02-23594. 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.

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: [phone]; e-mail address: [e-mail].

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 [phone].

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 [phone].

3. Electronically. You may submit your comments electronically by e-mail to: [e-mail], 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 end-use 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.