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Notice

Zinc Phosphide; Notice of Filing a Pesticide Petition to Establish a Tolerance for a Certain Pesticide Chemical in or on Food

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Information about this document as published in the Federal Register.

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AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Notice.

SUMMARY:

This notice announces the initial filing of a pesticide petition proposing the establishment of regulations for residues of a certain pesticide chemical in or on various food commodities.

DATES:

Comments, identified by docket ID number OPP-2003-0204, must be received on or before August 8, 2003.

ADDRESSES:

Comments may be submitted electronically, by mail, or through hand delivery/courier. Follow the detailed instructions as provided in Unit I. of the SUPPLEMENTARY INFORMATION.

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FOR FURTHER INFORMATION CONTACT:

Sidney Jackson, Registration Division (7505C), Office of Pesticide Programs, Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; telephone number: (703) 305-7610; e-mail address: jackson.sidney@epa.gov.

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SUPPLEMENTARY INFORMATION:

I. General Information

A. Does this Action Apply to Me?

You may be potentially affected by this action if you are an agricultural producer, food manufacturer, or pesticide manufacturer. The North American Industrial Classification System (NAICS) codes have been provided to assist you and others in determining whether this action might apply to certain entities. Potentially affected entities may include, but are not limited to:

  • Crop production (NAICS 111)
  • Animal production (NAICS 112)
  • Food manufacturing (NAICS 311)
  • Pesticide manufacturing (NAICS 32532)

This listing is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be affected by this action. Other types of entities not listed in this unit could also be affected. 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 Copies of this Document and Other Related Information?

1. Docket. EPA has established an official public docket for this action under docket identification (ID) number OPP-2003-0204. The official public docket consists of the documents specifically referenced in this action, any public comments received, and other information related to this action. Although a part of the official docket, the public docket does not include Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. The official public docket is the collection of materials that is available for public viewing at the Public Information and Records Integrity Branch (PIRIB), Rm. 119, Crystal Mall #2, 1921 Jefferson Davis Hwy., Arlington, VA. This docket facility is open from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal holidays. The docket telephone number is (703) 305-5805.

2. Electronic access. You may access this Federal Register document electronically through the EPA Internet under the “Federal Register” listings at http://www.epa.gov/​fedrgstr/​.

An electronic version of the public docket is available through EPA's electronic public docket and comment system, EPA Dockets. You may use EPA Dockets at http://www.epa.gov/​edocket/​ to submit or view public comments, access the index listing of the contents of the official public docket, and to access those documents in the public docket that are available electronically. Start Printed Page 40940Although not all docket materials may be available electronically, you may still access any of the publicly available docket materials through the docket facility identified in Unit I.B.1. Once in the system, select “search,” then key in the appropriate docket ID number.

Certain types of information will not be placed in the EPA Dockets. Information claimed as CBI and other information whose disclosure is restricted by statute, which is not included in the official public docket, will not be available for public viewing in EPA's electronic public docket. EPA's policy is that copyrighted material will not be placed in EPA's electronic public docket but will be available only in printed, paper form in the official public docket. To the extent feasible, publicly available docket materials will be made available in EPA's electronic public docket. When a document is selected from the index list in EPA Dockets, the system will identify whether the document is available for viewing in EPA's electronic public docket. Although not all docket materials may be available electronically, you may still access any of the publicly available docket materials through the docket facility identified in Unit I.B. EPA intends to work towards providing electronic access to all of the publicly available docket materials through EPA's electronic public docket.

For public commenters, it is important to note that EPA's policy is that public comments, whether submitted electronically or in paper, will be made available for public viewing in EPA's electronic public docket as EPA receives them and without change, unless the comment contains copyrighted material, CBI, or other information whose disclosure is restricted by statute. When EPA identifies a comment containing copyrighted material, EPA will provide a reference to that material in the version of the comment that is placed in EPA's electronic public docket. The entire printed comment, including the copyrighted material, will be available in the public docket.

Public comments submitted on computer disks that are mailed or delivered to the docket will be transferred to EPA's electronic public docket. Public comments that are mailed or delivered to the docket will be scanned and placed in EPA's electronic public docket. Where practical, physical objects will be photographed, and the photograph will be placed in EPA's electronic public docket along with a brief description written by the docket staff.

C. How and to Whom Do I Submit Comments?

You may submit comments electronically, by mail, or through hand delivery/courier. To ensure proper receipt by EPA, identify the appropriate docket ID number in the subject line on the first page of your comment. Please ensure that your comments are submitted within the specified comment period. Comments received after the close of the comment period will be marked “late.” EPA is not required to consider these late comments. If you wish to submit CBI or information that is otherwise protected by statute, please follow the instructions in Unit I.D. Do not use EPA Dockets or e-mail to submit CBI or information protected by statute.

1. Electronically. If you submit an electronic comment as prescribed in this unit, EPA recommends that you include your name, mailing address, and an e-mail address or other contact information in the body of your comment. Also include this contact information on the outside of any disk or CD ROM you submit, and in any cover letter accompanying the disk or CD ROM. This ensures that you can be identified as the submitter of the comment and allows EPA to contact you in case EPA cannot read your comment due to technical difficulties or needs further information on the substance of your comment. EPA's policy is that EPA will not edit your comment, and any identifying or contact information provided in the body of a comment will be included as part of the comment that is placed in the official public docket, and made available in EPA's electronic public docket. If EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, EPA may not be able to consider your comment.

i. EPA Dockets. Your use of EPA's electronic public docket to submit comments to EPA electronically is EPA's preferred method for receiving comments. Go directly to EPA Dockets at http://www.epa.gov/​edocket, and follow the online instructions for submitting comments. Once in the system, select “search,” and then key in docket ID number OPP-2003-0204. The system is an “anonymous access” system, which means EPA will not know your identity, e-mail address, or other contact information unless you provide it in the body of your comment.

ii. E-mail. Comments may be sent by e-mail to opp-docket@epa.gov, Attention: Docket ID Number OPP-2003-0204. In contrast to EPA's electronic public docket, EPA's e-mail system is not an “anonymous access” system. If you send an e-mail comment directly to the docket without going through EPA's electronic public docket, EPA's e-mail system automatically captures your e-mail address. E-mail addresses that are automatically captured by EPA's e-mail system are included as part of the comment that is placed in the official public docket, and made available in EPA's electronic public docket.

iii. Disk or CD ROM. You may submit comments on a disk or CD ROM that you mail to the mailing address identified in Unit I.C.2. These electronic submissions will be accepted in WordPerfect or ASCII file format. Avoid the use of special characters and any form of encryption.

2. By mail. Send your comments to: Public Information and Records Integrity Branch (PIRIB) (7502C), Office of Pesticide Programs (OPP), Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460-0001, Attention: Docket ID Number OPP-2003-0204.

3. By hand delivery or courier. Deliver your comments to: Public Information and Records Integrity Branch (PIRIB), Office of Pesticide Programs (OPP), Environmental Protection Agency, Rm. 119, Crystal Mall #2, 1921 Jefferson Davis Hwy., Arlington, VA, Attention: Docket ID Number OPP-2003-0204. Such deliveries are only accepted during the docket's normal hours of operation as identified in Unit I.B.1.

D. How Should I Submit CBI to the Agency?

Do not submit information that you consider to be CBI electronically through EPA's electronic public docket or by e-mail. You may claim information that you submit to EPA as CBI by marking any part or all of that information as CBI (if you submit CBI on disk or CD ROM, mark the outside of the disk or CD ROM as CBI and then identify electronically within the disk or CD ROM the specific information that is 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 docket and EPA's electronic public docket. If you submit the copy that does not contain CBI on disk or CD ROM, mark the outside of the disk or CD ROM clearly that it does not contain CBI. Information not marked as CBI will be included in the public docket and EPA's electronic public docket without prior Start Printed Page 40941notice. If you have any questions about CBI or the procedures for claiming CBI, please consult the person listed 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 notice.

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. What Action is the Agency Taking?

EPA has received pesticide petitions as follow proposing the establishment and/or amendment of regulations for residues of a certain pesticide chemical in or on various food commodities under section 408 of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a. EPA has determined that these petitions contain data or information regarding the elements set forth in FFDCA section 408(d)(2); however, EPA has not fully evaluated the sufficiency of the submitted data at this time or whether the data support granting of the petitions. Additional data may be needed before EPA rules on the petitions.

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List of Subjects

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Dated: June 24, 2003.

Debra Edwards,

Director, Registration Division, Office of Pesticide Programs.

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Summary of Petitions

The petitioner's summary of the pesticide petitions is printed below as required by FFDCA section 408(d)(3). The summary of the petitions was prepared by the petitioner and represents the view of the petitioner. The petitions summary announces the availability of a description of the analytical methods available to EPA for the detection and measurement of the pesticide chemical residues or an explanation of why no such method is needed.

Interregional Research Project Number 4 (IR-4)

PP 2E6419, 1E6306, 1E6270, 1E6337, 9E5082, 0E6199, and 1E6292

EPA has received pesticide petitions (2E6419, 1E6306, 1E6270, 1E6337, 9E5082, 0E6199, 1E6292) from the IR-4 Project, Center for Minor Crop Pest Management, Rutgers, The State University of New Jersey, 681 U.S. Highway #1 South, North Brunswick, NJ 08902-3390 proposing, pursuant to section 408(d) of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a(d), to amend 40 CFR 180.284 by establishing tolerances for residues of the rodenticide zinc phosphide in or on the following raw agricultural commodities:

  • PP 2E6419 proposes to establish a tolerance in or on alfalfa, forage and alfalfa, hay at 0.1 parts per million (ppm).
  • PP 1E6306 proposes a tolerance in or on barley, grain and barley, hay at 0.05 ppm, and barley, straw at 0.2 ppm.
  • PP 1E6270 proposes a tolerance in or on bean, dry, seed at 0.05 ppm.
  • PP 1E6337 proposes tolerances in or on beet, sugar, roots at 0.05 ppm and beet, sugar, tops at 0.2 ppm.
  • PP 9E5082 proposes a tolerance in or on potato at 0.05 ppm.
  • PP 0E6199 proposes a tolerance in or on timothy hay and timothy forage at 0.05 ppm.
  • PP 1E6292 proposes a tolerance in or on wheat grain; wheat, hay; and wheat, straw at 0.05 ppm.

EPA has determined that these petitions contain data or information regarding the elements set forth in section 408(d)(2) of the FFDCA; however, EPA has not fully evaluated the sufficiency of the submitted data at this time or whether the data support granting of the requests. Additional data may be needed before EPA rules on the petitions.

A. Toxicological Profile

1. Acute toxicity. The rat acute oral lethal dose (LD)50 values for zinc phosphide technical (89% active ingredient (a.i.) ranged from 13-35 milligrams/kilogram (mg/kg) body weight (bwt) and averaged 21 mg/kg. The acute dermal LD50 was greater than 2,000 mg/kg for zinc phosphide technical (94% a.i.) in rabbits. The 4-hour inhalation lethal concentration (LC)50 on end-use product was less than 69 mg/cubic meter(m3) air (aerosol). Zinc phosphide was not irritating dermally to rabbit skin (94% a.i.) and caused only slight conjunctival redness, chemosis, and discharge in the rabbit's eyes. Zinc phosphide end-use product did not cause skin sensitization in guinea pigs. No toxicology studies were identified by EPA which demonstrated the need for an acute dietary risk assessment (65 FR 49936).

2. Genotoxicity. Salmonella TA-strains of bacteria were exposed to zinc phosphide (97% a.i.) suspended in dimethyl sulfoxide (DMSO), at doses up to 5,000 μg/plate, with and without metabolic activation (S9). Zinc phosphide was negative for gene mutation in the Ames test. Mouse lymphoma cells were exposed to zinc phosphide (97% a.i.) with and without mammalian metabolic activation (S9). Increased mutants at the thymidine kinase locus (TK) were induced in a dose-dependent manner at doses of 10 through 80 μg/mL (+/- S9). Zinc phosphide was positive for gene mutation in this mouse lymphoma assay. Mice were treated with zinc phosphide (97% a.i.) suspended in corn oil up to severely toxic levels (150 mg/kg). No increased aberrations (micronuclei) were induced. Zinc phosphide was negative for mutagenicity in this micronucleus test.

3. Reproductive and developmental toxicity. The requirements for a two-generation reproductive toxicity study in rats and a developmental study on a non-rodent species were waived in the Reregistration Eligibility Decision (RED Zinc Phosphide, EPA 738-R-98-006, July 1998). In a developmental toxicity study, the maternal no observed adverse effect level (NOAEL) was determined to be 2.0 mg/kg and the lowest effect level (LEL) was 4.0 mg/kg based on mortality. The developmental NOAEL was at or above 4.0 mg/kg, which was the highest dose tested.

4. Short- and intermediate-term toxicity. Based on the acute dermal LD50 study in rabbits, no appropriate toxic effects were identified for risk assessment. In that study no mortalities were observed at 5,000 mg/kg. At the lowest observed adverse effect level (LOAEL) of 2,000 mg/kg, there was a decrease in body weight. Based on the physical properties of the chemical, dermal absorption is expected to be very low, since zinc phosphide reacts with water and stomach acid to produce the toxic gas phosphine from oral, but not dermal exposure. As no endpoint of toxicological concern for dermal Start Printed Page 40942exposure has been identified, no dermal penetration data were required. The requirement for an acute inhalation study has been waived; thus, zinc phosphide has been placed in Toxicity Category I for acute inhalation exposure.

5. Chronic toxicity. EPA has established the Reference Dose (RfD) for zinc phosphide at 0.0001 mg/kg/day. This RfD is based on a subchronic oral study in rats with a NOAEL of 0.1 mg/kg/day and an uncertainty factor (UF) of 1,000 based on increased mortality, increase in absolute and relative liver weight and hematological changes at the LOAEL of 1 mg/kg/day. An uncertainty factor of 100 was applied to account for both the interspecies extrapolation and intraspecies variability. An additional UF of 10 was applied to account for the lack of reproductive data, and the lack of chronic toxicity data in a non-rodent species (65 FR 49936).

6. Animal metabolism. Since residues are expected to be minimal or nonexistent, the requirement for a metabolism study with zinc phosphide has been waived. If new uses result in detectable residues, then this requirement will be reinstated.

7. Metabolite toxicity. Since residues are expected to be minimal or nonexistent, the requirement for a metabolism study with zinc phosphide has been waived.

8. Carcinogenicity. The requirement for carcinogenicity studies has been waived for zinc phosphide because chronic exposure is expected to be negligible.

9. Endocrine disruption. There are no data available to suggest that zinc phosphide will adversely affect the immune or endocrine systems.

B. Exposures and Risks

1. From food and feed uses. Tolerances have been established (40 CFR 180.284) for the residues of phosphine resulting from the use of zinc phosphide, in or on a variety of raw agricultural commodities at levels ranging from 0.01 ppm in or on grapes to 0.1 ppm in or on grasses (rangeland). Zinc phosphide uses on grapes, pasture, and rangeland grasses, sugar beets, and sugar cane are classified as food uses. Currently registered uses on alfalfa, barley, wheat, and timothy are classified as non-food uses. The recently submitted petitions seek to amend the method of applications for these crops as follows:

i. Alfalfa; from underground or in burrow builder, or bait box use to above ground broadcast application. The proposed application would limit the timing of application to the period during dormant season (Idaho), or following removal of all cut alfalfa and prior to new growth obtaining 2 to 3 inches (California and Idaho),

ii. Barley and wheat; from dormant season use (underground or in burrow builders) to above ground broadcast application prior to grain head formation.

iii. Timothy; from dormant season use, with no animal grazing, to use during crop dormancy but permitting livestock grazing after 158 days. These types of applications are classified as food uses; therefore, a tolerance is required. There is no reasonable expectation of secondary residues in meat, milk, poultry, or eggs. Any residues of zinc phosphide ingested by livestock would be metabolized to naturally occurring phosphorous compounds. Risk assessments were conducted by EPA to assess dietary exposures and risks from zinc phosphide applied as non-food use as follows: Acute and chronic exposure and risk. Acute dietary risk assessments are performed for a food-use pesticide if a toxicological study has indicated the possibility of an effect of concern occurring as a result of a 1-day or single exposure. Currently, it is not known whether the proposed use of zinc phosphide on the subject crops will result in acute or chronic human dietary exposure to zinc phosphide.

However, the petitioner notes the following:

i. Zinc phosphide is not systemic (i.e., it will not move to other portions of the plant such as roots and affect a root crop such as potatoes or sugar beets).

ii. Residues of phosphine are less than the limit of quantification (0.05) in wheat and barley grain, in dry beans, in potatoes, in sugar beet roots, and in timothy hay.

iii. The grain and sugar beet roots will be processed prior to human consumption.

iv. There is no expectation of secondary residues in meat, milk, poultry, and eggs as a result of the registered and proposed uses.

2. From drinking water. Zinc phosphide degrades rapidly to phosphine and zinc ions both of which adsorb strongly to soil and are common nutrients in soil. Zinc phosphide and its degradation products appear to have low potential for ground water and surface water contamination. Therefore, dietary exposure is not expected from either ground water or surface water fed drinking water.

3. From non-dietary exposure. Zinc phosphide is currently registered for use on residential non-food sites. A detailed residential exposure assessment is contained in the RED for zinc phosphide (RED Zinc Phosphide, EPA 738-R-98-006, July 1998). The residential exposure assessment evaluated exposure from accidental ingestion of zinc phosphide. No other residential exposure assessment was required. It is stated in the RED that the Agency believes that “accidental ingestion” of zinc phosphide baits should not be included in the FQPA determination for tolerance setting.

4. Cumulative exposure to substances with a common mechanism of toxicity. Section 408(b)(2)(D)(v) requires that, when considering whether to establish, modify, or revoke a tolerance, the Agency considers “available information” concerning the cumulative effects of a particular pesticide's residues and “other substances that have a common mechanism of toxicity.” Zinc phosphide, aluminum phosphide, and magnesium phosphide all generate phosphine gas. However, the toxicity from phosphine gas is an acute effect and is readily eliminated from the body. Aluminum and magnesium phosphide, unlike zinc phosphide which is a bait, are used in fumigations. Exposure to phosphine gas from both bait and fumigation treatments is highly unlikely. It is unclear whether zinc phosphide has a common mechanism of toxicity with other substances or how to include this pesticide in a cumulative risk assessment. Unlike other pesticides, where a cumulative risk approach is based on a common mechanism of toxicity, zinc phosphide does not appear to produce a toxic metabolite produced by other substances.

C. Aggregate Exposure

1. Acute and chronic risk. There are currently no drinking water, residential, or dietary components to acute and chronic aggregate exposure to zinc phosphide residues. Thus, acute and chronic aggregate exposure assessments were not required in the RED (Zinc Phosphide, EPA 738-R-98-006, July 1998).

2. Short- and intermediate-term risk. Short- and intermediate-term aggregate exposure takes into account chronic dietary food and water (considered to be a background exposure level) plus indoor and outdoor residential exposure. No short- or intermediate-term dermal, oral or inhalation toxicological endpoints were identified for zinc phosphide. Thus, no short- or intermediate-term risk assessments were required in the RED (Zinc Phosphide, EPA 738-R-98-006, July 1998).

3. Aggregate cancer risk for U.S. population. Although zinc phosphide is registered for use on food crops, no chronic toxicity or carcinogenicity Start Printed Page 40943studies were required because chronic exposure to zinc phosphide or its byproducts were considered to be negligible. Thus, data are not available to classify zinc phosphide in terms of carcinogenicity and a cancer risk assessment was not performed.

D. Determination of Safety

1. U.S. population. The RED set the RfD at 0.0001. EPA generally has no concerns for exposures below 100% of the RfD, because the RfD represents the level at or below which daily aggregate exposure over a lifetime will not pose appreciable risks to human health.

2. Infants and children. The available data base for zinc phosphide does not indicate a potential for an increased sensitivity to infants or children; however it does not include a two-generation reproductive toxicity study in rats or a developmental toxicity study for a non-rodent species. The available data provided no indication of increased sensitivity of fetal rats to in utero exposure to zinc phosphide. The prenatal exposure developmental toxicity study in rats demonstrated no developmental effects at the highest dose tested (4.0 mg/kg/day) which was maternally toxic. There was no assessment of in utero exposure to non-rodents (rabbits), nor was there an assessment of early postnatal exposure. The EPA did not require these studies because exposure from food sources is expected to be minimal to non-existent. The additional uncertainty factor (referred to in Section A.5.) will also accommodate the inability to assess the potential for increased sensitivity of infants and children, because of the lack of sufficient animal data on in utero and early postnatal exposure to zinc phosphide (a prenatal developmental toxicity study in rabbits and a two-generation reproductive toxicity study in rats). Although residue studies show there were quantifiable residues in sugarcane, sugar beets, and grasses, these commodities are not direct human foods and no dietary consumption is expected. EPA has determined that there is no likelihood of residues of zinc phosphide occurring in any processed commodities. Also, there is no likelihood of residues of zinc phosphide or phosphine being found through transfer of residues on grasses to meat and milk.

Based upon the likelihood that residues of zinc phosphide will not occur in processed commodities, milk and meat, there is a reasonable certainty that no harm will result from aggregate exposure to zinc phosphide residues.

E. Other Considerations

1. Metabolism in plants and animals. The nature of the residue in plants is adequately understood. The residue of concern is zinc phosphide measured as phosphine. There is no expectation of secondary residues in meat, milk, poultry, and eggs as a result of the registered uses. Residues of zinc phosphide ingested by livestock would be immediately converted to phosphine and metabolized to naturally occurring phosphorous compounds.

2. Analytical enforcement methodology. Adequate enforcement methodology (colorimetric and GLC/FPD) is available (Pesticide Analytical Method II under aluminum phosphide) to enforce the tolerance expression. Residues were less than the limit of quantification in all raw agricultural commodities except for sugar beet tops (0.05 ppm for alfalfa, barley, grain and hay, dry beans, potatoes, sugar beet roots, timothy and wheat; 0.1 for barley straw),

i. Barley grown in the state of Idaho was treated with two applications of zinc phosphide at approximately 0.12 lb a.i./A per application, 23 to 28 days apart, and were harvested 50 or 60 days after the last application. Barley was also harvested 50 days following two applications at 0.96 lb a.i./A (8X the proposed application rate). Residues were less than the limit of quantification for barley grain and hay (0.05 ppm) and straw (0.1). Because no residues were found in samples treated at the 8X rate, no processing study is needed.

ii. Dry beans grown in the state of Idaho were treated with one application of zinc phosphide at approximately 0.12 lb a.i./A, and were harvested 31 days after the application and allowed to dry in the field. Seven days after harvesting the beans were thrashed and samples taken. Residues were less than the limit of quantification (0.05 ppm) on this commodity.

iii. Potatoes grown in the state of Idaho were treated with one application of zinc phosphide at approximately 0.2 lb a.i./A, and were harvested 28 to 31 days later. Potatoes were also harvested 28 to 31 days later following an application at 1.0 lb a.i./A (5x the proposed application rate). Residues were less than the limit of quantification (0.05 ppm) on this commodity. Because no residues were found in samples treated at the 5X rate, no processing study is needed.

iv. Sugar beets grown in the state of Idaho were harvested 27 to 29 days following two treatments of zinc phosphide at approximately 0.2 lb a.i./A. Sugar beets were also harvested 27 to 29 days following two treatments of zinc phosphide at approximately 4 lb a.i./A (20X the proposed application rate). Residues were less than the limit of quantification (0.05 ppm) on sugar beet roots. Sugar beet tops contained some residue and a tolerance of 0.2 ppm is being proposed for sugar beet tops. Because no residues were found in roots treated at the exaggerated rate, there is no need for data from processed roots. (OPPTS Harmonized Guideline 860.1520(f)(3)(iii)).

v. Timothy hay grown in the state of Washington was harvested 117 days following two treatments of zinc phosphide. The first treatment was at approximately 0.2 lb a.i./A and the second treatment was at approximately 0.4 lb a.i./A (due to applicator error). The hay was allowed to dry in the field after harvest. Residues were less than the limit of quantification (0.05 ppm) on timothy hay and timothy forage at harvest.

vi. Wheat grown in the state of Idaho was treated with two applications of zinc phosphide at approximately 0.12 lb a.i./A per application, 22 to 28 days apart, and were harvested 56 to 60 days after the last application. Wheat was also harvested 56 days following two applications at 0.96 lb a.i./A (8X the proposed application rate). Residues were less than the limit of quantification (0.05 ppm) for wheat grain, hay and straw. Because no residues were found in samples treated at the 8X rate, no processing study is needed.

vii. Fresh alfalfa grown in the state of California was harvested 32 days following one treatment of zinc phosphide at approximately 0.2 lb a.i./A. Fresh alfalfa was also harvested 32 days following one treatment of zinc phosphide at approximate 0.4 lbs a.i./A (2X the proposed application rate). Residues were less than the limit of quantification (0.05 ppm) on fresh alfalfa.

viii. Alfalfa hay and fresh alfalfa grown in the state of Nebraska were harvested 21 days following one treatment of zinc phosphide at approximately 0.2 lbs a.i./A. Residues were less than the limit of quantification (0.05 ppm) on alfalfa hay and fresh alfalfa.

ix. Alfalfa hay and alfalfa forage grown in the state of Idaho were harvested three times: 28-32 days, 78-83 days, and 121-129 days following the second of two treatments of zinc phosphide at approximately 0.2 lbs a.i./A. Residues were less than the limit of quantification (0.05 ppm) on alfalfa hay and alfalfa forage. (Petition for residue tolerance for alfalfa use in Idaho soon to be submitted.) Start Printed Page 40944

F. International Residue Limits

No CODEX, Canadian or Mexican maximum residue levels have been established for zinc phosphide.

G. Rotational Crop Restrictions

Data for confined accumulation in rotational crops have been waived because the physical properties of zinc phosphide precludes transfer of residues to rotated crops (Zinc Phosphide RED, EPA 738-R-98-006, July 1998). Thus, rotational crop restrictions are not required.

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[FR Doc. 03-17104 Filed 7-8-03; 8:45 am]

BILLING CODE 6560-50-S