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Chlorpyrifos - Pesticide Tolerance—Final Rule 1/96

[Federal Register: January 31, 1996 (Volume 61, Number 21)]
[Page 3399-3400]
From the Federal Register Online via GPO Access []
40 CFR Part 180
[PP 4E4288 and 4E4289/R2198; FRL-4995-1]
RIN 2070-AC18
Chlorpyrifos; Pesticide Tolerance
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.

SUMMARY: This rule revises tolerances for residues of the insecticide
chlorpyrifos in or on the raw agricultural commodities peaches, pears,
plums, and nectarines by establishing the current time-limited
tolerances as permanent tolerances. The regulations to establish
maximum permissible levels of residues of the insecticide were
requested in petitions submitted by DowElanco and are needed to cover
maximum expected residues in or on imported commodities.

EFFECTIVE DATE: This regulation became effective January 24, 1996.

ADDRESSES: Written objections and hearing requests, identified by the
docket control number, [PP 4E4288 and 4E4289/R2198], may be submitted
to: Hearing Clerk (A-110), Environmental Protection Agency, Rm. M3708,
401 M St., SW., Washington, DC 20460. A copy of any objections and
hearing requests filed with the Hearing Clerk should be identified by
the docket control number and submitted to: Public Response and Program
Resources Branch, Field Operations Division (7506C), Office of
Pesticide Programs, Environmental Protection Agency, 401 M St., SW.,
Washington, DC 20460. In person, bring copy of objections and hearing
requests to Rm. 1132, CM 1B2, 1921 Jefferson Davis Highway, Arlington,
VA. Fees accompanying objections shall be labeled Tolerance Petition
"Fees" and forwarded to: EPA Headquarters Accounting Operations Branch,
OPP (Tolerance Fees), P.O. Box 360277M, Pittsburgh, PA 15251.
    An electronic copy of objections and hearing requests filed with
the Hearing Clerk may be submitted to OPP by sending electronic mail
(e-mail) to:
    Copies of electronic objections and hearing requests must be
submitted as an ASCII file avoiding the use of special characters and
any form of encryption. Copies of electronic objections and hearing
requests will also be accepted on disks in WordPerfect 5.1 file format
or ASCII file format. All copies of electronic objections and hearing
requests must be identified by the docket number [PP 4E4288 and 4E4289/
R2198]. No Confidential Business Information (CBI) should be submitted
through e-mail. Copies of electronic objections and hearing requests on
this rule may be filed online at many Federal Depository Libraries.
Additional information on electronic submissions can be found below in
this document.

Product Manager (PM) 19, Registration Division (7505C), Office of
Pesticide Programs, Environmental Protection Agency, 401 M St., SW.,
Washington, DC 20460. Office location, telephone number, and e-mail
address: Rm. 207, CM #2, 1921 Jefferson Davis Highway, Arlington, VA,
(703) 305-6386;

SUPPLEMENTARY INFORMATION: EPA issued a proposed rule, published in the
Federal Register of September 28, 1993 (58 FR 68621) which announced
that DowElanco had submitted pesticide petitions (PP 4E4288 and PP
4E4289) to the Administrator, pursuant to section 408(e) of the Federal
Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a(e), to amend 40
CFR 180.342 by revising the tolerances for residues of the insecticide
chlorpyrifos [O,O-diethyl O-(3,5,6-trichloro-2-pyridyl) phosphorothioate] in
or on the raw agricultural commodity pears from 0.01 to 0.05 part per million
(ppm) and peaches, nectarines, and plums from 0.01 ppm to 0.05 ppm. These
revisions in the tolerances were needed because of differing use patterns of
chlorpyrifos in other parts of the world as compared to the U.S.
    The Agency reviewed preliminary residue data and concluded that
residues should not exceed the proposed tolerances, but determined that
additional residue data for imported pears, peaches (data for peaches
suffices for nectarines), plums and prunes (the processed commodity of
plums) were required.
    Pending submission and review of the data, the Agency issued a
final rule, published in the Federal Register of February 25, 1994 (59
FR 9095), which announced that the Agency had revised the tolerances
for a 2-year period. The expiration date is January 28, 1996, at which
time the tolerances would revert to the previous 0.01 ppm for the named
    Additional residue data for pears, peaches, and plums were
submitted. (It was determined that chlorpyrifos residues do not
concentrate in the processing of plums to prunes, and no data were
submitted or required.) The data were reviewed and were determined to
be sufficient to justify removing the time limitation from the existing
tolerances. The available data do not support a change in the U.S. use
pattern for the crops listed above. If such a change is desired,
additional residue data generated in the U.S. must be submitted.
    The scientific data submitted in the petitions and other relevant
material have been evaluated. The toxicological data considered in
support of the tolerance include:
    1. A 2-year dog feeding study with a no-observed-effect level
(NOEL) for systemic effects of 1.0 milligram (mg)/kilogram (kg)/day and
lowest effect level (LEL) (increased liver weight) of 3.0 mg/kg/day.
The NOELs for cholinesterase (ChE) inhibition were as follows: 0.01 mg/
kg/day for plasma, 0.1 mg/kg/day for red blood cells, and 1.0 mg/kg/day
for brain cells. Levels tested were 0, 0.01, 0.03, 0.1, 1.0, and 3 mg/
    2. A voluntary human study with chronic ChE NOEL of 0.03 mg/kg/day
(based on 20 days of exposure at this level).
    3. A 2-year mouse chronic toxicity/carcinogenicity study with a
NOEL of 15 ppm for systemic effects (equivalent to 2.25 mg/kg/day) and
no carcinogenic effects observed under the conditions of the study at
all levels tested (0, 0.5, 5, and 15 ppm, equivalent to 0.075, 0.75,
and 2.25 mg/kg/day).
    4. A voluntary human study with acute ChE NOEL of 0.10 mg/kg/day
(based on daily single-dose exposures of 0, 0.014, 0.03, or 0.10 mg/kg/
day) determined at 1, 3, 6, and 9 days of treatment.
    5. A 2-year rat feeding/carcinogenicity study with ChE NOEL of 0.1
and LEL of 1.0 mg/kg/day (based on decreased plasma and brain ChE
activity), and a systemic NOEL of 1.0 mg/kg/day and LEL of 10 mg/kg/day
(based on decreased erythrocyte and hemoglobin values and increased
platelet count during the first year). There were no observed
carcinogenic effects at the levels tested (0.05, 0.1, 1.0, and 10 mg/
kg/day) under the conditions of the study. Chlorpyrifos is classified
as a Group E chemical (no evidence of carcinogenicity).
    6. A three-generation reproduction study in rats with no
reproductive effects observed at the dietary levels tested (0, 0.1,
0.3, and 1.0 mg/kg/day).
    7. Two rat developmental toxicity studies: one negative for
developmental toxicity at all dose levels (levels tested were 0.1, 3.0,
and 15.0 mg/kg/day); and one with maternal NOEL of 15 mg/kg/day and
developmental NOEL of 2.5 mg/kg/day (levels tested, by gavage, were 0,
0.5, 2.5, and 15 mg/kg/day).
    8. A mouse developmental toxicity study with a teratogenic NOEL
greater than 25 mg/kg/day (highest dose tested) and a developmental
fetotoxic NOEL of 10 mg/kg/day and LEL of 25 mg/kg/day (decreased fetal
length and increased skeletal variants).
    9. A developmental toxicity study in rabbits with maternal and
developmental NOELs of 81 mg/kg/day, and maternal and developmental
LELs of 140 mg/kg/day (based on maternal decreased food consumption on
gestation day 15 to 19, and body weight loss during the dosing period
followed by a compensatory weight gain; and based on a slight reduction
in fetal weights and crown-rump lengths, and fetal increased incidence
of unossified fifth sternebrae and/or xiphisternum). Levels tested were
0, 1, 9, 81, and 140 mg/kg/day.
    10. An acute delayed neurotoxicity study in the hen that was
negative at 50 and 100 mg/kg/day.
    11. Several mutagenicity studies which were all negative. These
include an Ames assay, two Chinese hamster ovary cell mutation assays,
a micronucleus assay for chromosomal aberration, an in vitro
chromosomal aberration assay with and without enzymatic activation, and
an unscheduled DNA synthesis assay.
    12. A general metabolism study in rats shows that the major
metabolite of chlorpyrifos is 3,5,6-trichloro-2-pyridinol (TCP). The
studies listed below were conducted to demonstrate that TCP is less
toxic than chlorpyrifos and is not a ChE inhibitor.
    a. A 90-day rat feeding study with a systemic NOEL of 30 mg/kg/day.
Levels tested were 0, 10, 30, and 100 mg/kg/day.
    b. A rat developmental toxicity study with no developmental
toxicity observed at the dosages tested (0, 50, 100, and 150 mg/kg/
    c. Mutagenicity studies (including an Ames assay and an unscheduled
DNA synthesis assay) were negative for mutagenic effects.
    Based on the above studies, the Agency has concluded that the TCP
metabolite is not of toxicological concern.
    For the assessment of chronic dietary risk, the reference dose
(RfD) based on the human voluntary ChE study (ChE NOEL of 0.03 mg/kg/
day) and using a 10-fold uncertainty factor is calculated to be 0.003
mg/kg of body weight/day. Tolerances for food uses appear in 40 CFR
180.342 and 40 CFR 185.1000. The Dietary Risk Exposure Section (DRES)
used, when justified and appropriate, anticipated residues rather than
published tolerance values, and data regarding percent crop treated
(when less than 100%). The anticipated residue contribution (ARC) from
published uses of chlorpyrifos is 0.000860 mg/kg of body weight/day for
the overall U.S. population. This represents 28.7% of the RfD. None of
the DRES subgroups has an exposure that exceeds the RfD. The population
subgroup most highly exposed is non-nursing infants, less than 1 year
old, with an ARC from published uses of 0.002147 mg/kg of body weight/
day, 71.6% of the RfD. The next most highly exposed population subgroup
is children, 1-6 years old, with an ARC from published uses of 0.001914
mg/kg of body weight/day, 63.8% of the RfD. It should be noted that
these values include contributions from pears, nectarines, peaches, and
plums with tolerances of 0.05 ppm; the tolerances are already in place
as temporary tolerances. This rule converts existing, temporary
tolerances to permanent tolerances and does not raise the ARC as a
percentage of the RfD.
    The DRES detailed acute analysis estimates the distribution of single-day
exposures for the overall U.S. population and certain subgroups. The analysis
evaluates individual food consumption as reported by respondents in the USDA
1977-78 Nationwide Food Consumption Survey (NFCS) and accumulates exposure to
the chemical for each commodity. Each analysis assumes uniform distribution of
chlorpyrifos in the commodity. Since the toxicological endpoint to which
exposure is being compared in this analysis is neurotoxicity, four human
population subgroups (infants, less than 1 year old; children, 1-12 years old;
females, 13 years old and older; males, 13 years old and older), as well as
the overall population, are of interest.
    The Margin of Exposure (MOE) is the ratio of the NOEL to the
exposure (NOEL/exposure = MOE). For neurotoxicity, the Agency is
generally not concerned unless the MOE is below 10 when the NOEL is
based on human data. Using refined exposure estimates generated in the
preparation of the Reregistration Eligibility Document (RED) for
chlorpyrifos, MOEs are greater than 10 for all population subgroups
evaluated except for children 1 through 6 years. Although the Agency
has concerns when low MOEs are calculated, this tolerance action does
not raise risk concerns. The MOEs are not affected by the rule because
any incremental change in exposure resulting from the tolerances for
pears, nectarines, peaches, and plums is negligible. Thus MOEs are not
changed by the tolerances for these commodities, much less by the
raising of the tolerance from 0.01 ppm to 0.05 ppm. It should also be
noted that the Agency will reassess chlorpyrifos tolerances in general
as part of the reregistration process. The RED is scheduled to be
issued in 1996.
    A record has been established for this rulemaking under docket
number [PP 4E4288 and 4E4289/R2198] (including any objections and
hearing requests submitted electronically as described below). A public
version of this record, including printed, paper versions of electronic
comments, which does not include any information claimed as CBI, is
available for inspection from 8 a.m. to 4:30 p.m., Monday through
Friday, excluding legal holidays. The public record is located in Room
1132 of the Public Response and Program Resources Branch, Field
Operations Division (7506C), Office of Pesticide Programs,
Environmental Protection Agency, Crystal Mall #2, 1921 Jefferson Davis
Highway, Arlington, VA.
    The official record for this rulemaking, as well as the public
version, as described above will be kept in paper form. Accordingly,
EPA will transfer any copies of objections and hearing requests
received electronically into printed, paper form as they are received
and will place the paper copies in the official rulemaking record which
will also include all comments submitted directly in writing. The
official rulemaking record is the paper record maintained at the
address in "ADDRESSES" at the beginning of this document.
    Under Executive Order 12866 (58 FR 51735, October 4, 1993), the
Agency must determine whether the regulatory action is "significant"
and therefore subject to review by the Office of Management and Budget
(OMB) and the requirements of the Executive Order. Under section 3(f),
the order defines a "significant regulatory action" as an action that
is likely to result in a rule: (1) Having an annual effect on the
economy of $100 million or more, or adversely and materially affecting
a sector of the economy, productivity, competition, jobs, the
environment, public health or safety, or State, local or tribal
governments or communities (also referred to as economically
"significant"); (2) creating serious inconsistency or otherwise
interfering with an action taken or planned by another agency; (3)
materially altering the budgetary impacts of entitlement, grants, user
fees, or loan programs or the rights and obligations thereof; or (4)
raising novel legal or policy issues arising out of legal mandates, the
President's priorities, or the principles set forth in this Executive
    Pursuant to the terms of this Executive Order, EPA has determined
that this rule is not "significant" and is therefore not subject to
OMB review.
    Pursuant to the requirements of the Regulatory Flexibility Act
(Pub. L. 96-354, 94 Stat. 1164, 5 U.S.C. 601-612), the Administrator
has determined that regulations establishing new tolerances or raising
tolerance levels or establishing exemptions from tolerance requirements
do not have a significant economic impact on a substantial number of
small entities. A certification statement to this effect was published
in the Federal Register of May 4, 1981 (46 FR 24950).

List of Subjects in 40 CFR Part 180

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

    Dated: January 24, 1996.
Stephen L. Johnson,
Director, Registration Division, Office of Pesticide Programs.

    Therefore, 40 CFR part 180 is amended as follows:


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

    Authority: 21 U.S.C. 346a and 371.

    2. In Sec. 180.342, by revising paragraph (e), to read as follows:

Sec. 180.342   Chlorpyrifos; tolerances for residues.

*      *      *      *      *
    (e) Tolerances are established as follows for residues of the
insecticide chlorpyrifos [O,O-diethyl O-(3,5,6-trichloro-2-pyridyl)
phosphorothioate] in or on the following raw agricultural commodities:

                                                              Parts per
                         Commodity                             million

Nectarines.................................................         0.05
Peaches....................................................         0.05
Pears......................................................         0.05
Plums......................................................         0.05


*      *      *      *      *