhalation 

exposure to pet collars impregnated 

with carbaryl because EPA generally 

assumes that residential postapplication inhalation exposures are 

negligible due to the low vapor 

pressures associated with many 

pesticides. In the case of carbaryl, this 

assumption is warranted. The vapor 

pressure of carbaryl is sufficiently low 

(4.1 x 10-5 mmHg at 25 °C) so that the 

inhalation route of exposure will 

contribute insignificantly to the overall 

estimated daily dose when compared to 

the combined exposures resulting from 

the combination of the dermal and oral 

(i.e., hand-to-mouth) routes. In other 

cases, this assumption might not be 

warranted. For example, dichlorvos, 

another pesticide used in impregnated 

pet collars, has a vapor pressure of 1.2 

x 10-3 at 20 °C, which is considerably 

higher than that of carbaryl. The higher 

vapor pressure suggests rapid 

volatilization at room temperature; 

therefore, the Agency considered 

inhalation a potential route of exposure 

when assessing residential exposure to 

dischlorvos from impregnated pet 

collars. The Agency also considered 

dermal and hand-to-mouth routes of 

exposure, in addition to inhalation. All 

potential routes of exposure are 

considered for each pesticide on a caseby-case basis to determine which routes 

will be the most significant contributors 

to exposure and risk. 

In addition, as the basis for 

petitioning the Agency to cancel all 

carbaryl pet collar registrations 

(submitted as part of NRDC’s comments 

on the NMC cumulative assessment), 

NRDC asserts that changes in this 

algorithm made from the preliminary 

NMC cumulative assessment result in a 

repeated and additive bias towards 

reducing the exposure estimate so that 

it ‘‘appears’’ that the pet collar uses do 

not exceed the Agency’s level of 

concern. NRDC also criticizes the 

Agency for stating that the 

modifications result from the 

recommendations from the August 2005 

FIFRA SAP. To the contrary, NRDC 

contends that these modifications were 

never reviewed or recommended by the 

FIFRA SAP. NRDC then asserts that EPA 

cannot use this new method presented 

in the NMC cumulative assessment to 

‘‘reduce protections for children from 

pet uses of [carbamate] pesticides.’’ (Ref. 

2 at 7). 

EPA disagrees with NRDC’s assertion 

that the techniques used in the NMC 

cumulative assessment for pet collars 

results in an additive bias towards 

reducing exposures and risks. The main 

difference between the approach used to 

assess exposure to carbaryl from pet 

collars in the 2003 RED and the 

cumulative exposure assessment of the 

carbaryl pet collar is that the cumulative 

exposure assessment uses probabilistic 

techniques to estimate exposures and 

the single chemical assessment uses 

deterministic techniques to assess 

exposures. Probabilistic techniques have 

the advantage of using distributions of 

all available data to describe the myriad 

of potential combinations of residues 

and activity patterns that may occur as 

a child is interacting with a pet wearing 

a carbaryl-impregnated collar. These 

potential combinations of residues and 

activities provide a distribution of 

exposures for use in risk assessment. 

Deterministic techniques rely on point 

estimates of both residues and activity 

patterns. These point estimates may, for 

example, represent averages or absolute 

maximum values for residues and 

activity patterns. 

The specific modifications and the 

reasons for adopting the modification 

are provided below: 

∑ Assuming a child mouths only one 

hand at a time, thereby dividing the 

hand-loading residues by 2X. 

This assumption is consistent with 

the way EPA has assessed hand-tomouth exposure in the past. Both the 

EPA Residential SOP methodology 

(deterministic) and the revised hand-tomouth algorithm used in the Revised 

NMC cumulative risk assessment 

(probabilistic) are based upon the 

assumption that a child can only place 

one hand in his/her mouth at a time. 

∑ Assuming the hand is fully 

replenished with residues from a 

contaminated surface on an hourly basis 

rather than assuming (as done 

previously with flea collar assessments) 

full replenishment between each 

mouthing event, which NRDC contends 

is a more likely scenario for kids 

actively engaged with their pets. 

As stated in the preliminary NMC 

cumulative risk assessment, previous 

assumptions regarding replenishment 

were overly conservative when used in 

a probabilistic model. These low MOEs 

were mainly due to the incorporation of 

micro-activity data into EPA’s macro 

activity models (defined as human 

exposure models based on daily time 

step). The non-dietary ingestion 

pathway was the least refined of the 

residential exposure pathways modeled 

in the preliminary revised NMC 

cumulative risk assessment. This input 

is part of the revised approach that was 

developed in collaboration with ORD 

and is currently being used in the 

Stochastic Human Exposure and Dose 

Simulation (SHEDS) model. (For a full 

explanation of the implications of using 

microactivity data in a macro activity 

model, see Ref. 29 p. 91.) The data used 

in the revised assessment are based on 

a meta analysis provided by ORD. The 

meta analysis relies upon the best 

available observational data on 

children’s mouthing frequency. 

∑ Assuming that the maximum time 

spent with a pet is 1.03 hours/day. 

NRDC contends that EPA’s assumption 

in previous assessments of 2 hours/day 

is a much more likely scenario for premstockstill on PROD1PC66 with RULES9

Federal Register / Vol. 73, No. 210 / Wednesday, October 29, 2008 / Rules and Regulations 64245 

schoolers who are home all day with 

their pets and for school age kids lying 

with their pets watching TV. 

This assumption is based on data that 

involved videotaping children’s time 

spent with pets. (Ref. 30). As stated in 

the NMC Cumulative Risk Assessment 

document, the duration of exposure is 

assumed to be continuous contact rather 

than the intermittent contact normally 

associated with pet care (e.g. walking, 

feeding). OPP is attempting to draw the 

distinction between direct contact with 

a treated pet and the time spent with a 

pet where there is limited contact. For 

example, time spent with pets in and 

around the house may not result in 

direct contact for the entire duration. 

The pet collar scenario assessed in the 

revised NMC Risk Assessment uses pet 

fur residues transferred to individuals at 

a rate found during a study of 

shampooing and grooming for a 

duration of approximately 1 hour. Use 

of these data to represent residential 

exposure to pets is likely to encompass 

all other potential exposure scenarios 

involving direct or indirect contact with 

treated pets. 

∑ Assuming that only 1% of the 

surface area of a single hand is 

mouthed, which is approximately 1/75 

cm2 surface area. NRDC contends that 

EPA’s assumption in previous 

assessments of 20 cm2 is a more 

reasonable and realistic estimate of the 

surface area likely to contact a child’s 

mouth repeatedly. 

The Agency is unclear how NRDC 

determined that a surface area of 1% 

was used in the NMC cumulative risk 

assessment. It should be noted that the 

revised algorithm does not use a surface 

area (cm2), but rather a distribution of 

fraction of the hand mouthed (unitless). 

The distribution of fraction of surface 

area of hand mouthed ranged from a 

mean of 0.129 to a maximum of 0.305. 

This is equivalent to approximately 13 

to 30.5 cm2, respectively (assuming a 

100 cm2 total palmar surface area of the 

hand). In addition, as a part of the 

algorithm used in SHEDS and CARES, 

the fraction of the surface area of the 

hand mouthed is based on the best 

available data. In some places in the 

revised NMC cumulative risk 

assessment, the fraction of hand 

mouthed is referred to as surface area 

mouthed in error. 

∑ Assuming that only 20 to 50% of 

the pesticide is removed per mouthing 

event (saliva extraction factor). NRDC 

contends that EPA’s assumption in 

previous assessments that all of the 

pesticide is removed is more reasonable 

and realistic. 

The assumptions used in the hand-tomouth assessment are based upon data 

from several studies (Refs. 31, 32, and 

33). The studies were conducted to 

address the removal efficiency of 

residues from the hands by saliva and 

other substances (e.g., ethanol) during 

mouthing events. The resulting range, 

20–50% removal efficiency, is the same 

used for hand-to-mouth assessment in 

the Draft Residential SOPs and in the 

NMC cumulative risk assessment; 

however, the Residential SOPs rely 

upon the upper percentile of the range 

(50%) while the NMC cumulative risk 

assessment made use of all available 

data to better estimate exposure using a 

probabilistic approach. 

In sum, EPA made modifications in 

part because of the FIFRA SAP’s 

comments with respect to the 

limitations of the approach used in the 

preliminary NMC cumulative risk 

assessment—most notable of which was 

that the approach used in the 

preliminary NMC cumulative risk 

assessment was likely to overestimate 

exposure and EPA should consider not 

assessing this exposure pathway at all 

until it has better data. EPA assessed 

this pathway (which the FIFRA SAP 

also suggested EPA) but modified the 

algorithm in an effort to further refine 

the assessment. 

Furthermore, the FIFRA SAP provides 

independent scientific advice to the 

EPA on health and safety related issues 

related to pesticides. Thus, whether the 

FIFRA SAP reviewed and offered its 

recommendations on the specifics of the 

modifications does not preclude EPA 

from making such modifications 

(especially where the FIFRA SAP 

recommends that EPA consider how the 

approach should be modified). 

Similarly, review by the FIFRA SAP is 

not required in order for EPA to make 

a safety finding. Accordingly, the issues 

raised by NRDC do not provide a basis 

for revoking all carbaryl tolerances or 

cancelling pet collar registrations. 

4. Farm children—a. NRDC’s claims. 

Previously, NRDC had asserted that 

farm children are especially vulnerable 

to pesticide exposure and are not 

adequately considered. (Ref. 1. at 19). 

Notwithstanding EPA’s previous 

response to this issue, NRDC maintains 

that the Agency still has not adequately 

addressed this issue. 

b. Public comments. Bayer noted that 

EPA adequately responded to this issue 

in its October 26, 2004 Response to 

Comments on Phase 5 Risk Assessment 

(Docket ID No. 2003–0376–00008). 

c. EPA’s response. Simply asserting 

that the Agency has not (in NRDC’s 

opinion) adequately addressed an issue 

is not a basis upon which to revoke a 

tolerance. In particular, NRDC has not 

provided any additional information or 

data, nor has NRDC suggested in what 

respect it finds the Agency’s previous 

analysis and response to this issue is 

inadequate. See Imidacloprid; Order 

Denying Objections to Issuance of 

Tolerance, Final Order, 69 FR 30042 

(May 26, 2004). EPA hereby 

incorporates its prior response to this 

issue and finds NRDC’s contention 

without merit. 

D. Conclusion 

NRDC’s petitions to revoke all 

carbaryl tolerances are denied. NRDC’s 

arguments have not demonstrated that 

carbaryl tolerances are unsafe; to the 

contrary, EPA continues to believe that 

its risk assessments appropriately 

support its finding that the carbaryl 

tolerances pose a reasonable certainty of 

no harm. 

VIII. Regulatory Assessment 

Requirements 

As indicated previously, this action 

announces the Agency’s order denying 

a petition filed, in part, under section 

408(d) of FFDCA. As such, this action 

is an adjudication and not a rule. The 

regulatory assessment requirements 

imposed on rulemaking do not, 

therefore, apply to this action. 

IX. Submission to Congress and the 

Comptroller General 

The Congressional Review Act, (5 

U.S.C. 801 et seq.), as added by the 

Small Business Regulatory Enforcement 

Fairness Act of 1996, does not apply 

because this action is not a rule for 

purposes of 5 U.S.C. 804(3). 

X. References 

1. NRDC comments to IRED and 

petition to cancel registrations dated 

January 10, 2005. 

2. NRDC petition to cancel carbaryl 

registrations submitted as part of 

NRDC’s comments to N-methyl 

carbamate NMC cumulative dated 

September 24, 2007. 

3. USEPA. 2000a. ‘‘Choosing a 

Percentile of Acute Dietary Exposure as 

a Threshold of Regulatory Concern.’’ 

March 16, 2000. Available at: http:// 

www.epa.gov/pesticides/trac/science/ 

trac2b054.pdf 

4. US EPA Office of Pesticide 

Programs. 1998. Proposed Methods for 

Basin-Scale Estimation of Pesticide 

Concentrations in Flowing Water and 

Reservoirs for Tolerance Reassessment. 

Presentation to the FIFRA SAP, July 29, 

1998. 

5. US EPA Office of Pesticide 

Programs. 1999. Proposed Methods for 

Determining Watershed-derived Percent 

Crop Areas and Consideration for 

Applying Crop Area Adjustments to 

mstockstill on PROD1PC66 with RULES9

64246 Federal Register / Vol. 73, No. 210 / Wednesday, October 29, 2008 / Rules and Regulations 

Surface Water Screening Models. 

Presentation to the FIFRA SAP, May 27, 

1999. 

6. US EPA. Office of Pesticide 

Programs. 1997. Standard Operating 

Procedures (SOPs) for Residential 

Exposure Assessments (Draft December 

19, 1997). 

7. US EPA Office of Pesticide 

Programs. 2001. Science Advisory 

Council for Exposure (ExpoSAC) Policy 

12: Recommended Revisions to the 

Standard Operating Procedures (SOPs) 

for Residential Exposure Assessments. 

February 2001. 

8. US EPA Office of Pesticide 

Programs. 2002a. ExpoSAC Policy 13: 

Postapplication Exposure Assessment 

for Children from Pet Treatments. 

January 2002. 

9. US EPA Office of Pesticide 

Programs. 2002b. Office of Pesticide 

Programs’ Policy on the Determination 

of the Appropriate FQPA Safety 

Factor(s) for Use in Tolerance 

Assessment. Available at http:// 

www.epa.gov/oppfead1/trac/science/ 

determ.pdf. 

10. US EPA Office of Pesticide 

Programs. 2002c. Carbaryl: Updated 

Toxicology Chapter for RED. May 24, 

2002. See docket ID EPA–HQ–OPP– 

2002–0138. 

11. US EPA Office of Pesticide 

Programs. 2000b. The Use of Data on 

Cholinesterase Inhibition for Risk 

Assessments of Organophosphorous and 

Carbamate Pesticides (August 18, 2000). 

12. US EPA. Office of Research and 

Development. 2000. Benchmark Dose 

Technical Guidance Document. Draft 

report. Risk Assessment Forum, Office 

of Research and Development, U.S. 

Environmental Protection Agency. 

Washington, DC. EPA/630/R–00/001. 

13. FIFRA Science Advisory Panel. 

2002. Methods Used to Conduct a 

Preliminary Cumulative Risk 

Assessment for Organophosphate 

Pesticides. Final Report from the FIFRA 

Scientific Advisory Panel Meeting of 

February 5–7, 2002 (Report dated March 

19, 2002). FIFRA Scientific Advisory 

Panel, Office of Science Coordination 

and Policy, Office of Prevention, 

Pesticides and Toxic Substances, U.S. 

Environmental Protection Agency. 

Washington, DC. SAP Report 2002–01. 

14. FIFRA Science Advisory Panel. 

2005a. Final report on N-Methyl 

Carbamate Cumulative Risk Assessment: 

Pilot Cumulative Analysis. Final Report 

from the FIFRA Scientific Advisory 

Panel Meeting of February , 2005 

(Report dated September 2, 1998). 

Available at: http://www.epa.gov/ 

scipoly/sap/2005/february/minutes.pdf. 

15. FIFRA Science Advisory Panel. 

2005b. Final report on Preliminary NMethyl Carbamate Cumulative Risk 

Assessment. Final Report from the 

FIFRA Scientific Advisory Panel 

Meeting of July 29–30, 2005 (Report 

dated September -, 2005). Available at: 

http://www.epa.gov/scipoly/sap/2005/ 

august/minutes.pdf. 

16. US EPA Office of Pesticide 

Programs. 2004. Interim Reregistration 

Eligibility Decision for Carbaryl. 

(October 22, 2004). 

17. US EPA Office of Pesticide 

Programs. March 9, 2005 letter to Peg 

Cherney, Bayer Crop Science, Final 

Cancellation Order for Carbaryl Liquid 

Broadcast Application to Lawns/Turf; 

EPA Registration Numbers 264–324, 

264–325, and 264–328. 

18. US EPA Office of Pesticide 

Programs. 2007. Office of Prevention, 

Pesticides and Toxic Substances, EPA, 

Reregistration Eligibility Decision for 

Carbaryl (September 24, 2007). 

19. BayerCropScience, Comments of 

BayerCropScience on the Petition to 

Revoke or Modify Tolerances 

Established for Carbaryl. May 31, 2005. 

20. US EPA Office of Pesticide 

Programs. 2007. Carbaryl Refined 

Drinking Water Time Series Simulations 

Using Regional PCAs (March 13, 2007). 

21. UP3 2007. Pesticides in Urban 

Surface Water. Urban Uses Trends 

Annual Report, available at http:// 

www.up3project.org/documents/ 

FInal_UP3_Use_Report_2007.pdf. 

22. USEPA Office of Pesticide 

Programs. Report of the FIFRA SAP 

Meeting held April 30 to May 1, 2002. 

A Set of Scientific Issues Being 

Considered by the EPA regarding 

CARES model review. June 13. 2002. 

EPA SAP 2002–02. 

23. US EPA. Office of Research and 

Development. 2007. Report on 

Comparative Cholinesterase Study of 

Carbaryl May 7, 2007). 

24. US EPA Office of Pesticide 

Programs. 2007. Carbaryl: Updated 

Endpoint Selection for Single Chemical 

Risk Assessment (June 29, 2007). 

25. Padilla S, Setzer W, Marshall RS, 

et al. 2007. Time Course of 

cholinesterase inhibition in adult rats 

treated acutely with carbaryl, 

carbofuran, formetanate, methonmy, 

methiocarb, oxamyl, or propoxur. 

Toxicology and Applied Pharmacology 

219: 202–209. 

26. US EPA Office of Pesticide 

Programs. 2007. Carbaryl: Review of in 

vitro Dermal Absorption Study (MRID 

47151902). June 28, 2007. 

27. US EPA Office of Pesticide 

Programs. 2007. Carbaryl: Revisions to 

Residential Exposure and Risk 

Assessment. June 29, 2007. 

28. US EPA Office of Pesticide 

Programs. 1999. Overview of Issues 

Related to the Standard Operating 

Proceedures for Residential Exposure 

Assessment. Presented to the FIFRA 

SAP on September 21, 1999. 

29. US EPA Office of Pesticide 

Programs. 2007. Revised N-methyl 

Carbamate Cumulative Risk Assessment. 

September 24, 2007. (EPA–HQ–OPP– 

2007–0935–0003). 

30. Freeman, N. C. G., Jimenez, M., 

Reed, K. J., Gurunathan, S., Edwards, R. 

D., & Lioy, P. J. 2001. Quantitative 

Analysis of Children’s Microactivity 

Patterns: The Minnesota Children’s 

Pesticide Exposure Study. Journal of 

Exposure Analysis and Environmental 

Epidemiology. 11(6): 501–509. 

31. Geno PW, Camann DE, Harding, 

HJ, Villalobos K, Lewis RG. 1995. 

Handwipe Sampling and Analysis 

Procedure for the Measurement of 

Dermal Contact with Pesticides. Arch 

Environ Contam Toxicol. 30:132–138. 

32. Fenske R. and C. Lu. 1994. 

Determination of Handwash Removal 

Efficiency: Incomplete Removal of the 

Pesticide Chlorpyrifos from Skin by 

Standard Handwash Techniques. 

American Industrial Hygiene 

Association Journal. 55(5): 425–432. 

33. Wester RC, and Maibach HI. 1989. 

Dermal Decontamination and 

Percutaneous Absorption. In: 

Percutaneous Absorption. 2nd ed. R. 

Bronaugh and H.I. Maibach, editors. 

New York: Marcel Dekker, pp 335–342. 

List of Subjects in 40 CFR Part 180 

Environmental protection, Carbaryl, 

Pesticides and pest. 

Dated: September 30, 2008. 

Debra Edwards, 

Director, Office of Pesticide Programs. 

[FR Doc. E8–25693 Filed 10–28–08; 8:45 am] 

BILLING CODE 6560–50–S 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 180 

[EPA–HQ–OPP–2008–0609; FRL–8384–7] 

Pyrimethanil; Pesticide Tolerances 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Final rule. 

SUMMARY: This regulation amends the 

tolerances in the 40 CFR 180.518 for 

residues of the fungicide, pyrimethanil, 

4,6-dimethyl-N-phenyl-2- 

pyrimidinamine, in or on pome fruit 

crop group 11, establishes tolerances for 

the residues of pyrimethanil in or on 

apple wet pomace, and amends the 

tolerances for residues of pyrimethanil 

mstockstill on PROD1PC66 with RULES9