[Federal Register Volume 62, Number 16 (Friday, January 24, 1997)]
[Notices]
[Pages 3688-3691]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-1753]


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ENVIRONMENTAL PROTECTION AGENCY
[PF-685; FRL-5579-3]


Mycogen Corporation; Pesticide Tolerance Petition Filing

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of filing.

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SUMMARY: This notice announces the filing of a pesticide petition 
proposing a regulation establishing an exemption from the requirement 
of a tolerance for residues of the pesticide pelargonic acid on all raw 
agricultural commodities. This notice includes a summary of the 
petition that was prepared by the petitioner, Mycogen Corporation.

DATES: Comments, identified by the docket control number [PF-685], must 
be received by EPA on or before February 24, 1997.

ADDRESSES: By mail, submit written comments to: Public Response and 
Program Resources Branch, Field Operations Division (7506C), Office of 
Pesticide Programs, Environmental Protection Agency, 401 M St., SW., 
Washington, DC 20460. In person, bring comments to: Rm. 1132, Crystal 
Mall #2, 1921 Jefferson Davis Hwy., Arlington, VA.
    Comments and data may also be submitted electronically by sending 
electronic mail (e-mail) to: [email protected]. Electronic 
comments must be submitted as an ASCII file avoiding the use of special 
characters and any form of encryption. Comments and data will also be 
accepted on disks in WordPerfect 5.1 file format or ASCII file format. 
All comments and data in electronic form must be identified by docket 
number [PF-685]. No ``Confidential Business Information'' (CBI) should 
be submitted through e-mail. Electronic comments on this notice of 
filing may be filed online at many Federal Depository Libraries. 
Additional information on electronic submissions can be found in Unit 
II. of this document.
    Information submitted as a comment concerning this document may be 
claimed confidential 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. A copy of the comment that 
does not contain CBI must be submitted for inclusion in the public 
record. Information not marked confidential may be disclosed publicly 
by EPA without prior notice. All written comments will be available for 
public inspection in Rm. 1132 at the address given above, from 8:30 
a.m. to 4 p.m., Monday through Friday, excluding legal holidays.

FOR FURTHER INFORMATION CONTACT: Michael Mendelsohn, Biopesticides and 
Pollution Prevention Division (7501W), Office of Pesticide Programs, 
Environmental Protection Agency, 401 M St., SW., Washington, DC 20460. 
Office location, telephone number, and e-mail address: 5th Floor, CS 
#1, 2805 Jefferson Davis Highway, Arlington, VA, 703-308-8715; e-mail: 
[email protected].

SUPPLEMENTARY INFORMATION: EPA has received pesticide petition (PP) 
6F4625 from Mycogen Corporation, 4980 Carroll Canyon Road, San Diego, 
CA 92121. The petition proposes, pursuant to section 408 of the Federal 
Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a, to amend 40 CFR 
part 180 by establishing an exemption from the requirement of a 
tolerance for residues of pelargonic acid on all raw agricultural 
commodities. EPA has determined that the petition contains data or 
information regarding the elements set forth in 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 petition. 
Additional data may be needed before EPA rules on the petition.
    Mycogen has stated that an analytical method for the detection and 
measurement of pelargonic acid residues is not necessary to protect the 
public health and environment. They state that the natural occurrence 
of pelargonic acid in our food supply and environment, and the rapid 
metabolism and degradation of pelargonic acid to background levels in 
humans, plants and soil, eliminate the need to quantify pelargonic acid 
residues.
    As required by section 408(d) of the FFDCA, as recently amended by 
the Food Quality Protection Act, Mycogen included in the petition a 
summary of the petition and authorization for the summary to be 
published in the Federal Register in a notice of receipt of the 
petition. The summary represents the views of Mycogen; EPA, as 
mentioned above, is in the process of evaluating the petition. As 
required by section 408(d)(3) EPA is including the summary as a part of 
this notice of filing. EPA may have made minor edits to the summary for 
the purpose of clarity.

I. Petition Summary

    This unit summarizes information cited by Mycogen to support the 
proposed tolerance.

A. Pelargonic Acid Uses

    Pelargonic acid is currently used as the active ingredient in two 
unique pesticide products. First, it is used as a contact, non-
selective, broadspectrum, foliar-applied herbicide. As the active 
ingredient in Scythe Herbicide (EPA Reg. No. 53219-7), 
registered by EPA for non-crop uses on April 7, 1994, pelargonic acid 
will only control actively growing emerged green vegetation. Pelargonic 
acid provides burndown of both annual and perennial broadleaf and grass 
weeds, as well as most mosses and other cryptogams. The spray quickly 
penetrates plant tissue and disrupts normal cell membrane permeability 
and cellular physiology. The disruption of the cell membrane results in 
cell leakage and death of all contacted tissue. The product does not 
translocate, and it will burn only those plant parts that make contact 
with spray solution. Scythe provides no residual

[[Page 3689]]

weed control; therefore, repeat treatments may be necessary for new 
plants emerging from seed or regrowth of treated vegetation.
    Scythe Herbicide contains as the active ingredient 57 percent 
pelargonic acid and 3 percent related fatty acids (C6 - C12). 
One gallon of Scythe contains 4.2 pounds (lbs) of pelargonic acid. The 
application rate will range from 3 percent to 10 percent v/v delivered 
at 75 to 200 gallons of spray solution per acre through boom, hand-
held, or high volume equipment. Therefore, the rate of use of 
pelargonic acid will be 9.45 lbs to 84 lbs per acre. Combinations with 
selected products may further reduce the application rate to a low 0.78 
lbs to 2.1 lbs per acre (0.25 percent solution in 75 or 200 gallons 
spray per acre).
    Second, pelargonic acid is used as a fruit blossom thinner that 
promotes return bloom (annual bearing) and increased fruit size and 
quality in apple and pear. Thinex Blossom Thinner (EPA Reg. 
No. 53219-11) was registered as a biochemical pesticide due to the 
natural occurrence of pelargonic acid, the low use rates and the unique 
non-toxic mode of action. Thinex works on contact by damaging the 
stigma or female flower part of the blossom, thus preventing 
pollination of a certain percentage of flowers. A blossom that has 
already been fertilized at the time of application will be undamaged by 
Thinex. No more than 2 applications per year are made. On February 14, 
1996, pelargonic acid was exempt under 40 CFR 180.1159 from the 
requirement of a tolerance when used as a blossom thinning agent on 
apple and pear.
    Thinex Blossom Thinner contains as the active ingredient 57 percent 
pelargonic acid and 3 percent related fatty acids (C6 - C12). 
The application rate as a blossom thinner ranges from 0.5 pints to 4 
pints of product to make 100 gallons of spray solution. One hundred to 
400 gallons of spray solution per acre may be used. Therefore, the rate 
of use of pelargonic acid as a blossom thinning agent ranges from a low 
0.26 lbs to a high 8.4 lbs per acre.

B. Product Identity/Chemistry

    Pelargonic acid (C8H17COOH), a nine-carbon straight-chain 
fatty acid commonly referred to as nonanoic acid, is a naturally-
occurring fatty acid found in the environment and in our food supply.
    Pelargonic acid has been found to occur naturally in low 
concentrations in soil. The degradation of pelargonic acid applied to 
soil occurs very rapidly by microbial means, not through hydrolysis or 
photolysis. Degradation occurs under aerobic conditions with beta-
oxidation being the principal pathway of metabolism.
    Pelargonic acid has been shown to occur naturally in our food 
supply. For example, it has been identified in grapes, cheese and milk 
at levels from 10 parts per million (ppm) to 400 ppm. Some literature 
references cite its natural occurrence in soybeans (trace levels), 
oranges (130 ppm), beans (trace levels), tobacco (0.27 ppm) and 
potatoes (1.18 ppm). In a cross-section of apple varieties analyzed by 
Mycogen, pelargonic acid was found at levels from 20 parts per billion 
(ppb) to 320 ppb.
    Fatty acids, including pelargonic acid, are metabolized in 
mammalian systems to produce energy. The oxidative degradation of fatty 
acids is a central metabolic pathway in humans, animals and plants. 
Fatty acids of varying chain lengths are metabolized into two-carbon 
fragments through a sequence of enzyme-catalyzed reactions. The 
metabolic products are then incorporated into fats, carbohydrates and 
amino acids.
    The magnitude of pelargonic acid residues from applications of 
Scythe Herbicide anticipated at time of harvest will be insignificant 
beyond naturally-occurring levels and to normal dietary exposure. 
Applications of Scythe Herbicide will not directly contact desirable 
food commodities since exposure will be intentionally avoided by the 
grower because crop damage may result. Any residues of pelargonic acid 
on food commodities will only occur as a result of spray drift, thus 
minimizing residues of pelargonic acid on the food commodity.
    An analytical method for detecting and measuring the levels of 
pelargonic acid residue is not necessary to protect the public health 
and environment. The natural occurrence of pelargonic acid in our food 
supply and environment, and the rapid metabolism and degradation of 
pelargonic acid to background levels in humans, plants and soil, 
eliminate the need to quantify pelargonic acid residue from 
applications as a herbicide or a blossom thinner.

C. Mammalian Toxicological Profile

    Mycogen has submitted to EPA a comprehensive toxicology data 
package and referenced several published articles concluding that 
residues of pelargonic acid will be safe to human health.
    Although a significant concentration of pelargonic acid can be 
irritating to eyes and skin, toxicology data confirms that exposure to 
residues of pelargonic acid beyond naturally occurring background 
levels will be practically non-toxic to human health. The following 
mammalian toxicity studies have been conducted to support the tolerance 
exemption for residues of pelargonic acid:

    Acute Oral LD50:    >5000 mg/kg
    Acute Dermal LD50:   >2000 mg/kg
    Acute Inhalation LC50:   >1.244 mg/L
    Dermal Irritation (Rat):   Severely Irritating
    Eye Irritation (Rabbit):   Severely Irritating
    Skin Sensitization (Guinea Pig):   Not sensitizing

    A range finding test to determine dosing concentrations for a 90-
Day Rat Oral Toxicity study produced no adverse effects from pelargonic 
acid at any dose level for 3 weeks, including the highest dose of 
20,000 ppm (2 percent), or 1,834 mg/kg/day, for a period of 2 weeks.
    A developmental toxicity screen study in rats produced a NOEL of 
1,500 mg/kg/day (only dose tested). Pelargonic acid was tested at one 
dose administered by gavage in corn oil to 22 CD rats (20 pregnant) on 
days 6 through 15 of gestation. No evidence of maternal or 
developmental toxicity was seen.
    A chronic dermal toxicity study in mice resulted in no evidence of 
severe dermal or systemic toxicity. Fifty mice were treated twice-
weekly with 50 mg doses of undiluted pelargonic acid for 80 weeks. 
Histopathology revealed no tumors of the skin or the internal organs.
    A gene mutation assay in mouse lymphoma cells (L5178Y TK ) concluded that pelargonic acid was negative for inducing 
mutations without metabolic activation, and was considered weakly 
positive for inducing mutations at the TK locus of culture mouse 
(L5178Y TK ) cells in the presence of S9-induced metabolic 
activation. Mutations were induced at levels greater than or equal to 
50 mg/ml. However, this occurred in the presence of increasing 
moderate-to-severe cytotoxicity and small colony development and may 
reflect gross chromosomal changes or damage rather than actual 
mutational changes within the TK gene locus.
    In an in-vivo mouse micronucleus assay, groups of ICR mice (15/sex/
dose) were administered single oral doses of 1,250, 2,500, or 5,000 mg/
kg pelargonic acid. The bone marrow cells were harvested 24, 48, and 72 
hours post-treatment. No significant increases in the frequency of 
micronucleated polychromatic erythrocytes (PCEs) were observed in 
either sex at any dose; thus, pelargonic acid was negative in the 
micronucleus assay.
    A reverse gene mutation assay (Ames Test) concluded that pelargonic 
acid was not mutagenic under the conditions of the study.

[[Page 3690]]

D. Aggregate Exposure

    Pelargonic acid is a naturally-occurring fatty acid found in our 
food supply. Mycogen Corporation has estimated the potential worst case 
dietary exposure of pelargonic acid beyond existing natural background 
levels after an application of Scythe Herbicide between grape vine 
rows. The commodity grape was selected because the use of Scythe 
Herbicide between grape vine rows is a representative and major use 
pattern intended for the product. In an effort to make a worst case 
scenario for residue calculations, Mycogen has suggested a 10 percent 
deposition on the crop, even though such a drift rate will be 
intentionally avoided by the grower because crop damage may result. 
Drift deposition would likely be less than 1 percent of applied spray 
volume.
    The worst case human daily consumption level of pelargonic acid 
from treated grapes has been estimated to be 0.397 mg/kg/day. This 
exposure dose after applications of Scythe Herbicide must be compared 
to the highest dose level tested in the dietary range-finding 
toxicology study. In this study, a daily feeding dose of 1,834 mg/kg/
day (20,000 ppm) did not produce any signs of toxicity or abnormalities 
for a period of 2 weeks.
    Exposure to drinking water will be minimal. Scythe Herbicide will 
not be applied directly to water. The proposed label includes 
applications to dry ditches, dry canals, ditch banks, and for use above 
the water line or after draw-down of agricultural irrigation water and 
ditch systems, industrial ponds and disposal systems, and impounded 
water areas. Taking potential spray drift into consideration, the rapid 
degradation of pelargonic acid to naturally-occurring background levels 
in our environment will mitigate the exposure of residues to drinking 
water to insignificant amounts. In addition, the degradation of 
pelargonic acid will ensure that no contamination to groundwater will 
occur.
    If residues of pelargonic acid do occur in food or in drinking 
water, information on the metabolism of fatty acids in the body 
confirms that residues of pelargonic acid would present minimal risk to 
humans. Fatty acids are digested in mammalian systems through normal 
metabolic pathways. While pelargonic acid is not as widespread in our 
diet as other fatty acids, the only difference is that most dietary 
fatty acids have even-numbered carbon chains and are ingested initially 
in the form of triglycerides. It is likely that pelargonic acid, when 
it is absorbed from the gastrointestinal tract into the blood, would be 
treated little differently from the free fatty acids released from 
adipose tissue.
    Non-dietary exposure of pelargonic acid will be mitigated through 
the use of proper personal protective equipment. For non-occupational 
uses or exposure to sites not associated with food or drinking water, 
data on the natural occurrence and rapid microbiological degradation of 
pelargonic acid in the environment confirms that exposure will be 
minimal. EPA has waived all environmental fate data requirements for 
the current registration of Scythe Herbicide.

E. Cumulative Exposure

    No cumulative exposure through other pesticides and substances with 
common mode of toxicity is expected. Pelargonic acid has a unique mode 
of action. Residues will not increase or sustain as a result of 
exposure to other materials. Pelargonic acid will degrade by microbial 
action to background levels over a period of 24 - 48 hours regardless 
of contact with substances either through pesticide tank mixing or 
exposure to other chemical residues in the environment. Normal use 
patterns will not lead to accumulation of pelargonic acid in the 
environment.

F. Safety Determination

    Mycogen believes that the use of pelargonic acid as a naturally-
occurring, lower toxicity, environmentally compatible material fits 
with EPA's objective to register reduced risk pesticides. The common 
dietary intake of the U.S. population includes low concentrations of 
naturally-occurring fatty acids, including pelargonic acid. The rapid 
environmental breakdown of pelargonic acid will significantly decrease 
any residues as a result of applications from Scythe Herbicide. Mycogen 
believes that under worst case exposure calculations, and based on 
established toxicology data, any increased levels of pelargonic acid 
will present no adverse effects to the consumer.
    Mycogen believes that a determination of safety for infants and 
children can be made due to the insignificant exposure expected beyond 
naturally-occurring background levels, the fact that fatty acids are 
digested in mammalian systems through normal metabolic pathways, and 
the toxicology data base concludes that pelargonic acid is practically 
non-toxic when administered orally. The developmental toxicity screen 
study in rats produced a NOEL of 1,500 mg/kg/day (only dose tested), 
and no evidence of maternal or developmental toxicity was seen.

G. Existing Tolerances

    Pelargonic acid is exempt under 40 CFR 180.1159 from the 
requirement of a tolerance when used as a blossom thinning agent on 
apple and pear. Pelargonic acid has been added to the Food and Drug 
Administration's list of approved chemicals that may be safely used in 
washing or to assist in the lye peeling of fruits and vegetables in 
concentrations of up to 1 percent (21 CFR 173.315). The same use is 
cleared by the United States Department of Agriculture under the USDA 
List of Authorized Substances, 1990, 7 CFR 5.14, Fruit & Vegetable 
Washing Compounds. In addition, pelargonic acid is cleared by the Food 
and Drug Administration as a sanitizer solution to be used on food-
contact articles [21 CFR 178.1010(b) (42)], or as a synthetic food 
flavoring agent and adjuvant (21 CFR 172.515).

II. Administrative Matters

    Interested persons are invited to submit comments on this notice of 
filing. Comments must bear a notation indicating the document control 
number, [PF-685]. All written comments filed in response to this 
petition will be available in the Public Response and Program Resources 
Branch, at the address given above from 8:30 a.m. to 4 p.m., Monday 
through Friday, except legal holidays.
     A record has been established for this notice of filing under 
docket number [PF-685] (including comments and data submitted 
electronically as described below). A public version of this record, 
including printed, paper versions of electronic comments, which does 
not include any information claimed as CBI, is available for inspection 
from 8:30 a.m. to 4 p.m., Monday through Friday, excluding legal 
holidays. The public record is located in Rm. 1132 of the Public 
Response and Program Resources Branch, Field Operations Division 
(7506C), Office of Pesticide Programs, Environmental Protection Agency, 
Crystal Mall #2, 1921 Jefferson Davis Hwy., Arlington, VA.
    Electronic comments can be sent directly to EPA at:
    [email protected]


    Electronic comments must be submitted as an ASCII file avoiding the 
use of special characters and any form of encryption.
    The official record for this notice of filing, as well as the 
public version, as described above will be kept in paper form. 
Accordingly, EPA will transfer all

[[Page 3691]]

comments received electronically into printed, paper form as they are 
received and will place the paper copies in the official rulemaking 
record which will also include all comments submitted directly in 
writing. The official record is the paper record maintained at the 
address in ``ADDRESSES'' at the beginning of this document.

    Authority: 21 U.S.C. 346a.

List of Subjects

    Environmental protection, Agricultural commodities, Pesticides and 
pests, Reporting and recordkeeping requirements.

    Dated: January 16, 1997.

Flora Chow,

Acting Director, Biopesticides and Pollution Prevention Division, 
Office of Pesticide Programs.

[FR Doc. 97-1753 Filed 1-23-97; 8:45 am]
BILLING CODE 6560-50-F