
[Federal Register: November 12, 2008 (Volume 73, Number 219)]
[Rules and Regulations]               
[Page 66780-66786]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr12no08-16]                         

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[EPA-HQ-OPP-2007-0945; FRL-8387-1]

 
MCPB; Pesticide Tolerances

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes tolerances for combined residues 
of free and conjugated MCPB and its metabolite MCPA in or on 
peppermint, tops and spearmint, tops. Interregional Research Project 
Number 4 (IR-4) requested these tolerances under the Federal Food, 
Drug, and Cosmetic Act (FFDCA).

DATES: This regulation is effective November 12, 2008. Objections and 
requests for hearings must be received on or before January 12, 2009, 
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-2007-0945. All documents in the 
docket are listed in the docket index available at http://
www.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: Susan Stanton, Registration Division 
(7505P), Office of Pesticide Programs, Environmental Protection Agency, 
1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone 
number: (703) 305-5218; e-mail address: stanton.susan@epa.gov.

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this Action Apply to Me?

    You may be potentially affected by this action if you are an 
agricultural producer, food manufacturer, or pesticide manufacturer. 
Potentially affected entities may include, but are not limited to those 
engaged in the following activities:
     Crop production (NAICS code 111).
     Animal production (NAICS code 112).
     Food manufacturing (NAICS code 311).
     Pesticide manufacturing (NAICS code 32532).
    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.

[[Page 66781]]

B. How Can I Access Electronic Copies of this Document?

    In addition to accessing electronically available documents 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, 21 U.S.C. 346a, 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-2007-0945 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 January 12, 2009.
    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-2007-0945, 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 Facility'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. Petition for Tolerance

    In the Federal Register of October 24, 2007 (72 FR 60369) (FRL-
8150-8), EPA issued a notice pursuant to section 408(d)(3) of FFDCA, 21 
U.S.C. 346a(d)(3), announcing the filing of a pesticide petition (PP 
7E7257) by Interregional Research Project Number 4 (IR-4), 500 College 
Road East, Suite 201 W., Princeton, NJ 08540. The petition requested 
that 40 CFR 180.318 be amended by establishing a tolerance for residues 
of the herbicide MCPB, 4-(2-methyl-4-chlorophenoxy) butyric acid, in or 
on mint tops (leaves and stems) at 0.25 parts per million (ppm). That 
notice referenced a summary of the petition prepared by Nufarm, Inc., 
the registrant, on behalf of IR-4, which is available to the public in 
the docket, http://www.regulations.gov. There were no comments received 
in response to the notice of filing.
    Based upon review of the data supporting the petition, EPA has 
revised the commodity terms and tolerance level. EPA has also revised 
the tolerance expression to include combined residues of free and 
conjugated MCPB and its metabolite MCPA. The reasons for these changes 
are explained in Unit IV.C.

III. Aggregate Risk Assessment and Determination of Safety

    Section 408(b)(2)(A)(i) of FFDCA allows EPA to establish a 
tolerance (the legal limit for a pesticide chemical residue in or on a 
food) only if EPA determines that the tolerance is ``safe.'' Section 
408(b)(2)(A)(ii) of FFDCA defines ``safe'' 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.'' This includes exposure through drinking water and in 
residential settings, but does not include occupational exposure. 
Section 408(b)(2)(C) of FFDCA requires EPA to give special 
consideration to exposure of infants and children to the pesticide 
chemical residue in establishing a tolerance and to ``ensure that there 
is a reasonable certainty that no harm will result to infants and 
children from aggregate exposure to the pesticide chemical residue. . . 
.''
    Consistent with section 408(b)(2)(D) of FFDCA, and the factors 
specified in section 408(b)(2)(D) of FFDCA, EPA has reviewed the 
available scientific data and other relevant information in support of 
this action. EPA has sufficient data to assess the hazards of and to 
make a determination on aggregate exposure for the petitioned-for 
tolerances for combined residues of free and conjugated MCPB and its 
metabolite MCPA on peppermint, tops and spearmint, tops at 0.20 ppm. 
EPA's assessment of exposures and risks associated with establishing 
tolerances follows.

A. Toxicological Profile

    EPA has evaluated the available toxicity data and considered its 
validity, completeness, and reliability as well as the relationship of 
the results of the studies to human risk. EPA has also considered 
available information concerning the variability of the sensitivities 
of major identifiable subgroups of consumers, including infants and 
children.
    The currently available toxicological database for MCPB is limited; 
thus it was supplemented with data on the closely related compound, 4-
(chloro-2-methylphenoxy)acetic acid (MCPA). Structurally, MCPB and MCPA 
differ only in that MCPB contains two additional carbon atoms. In both 
animal and plant metabolism studies, the data indicate that MCPB is 
readily converted to MCPA. Therefore, EPA has concluded that the 
toxicity of these compounds is similar at sub-lethal dose levels.
    MCPB has low to moderate acute toxicity via the oral, dermal and 
inhalation routes of exposure. It is mildly to moderately irritating to 
the eye but is not a dermal irritant or skin sensitizer. In longer-term 
studies, nephrotoxicity and hepatotoxicity appear to be the most 
prevalent hazard concerns for MCPB, based on the effects seen 
throughout the MCPA database and the limited toxicity data set 
available for MCPB. Signs of neurotoxicity (decreased arousal, impaired 
coordination and gait, reduced motor activity and reduced grip 
strength) were also reported after MCPB or MCPA exposure. Developmental 
and reproduction toxicity studies conducted with MCPB and/or MCPA did 
not indicate an enhanced sensitivity or susceptibility of the young, as 
developmental effects (delayed ossifications and decreased fetal or pup 
body weight) occurred at the same doses eliciting toxicity in the 
parental animals (mortality, decreased body weight, body weight gain 
and food consumption and increased absolute and relative ovary 
weights). MCPB and MCPA have been classified as ``not likely to be 
carcinogenic to humans'' based on the absence of increased numbers of 
tumors in the rat and mouse carcinogenicity studies and no evidence of 
mutagenicity.

[[Page 66782]]

     Specific information on the studies received and the nature of the 
adverse effects caused by MCPB and MCPA, as well as the no-observed-
adverse-effect-level (NOAEL) and the lowest-observed-adverse-effect-
level (LOAEL) from the toxicity studies, can be found at http://
www.regulations.gov in the document 4-(4-chloro-2-
methylphenoxy)butanoic acid (MCPB); Human-Health Risk Assessment for 
Proposed Section 3 New Use on Mint, page 29 in docket ID number EPA-HQ-
OPP-2007-0945.

B. Toxicological Endpoints

    For hazards that have a threshold below which there is no 
appreciable risk, a toxicological point of departure (POD) is 
identified as the basis for derivation of reference values for risk 
assessment. The POD may be defined as the highest dose at which no 
adverse effects are observed (the NOAEL) in the toxicology study 
identified as appropriate for use in risk assessment. However, if a 
NOAEL cannot be determined, the lowest dose at which adverse effects of 
concern are identified (the LOAEL) or a Benchmark Dose (BMD) approach 
is sometimes used for risk assessment. Uncertainty/safety factors (UFs) 
are used in conjunction with the POD to take into account uncertainties 
inherent in the extrapolation from laboratory animal data to humans and 
in the variations in sensitivity among members of the human population 
as well as other unknowns. Safety is assessed for acute and chronic 
dietary risks by comparing aggregate food and water exposure to the 
pesticide to the acute population adjusted dose (aPAD) and chronic 
population adjusted dose (cPAD). The aPAD and cPAD are calculated by 
dividing the POD by all applicable UFs. Aggregate short-term, 
intermediate-term, and chronic-term risks are evaluated by comparing 
food, water, and residential exposure to the POD to ensure that the 
margin of exposure (MOE) called for by the product of all applicable 
UFs is not exceeded. This latter value is referred to as the Level of 
Concern (LOC).
    For non-threshold risks, the Agency assumes that any amount of 
exposure will lead to some degree of risk. Thus, the Agency estimates 
risk in terms of the probability of an occurrence of the adverse effect 
greater than that expected in a lifetime. For more information on the 
general principles EPA uses in risk characterization and a complete 
description of the risk assessment process, see http://www.epa.gov/
pesticides/factsheets/riskassess.htm.
    A summary of the toxicological endpoints for MCPB used for human 
risk assessment is shown in the following Table.

        Table 1.--Summary of Toxicological Doses and Endpoints for MCPB for Use in Human Risk Assessment
----------------------------------------------------------------------------------------------------------------
                                        Point of Departure and
          Exposure/Scenario               Uncertainty/Safety     RfD, PAD, LOC for Risk  Study and Toxicological
                                               Factors                 Assessment                Effects
----------------------------------------------------------------------------------------------------------------
Acute dietary                          NOAEL = 200 milligrams/  Acute RfD = 0.2 mg/kg/   Acute neurotoxicity
(General population including infants   kilograms/day (mg/kg/    day                      (MCPA), rat
 and children; and females 13-50        day)                    aPAD = 0.2 mg/kg/day...  LOAEL = 400 mg/kg/day
 years of age).                        UFA = 10x..............                            based on gait
                                       UFH = 10x..............                            impairment in males
                                       FQPA SF = 10x (UFDB)...
----------------------------------------------------------------------------------------------------------------
Chronic dietary                        NOAEL= 4.4 mg/kg/day     Chronic RfD = 0.0044 mg/ Chronic toxicity
(All populations)....................  UFA = 10x..............   kg/day                   (MCPA), rat
                                       UFH = 10x..............  cPAD = 0.0044 mg/kg/day  LOAEL = 17.6 mg/kg/day
                                       FQPA SF = 10x (UFDB)...                            based on liver and
                                                                                          kidney toxicity.
----------------------------------------------------------------------------------------------------------------
Dermal short-term                      Dermal study             LOC for MOE = 100        21-Day dermal toxicity
(1 to 30 days) and intermediate-term   NOAEL = 25 mg/kg/day...                            (MCPA), rabbit
 (1 to 6 months).                      UFA = 10x..............                           NOAEL = 100
                                       UFH = 10x..............                           LOAEL = 1,000 mg/kg/day
                                       FQPA SF = 1x...........                            based on kidney
                                                                                          toxicity and decreased
                                                                                          body weight gain
                                                                                         Dermal absorption of
                                                                                          MCPB is 4x that of
                                                                                          MCPA.
----------------------------------------------------------------------------------------------------------------
Dermal long-term                       Oral study               LOC for MOE = 100        Chronic toxicity
(> 6 months).........................  NOAEL = 4.4 mg/kg/day                              (MCPA), rat
                                        (dermal absorption                               LOAEL = 17.6 mg/kg/day
                                        rate = 31%).                                      based on liver and
                                       UFA = 10x..............                            kidney toxicity.
                                       UFH = 10x..............
                                       FQPA SF = 1x...........
----------------------------------------------------------------------------------------------------------------
Inhalation short-term                  Oral study               LOC for MOE = 100        Developmental toxicity
(1 to 30 days) and intermediate-term   NOAEL= 5 mg/kg/day                                 (MCPB), rabbit
 (1 to 6 months).                       (inhalation absorption                           LOAEL = 20 mg/kg/day
                                        rate = 100%).                                     based on maternal
                                       UFA = 10x..............                            mortality
                                       UFH = 10x..............
                                       FQPA SF = 1x...........
----------------------------------------------------------------------------------------------------------------
Inhalation long-term (> 6 months)      Oralstudy NOAEL = 4.4    LOC for MOE = 100        Chronic toxicity
                                        mg/kg/day (inhalation                             (MCPA), rat
                                        absorption rate =                                LOAEL = 17.6 mg/kg/day
                                        100%)                                             based on liver and
                                       UFA = 10x..............                            kidney toxicity
                                       UFH = 10x..............
                                       FQPA SF = 1x...........
----------------------------------------------------------------------------------------------------------------

[[Page 66783]]


Cancer (oral, dermal, inhalation)               Classification: Not likely to be carcinogenic to humans.
----------------------------------------------------------------------------------------------------------------
UFA = extrapolation from animal to human (interspecies). UFH = potential variation in sensitivity among members
  of the human population (intraspecies). UFL = use of a LOAEL to extrapolate a NOAEL. UFS = use of a short-term
  study for long-term risk assessment. UFDB = to account for the absence of data or other data deficiency. FQPA
  SF = FQPA Safety Factor. PAD = population adjusted dose (a = acute, c = chronic). RfD = reference dose. MOE =
  margin of exposure. LOC = level of concern.

C. Exposure Assessment

     While the Agency has concluded that MCPB converts to MCPA in the 
environment, and that MCPA may be present in crops, residues of MCPA 
resulting from the existing use of MCPB on peas and the new use on mint 
are expected to be negligible, and significantly below analytical 
method limits of detection. These residues will not contribute 
significantly to the aggregate exposure to MCPA from other sources, 
and, therefore, EPA did not conduct an aggregate assessment combining 
MCPA exposures from MCPA and MCPB uses. The exposure assessments 
presented here are for MCPB only. A discussion of aggregate risks 
associated with MCPA can be found in the MCPA Reregistration 
Eligibility Decision (RED), available on the Office of Pesticide 
Programs web site at http://www.epa.gov/oppsrrd1/REDs/mcpa_red.pdf
    1. Dietary exposure from food and feed uses. In evaluating dietary 
exposure to MCPB, EPA considered exposure under the petitioned-for 
tolerances as well as the existing MCPB tolerance in 40 CFR 180.318 on 
peas, the only commodity for which a tolerance currently exists. EPA 
assessed dietary exposures from MCPB in food as follows:
    i. Acute exposure. Quantitative acute dietary exposure and risk 
assessments are performed for a food-use pesticide, if a toxicological 
study has indicated the possibility of an effect of concern occurring 
as a result of a 1-day or single exposure.
    In estimating acute dietary exposure, EPA used food consumption 
information from the United States Department of Agriculture (USDA) 
1994-1996 and 1998 Nationwide Continuing Surveys of Food Intakes by 
Individuals (CSFII). As to residue levels in food, EPA assumed that all 
pea and mint commodities contain tolerance-level residues and that 100 
percent of pea and mint commodities are treated with MCPB.
    ii. Chronic exposure. In conducting the chronic dietary exposure 
assessment EPA used the food consumption data from the USDA 1994-1996 
and 1998 CSFII. As in the acute exposure assessment, EPA assumed 
tolerance-level residues and 100 percent crop treated (PCT) for all pea 
and mint commodities.
    iii. Cancer. Based on the results of carcinogenicity studies in 
rats and mice, EPA classified MCPB as ``not likely to be carcinogenic 
to humans.'' Therefore, an exposure assessment for evaluating cancer 
risk is unnecessary.
    iv. Anticipated residue and PCT information. EPA did not use 
anticipated residue or PCT information in the dietary assessment for 
MCPB. Tolerance level residues and/or 100 PCT were assumed for all food 
commodities.
    2. Dietary exposure from drinking water. The Agency used screening 
level water exposure models in the dietary exposure analysis and risk 
assessment for MCPB in drinking water. These simulation models take 
into account data on the physical, chemical, and fate/transport 
characteristics of MCPB. Further information regarding EPA drinking 
water models used in pesticide exposure assessment can be found at 
http://www.epa.gov/oppefed1/models/water/index.htm.
    Based on the First Index Reservoir Screening Tool (FIRST) and 
Screening Concentration in Ground Water (SCI-GROW) models, the 
estimated drinking water concentrations (EDWCs) of MCPB for acute 
exposures are estimated to be 54.7 parts per billion (ppb) for surface 
water and 2.1 ppb for ground water. The EDWCs for chronic exposures for 
non-cancer assessments are estimated to be 13.5 ppb for surface water 
and 2.1 ppb for ground water.
    Modeled estimates of drinking water concentrations were directly 
entered into the dietary exposure model. For acute dietary risk 
assessment, the water concentration value of 54.7 ppb was used to 
assess the contribution to drinking water. For chronic dietary risk 
assessment, the water concentration of value 13.5 ppb was used to 
assess the contribution to drinking water.
    3. From non-dietary exposure. The term ``residential exposure'' is 
used in this document to refer to non-occupational, non-dietary 
exposure (e.g., for lawn and garden pest control, indoor pest control, 
termiticides, and flea and tick control on pets).
    MCPB is not registered for any specific use patterns that would 
result in residential exposure.
    4. Cumulative effects from substances with a common mechanism of 
toxicity. Section 408(b)(2)(D)(v) of FFDCA requires that, when 
considering whether to establish, modify, or revoke a tolerance, the 
Agency consider ``available information'' concerning the cumulative 
effects of a particular pesticide's residues and ``other substances 
that have a common mechanism of toxicity.''
    EPA has not found MCPB to share a common mechanism of toxicity with 
any other substances, and MCPB does not appear to produce a toxic 
metabolite produced by other substances. For the purposes of this 
tolerance action, therefore, EPA has assumed that MCPB does not have a 
common mechanism of toxicity with other substances. For information 
regarding EPA's efforts to determine which chemicals have a common 
mechanism of toxicity and to evaluate the cumulative effects of such 
chemicals, see EPA's website at http://www.epa.gov/pesticides/
cumulative.

D. Safety Factor for Infants and Children

    1. In general. Section 408(b)(2)(c) of FFDCA provides that EPA 
shall apply an additional tenfold (10X) 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 database on toxicity 
and exposure unless EPA determines based on reliable data that a 
different margin of safety will be safe for infants and children. This 
additional margin of safety is commonly referred to as the FQPA safety 
factor (SF). In applying this provision, EPA either retains the default 
value of 10X, or uses a different additional safety factor when 
reliable data available to EPA support the choice of a different 
factor.

[[Page 66784]]

    2. Prenatal and postnatal sensitivity. The prenatal and postnatal 
toxicology database for MCPB includes rat and rabbit developmental 
toxicity studies; for MCPA it includes rat and rabbit developmental 
toxicity studies and a 2-generation reproduction toxicity study in 
rats. There was no evidence of increased quantitative or qualitative 
susceptibility of fetuses or offspring to MCPA or MCPB exposure in any 
of these studies. In the developmental rat studies with MCPB and MCPA, 
decreased ossification and decreased fetal body weights occurred at the 
same dose causing maternal effects (decreased body weight gain and food 
consumption). No toxicity to fetuses occurred in the MCPB and MCPA 
rabbit developmental studies at doses resulting in maternal toxicity 
(mortality, decreased body weight and food consumption). In the rat 
reproduction study for MCPA, the only offspring toxicity was decreased 
weight gain while nursing, which occurred at the same dose causing 
maternal toxicity (increased absolute and relative ovary weights).
    3. Conclusion. EPA has determined that the FQPA safety factor of 
10X must be retained as a database uncertainty factor for MCPB acute 
and chronic risk assessments. This decision is based on the following 
findings:
    i. The toxicity database for MCPB is not complete. Additional data 
pertaining to MCPB's potential to cause developmental neurotoxicity 
(DNT) or immunotoxicity are outstanding. EPA's assessment of the 
uncertainties arising from these data deficiencies follows:
    a. Developmental neurotoxicity: EPA has required a developmental 
neurotoxicity study to be submitted because neurotoxicity was found in 
acute and subchronic neurotoxicity studies with MCPA in rats (decreased 
arousal, impaired coordination and gait, reduced motor activity, 
reduced grip strength), and similar signs of neurotoxicity can be 
expected with MCPB. The neurotoxic effects seen in the acute 
neurotoxicity studies were the most sensitive acute effect identified 
and therefore were used in calculating the aRfD for MCPB. Given these 
findings of neurotoxicity and sensitivity of the neurotoxic effects, 
EPA has concluded that it lacks reliable data to remove the FQPA 10X 
safety factor.
    b. Immunotoxicity: EPA began requiring functional immunotoxicity 
testing (series 870.7800) of all food and non-food use pesticides on 
December 26, 2007. Since the requirement went into effect after this 
tolerance petition was submitted, these studies are not yet available 
for MCPB. In the absence of specific immunotoxicity studies, EPA has 
evaluated the available toxicity data for MCPB and MCPA regarding 
potential immunotoxic effects. Evidence of potential immunotoxicity was 
observed in subchronic 28-day oral toxicity studies in the mouse and 
dog with MCPA. Involution of the spleen due to lymphocytic depletion 
was observed in both sexes at the highest dose tested (HDT) and LOAEL 
of 453.7/223.9 milligrams kilogram day (mg/kg/day) male/female (M/F) in 
the mouse, and decreased thymus weights were seen in the dog at a dose 
of 30 mg/kg/day HDT. Lymphoid depletion was observed in the subchronic 
toxicity study in the dog at a dose of 44 mg/kg/day (HDT) of MCPB. The 
NOAEL in the mouse and dog for potential immunotoxic effects was 173.4/
69.2 mg/kg/day M/F and 20 mg/kg/day, respectively. The NOAEL being used 
for calculation of the chronic reference dose (cRfD) is 4.4 mg/kg/day. 
The NOAEL from the mouse study (173.4/69.2 mg/kg/day (M/F)) provides 
the more appropriate reference for evaluating potential immunotoxic 
effects in humans. Unlike rodents and humans, dogs are uniquely 
sensitive to the toxic effects of chlorophenoxy compounds such as MCPB 
due to their decreased ability to excrete organic acids, and thus the 
effect levels in the mouse are more relevant to potential 
immunotoxicity in humans.
    After weighing this evidence, EPA retains significant uncertainty 
regarding potential neurotoxic effects in infants and children but does 
not have such concerns for immunotoxicity. The immunotoxic effects with 
most relevance to humans had a NOAEL over 10X greater than the NOAEL 
used in establishing the cRfD. On the other hand, neurotoxic effects 
were the most sensitive acute effects seen in the database. 
Additionally, the DNT study specifically addresses potential risks to 
developing animals. Given these considerations, EPA has concluded that 
it lacks reliable data to remove the FQPA children's safety factor.
    ii. There is no evidence that MCPB or MCPA results in increased 
susceptibility in in utero rats or rabbits in the prenatal 
developmental studies or in young rats in the 2-generation reproduction 
study.
    iii. There are no residual uncertainties identified in the exposure 
databases. The dietary food exposure assessments were performed based 
on 100 PCT and tolerance-level residues. EPA made conservative 
(protective) assumption's in the ground and surface water modeling used 
to assess exposure to MCPB in drinking water, and residential exposures 
are not expected. These assessments will not underestimate the exposure 
and risks posed by MCPB.

E. Aggregate Risks and Determination of Safety

    EPA determines whether acute and chronic pesticide exposures are 
safe by comparing aggregate exposure estimates to the aPAD and cPAD. 
The aPAD and cPAD represent the highest safe exposures, taking into 
account all appropriate SFs. EPA calculates the aPAD and cPAD by 
dividing the POD by all applicable UFs. For linear cancer risks, EPA 
calculates the probability of additional cancer cases given the 
estimated aggregate exposure. Short-term, intermediate-term, and 
chronic-term risks are evaluated by comparing the estimated aggregate 
food, water, and residential exposure to the POD to ensure that the MOE 
called for by the product of all applicable UFs is not exceeded.
    1. Acute risk. An acute aggregate risk assessment takes into 
account exposure estimates from acute dietary consumption of food and 
drinking water. Using the exposure assumptions discussed in this unit 
for acute exposure, the acute dietary exposure from food and water to 
MCPB will occupy 5.4% of the aPAD for infants, less than one year old, 
the population group receiving the greatest exposure.
    2. Chronic risk. Using the exposure assumptions described in this 
unit for chronic exposure, EPA has concluded that chronic exposure to 
MCPB from food and water will utilize 22% of the cPAD for infants, less 
than one year old, the population group receiving the greatest 
exposure. There are no residential uses for MCPB.
    3. Short-term risk. Short-term aggregate exposure takes into 
account short-term residential exposure plus chronic exposure to food 
and water (considered to be a background exposure level). MCPB is not 
registered for any use patterns that would result in residential 
exposure. Therefore, the short-term aggregate risk is the sum of the 
risk from exposure to MCPB through food and water and will not be 
greater than the chronic aggregate risk.
    4. Intermediate-term risk. Intermediate-term aggregate exposure 
takes into account intermediate-term residential exposure plus chronic 
exposure to food and water (considered to be a background exposure 
level). MCPB is not registered for any use patterns that would result 
in intermediate-term residential exposure. Therefore, the intermediate-
term aggregate risk is the sum of the risk from exposure to MCPB 
through food and

[[Page 66785]]

water, which has already been addressed, and will not be greater than 
the chronic aggregate risk.
    5. Aggregate cancer risk for U.S. population. EPA has classified 
MCPB into the category ``Not Likely to be Carcinogenic to Humans''. 
MCPB is not expected to pose a cancer risk.
    6. Determination of safety. Based on these risk assessments, EPA 
concludes that there is a reasonable certainty that no harm will result 
to the general population, or to infants and children from aggregate 
exposure to MCPB residues.

IV. Other Considerations

A. Analytical Enforcement Methodology

    Adequate enforcement methodology (Gas chromatography/Mass 
Spectrometry) is available to enforce the tolerance expression. The 
method may be requested from: Chief, Analytical Chemistry Branch, 
Environmental Science Center, 701 Mapes Rd., Ft. Meade, MD 20755-5350; 
telephone number: (410) 305-2905; e-mail address: 
residuemethods@epa.gov.

B. International Residue Limits

    There are no established or proposed Codex, Canadian, or Mexican 
maximum residue limits (MRLs) for MCPB.

C. Revisions to Petitioned-For Tolerances

    IR-4 proposed a tolerance for residues of MCPB per se on mint tops 
(leaves and stems) at 0.25 ppm. EPA has determined that separate 
tolerances at 0.20 ppm should be established for combined residues of 
free and conjugated MCPB (4-(4-chloro-2-methylphenoxy)butanoic acid) 
and MCPA (4-chloro-2-methylphenoxy)acetic acid) on the commodities 
``spearmint, tops'' and ``peppermint, tops. The commodity terms were 
revised to agree with the preferred commodity terms in the Agency's 
Food and Feed Commodity Vocabulary. EPA determined the appropriate 
tolerance level for mint tops based on analysis of the residue field 
trial data using the Agency's Tolerance Spreadsheet in accordance with 
the Agency's Guidance for Setting Pesticide Tolerances Based on Field 
Trial Data. Finally, EPA revised the residues of concern to be included 
in the tolerance expression based on the results of plant metabolism 
studies.

V. Conclusion

    Therefore, tolerances are established for combined residues of free 
and conjugated MCPB and MCPA in or on peppermint, tops and spearmint, 
tops at 0.20 ppm.

VI. Statutory and Executive Order Reviews

    This final rule establishes tolerances under section 408(d) of 
FFDCA in response to a petition submitted to the Agency. The Office of 
Management and Budget (OMB) has exempted these types of actions from 
review under Executive Order 12866, entitled Regulatory Planning and 
Review (58 FR 51735, October 4, 1993). Because this final rule has been 
exempted from review under Executive Order 12866, this final rule is 
not subject to Executive Order 13211, entitled Actions Concerning 
Regulations That Significantly Affect Energy Supply, Distribution, or 
Use (66 FR 28355, May 22, 2001) or Executive Order 13045, entitled 
Protection of Children from Environmental Health Risks and Safety Risks 
(62 FR 19885, April 23, 1997). This final rule does not contain any 
information collections subject to OMB approval under the Paperwork 
Reduction Act (PRA), 44 U.S.C. 3501 et seq., nor does it require any 
special considerations under Executive Order 12898, entitled Federal 
Actions to Address Environmental Justice in Minority Populations and 
Low-Income Populations (59 FR 7629, February 16, 1994).
    Since tolerances and exemptions that are established on the basis 
of a petition under section 408(d) of FFDCA, such as the tolerance in 
this final rule, do not require the issuance of a proposed rule, the 
requirements of the Regulatory Flexibility Act (RFA) (5 U.S.C. 601 et 
seq.) do not apply.
    This final rule directly regulates growers, food processors, food 
handlers, and food retailers, not States or tribes, nor does this 
action alter the relationships or distribution of power and 
responsibilities established by Congress in the preemption provisions 
of section 408(n)(4) of FFDCA. As such, the Agency has determined that 
this action will not have a substantial direct effect on States or 
tribal governments, on the relationship between the national government 
and the States or tribal governments, or on the distribution of power 
and responsibilities among the various levels of government or between 
the Federal Government and Indian tribes. Thus, the Agency has 
determined that Executive Order 13132, entitled Federalism (64 FR 
43255, August 10, 1999) and Executive Order 13175, entitled 
Consultation and Coordination with Indian Tribal Governments (65 FR 
67249, November 9, 2000) do not apply to this final rule. In addition, 
this final rule does not impose any enforceable duty or contain any 
unfunded mandate as described under Title II of the Unfunded Mandates 
Reform Act of 1995 (UMRA) (Public Law 104-4).
    This action does not involve any technical standards that would 
require Agency consideration of voluntary consensus standards pursuant 
to section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (NTTAA), Public Law 104-113, section 12(d) (15 U.S.C. 272 
note).

VII. Congressional Review Act

    The Congressional Review Act, 5 U.S.C. 801 et seq., generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report to each House of the Congress and to 
the Comptroller General of the United States. EPA will submit a report 
containing this rule and other required information to the U.S. Senate, 
the U.S. House of Representatives, and the Comptroller General of the 
United States prior to publication of this final rule in the Federal 
Register. This final rule is not a ``major rule'' as defined by 5 
U.S.C. 804(2).

List of Subjects in 40 CFR Part 180

    Environmental protection, Administrative practice and procedure, 
Agricultural commodities, Pesticides and pests, Reporting and 
recordkeeping requirements.

    Dated: October 31, 2008.
Lois Rossi,
Director, Registration Division, Office of Pesticide Programs.

0
Therefore, 40 CFR chapter I is amended as follows:

PART 180--[AMENDED]

0
1. The authority citation for part 180 continues to read as follows:

    Authority: 21 U.S.C. 321(q), 346a and 371.

0
2. Section 180.318 is amended in paragraph (a) by redesignating the 
existing text as paragraph (a)(1) and by adding paragraph (a)(2) to 
read as follows:


180.318  4-(2-Methyl-4-chlorophenoxy) butyric acid; tolerances for 
residues.

    (a) General. (1) * * *
    (2) Tolerances are established for the combined residues, free and 
conjugated, of the herbicide MCPB, 4-(4-chloro-2-methylphenoxy)butanoic 
acid, and its metabolite MCPA, (4-chloro-2-methylphenoxy)acetic acid, 
in or on the following food commodities:

[[Page 66786]]



------------------------------------------------------------------------
              Commodity                        Parts per million
------------------------------------------------------------------------
Peppermint, tops....................                                0.20
Spearmint, tops.....................                                0.20
------------------------------------------------------------------------

* * * * *
[FR Doc. E8-26875 Filed 11-10-08; 8:45 am]

BILLING CODE 6560-50-S
