[Federal Register Volume 68, Number 48 (Wednesday, March 12, 2003)]
[Notices]
[Pages 11850-11855]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-5914]


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ENVIRONMENTAL PROTECTION AGENCY

[OPP-2003-0022; FRL-7295-9]


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

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice.

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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-2003-0022, must be 
received on or before April 11, 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.

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: [email protected].

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. 
Potentially affected entities may include, but are not limited to:
    [sbull] Industry (NAICS 111), e.g., Crop production.
    [sbull] Industry (NAICS 112), e.g., Animal production.
    [sbull] Industry (NAICS 311), e.g., Food manufacturing.
    [sbull] Industry (NAICS 32532), e.g., Pesticide manufacturing.
    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. 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. To determine 
whether you or your business may be affected by this action, you should 
carefully examine the applicability provisions in Unit I.A. 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-2003-0022. 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

[[Page 11851]]

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. 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.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-2003-0022. 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 [email protected], 
Attention: Docket ID Number OPP-2003-0022. 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-2003-0022.
    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-2003-0022. 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.

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    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 notice. 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 a pesticide petition as follows 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 this petition contains 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 petition. 
Additional data may be needed before EPA rules on the petition.

List of Subjects

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


    Dated: March 4, 2003.
Debra Edwards,
Acting Director, Registration Division, Office of Pesticide Programs.

Summary of Petition

    The petitioner summary of the pesticide petition is printed below 
as required by FFDCA section 408(d)(3). The summary of the petition was 
prepared by the petitioner and represents the view of the petitioner. 
The petition 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.

PP 0E6196

    EPA has received a pesticide petition (PP 0E6196) from the 
Interregional Research Project No. 4 (IR-4), Technology Centre of New 
Jersey, 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 FFDCA, 21 U.S.C. 346a(d), to amend 40 CFR part 
180.464 by establishing tolerances for residues of dimethenamid, (R,S)-
2-chloro-N-[(1-methyl-2-methoxy) ethyl]-N-(2,4-dimethyl-thien-3-yl)-
acetamide in or on the raw agricultural commodities beet, garden, roots 
at 0.01 parts per million (ppm); beet, garden, tops at 0.01 ppm; beet, 
sugar, roots at 0.01 ppm; beet, sugar, tops at 0.01 ppm; garlic, dry 
bulb at 0.01 ppm; horseradish at 0.01 ppm; onion, dry bulb at 0.01 ppm, 
shallot, dry bulb at 0.01 ppm; and tuberous and corm vegetables 
subgroup (Crop group 1C) at 0.01 ppm. EPA has determined that the 
petition contains 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 
supports granting of the petition. Additional data may be needed before 
EPA rules on the petition. This petition summary was prepared by the 
registrant, BASF Corporation, P.O. Box 13528, Research Triangle Park, 
NC 27709-3528.

A. Residue Chemistry

    1. Plant and animal metabolism. BASF Corporation notes that 
metabolism in plants and animals is understood.
    2. Analytical method. The proposed analytical method uses 
extraction and clean-up followed by quantification with capillary 
column gas chromatography (GC) using thermionic nitrogen specific 
detector. A GC/mass spectrocopy (MS) method for identification is also 
available. This method is not selective towards the dimethenamid isomer 
and is therefore valid for residues from both dimethenamid and the 
enriched dimethenamid-P. Tolerances are proposed based on a non-isomer 
specific basis.
    3. Magnitude of residues. For onion, magnitude of the residue data 
are based on applications with dimethenamid. Residue trials were 
conducted at 8 locations in California, Michigan, New York, Oregon, 
Texas, Washington, and Wisconsin. Treatments were made at 1.5 lbs 
active ingredient/acre (ai/A) 30 or 45 days before harvest. No residues 
above the limit of quantitation (LOQ) of 0.01 ppm were detected in dry 
bulb onion. Residue data from dry bulb onion will be used as surrogate 
data for dry bulb garlic and shallots.
    For sugar beet, magnitude of the residue data are based on 
dimethenamid-P applications to sugar beet at 0.98 lb ai/A. 
Dimethenamid-P is the biologically active isomer from the racemic 
dimethenamid mixture. The method measures both dimethenamid and 
dimethenamid-P, so the sugar beet residue determinations for 
dimethenamid-P are considered representative of the proposed treatments 
with dimethenamid. No residues were detected in sugar beet roots or 
tops from a testing program conducted in 12 locations across 8 states. 
Data from processing studies indicate that no residues are detected in 
the roots even at exaggerated rates of 3.15 lbs ai/A. The limit of 
quantitation is 0.01 ppm. The sugar beet trials also support the 
tolerances for table beet.
    For the tuberous and corm vegetable subgroup, magnitude of the 
residue data for potatoes are based on applications with dimethenamid-
P. Residue trials were conducted at 17 locations in California, 
Colorado, Florida, Idaho, Michigan, New Jersey, North Carolina, Oregon, 
Pennsylvania, Washington, and Wisconsin. Treatments were made at 1.25 
lbs ai/A 40 days before harvest. No residues above the LOQ of 0.01 ppm 
were detected in potato tubers. Data from processing studies indicate 
that no residues are detected in the tubers even at exaggerated rates 
of 12.5 lbs ai/A. Residue data from potato tubers will be used as 
surrogate data for horseradish.
    BASF believes that due to the low levels of residue in the RAC's, 
tolerances in animals are not required.

[[Page 11853]]

B. Toxicological Profile

    1. Acute toxicity. Based on available acute toxicity data, 
dimethenamid and dimethenamid-P do not pose an acute dietary risk. The 
acute toxicity studies place both technical materials in acute toxicity 
category II for acute oral; in acute toxicity category III for acute 
dermal, inhalation, and eye; and in acute toxicity category IV for 
dermal irritation. The technical materials are a positive skin 
sensitizer.
    2. Genotoxicity. The following testing was performed with 
dimethenamid for genotoxicity. A modified ames test: Negative; in vitro 
CHO/HGPRT mammalian cell mutation assay: Negative; in vitro cytogentics 
- CHO cells (1 study; chromosome aberrations): Weakly positive; in 
vitro UDS test using rat hepatocytes (3 studies; DNA damage and 
repair): 2 negative; 1 equivocally positive, mouse micronucleus assay 
(2 studies; chromosome aberrations): Negative, rat dominant lethal 
assay: 1 study equivocally positive, 1 study negative. Overall 
dimethenamid has been tested in 14 genetic toxicology assays. The 
weight of the evidence demonstrates that dimethenamid is not genotoxic.
    The following testing was performed with dimethenamid-P for 
genotoxicity. A modified ames test (3 studies; point mutation): 
Negative; in vitro CHO/HGPRT mammalian cell mutation assay (1 study; 
point mutation): Negative; in vitro cytogentics - CHO cells (1 study; 
chromosome aberrations): Negative; in vitro UDS test using rat 
hepatocytes (1 study; DNA damage and repair): Negative; mouse 
micronucleus assay (1 study; chromosome aberrations): Negative. 
Dimethenamid-P has been tested in a total of 7 genetic toxicology 
assays. These assays were performed both in vitro and in vivo and 
multiple assays were conducted for each of the three EPA Guideline 
requirement categories. Based on the data presented above, the data 
indicates that dimethenamid-P does not induce gene mutations, is not 
clastogenic and does not induce other effects indicative of 
genotoxicity. Therefore, BASF concludes that dimethenamid-P does not 
pose a mutagenic hazard to humans.
    3. Reproductive and developmental toxicity--i. Rat. A developmental 
rat study using dimethenamid via oral gavage resulted in dosages of 0, 
50, 215, and 425 milligram per kilogram (mg/kg)/day with a development 
toxicity no observed adverse effect level (NOAEL) of 215 mg/kg/day and 
a maternal toxicity of 50 mg/kg/day based on the following: (1) Signs 
of maternal toxicity, in the form of reduced body weight gain and food 
consumption, increased liver weight and clinical observations were 
observed at dose levels > 215 mg/kg/day with an increase in effects to 
the upper dose level; (2) at the = 215 mg/kg/day dose levels slight 
decreases in fetal body weights were observed which are not indicative 
a teratogenic effect; and (3) at the 425 mg/kg/day dose level a slight 
increase in resorptions was observed, and two fetuses had incomplete 
ossified manubria. These effects are not indicative of a teratogenic 
effect.
    A developmental rat study using dimethenamid-P via oral gavage 
resulted in dosages of 0, 25, 150, and 300 mg/kg/day with a development 
toxicity NOAEL of 25 mg/kg/day and a maternal toxicity of 25 mg/kg/day 
based on based on the following: (1) Signs of maternal toxicity, in the 
form of decreased body weights and food consumption were observed at 
dose levels > 150 mg/kg/day with an increase in effects to the upper 
dose level; (2) at the 150 mg/kg/day dose level slight decreases in 
fetal body weights and retarded ossification of the pelvis pubis were 
observed which are not indicative a teratogenic effect; and (3) at the 
300 mg/kg/day dose level slight decreases in fetal body weights, 
microphthalmia in two fetuses/two litters, distended ureters, and 
retarded ossification of the 2nd sternal centra and pelvis pubis were 
observed, similarly, these effects are not indicative of a teratogenic 
effect.
    ii. Rabbits. A developmental study in rabbits using dimethenamid 
via oral gavage resulted in dosages of 0, 37.5, 75, and 150 mg/kg/day 
(HDT) with a development toxicity NOAEL of 75 mg/kg/day and a maternal 
toxicity of 37.5 mg/kg/day based on: (1) Decreased body weight, food 
consumption, and absorption/premature delivery in the 75 and 150 mg/kg/
day dose groups; and (2) effects on fetal development were a low 
incidence of absorption/premature delivery and hyoid angulated changes 
in the 150 mg/kg/day dose group which are not are indicative of a 
teratogenic effect.
    iii. Two-generation reproduction - rats. A two-generation 
reproduction study using dimethenamid with rats fed dosages of 0, 7.5, 
38, and 155 mg/kg/day (average mg/kg/day dose levels for both male and 
female rats) with a reproductive NOAEL of 38 mg/kg/day and with a 
parental NOAEL of 38 mg/kg/day based on: (1) Parental toxicity as 
evident by reduction in body weight and food consumption and 
significant increases in absolute and/or relative liver weights in both 
males and female rats in the 155 mg/kg/day dose group; and (2) 
significant reductions in pup weight during lactation were observed in 
the 150 mg/kg/day dose group. No changes in pregnancy rates, fertility 
or length of gestation were observed at all dose levels tested.
    4. Chronic feeding and carcinogenicity. The established reference 
dose (RfD) for dimethenamid and dimethenamid-P is based on a 2-year 
feeding study in rats with dimethenamid, with a threshold NOAEL of 5.1 
mg/kg/day. Using an uncertainty factor of 100, the RfD is calculated to 
be 0.05 mg/kg/day. The following are summaries of the pertinent 
toxicity data supporting dimethenamid tolerances:
    i. Chronic feeding - nonrodent. A 1-year feeding study in dogs fed 
dimethenamid at dosages of 0, 2, 9.6, or 49 mg/kg/day with a NOAEL of 
9.6 mg/kg/day based on the following effects: (1) Slight decreases in 
body weights for both the high dose male and female dogs as compared to 
controls; (2) a variable degree of periportal hepatocyte vacuolation in 
the high-dose male and female dogs; (3) minimal or mild hepatocyte 
enlargement was similarly observed in the high-dose dogs; and (4) the 
liver changes at the high-dose group correlated with increase in serum 
alkaline phosphatase activity and cholesterol levels and increased 
liver-to-body weight ratios in both male and female dogs.
    ii. Chronic feeding/carcinogenicity - rat. A combined chronic 
feeding/carcinogenicity study using dimethenamid was performed in rats 
being fed dosages of 0, 5.1, 36, and 80 mg/kg/day (males) and 0, 6.8, 
49, and 109 mg/kg/day (females) with a NOAEL of 5.1 mg/kg/day (males) 
and 6.8 mg/kg/day (females) based on the following effects: (1) 
Decreased body weights in both males and female rat at dose levels > 36 
mg/kg/day dose groups with a slight progression of severity to the 
upper level; (2) decreased food consumption in both males and female 
rats at dose levels > 36 mg/kg/day dose groups with a slight 
progression of severity to the upper dose level; (3) minimal 
hematological and clinical chemistry value changes at dose levels > 36 
mg/kg/day dose groups with very slight increase of severity at the 
higher dose tested; (4) increased absolute liver weights for females at 
dose levels > 49 mg/kg/day; (5) microscopic findings were observed in 
the liver, parathyroid, and stomach of high-dose males, only, and 
ovaries of high-dose females; and (6) an increased incidence of benign 
and malignant tumors of the liver at the highest dose level tested. The 
liver tumors observed in this study occurred at an incidence which was 
slightly beyond the historical control range for this tumor type, and 
occurred at the

[[Page 11854]]

maximum tolerated dose (MTD). Given the lack of structural activity 
relationship (SAR) and the lack of mutagenicity discussed in section 
B.2., it is BASFs opinion that dimethenamid-P should not be considered 
a biologically relevant carcinogen in rats and the assessment is made 
that the results of this carcinogenicity study do not indicate a 
carcinogenic potential of the test substance for humans.
    iii. Carcinogenicity - mice. A carcinogenicity study using 
dimethenamid in mice fed dosages of 0, 3.8, 41, 205, and 431 (HDT) mg/
kg/day (males) and 0, 4.1, 41, 200, and 411 (HDT) mg/kg/day (females) 
with a NOAEL of 41 mg/kg/day for male and female mice based on the 
following effects: (1) Decreased body weights and food consumption were 
observed in both males and female mice at the highest dose tested; (2) 
increased liver weights were observed for male and female mice at the 
highest dose tested at an interim sacrifice and increased weights for 
kidney and liver were observed for female mice at dose levels > 200 mg/
kg/day at terminal sacrifice; (3) microscopic findings were observed in 
the liver and stomach for both male and female mice at the upper dose 
levels; (4) concerning the finding in the stomach, EPA has determined 
that this finding was attributed to irritation of the material and the 
finding was not toxicology significant; and (4) no increased incidence 
of neoplasms occurred at any dose levels tested in this study. EPA has 
concluded that this product is not carcinogenic under the conditions of 
this study.
    Dimethenamid is considered not to be carcinogenic in mice by BASF. 
In the rat carcinogenicity study, a slight increase in liver tumors was 
observed in males, only, at the highest dose tested. The liver tumors 
observed in this study occurred at an incidence that was slightly 
beyond the historical control range for this tumor type, and occurred 
at the MTD. Dimethenamid shares no common mechanisms with other 
compounds in the chloroacetanilide class of compounds. It is BASF's 
opinion that dimethenamid and dimethenamid-P should not to be 
considered biologically relevant carcinogens in rats and the assessment 
is made that the results of this carcinogenicity study do not indicate 
a carcinogenic potential of these substances for humans.
    However, EPA has determined that dimethenamid is considered to be a 
Group C carcinogen - possible human carcinogen - based on the judgment 
of the EPA Carcinogenicity Peer Review Committee assessment. Also, the 
Committee determined for risk assessment purposes, the RfD approach 
should be used to quantify human risk. BASF agrees with the Agency that 
the RfD approach for human risk assessment is valid.
    5. Endocrine disruption. No specific tests have been performed with 
dimethenamid-P or dimethenamid to determine whether the chemical may 
have an effect in humans that is similar to an effect produced by 
naturally occurring estrogen or other endocrine effects. However, there 
are no significant findings in other relevant toxicity studies, i.e. 
teratology and multi-generation reproductive studies, that would 
suggest the dimethenamid produces endocrine related effects.

C. Aggregate Exposure

    1. Dietary exposure--i. Food. BASF has reviewed the available 
toxicology database to determine the endpoints of concern. For 
dimethenamid and dimethenamid-P, BASF believes there is no concern 
regarding an acute dietary risk since the available data do not 
indicate any evidence of significant toxicity from a 1 day or single 
event exposure by the oral route.
    For the purpose of assessing the potential chronic dietary 
exposure, BASF has estimated aggregate exposure based on theoretical 
maximum residue contribution (TMRC) from the tolerance of dimethenamid 
on sweet corn, sorghum, peanuts, and dry beans at 0.01 ppm for all uses 
stated, respectively. The TMRC is a ``worse case'' estimate of dietary 
exposure since it is assumed that 100% of all crops for which the 
tolerances are established are treated and that pesticide residues are 
always found at tolerance levels. EPA in a letter issued on October 13, 
1995, for dimethenamid, determined the TMRC for the crops mentioned in 
section C.1. to be 0.076 and 0.341 microgram (ug)/kg/day for the 
general U.S. population and non-nursing infants (< 1), respectively. 
Dimethenamid treated crops using the TMRC values utilized 0.15% and 
0.683% for the general U.S. population and non-nursing infants (< 1), 
respectively, of the RfD (0.05 mg/kg/day). These assessments are also 
valid for dimethenamid-P. BASF concurs with this assessment.
    The addition of an onion tolerance at 0.01 ppm has a TMRC of 0.0011 
ug/kg/day for the general population and a TMRC of 0.0004 ug/kg/day for 
non-nursing infants. Sugar beet tolerances at 0.01 ppm, add 0.0033 ug/
kg/day to the TMRC for the general population and 0.0013 ug/kg/day to 
the TMRC for non-nursing infants. The addition of table beet tops, dry 
bulb garlic, horseradish, and dry bulb shallot is negligible; table 
beet root tolerances at 0.01 ppm add 0.00022 ug/kg/day to the TMRC for 
the general population and 0.0019 ug/kg/day to the TMRC for non-nursing 
infants. The addition of potato tolerances at 0.01 ppm would contribute 
0.011 ug/kg/day to the TMRC for the general population and 0.014 ug/kg/
day to the TMRC for non-nursing infants. The addition of sweet potato 
tolerances at 0.01 ppm would contribute 0.00039 ug/kg/day to the TMRC 
for the general population and 0.0029 ug/kg/day to the TMRC for non-
nursing infants. The total RfD utilization from all uses, both 
registered and proposed, is 0.18% for the general population, and 0.72% 
for non-nursing infants.
    Therefore, based on the completeness and reliability of the 
toxicity data, and the exposure assessment discussed in section C.1., 
BASF concludes that there is a reasonable certainty that no harm will 
result from aggregate exposure to residues of dimethenamid and 
dimethenamid-P, including all anticipated dietary exposure.
    ii. Drinking water. Other potential sources of exposure to 
dimethenamid for the general population are residues in drinking water 
and exposure from non-occupational sources. In a dimethenamid-P 
environmental-fate risk assessment dated December 1998, EPA calculated 
the following maximum concentrations for drinking water: Based on SCI-
GROW model calculations, ground-water concentrations were expected to 
be < 1.0 parts per billion (ppb). Based on PRZM/EXAMS model 
calculations for surface water, the maximum yearly average (chronic) 
concentration was 5.4 ug/l from a Southeast corn scenario. Using these 
values, the drinking water level of comparison (DWLOC) and the 
aggregate RfD utilization are summarized in the table below.

------------------------------------------------------------------------
                                                    U.S.     Non-nursing
                                                 population   infants (%
                                                 (% of RfD)    of RfD)
------------------------------------------------------------------------
Chronic dietary exposure                               0.18         0.72
------------------------------------------------------------------------
Remainder RfD available for water (%)                 99.82        99.32
 (drinking water level of comparison)
------------------------------------------------------------------------

[[Page 11855]]

 
SCI-GROW ground water estimation\1\                  < 0.10         0.20
------------------------------------------------------------------------
PRZM/EXAMS surface water estimation\1\                 0.30         1.10
------------------------------------------------------------------------
Total of RfD used by diet and water                    0.58         2.00
------------------------------------------------------------------------
1Used highest values predicted from the model for all agricultural uses.
  Assumes 2L/day and 70 kg adult; 1L/day and 10 kg infant.

    2. Non-dietary exposure. For non-occupational exposure, 
dimethenamid/ dimethenamid-P is not registered for either golf course 
or homeowner uses which could contribute to ``non-dietary or other 
exposure.''

D. Cumulative Effects

    BASF has considered the potential for cumulative effects of 
dimethenamid and other substances that have a common mechanism of 
toxicity. BASF is aware of several other chloroacetanilide herbicides 
that have been considered structurally similar to dimethenamid, these 
being: Acetochlor, propachlor, butachlor, metolachlor, and alachlor. 
However, BASF believes that consideration of a common mechanism of 
toxicity to these products is not appropriate or valid. This conclusion 
was based on the presentation EPA made to the EPA FIFRA Science 
Advisory Panel (SAP) on March 20, 1997. The title of the presentation 
was ``Grouping of Chloroacetanilide Pesticides Based on a Common 
Mechanism of Toxicity.'' In this presentation EPA showed the structure 
of several chloroacetanilides that included dimethenamid. BASF is 
identifying Chlor-7 as dimethenamid. EPA concluded that Chlor-7 should 
not be considered to have a common mechanism to the other 
chloroacetanilides based on the following reasons:
    [sbull] Except for Chlor-7 all other members of this case study 
have a potential to generate a quinone imine. The quinone imine 
intermediate, is capable of reacting with macromolecules.
    [sbull] Chlor-7 has not produced nasal nor thyroid tumors in rats, 
thus does not support inclusion in the group for a common mechanism for 
these tumor types.
    For liver tumors, Chlor-1, Chlor-7, Chlo-r5, and Chlor-6, can be 
potentially grouped for a common mechanism, but EPA determined that 
there is no knowledge of a common mechanism of toxicity or of a common 
toxic species responsible for the effect. Therefore, EPA concluded that 
because a mechanism can not be postulated, it believes that sufficient 
evidence is not available to support a common mechanism for this tumor 
type with these materials.
    Therefore, BASF agrees with the position put forward by the Agency 
and confirmed by the SAP that a common mechanism is inappropriate for 
dimethenamid (Chlor-7) and the other chloroacetanilides mentioned in 
section D. BASF has considered only the potential risks of dimethenamid 
in its exposure assessment.

E. Safety Determination

    1. U.S. population. Using the exposure assumptions described in 
section C., based on the completeness and the reliability of the 
toxicity data, BASF has estimated that aggregate exposure to 
dimethenamid will utilize < 1% of the RfD (0.05 mg/kg/day) for the U.S. 
population. EPA generally has no concern for exposure below 100% of the 
RfD. Therefore, based on the completeness and reliability of the 
toxicity data, and the exposure assessment discussed in sections B. and 
C., BASF concludes that there is a reasonable certainty that no harm 
will result from aggregate exposure to residues of dimethenamid 
including all anticipated dietary exposure and all other non-
occupational exposures.
    2. Infants and children. BASF cites results of developmental 
toxicity studies reported in section B.3. including:
    [sbull] Observed developmental toxicity effects in rats are not 
indicative of teratogenic effect.
    [sbull] The results of developmental study in rabbits also 
demonstrated that dimethenamid is not a teratogenic compound and has a 
development toxicity NOAEL of 75 mg/kg/day and a maternal toxicity of 
37.5 mg/kg/day.
    BASF believes that these test results demonstrate that the rat and 
rabbit are similarly sensitive to dimethenamid. Additionally, the NOAEL 
of 5 mg/kg/day from the chronic rat study used to set the RfD is 7.5X 
and 5X lower than the maternal NOAELs established in the rabbit and rat 
teratology studies, respectively. The developmental effects observed in 
either the rat or rabbit occurred only at maternally toxic doses. 
Therefore, BASF concludes that no additional safety factor is needed 
for children.

F. International Tolerances

    A maximum residue level has not been established under Codex 
Alimentarius Commission for dimethenamid for any of the proposed uses.

[FR Doc. 03-5914 Filed 3-11-03; 8:45 am]
BILLING CODE 6560-50-S