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Diquat Dibromide - Label Modification Request Decision 9/02

ENVIRONMENTAL PROTECTION AGENCY
[OPP-2002-0192; FRL-7197-9]

Diquat Dibromide; Notice of Availability of Decision on
Syngenta's Request to Modify Label Requirements and Closure of 1995 RED

AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice.

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SUMMARY:  This notice announces EPA's intention to modify certain
occupational and residential risk mitigation measures that were imposed
as a result of the 1995 Reregistration Eligibility Decision (RED) for
diquat dibromide. At the end of the comment period, the Agency will
consider this action an immediate final decision and the 1995 RED
closed, unless adverse comments are received. The Agency conducted this
reassessment in response to new data submitted by the technical
registrant, Syngenta Crop Protection, Inc. Syngenta has requested the
Agency modify certain diquat dibromide label requirements including:
Personal protective equipment (PPE), closed loading system for aerial
applications, reentry intervals, and allow residential broadcast spray
uses.

DATES: Comments, identified by docket identification (ID) number OPP-
2002-0192, must be received on or before October 18, 2002.

ADDRESSES: Comments may be submitted by mail, electronically, or in
person. Please follow the detailed instructions for each method as
provided in Unit I. of the SUPPLEMENTARY INFORMATION. To ensure proper

receipt by EPA, it is imperative that you identify docket ID number
OPP-2002-0192 in the subject line on the first page of your response.

FOR FURTHER INFORMATION CONTACT:  Tyler Lane, Special Review and
Reregistration Division (7508C), Office of Pesticide Programs,
Environmental Protection Agency, 1200 Pennsylvania Ave., NW.,
Washington, DC 20460; telephone number: (703) 305-2737; e-mail address:
lane.tyler@epa.gov.

SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this Action Apply to Me?

    This action is directed to the public in general, nevertheless, a
wide range of stakeholders will be interested in obtaining information
on the label adjustments for diquat dibromide, including environmental,
human health, and agricultural advocates; the chemical industry;
pesticide users; and members of the public interested in the use of
pesticides on food. Since other entities also may 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
listed under FOR FURTHER INFORMATION CONTACT.

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 http://www.epa.gov/.
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 at http://www.epa.gov/
fedrgstr/. Copies of the tolerance reassessment decision and supporting
risk assessment documents for the reregistration of diquat dibromide
may also be accessed at

http://www.epa.gov/pesticides/reregistration/diquat_dibromide.htm.
    2. In person. The Agency has established an official record for
this action under docket ID number OPP-2002-0192. 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.

C. How and to Whom Do I Submit Comments?

    You may submit comments through the mail, in person, or
electronically. To ensure proper receipt by EPA, it is imperative that
you identify docket ID number OPP-2002-0192 in the subject line on the
first page of your response.
    1. By mail. Submit your comments to: Public Information and Records
Integrity Branch (PIRIB), Information Resources and Services Division
(7502C), Office of Pesticide Programs (OPP), Environmental Protection
Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460.
    2. In person or by courier. Deliver your comments to: Public
Information and Records Integrity Branch (PIRIB), Information Resources
and Services Division (7502C), Office of Pesticide Programs (OPP),
Environmental Protection Agency, Rm. 119, Crystal Mall #2, 1921
Jefferson Davis Highway, Arlington, VA. The PIRIB is open from 8:30
a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The
PIRIB telephone number is (703) 305-5805.
    3. Electronically. You may submit your comments electronically by
e-mail to: opp-docket@epa.gov, or you can submit a computer disk as
described above. Do not submit any information electronically that you
consider to be CBI. Avoid the use of special characters and any form of
encryption. Electronic submissions will be accepted in WordPerfect 6.1/
8.0/9.0 or ASCII file format. All comments in electronic form must be
identified by docket ID number OPP-2002-0192. Electronic comments may
also be filed online at many Federal Depository Libraries.

D. How Should I Handle CBI That I Want to Submit to the Agency?

    Do not submit any information electronically that you consider to
be CBI. You may claim information that you submit to EPA in response to
this document as CBI by marking any part or all of that information as
CBI. Information so marked will not be disclosed except in accordance
with procedures set forth in 40 CFR part 2. In addition to one complete
version of the comment that includes any information claimed as CBI, a
copy of the comment that does not contain the information claimed as
CBI must be submitted for inclusion in the public version of the
official record. Information not marked confidential will be included
in the public version of the official record without prior notice. If
you have any questions about CBI or the procedures for claiming CBI,
please consult the person identified under FOR FURTHER INFORMATION
CONTACT.

E. What Should I Consider as I Prepare My Comments for EPA?

    You may find the following suggestions helpful for preparing your
comments:
    1. Explain your views as clearly as possible.
    2. Describe any assumptions that you used.
    3. Provide copies of any technical information and/or data you used
that support your views.
    4. If you estimate potential burden or costs, explain how you
arrived at the estimate that you provide.
    5. Provide specific examples to illustrate your concerns.
    6. Make sure to submit your comments by the deadline in this
document.
    7. To ensure proper receipt by EPA, be sure to identify the docket
ID number assigned to this action in the subject line on the first page
of your response. You may also provide the name, date, and Federal
Register citation.

II. Background

A. What Action is the Agency Taking?

    In 1995, the Agency published its Reregistration Eligibility

Decision (RED) for diquat dibromide. Subsequent to the publication of
the 1995 RED, the technical registrant submitted additional data to
further refine diquat dibromide worker exposure and residential
broadcast spray use scenarios.
    Changes to the PPE label requirements of the 1995 RED are based on
the submission of additional data from a biomonitoring study of
knapsack applications of the closely related chemical paraquat, and a
reconsideration of the acute dermal toxicity endpoint. The Agency
reevaluated the dermal toxicity endpoint and rendered a decision that
the repeated dose dermal toxicity study used for the 1995 RED was not
appropriate for use in the risk assessment because the skins of the
rats used in the study were compromised. Instead, the Agency
extrapolated a dermal toxicity endpoint from a short-term oral study on
rabbits.
    The Agency has also reevaluated dermal absorption assumptions.
Previously, EPA assumed a standard absorption rate of 4.1%, based on a
rat dermal absorption study. Syngenta cited a human dermal absorption
study estimating a 0.3% dermal absorption rate for diquat dibromide
(Feldman RJ and Maibach HI, "Percutaneous penetration of some
pesticides and herbicides in man" Tox. Appl. Pharm. 28 126-132, 1974).
The Agency has relied on data provided by the Feldman-Maibach study for
previous risk assessments, and believes the study to be acceptable and
the data valid for use in this risk assessment. The use of the dermal
absorption factor of 0.3% further refines all aggregate margins of
exposure (MOEs) above the target MOE of 100, which would not be of
concern to the Agency.
    The Agency has evaluated the request to modify the cited label
requirements and summarized its assessment in the Occupational Risk
Evaluation: "Assessing Syngenta's Request to Modify Diquat Dibromide
Label Requirements," dated February 14, 2002. In addition, the "HED
Risk Assessment for Tolerance Reassessment Eligibility Document
(TRED)," March 6, 2002, and the "Re-characterization of Risk for the
Diquat Dibromide Tolerance Reassessment Eligibility Decision (TRED)
Based on New Dermal Absorption Data," March 13, 2002, were used to aid
in the assessment of aggregate risks from residential uses. Any
labeling changes are presented in the "Required Labeling Changes
Summary Table," which summarizes the labeling requirements for this
action. All supporting documents referenced in this document are
available in the public docket and at

http://www.epa.gov/pesticides/reregistration/diquat_dibromide.htm.
    In summary, the Agency expects to change the label requirements of
the 1995 RED for worker PPE and residential broadcast spray uses. The
following table presents the 1995 RED decisions being reevaluated, the
requests to change these requirements made by Syngenta, and the current
Agency decisions to amend the 1995 RED:
July 1995 RED
Syngenta Request
Amendments to 1995 RED
All workers required to wear a double layer
of clothing (coveralls over long sleeved
shirt, long pants), chemical resistant
gloves, chemical resistant footwear plus
socks, chemical resistant headgear for
overhead exposure, and a chemical resistant
apron when cleaning equipment, mixing
or loading)
Reduced PPE requirements due potential
for heat stress to field
workers and applicators
All workers must continue to wear protective footwear
and coveralls over a single layer of clothes (products
with a dermal toxicity of III or IV may reduce PPE to
protective footwear and coveralls over short pants and
short sleeve shirts). Mixers, loaders and hand applicators
must wear chemical resistant gloves, while applicators
who are operating closed cab equipment are
not required to wear chemical resistant gloves due to
MOEs over 1,000.
Respirators for mixing and loading No respirator requirements for mixing
and loading due to potential
for heat stress
Respirator requirement for mixer/loaders reduced to a
face shield to prevent droplets from entering the eyes,
mouth or nose areas
Closed mixing system for aerial applications. Open mixing system for aerial applications. Closed mixing/loading requirements remain for aerial applications.
7–Day restricted entry interval (REI) for
products used under the Worker Protection
Standard (WPS) unless there is no
contact with treated surfaces (such as mechanical harvesting)
4–Hour REI for potato desiccation
and seed crops
REI reduced to 24 hours for all WPS uses, based on
default reentry analysis findings of MOEs between
150 and 1,500 and a toxicity category II for eye irritation
4–Day REI for non-WPS uses other than
aquatic and spot treatment at residential sites
REI when spray is dry for non-WPS
uses
REI reduced to "when sprays are dry" for non-WPS
uses, also based on default reentry analysis
Prohibition of broadcast spray applications
for homeowner and residential uses
Broadcast spray applications for
homeowner and residential uses
Generic data requirements have been fulfilled for residential
broadcast spray uses. Broadcast spray applications
for homeowner and residential uses for enduse
products will be decided on a case-by-case basis
upon review of end-use product toxicity, based on
short-term exposure and individual risk assessments.
B. What is the Agency's Authority for Taking this Action?

    The legal authority for this decision falls under FIFRA, as amended
in 1988 and 1996. Section 4(g)(2)(A) of FIFRA directs that, after
submission of all data concerning a pesticide active ingredient, "the
Administrator shall determine whether pesticides containing such active
ingredient are eligible for reregistration," and either reregister
products or take other "appropriate regulatory action."

List of Subjects

    Environmental protection, Chemicals, Aquatic herbicides.

    Dated: September 5, 2002.
Lois Rossi,
Director, Special Review and Reregistration Division, Office of
Pesticide Programs.
[FR Doc. 02-23594 Filed 9-17-02; 8:45 am]