Document ID: EPA-HQ-OPP-2005-0268-0008
Agency: epa
Document Type: Rule
Title: Poly(hexamethylenebiguanide) hydrochloride (PHMB); Exemption from the Requirement of a Tolerance
Posted Date: 2008-01-09T05:00Z

[Federal Register: January 9, 2008 (Volume 73, Number 6)]
[Rules and Regulations]               
[Page 1512-1517]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr09ja08-7]                         

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[EPA-HQ-OPP-2005-0268; FRL-8345-8]

 
Poly(hexamethylenebiguanide) hydrochloride (PHMB); Exemption from 
the Requirement of a Tolerance

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes an exemption from the requirement 
of a tolerance for residues of the insecticide, 
Poly(hexamethylenebiguanide) hydrochloride (PHMB) on all food when 
residues are the result of lawful application of a food contact surface 
sanitizer containing PHMB as a sanitizer solution in food handling 
establishments when applied as a sanitizer. Arch Chemicals Inc. 
submitted a petition to EPA under the Federal Food, Drug, and Cosmetic 
Act (FFDCA), as amended by the Food Quality Protection Act of 1996 
(FQPA), requesting an exemption from the requirement of a tolerance. 
This regulation eliminates the need to establish a maximum permissible 
level for residues of PHMB.

DATES: This regulation is effective January 9, 2008. Objections and 
requests for hearings must be received on or before March 10, 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-2005-0268. 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 either in the electronic docket at http://www.regulations.gov
, or, if only

[[Page 1513]]

available in hard copy, at the Office of Pesticide Programs (OPP) 
Regulatory Public Docket in Rm. S-4400, One Potomac Yard (South Bldg.), 
2777 S. Crystal Dr., Arlington, VA. The hours of operation of this 
Docket Facility are 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: Adam Heyward, Antimicrobials Division 
(7510P), Environmental Protection Agency, 1200 Pennsylvania Ave., NW., 
Washington, DC 20460-0001; telephone number: (703) 308-6422; e-mail 
address: heyward.adam@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:
     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 provides 
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. To determine 
whether you or your business may be affected by this action, you should 
carefully examine the applicability provisions in 40 CFR 180.940(a) 
Tolerance exemptions for active and inert ingredients for use in 
antimicrobial formulations (Food-contact surface sanitizing solutions. 
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 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, as amended by FQPA, any person may 
file an objection to any aspect of this regulation and may also request 
a hearing on those objections. The EPA procedural regulations which 
govern the submission of objections and requests for hearings appear in 
40 CFR part 178. 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-2005-0268 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 on or before March 10, 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 your copies, identified by docket ID 
number EPA-HQ-OPP-2005-0268, 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. Background and Statutory Findings

    In the Federal Register of December 21, 2005 (70 FR 75805) (FRL-
7745-8), 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 tolerance 
petition (PP 5F6975) by Arch Chemical Inc.,1955 Lake Park Drive, Suite 
100, Smyrna, GA 30080. The petition requested that 40 CFR part 180 be 
amended by establishing an exemption from the requirement of a 
tolerance for residues of Poly(hexamethylenebiguanide) hydrochloride. 
This notice included a summary of the petition prepared by the 
petitioner Arch Chemical Inc. There were no comments received in 
response to the notice of filing.
    Section 408(c)(2)(A)(i) of FFDCA allows EPA to establish an 
exemption from the requirement for 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(c)(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. Pursuant to section 408(c)(2)(B) of FFDCA, in 
establishing or maintaining in effect an exemption from the requirement 
of a tolerance, EPA must take into account the factors set forth in 
section 408(b)(2)(C) of FFDCA, which 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....''
    EPA performs a number of analyses to determine the risks from 
aggregate exposure to pesticide residues. First, EPA determines the 
toxicity of pesticides. Second, EPA examines exposure to the pesticide 
through food, drinking water, and through other exposures that occur as 
a result of pesticide use in residential settings.

III. Toxicological Profile

A. Toxic Effects

    Consistent with section 408(b)(2)(D) of FFDCA, EPA has reviewed the 
available scientific data and other relevant information in support of 
this action and considered its validity, completeness and reliability 
and the relationship of this information 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

[[Page 1514]]

nature of the toxic effects are discussed in this unit.
    There are adequate toxicology data available to characterize the 
toxicity of PHMB. PHMB is a severe eye irritant and is a moderate 
dermal irritant and sensitizer. Acute oral, inhalation and dermal 
toxicity are acute toxicity, category III, which requires the signal 
word caution to appear on the product label as defined in 40 CFR 
156.64(3).

B. Toxic Endpoints

    For hazards that have a threshold below which there is no 
appreciable risk, the dose at which no adverse effects are observed 
(NOAEL) from the toxicology study identified as appropriate for the 
risk assessment is used to estimate the toxicological level of concern 
(LOC).
    The Agency's level of concern for residential PHMB dermal, 
inhalation and oral exposures is 100 (i.e. a margin of exposure (MOE) 
less than 100 exceeds the Agency's level of concern). The level of 
concern is based on 10x for interspecies extrapolation and 10x for 
intraspecies variability. A summary of the toxic endpoints for PHMB is 
listed in the following table.

           Table 1--Toxicological Endpoints for Assessing Occupational and Residential Exposures/Risk*
----------------------------------------------------------------------------------------------------------------
                                                                 Special FQPA SF and
          ExposureScenario               Dose Used in Risk      Level of Concern for    Study and Toxicological
                                           Assessment, UF          Risk Assessment              Effects
----------------------------------------------------------------------------------------------------------------
Acute Dietary (Females 13-50 years    NOAEL = 20 mg/kg/day     FQPA SF = 1             Rabbit Developmental
 of age)                              UF = 100...............  aPAD = acute RfD /       Study (MRID 42865901)
                                      Acute RfD = 0.2 mg/kg/    FQPA SF= 0.2 mg/kg/    LOAEL = 40 mg/kg/day
                                       day.                     day.                    based on a reduced
                                                                                        number of litters and
                                                                                        skeletal abnormalities.
----------------------------------------------------------------------------------------------------------------
Acute Dietary (General population          No appropriate single dose effect was identified for the general
 including infants and children)                                      population.
----------------------------------------------------------------------------------------------------------------
Chronic Dietary (All populations)     NOAEL = 20 mg/kg/day     FQPA SF = 1             Rabbit Developmental
                                      UF = 100...............  cPAD = chronic RfD /     Study (MRID 42865901)
                                      Chronic RfD = 0.2 mg/kg/  FQPA SF= 0.2 mg/kg/    LOAEL = 40 mg/kg/day
                                       day.                     day.                    Based on increased
                                                                                        mortality, reduced food
                                                                                        consumption, and
                                                                                        clinical toxicity;
                                                                                       Mouse Developmental Study
                                                                                        (Report No. CTL/P/335,
                                                                                        1977 (cited in Report
                                                                                        No. 003810, 1978.
                                                                                        Section C-9))
                                                                                       LOAEL = 40 mg/kg/day
                                                                                        Based on reduced body
                                                                                        weight gain; and
                                                                                       Rat Developmental Study
                                                                                        (Report No. CTL/P/1262,
                                                                                        1976 (cited in Report
                                                                                        No. 003810, 1978.
                                                                                        Section C-11))
                                                                                       LOAEL = 50 mg/kg/day
                                                                                        Based on reduced food
                                                                                        consumption.
----------------------------------------------------------------------------------------------------------------
Short-Term Incidental Oral (1-30      NOAEL = 20 mg/kg/day     Residential LOC for     Rabbit Developmental
 days)                                UF = 100...............   MOE = 100               Study (MRID 42865901)
                                                                                       LOAEL = 40 mg/kg/day
                                                                                        Based on the increased
                                                                                        mortality, reduced food
                                                                                        consumption, and
                                                                                        clinical toxicity;
                                                                                       Mouse Developmental Study
                                                                                        (Report No. CTL/P/335,
                                                                                        1977 (cited in Report
                                                                                        No. 003810, 1978.
                                                                                        Section C-9))
                                                                                       LOAEL = 40 mg/kg/
                                                                                        day;Based on reduced
                                                                                        body weight gain; and
                                                                                       Rat Developmental Study
                                                                                        (Report No. CTL/P/1262,
                                                                                        1976 (cited in Report
                                                                                        No. 003810, 1978.
                                                                                        Section C-11))
                                                                                       LOAEL = 50 mg/kg/day
                                                                                        Based on reduced food
                                                                                        consumption.
----------------------------------------------------------------------------------------------------------------
Intermediate-Term Incidental Oral (1  NOAEL = 20 mg/kg/day     Residential LOC for     See Short-Term Incidental
 - 6 months)                          UF = 100...............   MOE = 100               Oral Endpoint
----------------------------------------------------------------------------------------------------------------
Short-Term, Intermediate-Term and     Dermal (or oral) study   Residential LOC for     80-Week Skin Painting
 Long-Term Dermal Exposure            NOAEL= 150 mg/kg/day...   MOE = 100               Study - Mouse (MRIDs
                                      UF = 100...............                           00066475 and 00104796)
                                      (Relative dermal                                 LOAEL = 750 mg/kg/day
                                       absorption rate =100%).                          based on decreased body
                                                                                        weight and liver tumors.
----------------------------------------------------------------------------------------------------------------
Short-Term, Intermediate-Term and      An appropriate route-specific inhalation study is not available. The oral
 Long-Term Inhalation Exposure            endpoint of 20 mg/kg/day with a target MOE of 100 (10x inter-species
                                         extrapolation, 10x intra-species variation) is used. An additional 10x
                                          route-to-route extrapolation is used to determine if a confirmatory
                                                        inhalation toxicity study is warranted.
----------------------------------------------------------------------------------------------------------------
Cancer (oral, dermal)                  EPA has classified PHMB as having suggestive evidence of carcinogenicity
                                        but the evidence was too weak to warrant quantification of human cancer
                                                                          risk

----------------------------------------------------------------------------------------------------------------
*UF = uncertainty factor, FQPA SF = FQPA safety factor, NOAEL = no observed adverse effect level, LOAEL = lowest
  observed adverse effect level, PAD = acute population adjusted dose (a = acute, c = chronic) RfD = reference
  dose, LOC = level of concern, MOE = margin of exposure

[[Page 1515]]

IV. Aggregate Exposures

    In examining aggregate exposure, FFDCA section 408 directs EPA to 
consider available information concerning exposures from the pesticide 
residue in food and all other non-occupational exposures, including 
drinking water from ground water or surface water and exposure through 
pesticide use in gardens, lawns, or buildings (residential and other 
indoor uses).

A. Dietary Exposure

    PHMB is an antimicrobial that is used as a hard surface sanitizer 
and may be in or on food processing equipment, premises of food 
processing plants, milk processing equipment, milk processing plants, 
eating establishments, food contact surfaces, adhesives, and slurries. 
The use of PHMB as an antimicrobial product on these various surfaces 
may result in pesticide residues in human food. Residues from treated 
surfaces can migrate to food that comes into contact with the treated 
surfaces which then can result in human ingestion.
    1. Food. The Agency assessed acute and chronic dietary exposure 
from the use of PHMB as a disinfectant and food contact sanitizer on 
direct and indirect food-contact surfaces. This assessment calculated 
the Daily Dietary Dose (DDD) and the Estimated Daily Intake (EDI) using 
an FDA model (``Sanitizing Solutions: Chemical Guidelines for Food 
Additives Petition, January 1993''). The FDA model takes into account 
application rates, residual solution, area of the treated surface which 
comes into contact with food, pesticide migration fraction, and body 
weight of the population exposed.
    To calculate the EDI (estimated daily intake) values for PHMB when 
it is used as a sanitizer in public eating spaces, it was assumed that 
PHMB would be used at a concentration of 550 parts per million (ppm), 
the thickness of the PHMB residues on surfaces would be 1 mg per square 
centimeter of treated surface, and the surface area of the food contact 
surface being sanitized to which a person would be exposed on a daily 
basis is 4,000 cm2 (which includes contact with treated 
silverware, china, and glass used by an individual who regularly eats 
three meals per day at an institutional or public facility). It was 
also assumed that 100% of the pesticide would migrate to food.
    To calculate the EDI (estimated daily intake) values for PHMB when 
it is used in the food processing industry, it was also assumed to be 
used at a concentration of 550 ppm. However, specific to this scenario, 
the exposure estimates were calculated using the milk truck model that 
is described in the FDA document, ``Sanitizing Solutions: Chemistry 
Guidelines For Food Additive Petitions.'' This includes the assumption 
that estimates of sanitary exposure from use in dairy processing plants 
significantly exceed estimates based on other uses with food processing 
equipment and utensils. For the purpose of assessing risks stemming 
from food processing uses, parameters assuming a sanitized milk truck 
were used as the worst case scenario. The various input parameters, 
such as the size of the truck, internal surface area, residual 
thickness, and application rate of PHMB were used to calculate 
potential residues present in the truck per liter of food (i.e. milk).
    For each dietary exposure assessment it was assumed that adults 
(both male and female) consume 3,000 grams of food a day and a child, 
1,500 grams. This allowed for an estimation of the amount of PHMB that 
is anticipated to be present in an average adult's or child's daily 
intake from these uses, and in turn, the calculation of a daily dietary 
dose.
    2. Drinking water exposure. The uses of PHMB are not expected to 
significantly contaminate drinking water sources. As provided in the 
PHMB Reregistration Eligibility Document, ``none of the uses associated 
with PHMB are expected to impact either surface or ground water 
resources.'' Therefore, the PHMB contributions for drinking water 
exposure are considered to be negligible and are not quantified.

B. Other Non-Occupational Exposure

    The residential exposure assessment considers all potential non-
occupational pesticide exposure, other than exposure due to residues in 
food or in drinking water. Exposures may occur during and after 
application as a hard surface disinfectant (e.g. walls, floors, tables, 
fixtures) and to swimming pools. Each route of exposure is assessed, 
where appropriate, and risk is expressed as a margin of exposure (MOE), 
which is the ratio of estimated exposure to an appropriate NOAEL.
    Residential exposure may occur during application of PHMB to indoor 
hard surfaces (e.g., mopping, wiping, trigger pump sprays) and to 
swimming pools. The residential handler scenarios were assessed to 
determine dermal and inhalation exposures. Surrogate dermal and 
inhalation unit exposure values were estimated using Pesticide Handler 
Exposure Database (PHED) data and the Chemical Manufactures Association 
Anitmicrobial Exposure Assessment Study (USEPA, 1999) and the SWIMODEL 
3.0 was utilized to conduct exposure assessments of pesticides found in 
swimming pools and spas (Versar, 2003). Note that for this assessment, 
EPA assumed that residential users complete all elements of an 
application (mix/load/apply) without the use of personal protective 
equipment.
    The duration for most residential exposures is believed to be best 
represented by short-term duration (1 to 30 days). The short-term 
duration was chosen for this assessment because the residential handler 
and post-application scenarios are assumed to be performed on an 
episodic, not a daily basis.
    Based on toxicological criteria and the potential for exposure, the 
Agency has conducted incidental oral, dermal and inhalation exposure 
assessments for PHMB residential use. As noted previously, MOEs greater 
than or equal to 100 are considered adequately protective for the 
residential exposure assessment.
    Specific information on the residential exposure for PHMB can be 
found at http://www.regulations.gov, docket ID No. EPA-HQ-OPP-2005-

0268.

V. Cumulative Effects

    Section 408(b)(2)(D)(v) of the 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.''
    Unlike other pesticides for which EPA has followed a cumulative 
risk approach based on a common mechanism of toxicity, EPA has not made 
a common mechanism of toxicity finding as to PHMB and any other 
substances and PHMB does not appear to produce a toxic metabolite 
produced by other substances. For the purposes of this tolerance 
action, therefore, EPA has not assumed that PHMB has 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.

VI. Safety Factor for Infants and Children

    1. In general. Section 408 of FFDCA provides that EPA shall apply 
an additional (``10x'') tenfold margin of safety for infants and 
children in the

[[Page 1516]]

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 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. In applying 
this provision, EPA either retains the default value of 10x when 
reliable data do not support the choice of a different factor, or, if 
reliable data are available, EPA uses a different additional FQPA 
safety factor value based on the use of traditional uncertainty/safety 
factors and/or special FQPA safety factors, as appropriate.
    2. Prenatal and postnatal sensitivity. There is no quantitative or 
qualitative evidence of increased susceptibility to the fetus following 
in utero exposure to PHMB in the prenatal developmental toxicity 
studies, and no quantitative or qualitative evidence of increased 
susceptibility to the offspring when adults are exposed to PHMB in the 
two-generation reproductive study. In each study, any development/
reproductive effect observed occurred at doses equal to or higher than 
the doses at which maternal toxicity was observed. This, together with 
the nature of the effects seen in the studies has led the Agency to 
conclude that there is no evidence of increased susceptibility.
    EPA has determined that reliable data show that it would be safe 
for infants and children to reduce the FQPA safety factor to 1x. That 
decision is based on the following findings:
    i. The toxicity database for Poly(hexamethylenebiguanide) 
hydrochloride (PHMB) is complete for assessing risk to infants and 
children under the FFDCA.
    ii. There is no indication that PHMB is a neurotoxic chemical and 
there is no need for a developmental neurotoxicity study or additional 
uncertainty factors to account for neurotoxicity.
    iii. There is no evidence that PHMB results in increased 
susceptibility in in utero rats or rabbits in the prenatal 
developmental studies or in young rats in the two-generation 
reproduction study.
    iv. There are no residual uncertainties identified in the exposure 
databases. The dietary food exposure assessments were performed based 
on 100% crop treated (CT) and tolerance-level residues and will not 
underestimate the exposure and risk. Conservative ground and surface 
water modeling estimates were used. Similarly conservative Residential 
SOPs were used to assess post-application exposure to children as well 
as incidental oral exposure of toddlers. These assessments will not 
underestimate the exposure and risks posed by PHMB.

VII. Determination of Safety for U.S. Population, Infants and Children

    Safety is assessed for acute and chronic risks by comparing 
aggregate 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 LOC by all applicable 
uncertainty/safety factors. For linear cancer risks, EPA calculates the 
probability of additional cancer cases given aggregate exposure. Short-
, intermediate-, and long-term risks are evaluated by comparing 
aggregate exposure to the LOC to ensure that the MOE called for by the 
product of all applicable uncertainty/safety factors is not exceeded.
    1. Acute and chronic risk. EPA compares the estimated dietary 
exposures to an aPAD and a cPAD, both of which are 0.2 mg/kg/day for 
PHMB. Generally, a dietary exposure estimate that is less than 100% of 
the aPAD or cPAD does not exceed the Agency's levels of concern.
    The antimicrobial indirect food use acute/chronic risk estimates 
from exposure to treated utensils and countertops as well as from food 
processing facility sanitation are below the Agency's level of concern. 
For adults females of child bearing age (13 to 49 years old), the 
cumulative (food utensils and food processing) acute and chronic 
dietary exposure risk estimates are 18.8% of the acute and chronic 
PADs. For children ages 3 to 5 years old, the most highly exposed 
population subgroup, the cumulative chronic dietary risk estimates are 
37.2% of chronic PAD (there are no effects anticipated for the acute 
exposures). Therefore, dietary exposure estimates are below the 
Agency's level of concern for all population subgroups. Based on the 
information in this preamble, EPA concludes that there is a reasonable 
certainty of no harm from aggregate exposure to residues. Accordingly, 
EPA finds that exempting from the requirement of a tolerance will be 
safe.
    2. Non-occupational risk. Aggregate exposure takes into account 
residential exposure plus chronic exposure to food and water 
(considered to be a background exposure level).
    Using the exposure assumptions described in this unit for other 
non-occupational exposures, EPA has concluded that food, water, and 
residential exposures aggregated result in aggregate MOEs greater than 
or equal to 100 for the inhalation route of exposure and 100 for dermal 
exposure. Therefore, these levels of exposure are not of concern.
    3. Aggregate cancer risk for U.S. population. EPA has classified 
PHMB as having no greater than suggestive evidence of carcinogenicity. 
The weight-of-the-evidence considerations for this classification are 
as follows:
    i. A treatment-related statistically significant increase (trend 
and pair-wise) in vascular tumors (mainly benign) was seen in female 
rats at an oral dose that was considered to be adequate, but not 
excessive. This was considered the strongest evidence on the Agency's 
evaluation of PHMB.
    ii. Oral exposure to male and female mice also resulted in 
treatment-related vascular tumors seen at an excessive dose. However, 
at the next highest dose level, which was considered adequate but not 
excessive, there was a slight, but not statistically significant, 
increase in this same tumor, which added to the Agency's concern for 
this tumor type.
    iii. It is noted that dermal exposure to female mice resulted in an 
equivocal increase in vascular tumors seen at only an excessive dose.
    iv. No treatment-related increase in any tumors was seen in male 
rats via the oral route or in male mice via the dermal route of 
exposure.
    Based on the findings above, the Agency has determined that PHMB 
posed no greater than a negligible cancer risk.
    4. 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 PHMB. Accordingly, EPA finds that exempting PHMB from the 
requirement of a tolerance will be safe.

VII. Other Considerations

A. Endocrine Disruptors

    EPA is required under the FFDCA, as amended by FQPA, to develop a 
screening program to determine whether certain substances (including 
all pesticide active and other ingredients) ``may have an effect in 
humans that is similar to an effect produced by a naturally occurring 
estrogen, or other such endocrine effects as the Administrator may 
designate.'' Following the recommendations of its Endocrine Disruptor 
Screening and Testing Advisory Committee (EDSTAC), EPA determined that 
there was scientific basis for including, as part of the program, the 
androgen and thyroid hormone systems, in addition to the estrogen 
hormone system. EPA also

[[Page 1517]]

adopted EDSTAC's recommendation that the Program include evaluations of 
potential effects in wildlife. For pesticide chemicals, EPA will use 
the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), and, 
to the extent that effects in wildlife may help determine whether a 
substance may have an effect in humans, FFDCA has authority to require 
the wildlife evaluations. As the science develops and resources allow, 
screening of additional hormone systems may be added to the Endocrine 
Disruptor Screening Program (EDSP).
    When the appropriate screening and/or testing protocols being 
considered under the Agency's EDSP have been developed, PHMB may be 
subjected to additional screening and/or testing to better characterize 
effects related to endocrine disruption.

B. Analytical Method(s)

    An analytical method for food is not needed. Food contact 
sanitizers are typically regulated by state health departments to 
ensure that the food industry is using these products in compliance 
with regulations in 40 CFR 180.940. The end use solution that is 
applied to the food contact surface is analyzed not food items that may 
come into contact with the treated surface. An analytical method is 
available to analyze the use dilution that is applied to food contact 
surfaces. The solution can be analyzed by use of the spectrophotometric 
method.

C. Existing Tolerances

    There is no existing tolerance or exemption from tolerance for 
PHMB.

D. International Tolerances

    No Codex, Canadian, or Mexican maximum residue limits (MRLs) have 
been established for any food uses at this time.

VIII. Statutory and Executive Order Reviews

    This final rule establishes a tolerance 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 rule is not 
subject to Executive Order 13211, 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 6, 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).

IX. 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: December 18, 2007.
Betty Shackleford,
Acting Director, Antimicrobials 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 180.1280 is added to subpart D to read as follows:

Sec.  180.1280  Poly(hexamethylenebiguanide) hydrochloride (PHMB) 
exemption from the requirement of a tolerance.

    Poly(hexamethylenebiguanide) hydrochloride (PHMB)(CAS Reg. No. 
32289-58-0) is exempt from the requirement of a tolerance for residues 
of the antimicrobial in or on all food commodities when the residues 
are the result of the lawful application of a food contact surface 
sanitizer containing PHMB at 550 parts per million (ppm).

[FR Doc. E8-189 Filed 1-8-08; 8:45 am]

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