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butylate (Sutan, Sutan+) Tolerance Reassessment by EPA 7/02

[OPP-2002-0156; FRL-7188-5]
Butylate Tolerances are Considered to be Reassessed by EPA
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice.
SUMMARY: This notice announces that EPA is considering as reassessed
all tolerances for residues of the herbicide butylate. The Agency has
determined that no common mechanism exists among butylate and the
thiocarbamates. Therefore, the Agency is not amending its previous
notice which constituted EPA's report on the Food Quality Protection
Act (FQPA) of 1996 tolerance reassessment progress and interim risk
management decision for butylate. By itself, butylate poses no risk
concerns within the limits of the existing tolerances, which will
remain in effect at 0.1 part per million (ppm) for all registered
commodities; however, the Agency intends to revise the commodity
definitions in accordance with current Agency administrative practice.
By law, EPA is required by August 2002 to reassess 66% of the
tolerances in existence on August 2, 1996, or about 6,400 tolerances.
The regulatory actions in this document pertain to the reassessment of
seven tolerances which are counted among tolerance/exemption
reassessments made toward the August 2002 review deadline.
FOR FURTHER INFORMATION CONTACT: By mail: Joseph Nevola, Special Review
and Reregistration Division (7508C), Office of Pesticide Programs,
Environmental Protection Agency, 1200 Pennsylvania Ave., NW.,
Washington, DC 20460; telephone number: (703) 308-8037; e-mail address:
I. General Information
A. Does this Action Apply to Me?
    This action is directed to the public in general. This action may,
however, be of interest to persons who are or may be required to
conduct testing of chemical substances under the Federal Insecticide,
Fungicide, and Rodenticide Act (FIFRA) or the Federal Food, Drug, and
Cosmetic Act (FFDCA); environmental, human health, and agricultural
advocates; pesticides users; and members of the public interested in
the use of pesticides. Since other entities may also be interested, the
Agency has not attempted to describe all the specific entities that may
be affected by this action. If you have any questions regarding the
applicability of this action to a particular entity, consult the person
B. How Can I Get Additional Information, Including Copies of This
Document and Other Related Documents?
    1. Electronically. You may obtain electronic copies of this
document, and certain other related documents that might be available
electronically, from the EPA Internet Home Page at
To access this document, on the Home Page select ``Laws and
Regulations,'' ``Regulations and Proposed Rules,'' and then look up the
entry for this document under the ``Federal Register--Environmental
Documents.'' You can also go directly to the Federal Register listings
    To access the butylate TRED (Report on FQPA Tolerance Reassessment
Progress and Interim Risk Management Decision) and butylate TRED
support documents electronically, go directly to
pesticides/reregistration/butylate/. You can also go to the EPA Office
of Pesticide Programs website for Tolerance Reassessment and
Reregistration, at
status.htm for additional information on butylate.
    2. In person. The Agency has established an official record for
this action under docket ID number OPP-2002-0156. The official record
consists of the documents specifically referenced in this action, and
other information related to this action, including any information
claimed as Confidential Business Information (CBI). This official
record includes the documents that are physically located in the
docket, as well as the documents that are referenced in those
documents. The public version of the official record does not include
any information claimed as CBI. The public version of the official
record is available for inspection in the Public Information and
Records Integrity Branch (PIRIB), Rm. 119, Crystal Mall #2, 1921
Jefferson Davis Hwy., Arlington, VA, from 8:30 a.m. to 4 p.m., Monday
through Friday, excluding legal holidays. The PIRIB telephone number is
(703) 305-5805.
II. Background
A. What Action is the Agency Taking?
    This notice announces to the general public that EPA has determined
that seven tolerances for residues of butylate are considered to be
reassessed. EPA evaluated existing pesticide tolerances under the FQPA
of 1996. The butylate tolerances included in this notice have been
found to meet the FQPA safety standard.
    On September 11, 2001 (66 FR 47219) (FRL-6796-3), EPA published a
notice in the Federal Register, entitled ``Butylate; Notice of
Pesticide Report on FQPA Tolerance Reassessment Progress and Interim
Risk Management Decision.'' That notice constituted the Agency's report
on the FQPA tolerance reassessment progress and interim risk management
decision for butylate. At that time, the Agency had not made a full
reassessment because the cumulative risk from thiocarbamates, such as
butylate, had not been evaluated. The September 11, 2001, notice
provided a 30-day comment period and invited public comment for
consideration. No comments were received by the Agency. Since then, the
Agency has made a determination on whether two subgroups of the
pesticides, thiocarbamates and dithiocarbamates, belong to a larger
group of chemicals known as carbamates and share a common mechanism of
toxicity. The Agency considered whether they cause a common effect that
is attributable to a common mechanism. A total of four common effects
were considered, including acetylcholinesterase inhibition. The Agency,
guided by several relevant science policies, summarized its position on
December 19, 2001, with respect to the grouping of the thiocarbamate
pesticides based on a common mechanism of toxicity and the results of a
screening level cumulative risk assessment. That December memorandum is
entitled ``Thiocarbamates: A Determination of the Existence of a Common
Mechanism of Toxicity and a Screening Level Cumulative Food Risk
Assessment.'' In that memorandum, EPA announced its determinations
    1. Some thiocarbamates (EPTC, molinate, pebulate, and cycloate)
share a common mechanism of toxicity for acetylcholinesterase
    2. There is insufficient evidence for grouping the thiocarbamate
pesticides based on a common mechanism for toxicity for effects other
than acetylcholinesterase inhibition.
    Although, structural and metabolic similarities exist among the
thiocarbamates and there is evidence that the thiocarbamates may
produce a common effect (neuropathology), this evidence is insufficient
to warrant a determination of common mechanism.
    Also, EPA conducted a preliminary screening level cumulative food
risk assessment for thiocarbamates which incorporated very conservative
assumptions; i.e., assumptions which overstate significantly the actual
level of potential risk. While a common mechanism of toxicity could not
be established for neuropathology, the effect was selected as the
endpoint for use in a screening level cumulative risk assessment to
assure that risks would not be underestimated. In part, the Agency
concluded that given the high dose required to provide evidence of
neuropathological potential and the questionable significance of the
solitary finding in a single study conducted with butylate, it is
unlikely that butylate would contribute to any cumulative dietary risk
that might result from dietary exposure to two or more thiocarbamates.
Because the ``No Observed Adverse Effect Level'' (NOAEL) for
neuropathological effects of butylate is substantially higher (120-
times greater) than the NOAEL used to establish a reference dose (RfD)
for butylate, and because neuropathology was observed at a limit dose
(2,000 milligrams/kilograms/day (mg/kg/day), it is unlikely that
butylate would contribute to potential cumulative risks of the
    EPA placed the December 19, 2001 memorandum, entitled ``A Common
Mechanism of Toxicity Determination for Thiocarbamate Pesticides.'' in
a docket with its attachments. Also, the memorandum is available on the
Agency's website at
thiocar.htm. EPA notified its stakeholders of its determination using
the Pesticide Program Update Messaging System and announced the
availability of these documents to the media. Further, EPA invited the
public to submit comments on these determinations during a 60-day
period, until February 22, 2002. No significant comments were received
regarding butylate during the provided 60-day period. Therefore,
chronic cumulative dietary risks for butylate are not of concern to the
Agency, and all tolerances for butylate in 40 CFR 180.232 for corn,
field, grain; corn, pop, grain; corn, sweet (kernels, plus cob with
husk removed); corn, field, stover; corn, field, forage; corn, pop,
forage; and corn, sweet, forage are now considered fully reassessed
according to FQPA because aggregate risks were previously assessed (66
FR 47219) and cumulative risk does not apply. These commodity
tolerances are each maintained at 0.1 ppm.
    In addition, to conform to current Agency practice, EPA will revise
specific commodity tolerance definitions in 40 CFR 180.232, according
to its prior notice of September 11, 2001 (66 FR 47219), in a future
action that will be published in the Federal Register.
B. What is the Agency's Authority for Taking this Action?
    The legal authority for tolerance reassessment falls under FFDCA,
as amended in 1996. Section 408(q) of FFDCA directs that ``the
Administrator shall review tolerances and exemptions for pesticide
chemical residues in effect on the day before the date of the enactment
of the FQPA of 1996, as expeditiously as practicable, assuring that--66
percent of such tolerances and exemptions are reviewed within 6 years
(i.e., by August 3, 2002), of the date of enactment of such Act (i.e.,
on August 3, 1996), and--shall determine whether the tolerance or
exemption meets the requirements of sections 408(b)(2) or (c)(2) and
shall, by the deadline for the review of the tolerance or exemption,
issue a regulation under section 408 (d)(4) or (e)(1) to modify or
revoke the tolerance or exemption if the tolerance or exemption does
not meet such requirements.'' Under section 408 of the FFDCA, a
tolerance may only be maintained if EPA determines that the tolerance
is safe based on a number of factors, including an assessment of the
aggregate exposure to the pesticide and an assessment of the cumulative
effects of such pesticide and other substances that have a common
mechanism of toxicity. In section 408(b)(2) of the FFDCA, ``the term
`safe,' with respect to a tolerance for a pesticide chemical residue,
means that the Administrator has determined 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.''
List of Subjects
    Environmental protection. Chemicals, Pesticides and pests,
    Dated: July 19, 2002.
  Lois Ann Rossi,
Director, Special Review and Reregistration Division, Office of
Pesticide Programs.
[FR Doc. 02-19105 Filed 7-30-02; 8:45 am]