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Butylate Tolerances are Considered to be Reassessed by EPA

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Environmental Protection Agency (EPA).




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.

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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:

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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 listed under FOR FURTHER INFORMATION CONTACT.Start Printed Page 49690

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 at​fedrgstr/​.

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​pesticides/​reregistration/​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 that:

1. Some thiocarbamates (EPTC, molinate, pebulate, and cycloate) share a common mechanism of toxicity for acetylcholinesterase inhibition.

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 thiocarbamates.

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​pesticides/​cumulative/​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.Start Printed Page 49691

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.”

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List of Subjects

  • Environmental protection Chemicals
  • Pesticides and pests, thiocarbamate(s)
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Dated: July 19, 2002.

 Lois Ann Rossi,

Director, Special Review and Reregistration Division, Office of Pesticide Programs.

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[FR Doc. 02-19105 Filed 7-30-02; 8:45 am]