United States
Environmental Protection
Agency
Office of
Pesticides and Toxic Substances
Washington DC 20460
January 1985
&EPA
Pesticides
TPTH (Triphenyltin Hydroxide)
Special Review Position
Document 1
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TRIPHENYLTIN HYDROXIDE
POSITION DOCUMENT 1
U.S. Environmental Protection Agency
Office of Pesticides and Toxic Substances
Office of Pesticide Programs
401 M Street, S.W.
Washington, D.C.
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6560-50
ENVIRONMENTAL PROTECTION AGENCY
[OPP-30000/42]
TRIPHENYLTIN HYDROXIDE
SPECIAL REVIEW OF CERTAIN PESTICIDE PRODUCTS
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice.
SUMMARY: JT,his Notice announces that EPA is initiating a
Special Review of all pesticide products containing the
active ingredient triphenyltin hydroxide (TPTH^j. EPA has
determined that TPTH which is registered as a fungicide and
mite suppressant, produces teratogenic effects in laboratory
rats and that sufficient exposure to applicators exists to
meet the risk criterion described in 40 CFR 162.11. Accordingly,
a Special Review of products containing TPTH has been initiated
to determine whether additional regulatory actions, if any,
are required. During the Special Review process, EPA will
carefully examine the risks and benefits of using TPTH products.
DATE: Comments, evidence to rebut the presumptions in this
Notice, and other relevant information must be received no later
than 45 days from the date this notice is received or until
(insert date 45 days after date of publication in the
FEDERAL REGISTER) (whichever is later).
84P-4070
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ADDRESS: Written comments identified as "OPP-30000/42"
should be sent by mail to:
Information Services Section,
Program Management and Support Division (TS-757C),
Office of Pesticide Programs,
Environmental Protection Agency,
401 M St., SW.,
Washington, D.C. 20460.
In person, bring comments to:
Rm. 236, CM #2,
1921 Jefferson Davis Highway,
Arlington, VA.
Information submitted in any comment concerning this
notice may be claimed confidential by marking any part or all
of that information as "Confidential Business Information"
(CBI). Information so marked will not be disclosed except in
accordance with procedures set forth in 40 CFR Part 2. An
edited copy of the comment containing material claimed to be
CBI must be submitted (with the CBI portions deleted) for
inclusion in the public record. Information not marked
confidential may be disclosed publicly by EPA without prior
notice to the submitter. All non-CBI written comments will
be available for public inspection in Rm. 236 at the Virginia
address given above, from 8 a.m. to 4 p.m., Monday through
Friday, excluding legal holidays.
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FOR FURTHER INFORMATION CONTACT: By mail:
Betty Shackleford,
Registration Division (TS-767C),
Office of Pesticide Programs,
Environmental Protection Agency,
401 M St., SW.,
Washington, D.C. 20460.
Office location and telephone number:
Rm. 717, CM #2,
1921 Jefferson Davis Highway,
Arlington, VA,
(703-557-7400).
SUPPLEMENTARY INFORMATION: The term "Special Review" is the
name now being used by EPA for the process previously called
the Rebuttable Presumption Against Registration (RPAR) process.
Modifications in the process will be proposed in regulations
in the near future. Until other applicable final regulations
are adopted, the present Special Review will adhere to RPAR
procedures now in effect and set forth in 40 CFR 162.11.
EPA has determined that a Special Review will be conducted
for all pesticide products containing TPTH as an active
ingredient. EPA has also determined that data necessary to
conduct the Agency's risk assessment must be developed on an
accelerated basis, and that precautionary labeling is required
to reduce risk during the Special Review process.
Issuance of this Notice means that potential hazards
associated with the use of TPTH have been identified. These
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hazards will be examined further to determine the nature and
extent of the risk, and considering the benefits of TPTH,
whether such risks cause unreasonable adverse effects on the
environment.
A document entitled "Guidance for the Interim Registration
of Pesticide Products Containing TPTH" (Guidance Document) has
been issued. (The Guidance Document is also referred to as a
Registration Standard.) The Guidance Document is available to
the public from the contact person named above. This Guidance
Document explains the basis of EPA's decision to start a Special
Review and also contains references, background information,
data requirements, and other information pertinent to the con-
tinued registration of pesticides containing TPTH.
I. INITIATION OF A SPECIAL REVIEW
A. GENERAL
A pesticide product may be sold or distributed in the
United States only if it is registered or exempt from registra-
tion under the Federal Insecticide, Fungicide, and Rodenticide
Act (FIFRA) (7 U.S.C. 136 e_t seq. ) . Before a product can be
registered, it must be shown that it can be used without "un-
reasonable adverse effects on the environment" (FIFRA section
3(c)(5)), that is, without causing "any unreasonable risk to
man or the environment, taking into account the economic,
social, and environmental costs and benefits of the use of the
pesticide" (FIFRA section 2(bb)). The burden of proving that
a pesticide meets this standard for registration is on the
proponent of initial or continued registration. If at any
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time the Agency determines that a pesticide no longer meets
this standard for registration, the Administrator may cancel
the registration under section 6 of FIFRA.
The Agency has created an administrative process for
fully evaluating whether a pesticide satisfies or continues to
satisfy the statutory standard for registration. This Special
Review process provides an informal procedure through which
EPA may gather and evaluate information about the risks and
benefits of a pesticide's use. It also provides a means by
which interested members of the public may comment on and
participate in EPA's decision making process. The regulations
governing this process are set forth at 40 CFR 162.11.
A Special Review is begun when EPA determines that a
pesticide meets or exceeds one or more of the risk criteria
set out in the regulations (40 CFR 162.11(a)(3)). The Agency
generally announces the beginning of the Special Review by
issuing a Position Document 1 (PD 1) which is published in
the FEDERAL REGISTER. In addition, registrants of affected
products will receive the PD 1 by certified mail. Registrants
and other interested persons are invited to scrutinize the
basis for the Agency's decision to initiate the Special
Review and to submit data and information which rebuts or
supports the Agency's determination of risk. Commenters may
also suggest methods to reduce risks of use of the pesticide.
In addition to addressing risk issues, commenters are encouraged
to submit evidence and discussions of the biological, economic,
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social, and environmental costs and benefits of use of the
pesticide. The public participation stage is described in more
detail in Unit IV. This Notice constitutes Position Document 1
for pesticide products containing TPTH.
If risk issues are not satisfactorily resolved, EPA will
proceed to evaluate the risks and benefits of TPTH in order to
determine whether to propose regulatory actions to reduce the
risks. After providing an opportunity for comment by the Scientific
Advisory Panel, the Secretary of Agriculture, registrants, and the
public on those actions and the reasons for them, EPA will issue
an appropriate final notice. If EPA determines that the risks of
use exceed the benefits, EPA will issue a notice of intent to
cancel the registration of products intended for such use. The
notice may state athe intention to cancel registrations outright
or may require certain changes in the composition, packaging,
application methods and/or labeling of the product. These changes
would be intended to reduce the risks to levels that when considered
against the benefits will not pose unreasonable adverse effects
to man or the environment.
A notice initiating a Special Review is not a notice of
intent to cancel the registration of a pesticide, and a Special
Review may or may not lead to cancellation. This notice initiating
the Special Review for TPTH products is an announcement of EPA's
concern about the safety of the pesticide's use, and only after
carefully considering the risks and benefits of TPTH and determining
that it appears to cause unreasonable adverse effects on the
environment, would EPA issue a notice of intent to cancel.
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B. PRESUMPTION
EPA has determined that the use of pesticide products
containing TPTH has exceeded one of the risk criteria in
40 CFR 162.11(a)(3)(ii)(B) which provides that a Special
Review shall be conducted if the use of a pesticide "produces
any other chronic or delayed toxic effect in test animals at
any dosage up to a level, as determined by the Administrator.-
which is substantially higher than that to which humans can
reasonably be anticipated to be exposed, taking into account
ample margins of safety." Studies submitted to the Agency in
support of the continued registration of TPTH have shown that
TPTH produces teratogenic effects in laboratory animals.
Based on these data and on an evaluation of potential exposure
of applicators to TPTH, the Agency concluded that TPTH has
exceeded the risk criterion for initiation of a Special
Review.
1. Toxicological concerns. As part of the data require-
ments necessary to maintain the continued registration of the
pesticide, two independent laboratories conducted studies in
Sprague-Dawley rats to ascertain the teratogenic potential of
TPTH. In the first study, conducted in 1976 by Cannon Labora-
tories, Inc., varying dosage levels of technical grade TPTH
were orally administered by gavage to pregnant rats on days 6
through 15 of gestation. Increases in the incidences of
hydrocephalus (the abnormal accumulation of serous fluid with-
in the cranium accompanied by enlargement of the head, prominence
of the forehead, atrophy of the brain, mental weakness and.
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convulsions) and hydronephrosis (distention of the pelvis
and calyces of the kidney with urine, as a result of obstruction
of the ureter with accompanying atrophy of the parenchyma of
the organ) above the incidences in concurrent control animals
were observed in the fetuses at all dosage levels tested.
A second teratogenicity study was performed by Battelle
Columbus Laboratories and submitted to the Agency in 1981. In
this study, rats were mated and dosed with TPTH on days 5
through 19 of gestation. Increased incidences of hydronephrosis
above the incidence in the concurrent control fetuses were
again observed at all dosage levels tested. Although hydro-
cephalus was seen in only one fetus, an increased incidence
of hydroureter (abnormal distention of the ureter of the kidneys
with urine or with a watery fluid) above the concurrent control
incidence occurred at all dosage levels tested. Based on
these studies, the Agency has determined that TPTH produces
teratogenic effects in laboratory animals. A "no-observed-
effect-level" (NOEL) for these teratogenic effects has not
been determined because these lesions were observed at all
dosage levels. The "lowest-observed-effect-level" (LOEL) was
1.0 mg/kg/day.
To clarify whether some or all of the effects observed
in the teratogenicity studies are true developmental anomalies,
delayed maturation, or the like, the Agency has required a
"postnatal" teratology study. The Agency believes this study
will elucidate the nature, severity, and/or reversibility of
the teratogenic effects manifested in the two studies referred
to above.
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In the postnatal teratology study, twice the number of
dams typically observed in a teratology study are to be used.
One half of the dams are to be sacrificed near parturition
and the remaining half of the animals are permitted to deliver
normally with post-weaning sacrifice and examination of the
pups. The specific test requirements are outlined in the
Guidance Document. Results of the postnatal teratology study
must be submitted to the Agency by December 7, 1985. In addition,
the Agency is conducting a teratogenicity "screening test" at
Research Triangle Park, N.C. This testing is being performed
in two phases and is designed to provide insight into the
severity of the observed teratogenic effects. Based on the
results of these data, which will be available in March 1985,
the Agency may initiate additional immediate regulatory actions.
2. Applicator risk assessment. The Agency has estimated
potential applicator exposure to TPTH. Because most applicator
exposure occurs by the dermal route, a risk assessment has been
performed based on dermal exposure to TPTH resulting from the
air blast application to pecan trees. The risk assessment was
limited to this site and application method because 72 to 82
percent of the pesticidal use of TPTH is for controlling fungal
diseases in pecan culture. TPTH is generally applied by air
blast application in pecan culture, although it may be applied
aerially.
In calculating the dermal exposure risk calculation for
pecan tree applicators, the Agency made the following assumptions.
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a. Applicators have an average body weight of 70 kg.
b. Mixing/loading and pesticide application are done by
the same individual.
c. Potential inhalation exposure would be minimal when
compared to potential dermal exposure.
d. It was estimated that 3,000 cm2 of the skin surface
area would be exposed during the pesticide application. This
is equivalent to wearing a short-sleeved, open-necked shirt,
long pants, and neither head covering nor gloves.
e. Exposure during mixing/loading assumes a worker handles
a 50 percent wettable powder (WP) formulation packaged in
conventional bags.
f. In the absence of empirical dermal absorption data,
the Agency assumed dermal absorption would be 100 percent.
Unit dermal exposure (mg/kg body weight/day) (mg/kg/ bw/day)
during application was calculated from the linear regression
correlation derived from the Office of Pesticide Programs
Exposure Assessment Branch data base for air blast application
to orchards (p < 0.01). Exposure during mixing and loading of
the wettable powder was calculated from the same data base.
Application rates typically range from 1.5 to 18.4 oz active
ingredient per acre (ai/A).
The Agency estimated a typical exposure value for a
mixer/loader/applicator of 0.74 mg/kg/day, with a lowest value
of 0.68 mg/kg/day and an upper value of 0.88 mg/kg/day. This
range is derived from the range in application rates.
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Because the teratogenic effects seen in the animal studies
occurred at all test dosage levels, the Agency has been unable to
determine "margins of safety" (MOS) (ratio of NOEL to exposure)
from the available test results. Therefore, teratogenic "risk
quotients" (ratio of LOEL to exposure) were calculated based on
the LOEL.
The risk quotient determination for teratogenicity indicates
that potential exposure of pesticide applicators in pecan
culture to TPTH occurs at a level that is known to produce
teratogenic effects in laboratory animals, thereby resulting in
a highly significant teratogenic risk for pregnant women.
3. Dietary exposure. To assess potential teratogenic
hazards that might be associated with dietary exposure to TPTH,
the Agency has performed a risk assessment for the food commodities
listed in 40 CFR 180.236. "Risk quotients" were again determined
because a NOEL was not observed in the teratogenicity studies.
The risk quotients are based on eating a single serving of the
respective food items by a 60 kg pregnant woman. These data
are presented in Table I.
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TABLE I — DIETARY RISK QUOTIENT DETERMINATION FOR TERATOGENICITY
Commodity
Carrots
raw
cooked
Sugar
(beet)
Pecans
Peanuts
Potatoes
Kidney
Liver
Estimated
Serving Weight
Size (kg)l/
1 cup
1 cup
1/2 cupV
1/2 cup
1/2 cup
1 cup
3 oz .
3 oz .
0
0
0
0
0
0
0
0
.11
.15
.12
.06
.07
.20
.09
.09
TPTH
Tolerance
(ppm)
0
0
0
0
0
0
0
0
.10
.10
.10
.05
.05
.05
.05
.05
mq/serving
0
0
0
0
0
0
0
0
.011
.015
.012
.003
.0035
.010
.0045
.0045
11 R
mg/kg/body (
weight
b .w. =60kg
0
0
0
0
0
0
0
0
.00018
.00025
.00020
.00005
.00006
.00017
.00008
.00008
isk Quotient"
LOEL of 1.0
mg/kg/day divided
by mg/kg body weight)
5,
4,
5,
20
16
5,
12
12
600
000
000
,000
,700
900
,500
,500
ro
i
From "Nutritive Value of American Foods," Agriculture Handbook No. 456, USDA
Washington, D.C., 1975.
_£/ Estimated total daily intake
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The risk quotients presented in Table I indicate that
the existing tolerances provide a substantial or ample level of
protection from potential teratogenic effects that may be
associated with dietary exposure to the parent TPTH. Because
the risk quotient determinations are based on a single serving
of the respective food commodities, individual dietary practices
may augment or lessen the risks accordingly. However, adequate
protection exists even if multiple servings of the food commodities
listed in Table I are consumed.
The Agency does not expect residues of the parent TPTH to
exceed the current existing tolerance levels. However, there
is significant concern about the potential toxicological
activity of the mono- and diphenyltin metabolites of TPTH and
their contribution to the total food residue. A reassessment
of the existing tolerances will be made once the analytical
methodology and residue data, including storage stability data,
for TPTH and its mono- and diphenyltin metabolites are submitted
for the plant commodities listed in 40 CFR 180.236. Similar
residue data and storage stability studies for processed com-
modities derived from peanuts, potatoes, and sugarbeets are
also needed. Studies on processed commodities must include
data for tetraphenyltin in addition to data for TPTH and the
mono- and diphenyltin metabolites. Residue data and analytical
methodology for meat, milk, poultry, and eggs are also being
required. The above information is being requested from the
registrants in the Guidance Document.
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The Agency is also aware that TPTH and its acetate and
chloride analogues are used abroad. The treated commodities
include dry beans (Bolivia), cocoa (Brazil), potatoes (Brazil,
Cyprus, Ireland, Switzerland, and the United Kingdom), and rice
(Brazil). The recommended international maximum residue limits
for the triphenyltin derivatives do not include contributions
that may be made by inorganic tin and di- and monophenyltin
moieties. Subsequently, international commodities which do
not have an existing tolerance listed in 40 CFR 180.236 may be
subject to administrative action if found to contain TPTH residues
C. ADDITIONAL EFFECTS OF CONCERN
Additional data submitted to the Agency in support of the
continued registration of TPTH have precipitated further
concerns about the safety of the pesticide. At this time, the
available data on these effects are insufficient to determine
whether a Special Review risk trigger has been met or exceeded.
However, the Agency believes the effects described below merit
additional investigation and has required data to delineate
their exact nature and extent.
TPTH has produced immunotoxic effects in mice and guinea
pigs. A 90-day subchronic study using guinea pigs indicated
that the pesticide may inhibit lymphopoiesis and produce atrophy
of lymphoid tissues. In this study, performed in 1960,
leukocyte counts were depressed at the lowest dosage level
tested (2.5 ppm or 0.1 mg/kg/day). Although the Agency has
classified this study as minimally acceptable, the small number
of animals used in each test group as well as the absence of
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a NOEL for the observed effects have resulted in additional
data requirements.
Exposure to TPTH also produced decreased testicular
weights in rat pups in a three-generation reproduction study
performed in 1967. In this study, the F2b generation exhibited
decreased testicular weights when compared to the concurrent
controls at dosage levels of 1.0 ppm and above. A NOEL for
the reproductive effects was estimated to be 0.025 mg/kg/day.
This study has been classified as provisionally invalid because
only summary data were submitted. Registrants should submit
these supporting data, if available, to the Agency. In the
event these data are not available, a new study as required
in the Guidance Document must be submitted.
The oncogenic potential of TPTH cannot be determined
at this time. In one study, female mice dosed with TPTH
developed endometrial hyperplasia at the lowest dosage level
tested, 1.05 mg/kg/day. The development of a test chemical-
induced change in a reproductive organ is considered a serious
adverse effect by the Agency and because of the low dosage at
which the effect was observed it must be considered in the
overall assessment of TPTH toxicity. Additional studies have
been required on an expedited basis in the Guidance Document
to clarify this concern.
The Agency has also performed a preliminary risk
assessment, based on a 90-day inhalation study in rats and
calculated applicator inhalation exposure at 0.0016 mg/kg/day,
to determine potential risks to applicators by this exposure
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route. A NOEL was not established for the effects observed
in the rat study (ie., alopecia, nasal discharge, red ears,
piloerection, etc.) and the resultant risk quotient (151) deter-
mination indicates it may be prudent to require respiratory
protection since any "margin of safety" assessment would result
in a lower safety factor. TPTH is in EPA Toxicity Category I
(highest toxicity rating) by the inhalation exposure route.
Additional studies which have been submitted to support the
continued registration of TPTH indicate the pesticide is highly
toxic to aquatic invertebrates, warmwater fish and estuarine/
marine organisms and is moderately to highly toxic to birds.
These studies suggest continued use of TPTH may have potentially
deleterious effects on wildlife and aquatic organisms.
Data requirements are being mandated in the Guidance Document
on an expedited basis to clarify the environmental fate of TPTH.
These data include accumulation in rotational crops and fish,
leaching, adsorption, desorption, aerobic and anaerobic soil
metabolism, soil dissipation and photodegradation of the pesticide,
re-entry data, avian reproduction and dietary studies, and a
coldwater fish study.
Based on the evaluation of the results of the studies required
above, the Agency will determine whether additional information
and/or restrictions are necessary. Pivotal data requirements and
an expedited submission schedule are summarized in Table II.
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TABLE II — DATA PIVOTAL TO THE SPECIAL REVIEW
Data Requirements
Submission Date
Studies Pivotal to Teratogenicity
Teratogenicity
Postnatal Teratogenicity
Teratogenicityj/
(Dermal Exposure Route)
Analytical Methodology for
Plant and Animal Residues
Including Metabolites and
Tetraphenyltin Hydroxide
Residue Storage Stability
Data
Crop and Processed Commodities
Storage Stability Data
Including Metabolites and
Tetraphenyltin Hydroxide
Studies Pivotal to Additional Concerns
Soil and water photodegradation
Mobility Studies
Soil Dissipation Studies
Immunotoxicity Studies
Dermal Penetration
General Metabolism
Residue Determination for Food
Use Crops, Tobacco, Meat, Milk
Poultry and Eggs
Reproduction 2-generation
Chronic Toxicity
Oncogenicity
December 7, 1985
ii 11 n
Reserved
June 7, 1985
December 7, 1985
June 7, 1986
n n n
n n M
January 1, 1986
it n n
March 7, 1986
June 7, 1986
September 7, 1986
December 7, 1988
it M n
Contingent on the results of the postnatal and standard
teratogenicity and dermal penetration studies.
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D. CURRENT REGULATORY ACTIONS
Because the Agency has determined that TPTH produces terato-
genic effects in laboratory animals at concentrations to which
applicators may be exposed, the Guidance Document requires that a
warning be added to the pesticide label stating that TPTH causes
birth defects in laboratory animals and that exposure during
pregnancy should be avoided. Additional label changes include
the "Restricted Use" classification which limits the use of the
pesticide to certified applicators or to persons directly under
their supervision. Protective clothing including a long-sleeved
shirt, long pants, impermeable gloves, hat, boots, and an approved
pesticide respirator are also required.
In addition to the protective clothing described above, a
face shield is required when the technical product is being
handled. The Registration Standard also stipulates that no new
permits will be issued for the experimental use of TPTH as an
anti-fouling agent in marine paints, nor will any FIFRA section 3
registration applications be considered during the Special Review.
All currently registered TPTH products will remain registered
while the Special Review is in progress. However, the Agency is
deferring final decisions on the reregistration of any products
containing TPTH as a sole active ingredient until the Special
Review is concluded. No new uses for TPTH will be issued during
this period. The Agency also will not approve pending requests
for tolerances for TPTH on rice and soybeans or issue any new
tolerances during the Special Review.
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The Agency is also currently considering the issuance
of a Data Call-in Notice pursuant to FIFRA section 3(c)2(B) in
order to require registrants to submit specific information
on the use, exposure potential, and benefits of TPTH.
E. COMMENTS ON THE INITIATION OF THE SPECIAL REVIEW
Prior to the initiation of a Special Review, technical
registrants receive private notification of the Agency's
determination that the criteria to initiate a Special Review
may have been met. This notification includes information on
the toxicity findings, route of exposure and related general
information. Registrants then have 30 days following receipt of
the notification to rebut the Agency's conclusions.
In response to the Agency's notification that a Special
Review of TPTH was being considered, Uniroyal Corporation
proposed amending their product label in an effort to reduce
risks and obviate the Special Review of the pesticide. Uniroyal
proposed classifying the pesticide as a restricted use chemical,
a 24-hour reentry label statement, a prohibition for female
applicators of childbearing age, and cancellation of all products
except those packaged in water soluble bags.
The Agency believes the proposals submitted by Uniroyal
are generally in agreement with the requirements stipulated in
the Guidance Document. However, the Agency does not have the
information necessary to determine if these and other measures
will adequately reduce the risks from exposure to the pesticide
to an acceptable level. This determination will be made through
the Special Review of TPTH.
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F. REBUTTAL CRITERIA
All registrants, applicants for registration, and other
interested members of the public are invited to submit evidence
either to support or to rebut the presumption that TPTH causes
teratogenic effects in rats and may cause such effects in humans.
Under 40 CFR 162.11(a)(4)(iii) the presumption initiating a
Special Review must be rebutted by proving, in the case of acute
and chronic toxicity criteria, "that the determination by the
Agency that the pesticide meets or exceeds any of the criteria
for risk was in error."
G. BENEFITS INFORMATION
The Agency will conduct a comprehensive benefits review
and analysis for TPTH during the Special Review process and will
consider that information in setting forth the Agency's proposed
regulatory decision in the Position Document 2/3 (PD 2/3). A
preliminary analysis of the benefits of TPTH has been performed
and is presented here.
The major use of TPTH is on pecans. Over 72 percent of the
pesticide used annually is applied to this crop. Georgia is the
primary pecan-producing State accounting for between one third
and one half of the total annual production of pecans in the
United States. New Mexico, Texas, Alabama, and Louisiana make up
the remaining major pecan-producing States. Any one of the
following States, Arkansas, Florida, Mississippi, North Carolina,
Oklahoma, and South Carolina generally account for less than
3 percent of the total national production. Most of the
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TPTH applications occur in the Southeast because the environmental
conditions are conducive to disease development.
Scab is the most important fungal disease in pecan culture
both in the Southeast and Southwest. Preliminary data suggest
that although TPTH is the pesticide most commonly used in pecan
culture, registered alternatives are available for all pests with
the exception of sooty mold which is of minor concern. It is
estimated that without the use of any fungicide, there would be a
substantial loss in the annual yield. Use of the alternative
fungicide benomyl in pecan culture may reduce this loss signif-
icantly, although a major concern with the use of benomyl is
the development of benomyl resistant strains of fungi. To
date, fungal strains that attack pecans have not demonstrated
a resistance to TPTH. For this reason, TPTH and benomyl are
often used on an alternating schedule or applied in combination.
The chemical cost per acre difference between benomyl and TPTH
is minor.
TPTH is also registered for use in controlling fungal
diseases in sugarbeets, peanuts, carrots, and potatoes. On
peanuts, TPTH is used to control early leafspot and incidentally
contributes to mite suppression. TPTH is also registered for use
on potatoes in controlling late and early blight. Late blight is
the more serious concern in potato culture, especially in the
Northeast. Use of TPTH for control of diseases of carrots appears
to be minor but important for the control of Cercospora leafspot
of sugarbeets. Benomyl is often applied for control for Cercospora,
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but TPTH is used where benomyl-resistant strains have developed.
The efficacy and potential unreasonable adverse effects that may
be associated with alternatives for TPTH such as benomyl , metiram,
maneb, captafol, thiophanate-methyl, and others will be fully
reviewed in Position Document 2/3.
In addition to submitting evidence to rebut the presumptions
of risk in the Special Review, 40 CFR 162.11(a)(5)(iii) provides
that a registrant or applicant "may submit evidence as to whether
the economic, social and environmental benefits of the use of
the pesticide subject to the presumption outweigh the risk of
use." If the presumption of risk is not rebutted, the benefits
evidence submitted by registrants, applicants, and other inter-
ested persons will be considered by the Agency when determining
the appropriate regulatory action.
Registrants, applicants or other interested persons who
desire to submit benefits information should consider submitting
information on the following subjects along with any other
relevant information they desire:
1. Identification of the biological and economic importance
of TPTH uses.
2. Identification of alternative chemical and nonchemical
methods of control and any associated health effects and potential
for human exposure.
3. Determination of any change in costs to TPTH users for
obtaining equivalent disease control with available substitute
products or management techniques.
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4. Assessment of the expected changes in the level of
efficacy, crop yield, crop quality, crop injury, and environmental
impacts associated with the use of alternative control measures.
5. Identification of increased or reduced risks associated
with the mixing, loading, and applying of alternative chemicals,
with their potential increase in use if TPTH were not available.
6. Identification of cultural and spray application
practices, that impact on farmworker exposure to TPTH.
7. Identification of cultural or integrated pest manage-
ment practices which are enhanced or limited by use of TPTH.
II. REBUTTAL SUBMISSION PROCEDURES
All registrants and applicants for registration are
being notified by certified mail of the Special Review being
initiated on their products containing TPTH.
The registrants and applicants for registration will
have 45 days from the date this notice is received or until
(insert date 45 days after date of publication in the FEDERAL
REGISTER) (whichever is later) to submit evidence in rebuttal
to the Agency's presumption. Other interested parties may
submit comments during the same period.
III. DUTY TO SUBMIT INFORMATION ON ADVERSE EFFECTS
Registrants are required by section 6(a)(2) of FIFRA to
submit any additional information regarding unreasonable adverse
effects on man or the environment which comes to their attention
at any time. Registrants of TPTH products must immediately
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submit any published or unpublished information, studies,
reports, analyses, or reanalyses regarding any TPTH effects
in animal species or humans, and claimed or verified accidents
to humans, domestic animals, or wildlife which have not been
previously submitted to EPA. These data should be submitted
with a cover letter specifically identifying the information
as being submitted under section 6(a)(2) of FIFRA. Registrants
should notify EPA of any studies on TPTH currently in progress,
their purpose, the protocol, the approximate completion date,
a summary of all results observed to date, the name and
address of the laboratory performing the studies, and a
statement as to whether these studies are being conducted in
accordance with the Good Laboratory Practices specified in
40 CFR Part 160, published in the FEDERAL REGISTER of
November 29, 1983 (48 FR 53946).
IV. PUBLIC COMMENT OPPORTUNITY
During the time allowed for submission of rebuttal
evidence, specific comments are solicited on the presumptions
set forth in this Notice and in the Registration Standard. In
particular, any documented episodes of adverse effects on
humans or domestic animals should be submitted to the Agency
as soon as possible. Any information as to any laboratory
studies in progress or completed should be submitted to the
Agency as soon as possible with a statement as to whether
those studies are in compliance with the Good Laboratory
Practices specified in 40 CFR Part 160. Specifically, infor-
mation on any adverse toxicological effects of TPTH, its
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impurities, metabolites, and degradation products is solicited.
Similarly, submission of any studies or comments on the
benefits from the use of TPTH is requested. All comments and
information and analyses, which come to the attention of EPA,
may serve as a basis for final determination of regulatory
action following the Special Review.
All comments and information should be sent to the
address given above, preferably in triplicate, to facilitate
the work of EPA and others interested in inspecting them.
The comments and information should bear the identifying
notation [OPP-30000/42].
During the comment period, interested members of the
public or registrants may request a meeting to discuss the
risk issues and methods of reducing risks. Any records
pertaining to such meetings, including minutes, agendas, and
comments received will be filed under docket number OPP-30000/42
Dated: /"I/ /7 /
/ /
Director,
Office of Pesticide Programs.
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