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Oxyfluorfen. April 25, 1997. Pesticide Tolerance for Emergency Exemption. Final Rule. Federal Register.
[Federal Register: April 25, 1997 (Volume 62, Number 80)]
[Rules and Regulations]
[Page 20104-20111]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr25ap97-10]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
[OPP-300478; FRL-5713-1]
RIN 2070-AB78
Oxyfluorfen; Pesticide Tolerance for Emergency Exemption
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: This regulation establishes a time-limited tolerance for
residues of the herbicide Oxyfluorfen in or on the food commodity
strawberry in connection with EPA's granting of emergency exemptions
under the Federal Insecticide, Fungicide, and Rodenticide Act
authorizing use of Oxyfluorfen on strawberries in Massachusetts, New
Hampshire, Connecticut, Maine, Washington and Oregon. This regulation
establishes maximum permissible levels for residues of Oxyfluorfen in
this food pursuant to the Federal Food, Drug, and Cosmetic Act, as
amended by the Food Quality Protection Act of 1996. The tolerance will
expire and is revoked on April 15, 1998.
DATES: This regulation becomes effective April 25, 1997. Objections and
requests for hearings must be received by EPA on or before June 24,
1997.
ADDRESSES: Written objections and hearing requests, identified by the
docket control number, [OPP-300478], must be submitted to: Hearing
Clerk (1900), Environmental Protection Agency, Rm. M3708, 401 M St.,
SW., Washington, DC 20460. Fees accompanying objections and hearing
requests shall be labeled ``Tolerance Petition Fees'' and forwarded to:
EPA Headquarters Accounting Operations
[[Page 20105]]
Branch, OPP (Tolerance Fees), P.O. Box 360277M, Pittsburgh, PA 15251. A
copy of any objections and hearing requests filed with the Hearing
Clerk identified by the docket control number, [OPP-300478], must also
be submitted 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 a copy of objections and hearing requests to Rm. 1132,
CM #2, 1921 Jefferson Davis Highway, Arlington, VA.
A copy of objections and hearing requests filed with the Hearing
Clerk may also be submitted electronically by sending electronic mail
(e-mail) to: opp-docket@epamail.epa.gov. Such copies of objections and
hearing requests must be submitted as an ASCII file avoiding the use of
special characters and any form of encryption. Copies of objections and
hearing requests will also be accepted on disks in WordPerfect 5.1 file
format or ASCII file format. All copies of objections and hearing
requests in electronic form must be identified by the docket number
[OPP-300478]. No Confidential Business Information (CBI) should be
submitted through e-mail. Electronic copies of objections and hearing
requests on this rule may be filed online at many Federal Depository
Libraries.
FOR FURTHER INFORMATION CONTACT: By mail: Pat Cimino, Registration
Division (7505W), Environmental Protection Agency, 401 M St., SW.,
Washington, DC 20460. Office location, telephone number, and e-mail:
Sixth Floor, Crystal Station #1, 2800 Jefferson Davis Highway,
Arlington, VA, (703) 308-8328, e-mail: cimino.pat@epamail.epa.gov.
SUPPLEMENTARY INFORMATION: EPA, pursuant to section 408(e) and (l)(6)
of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a(e)
and (l)(6), is establishing a tolerance for residues of the herbicide
oxyfluorfen, [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-
(trifluoromethyl)benzene] in or on strawberries, at 0.05 part per
million (ppm). The residue requiring regulation is parent oxyfluorfen
only. This tolerance will expire and be revoked by EPA on April 15,
1998. After April 15, 1998, EPA will publish a document in the Federal
Register to remove the revoked tolerances from the Code of Federal
Regulations.
I. Background and Statutory Authority
The Food Quality Protection Act of 1996 (FQPA) (Pub. L. 104-170)
was signed into law August 3, 1996. FQPA amends both the Federal Food,
Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 301 et seq., and the Federal
Insecticide, Fungicide, and Rodenticide Act (FIFRA), 7 U.S.C. 136 et
seq. The FQPA amendments went into effect immediately. Among other
things, FQPA amends FFDCA to bring all EPA pesticide tolerance-setting
activities under a new section 408 with a new safety standard and new
procedures. These activities are described below and discussed in
greater detail in the final rule establishing the time-limited
tolerance associated with the emergency exemption for use of
propiconazole on sorghum (61 CFR 58135, November 13, 1996) (FRL-5572-
9).
New section 408(b)(2)(A)(i) allows EPA to establish a tolerance
(the legal limit for a pesticide chemical residue in or on a food) only
if EPA determines that the tolerance is ``safe.'' Section
408(b)(2)(A)(ii) defines ``safe'' to mean that ``there is a reasonable
certainty that no harm will result from aggregate exposure to the
pesticide chemical residue, including all anticipated dietary exposures
and all other exposures for which there is reliable information.'' This
includes exposure through drinking water, but does not include
occupational exposure. Section 408(b)(2)(C) requires EPA to give
special consideration to exposure of infants and children to the
pesticide chemical residue in establishing a tolerance and to ``ensure
that there is a reasonable certainty that no harm will result to
infants and children from aggregate exposure to the pesticide chemical
residue....''
Section 18 of FIFRA authorizes EPA to exempt any Federal or State
agency from any provision of FIFRA, if EPA determines that ``emergency
conditions exist which require such exemption.'' This provision was not
amended by FQPA. EPA has established regulations governing such
emergency exemptions in 40 CFR part 166.
Section 408(l)(6) requires EPA to establish a time-limited
tolerance or exemption from the requirement for a tolerance for
pesticide chemical residues in food that will result from the use of a
pesticide under an emergency exemption granted by EPA under section 18
of FIFRA. Section 408(l)(6) also requires EPA to promulgate regulations
by August 3, 1997, governing the establishment of tolerances and
exemptions under section 408(l)(6) and requires that the regulations be
consistent with section 408(b)(2) and (c)(2) and FIFRA section 18.
Section 408(l)(6) allows EPA to establish tolerances or exemptions
from the requirement for a tolerance, in connection with EPA's granting
of FIFRA section 18 emergency exemptions, without providing notice or a
period for public comment. Thus, consistent with the need to act
expeditiously on requests for emergency exemptions under FIFRA, EPA can
establish such tolerances or exemptions under the authority of section
408(e) and (l)(6) without notice and comment rulemaking.
In establishing section 18-related tolerances and exemptions during
this interim period before EPA issues the section 408(l)(6) procedural
regulation and before EPA makes its broad policy decisions concerning
the interpretation and implementation of the new section 408, EPA does
not intend to set precedents for the application of section 408 and the
new safety standard to other tolerances and exemptions. Rather, these
early section 18 tolerance and exemption decisions will be made on a
case-by-case basis and will not bind EPA as it proceeds with further
rulemaking and policy development. EPA intends to act on section 18-
related tolerances and exemptions that clearly qualify under the new
law.
II. Emergency Exemption for Oxyfluorfen on Strawberries and FFDCA
Tolerances
The Massachusetts Department of Food and Agriculture; Maine
Department of Agriculture, Food and Rural Resources; Connecticut
Department of Environmental Protection; and New Hampshire, Oregon and
Washington Departments of Agriculture requested specific exemptions
under FIFRA section 18 for the use of oxyfluorfen on strawberries to
control wood sorrel (Oxalis sp.), and field pansy (Viola tricolor) in
Massachusetts, Maine, Connecticut and New Hampshire and common
groundsel (Senecia vulgaris), common lambsquarter (Chenopodium album),
redroot pigweed (Amaranthus retroflexus), prostate knotweed, (Polygonum
aviculare), smartweed (Polygonum persicaria), corn spurry (Spergula
arvensis), wild buckwheat (Polygonum convolvulus), mayweed (Anthemis
cotula), and pineappleweed (Capsella bursa-pastoris) in Oregon and
Washington. The states indicated that an emergency situation is present
due to lack of registered, effective alternatives to control these
broadleaf weeds. The voluntary cancellations of chloroxuron (Tenoran)
and dipenamid (Enide), depletion of the existing stocks of these
materials, and recent label changes, varietal sensitivity and plant-
back restrictions for terbacil (Sinbar) have resulted in a lack of
effective materials
[[Page 20106]]
for control of the above weeds. The states indicate that they will
suffer significant losses without an effective control for these weeds.
After reviewing the applicants' submissions, the Agency concurs that
emergency conditions exist for these states.
As part of its assessment of these crisis declarations, EPA
assessed the potential risks presented by residues of oxyfluorfen in or
on strawberries. In doing so, EPA considered the new safety standard in
FFDCA section 408(b)(2), and EPA decided to grant the section 18
exemptions only after concluding that the necessary tolerance under
FFDCA section 408(l)(6) would clearly be consistent with the new safety
standard and with FIFRA section 18. This tolerance for oxyfluorfen will
permit the marketing of strawberries treated in accordance with the
provisions of the section 18 emergency exemptions. Consistent with the
need to move quickly on the emergency exemptions and to ensure that the
resulting food is safe and lawful, EPA is issuing this tolerance
without notice and opportunity for public comment under section 408(e)
as provided for in section 408(l)(6). Although this tolerance will
expire and is revoked on April 15, 1998, under FFDCA section 408(l)(5),
residues of oxyfluorfen not in excess of the amount specified in the
tolerance remaining in or on strawberries after that date will not be
unlawful, provided the pesticide is applied during the term of, and in
accordance with all the conditions of, section 18 of FIFRA. EPA will
take action to revoke this tolerance earlier if any experience with,
scientific data on, or other relevant information on this pesticide
indicate that the residues are not safe.
EPA has not made any decisions about whether oxyfluorfen meets the
requirements for registration under FIFRA section 3 for use on
strawberries, or whether a permanent tolerance for oxyfluorfen in or on
strawberries would be appropriate. This action by EPA does not serve as
a basis for registration of oxyfluorfen by a State for special local
needs under FIFRA section 24(c). Nor does this action serve as the
basis for any State other than Massachusetts, Maine, New Hampshire,
Connecticut, Oregon and Washington to use this product on this crop
under section 18 of FIFRA without following all provisions of section
18 as identified in 40 CFR part 166. For additional information
regarding the emergency exemptions for oxyfluorfen, contact the
Agency's Registration Division at the address provided above.
III. Risk Assessment and Statutory Findings
EPA performs a number of analyses to determine the risks from
aggregate exposure to pesticide residues. First, EPA determines the
toxicity of pesticides based primarily on toxicological studies using
laboratory animals. These studies address many adverse health effects,
including (but not limited to) reproductive effects, developmental
toxicity, toxicity to the nervous system, and carcinogenicity. For many
of these studies, a dose-response relationship can be determined, which
provides a dose that causes adverse effects (threshold effects) and
doses causing no observed effects (the ``no-observed effect level'' or
``NOEL'').
Once a study has been evaluated and the observed effects have been
determined to be threshold effects, EPA generally divides the NOEL from
the study with the lowest NOEL by an uncertainty factor (usually 100 or
more) to determine the Reference Dose (RfD). The RfD is a level at or
below which daily aggregate exposure over a lifetime will not pose
appreciable risks to human health. An uncertainty factor (sometimes
called a ``safety factor'') of 100 is commonly used since it is assumed
that people may be up to 10 times more sensitive to pesticides than the
test animals, and that one person or subgroup of the population (such
as infants and children) could be up to 10 times more sensitive to a
pesticide than another. In addition, EPA assesses the potential risks
to infants and children based on the weight of the evidence of the
toxicology studies and determines whether an additional uncertainty
factor is warranted. Thus, an aggregate daily exposure to a pesticide
residue at or below the RfD (expressed as 100 percent or less of the
RfD) is generally considered by EPA to pose a reasonable certainty of
no harm.
Lifetime feeding studies in two species of laboratory animals are
conducted to screen pesticides for cancer effects. When evidence of
increased cancer is noted in these studies, the Agency conducts a
weight-of-the-evidence review of all relevant toxicological data
including short-term and mutagenicity studies and structure-activity
relationships. Once a pesticide has been classified as a potential
human carcinogen, different types of risk assessments [e.g., linear
low-dose extrapolations or margin of exposure (MOE) calculation based
on the appropriate NOEL] will be carried out based on the nature of the
carcinogenic response and the Agency's knowledge of its mode of action.
In examining aggregate exposure, FFDCA section 408 requires that
EPA take into account available and reliable information concerning
exposure from the pesticide residue in the food in question, residues
in other foods for which there are tolerances, and other non-
occupational exposures, such as where residues leach into groundwater
or surface water that is consumed as drinking water. Dietary exposure
to residues of a pesticide in a food commodity are estimated by
multiplying the average daily consumption of the food forms of that
commodity by the tolerance level or the anticipated pesticide residue
level. The Theoretical Maximum Residue Contribution (TMRC) is an
estimate of the level of residues consumed daily if each food item
contained pesticide residues equal to the tolerance. The TMRC is a
``worst case'' estimate since it is based on the assumptions that food
contains pesticide residues at the tolerance level and that 100 percent
of the crop is treated by pesticides that have established tolerances.
If the TMRC exceeds the RfD or poses a lifetime cancer risk that is
greater than approximately one in a million, EPA attempts to derive a
more accurate exposure estimate for the pesticide by evaluating
additional types of information (anticipated residue data and/or
percent of crop treated data) which show, generally, that pesticide
residues in most foods when they are eaten are well below established
tolerances.
IV. Aggregate Risk Assessments, Cumulative Risk Discussion, and
Determination of Safety
Consistent with section 408(b)(2)(D), EPA has reviewed the
available scientific data and other relevant information in support of
this action. Oxyfluorfen is registered by EPA for outdoor residential
uses.
Tolerances have been established (40 CFR 180.381) for the combined
residues of oxyfluorfen, [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-
(trifluoromethyl)benzene] and its metabolites containing the diphenyl
ether linkage expressed in or on certain food commodities ranging from
0.05 ppm in stone fruits to 0.25 ppm in mint oil. There are no
livestock feed items associated with these section 18 requests and
secondary residues are not expected to occur in meat, milk, poultry or
eggs as a result of these section 18 uses. Based on information
submitted to the Agency, EPA has sufficient data to assess the hazards
of oxyfluorfen and to
[[Page 20107]]
make a determination on aggregate exposure, consistent with section
408(b)(2), for the time-limited tolerance for residues of oxyfluorfen
on strawberries at 0.05 ppm. EPA's assessment of the dietary exposures
and risks associated with establishing this tolerance follows.
A. Toxicological Profile
1. Acute risk. For the acute dietary risk assessment, the Agency
recommended use of the NOEL of 10 mg/kg/day, based on fused sternebrae
observed in pups at the Lowest Effect Level (LEL) of 30 mg/kg/day, from
the developmental toxicity study in rabbits. This NOEL is used to
evaluate the Margin of Exposure (MOE) from the acute dietary risk to
pregnant women 13+ years or older.
2. Chronic risk. The RfD of 0.003 mg/kg/day was established by the
Agency on April 14, 1986, based on a 20-month feeding study in mice
with a NOEL of 0.3 mg/kg/day and an uncertainty factor of 100. The
effects observed at the LEL of 3.0 mg/kg/day were necrosis,
hyperplastic nodules, and absolute liver weight.
3. Cancer risk. Oxyfluorfen has been classified as a Group C
chemical by the Agency based on liver adenomas and carcinomas in the
20-month feeding study in mice. The Agency recommended using the
Q1* approach to assess cancer risk. The Q1* is 0.128 (mg/kg/
day)-1.
4. Developmental toxicity risk. From the developmental toxicity
study in rats, the maternal NOEL was 18 mg/kg/day and the maternal LEL
was 183 mg/kg/day, based on decreased weight gain and food consumption,
increased incidences of soft or scant feces, increased alkaline
phosphatase and SGOT and mortality at high-dose. The developmental
(pup) NOEL was 18 mg/kg/day and the developmental LEL was 183 mg/kg/day
based on decreased fetal body weight, increased resorptions, and an
increase in the incidences of left carotid artery arising from the
innominate, bent bones of the forelimbs, and other ossification
irregularities; these effects were confined to the mid-dose level,
since there was 100% litter loss in the high-dose group [848 mg/kg/day]
as the result of maternal mortality and resorptions. From the
developmental toxicity study in rabbits, the maternal (systemic) NOEL
was 10 mg/kg/day and the maternal LEL was 30 mg/kg/day based on
anorexia and decreased body weight gain. The developmental (pup) NOEL
was 10 mg/kg/day and the developmental LEL was 30 mg/kg/day based on
fused sternebrae.
5. Reproductive toxicity risk. In the 2-generation reproduction
study in rats, the reproductive (pup) NOEL was 400 ppm [20 mg/kg/day]
and the reproductive LEL was 1,600 ppm [80 mg/kg/day] based on
decreased pup body weight during lactation in both the F1a and F2a
litters and also a decreased litter size at birth in F1a and F2a
litters. The systemic (parents) NOEL was 400 ppm and LEL was 1,600 ppm
based on pelvic mineralization of P1 males, P2 males and females, and
pelvic papillary hyperplasia in P1 and P2 males and P2 females. Also at
1,600 ppm, there were additional kidney effects, consisting of
dilatation of collecting ductules in both P2 sexes. Other high-dose
histological findings consisted of hepatocellular hypertrophy in both
sexes of P1 and P2 animals. Additional high-dose effects were alopecia
in both sexes of P1 and P2 animals during growth, and decreased weight
gain during growth and gestation of P1 and P2 parental animals.
B. Aggregate Exposure
In examining aggregate exposure, FQPA directs EPA to consider
available information concerning exposures from the pesticide residue
in food and all other non-occupational exposures. The primary non-food
sources of exposure the Agency looks at include drinking water (whether
from groundwater or surface water), and exposure through pesticide use
in gardens, lawns, or buildings (residential and other indoor uses).
Permanent oxyfluorfen food tolerances have been established and
there are no livestock feed items associated with these section 18
requests. Oxyfluorfen is registered for outdoor residential uses.
1. Chronic exposure-- i. Dietary risk assessment considerations. In
conducting exposure assessments for these section 18 requests, EPA
partially refined the chronic RfD and cancer risk assessments by using
a combination of the TMRC (worst-case) and dietary exposure assumptions
based on anticipated residues and/or percent of crop treated. Percent
of crop treated estimates are derived from reliable federal and private
market survey data. Typically, a range of estimates are supplied and
the upper end of this range is assumed for the exposure assessment. By
using this upper end estimate of percent crop treated, the Agency is
reasonably certain that exposure is not understated for any significant
subpopulation group. In addition, actual residues are expected to be
quite low because the majority of the use patterns direct sprays onto
weeds and away from the crop and there are long pre-harvest intervals
for sprays which are directly applied to crops.
To determine chronic (using the RfD) and cancer (using the Q1*
approach) risks, the Agency has utilized the TMRC to estimate dietary
exposure from proposed uses of oxyfluorfen on strawberries and peanuts,
and from registered uses of oxyfluorfen with tolerances established for
the following food items: dates, figs, guava, loquats, olives and olive
oil, papaya, persimmon, pomegranate, plantains, kiwi, cocoa butter,
coffee, artichokes, taro-roots and greens, garlic, shallots,
cauliflower, bok-choy and other chinese variety cole crops, dry beans,
crabapples, quince, blackberry, raspberry, brazil nut, cashew,
chestnuts, hazelnuts, hickory nuts, macadamias, pecans, horseradish and
peppermint and spearmint oils. The TMRC is obtained by multiplying the
tolerance level residue for these foods by the average consumption data
(estimates of the amount of the foods eaten by various population
subgroups). The risk assessment using TMRC assumptions is considered to
be overestimated.
Refined dietary exposure estimates using percent of crop treated
were used to assess chronic dietary risk for registered uses of
oxyfluorfen with established tolerances for the following foods and/or
animal feed items: pistachio nuts, cottonseed meal, cherries,
nectarines, plums, prunes, almonds and walnuts. Refined dietary
exposure estimates using anticipated residues were used to assess
chronic dietary risk for registered uses of oxyfluorfen with
established tolerances on the following food items: bananas, broccoli,
cabbage, apricots, meat and milk. Refined dietary exposure estimates
using percent of crop treated and anticipated residues were used to
assess chronic dietary risk for registered uses of oxyfluorfen with
established tolerances on the following food and/or animal feed items:
cottonseed oil, onions, soybeans, soybean oil, apples, pears, peaches,
grapes and corn.
The Agency considers the partially refined estimates for chronic
RfD and cancer risks to be conservative.
ii. Drinking water considerations. The Agency has reviewed
environmental fate data which indicate that oxyfluorfen is persistent
but non-mobile. There is no established Maximum Concentration Level
(MCL) for residues of oxyfluorfen in drinking water. No health advisory
levels for oxyfluorfen in drinking water have been established. As
noted in ``Pesticides in Groundwater Database'' EPA 734-12-92-001, Sept
1992, 188 wells were
[[Page 20108]]
monitored in Texas in 1987 and 1988. No detectable residues of
oxyfluorfen were found in any of the samples.
Because the Agency lacks sufficient water-related exposure data to
complete a comprehensive drinking water risk assessment for many
pesticides, EPA has commenced and nearly completed a process to
identify a reasonable yet conservative bounding figure for the
potential contribution of water related exposure to the aggregate risk
posed by a pesticide. In developing the bounding figure, EPA estimated
residue levels in water for a number of specific pesticides using
various data sources. The Agency then applied the estimated residue
levels, in conjunction with appropriate toxicological endpoints (RfD's
or acute dietary NOEL's) and assumptions about body weight and
consumption, to calculate, for each pesticide, the increment of
aggregate risk contributed by consumption of contaminated water. While
EPA has not yet pinpointed the appropriate bounding figure for
consumption of contaminated water, the ranges the Agency is continuing
to examine are all below the level that would cause oxyfluorfen to
exceed the RfD if the tolerance being considered in this document were
granted. In addition, chronic exposure to oxyfluorfen residues
resulting from potential water exposure would not increase the total
cancer risk so that it exceeds the Agency's level of concern. The
Agency has therefore concluded that the potential exposures associated
with oxyfluorfen in water, even at the higher levels the Agency is
considering as a conservative upper bound for RfD exposure
considerations, would not prevent the Agency from determining that
there is a reasonable certainty of no harm if the tolerance is granted.
iii. Non-dietary, non-occupational considerations. Oxyfluorfen is
registered for outdoor residential use. Acceptable, reliable data are
not currently available with which to assess acute risk. However, based
on the available residential exposure data and the best professional
judgment of scientists who have worked with the available occupational
exposure data, 5% of the risk for outdoor residential uses is a
reasonable, protective default assumption for this pesticide. In the
best scientific judgment of the Agency, chronic exposure to oxyfluorfen
residues resulting from potential outdoor residential exposure would
not increase the total chronic or cancer risks so that they exceed the
Agency's level of concern.
2. Acute exposure. Acute dietary risk assessments are performed for
a food-use pesticide if a toxicological study has indicated the
possibility of an effect of concern occurring as a result of a 1 day or
single exposure. Under FQPA, drinking water is also considered a
component of the acute dietary exposure.
Theoretically, it is also possible that a residential, or other
non-dietary, exposure could be combined with the acute total dietary
exposure from food and water. However, the Agency does not believe that
aggregating multiple exposure to large amounts of pesticide residues in
the residential environment via multiple products and routes for a 1-
day exposure is a reasonably probable event. It is highly unlikely
that, in 1 day, an individual would have multiple high-end exposures to
the same pesticide by treating their lawn and garden, treating their
house via crack and crevice application, swimming in a pool, and be
maximally exposed in the food and water consumed.
The acute dietary exposure endpoint of concern for oxyfluorfen is
fused sternebrae in developing pups which was observed in the rabbit
developmental study. The population subgroup of concern is females 13+
years old (women of childbearing age). Acute dietary exposure (food
only) was calculated using the TMRC (worst case) assumptions. An MOE of
100 (food only) or greater is acceptable for these section 18 requests.
Despite the potential for acute exposure to oxyfluorfen in drinking
water, EPA does not expect the aggregate acute exposure to exceed the
Agency's level of concern if the tolerance being considered in this
document were granted. The Agency has therefore concluded that the
potential acute term exposures associated with oxyfluorfen in water,
even at the higher levels the Agency is considering as a conservative
upper bound, would not prevent the Agency from determining that there
is a reasonable certainty of no harm if the tolerance is granted.
C. Cumulative Exposure to Substances with Common Mechanism of Toxicity
Section 408(b)(2)(D)(v) requires that, when considering whether to
establish, modify, or revoke a tolerance, the Agency consider
``available information'' concerning the cumulative effects of a
particular pesticide's residues and ``other substances that have a
common mechanism of toxicity.'' The Agency believes that ``available
information'' in this context might include not only toxicity,
chemistry, and exposure data, but also scientific policies and
methodologies for understanding common mechanisms of toxicity and
conducting cumulative risk assessments. For most pesticides, although
the Agency has some information in its files that may turn out to be
helpful in eventually determining whether a pesticide shares a common
mechanism of toxicity with any other substances, EPA does not at this
time have the methodologies to resolve the complex scientific issues
concerning common mechanism of toxicity in a meaningful way. EPA has
begun a pilot process to study this issue further through the
examination of particular classes of pesticides. The Agency hopes that
the results of this pilot process will increase the Agency's scientific
understanding of this question such that EPA will be able to develop
and apply scientific principles for better determining which chemicals
have a common mechanism of toxicity and evaluating the cumulative
effects of such chemicals. The Agency anticipates, however, that even
as its understanding of the science of common mechanisms increases,
decisions on specific classes of chemicals will be heavily dependent on
chemical specific data, much of which may not be presently available.
Although at present the Agency does not know how to apply the
information in its files concerning common mechanism issues to most
risk assessments, there are pesticides as to which the common mechanism
issues can be resolved. These pesticides include pesticides that are
toxicologically dissimilar to existing chemical substances (in which
case the Agency can conclude that it is unlikely that a pesticide
shares a common mechanism of activity with other substances) and
pesticides that produce a common toxic metabolite (in which case common
mechanism of activity will be assumed).
EPA does not have, at this time, available data to determine
whether oxyfluorfen has a common mechanism of toxicity with other
substances or how to include this pesticide in a cumulative risk
assessment. Unlike other pesticides for which EPA has followed a
cumulative risk approach based on a common mechanism of toxicity,
oxyfluorfen does not appear to produce a toxic metabolite produced by
other substances. For the purposes of this tolerance action, therefore,
EPA has not assumed that oxyfluorfen has a common mechanism of toxicity
with other substances.
D. Determination of Safety for U.S. Population
1. Chronic RfD and cancer risk. Using the partially refined dietary
exposure assumptions described above and taking
[[Page 20109]]
into account the completeness and reliability of the toxicity data, EPA
has concluded that aggregate dietary exposure (food only) to
oxyfluorfen will utilize <1% of the RfD for the U.S. population. EPA
generally has no concern for exposures below 100 percent of the RfD
because the RfD represents the level at or below which daily aggregate
dietary exposure over a lifetime will not pose appreciable risks to
human health. Despite the potential for exposure to oxyfluorfen in
drinking water and from the 5% default-level contribution from non-
dietary, non-occupational exposure, EPA does not expect the aggregate
exposure to exceed 100% of the RfD.
As noted above, oxyfluorfen has been classified as a Group C
chemical by the Agency based on liver adenomas and carcinomas in the
20-month mouse feeding study. The Agency recommended using the Q1*
approach to assess cancer risk, with a value of 0.128 (mg/kg/day)-
1. The partially refined dietary assumptions for existing oxyfluorfen
tolerances plus amortized section 18 strawberry use (adjusted for a 6
year duration of exposure to this section 18 use over a 70 year
lifetime) result in a Anticipated Residue Contribution (ARC) that is
equivalent to 1.8 x 10-6 (food only). Although this number is
partially refined, it is still considered conservative by the Agency.
Actual residues are expected to be quite low because the majority of
the use patterns direct sprays onto weeds and away from the crop and
there are long pre-harvest intervals for sprays which are directly
applied to crops. Environmental fate data indicate that oxyfluorfen
strongly adheres to soil, does not leach into groundwater and has not
been detected in sampled groundwater. Based on this information,
occurrence of oxyfluorfen in drinking water is unlikely. Outdoor
residential uses of oxyfluorfen are limited and exposure is expected to
be low. Oxyfluorfen is toxic to lawn grasses and certain ornamental
plants, and use is generally limited to spot treatments for non-
selective weed control. In the best scientific judgment of the Agency,
chronic exposure to oxyfluorfen residues resulting from potential
residential and/or water exposure would not increase the total cancer
risk so that it exceeds the Agency's level of concern. EPA concludes
that there is a reasonable certainty that no harm will result from
chronic aggregate exposure to oxyfluorfen residues.
2. Acute risk. The acute dietary exposure endpoint of concern for
oxyfluorfen is fused sternebrae in developing pups which was observed
in the rabbit developmental study. The population subgroup of concern
is females 13+ years old (women of childbearing age). For this
subgroup, the calculated MOE at the high end exposure is 5,000. The
Agency considers dietary (food) MOEs of greater than 100 to be
acceptable for oxyfluorfen. Acute dietary exposure (food only) was
calculated using the TMRC (worst case) assumptions.
In the absence of data for drinking water exposure, the ranges of
exposure being considered by the Agency for consumption of contaminated
water will be reserved for drinking water. The aggregate MOE level of
concern for dietary plus the addition of upperbound estimates for
drinking water is not likely to raise the MOE level of concern above
150. Despite the potential for acute exposure to oxyfluorfen in
drinking water, EPA does not expect the aggregate exposure to exceed
the Agency's level of concern if the tolerance being considered in this
document were granted. The Agency has therefore concluded that the
potential acute exposure associated with oxyfluorfen in water, even at
the higher levels the Agency is considering as a conservative upper
bound, would not prevent the Agency from determining that there is a
reasonable certainty of no harm if the tolerance is granted.
E. Determination of Safety for Infants and Children
In assessing the potential for additional sensitivity of infants
and children to residues of oxyfluorfen, EPA considered data from
developmental toxicity studies in the rat and rabbit and a 2-generation
reproduction study in the rat. The developmental toxicity studies are
designed to evaluate adverse effects on the developing organism
resulting from pesticide exposure during prenatal development to one or
both parents. Reproduction studies provide information relating to
effects from exposure to the pesticide on the reproductive capability
of mating animals and data on systemic toxicity.
FFDCA section 408 provides that EPA shall apply an additional
tenfold margin of safety for infants and children in the case of
threshold effects to account for pre- and post-natal toxicity and the
completeness of the database unless EPA determines that a different
margin of safety will be safe for infants and children. Margins of
safety are incorporated into EPA risk assessments either directly
through use of a margin of exposure analysis or through using
uncertainty (safety) factors in calculating a dose level that poses no
appreciable risk to humans. In either case, EPA generally defines the
level of appreciable risk as exposure that is greater than 1/100 of the
no observed effect level in the animal study appropriate to the
particular risk assessment. This hundredfold uncertainty (safety)
factor/margin of exposure (safety) is designed to account for combined
inter- and intra-species variability. EPA believes that reliable data
support using the standard hundredfold margin/actor not the additional
tenfold margin/factor when EPA has a complete database under existing
guidelines and when the severity of the effect in infants or children
or the potency or unusual toxic properties of a compound do not raise
concerns regarding the adequacy of the standard margin/factor.
The toxicology data base is complete for oxyfluorfen relative to
pre- and post-natal toxicity. In the developmental toxicity study in
rabbits, at the maternally toxic dose of 30 mg/kg/day, there were
developmental anomalies (fused sternebrae) in the fetuses which
demonstrated that pre-natal toxicity should be evaluated by an acute
dietary risk estimate. As described above, the acute dietary MOE for
pregnant women 13+ years old was 5,000 based on the developmental NOEL
of 10 mg/kg/day. This MOE is much higher than the minimal acceptable
MOE (100 for dietary-food only) and suggests that pre-natal
developmental risks to infants and children from exposure to
oxyfluorfen dietary residues is not a concern. Additionally, the rabbit
developmental NOEL of 10 mg/kg/day is 33 times greater than the NOEL of
0.3 mg/kg/day used to calculate the RfD. In the developmental toxicity
study in rats, both the developmental and maternal NOEL and LOEL of 18
and 183 mg/kg/day, respectively, occurred at the same dose levels and
demonstrates that there is no special sensitivity in infants and
children exposed to oxyfluorfen. Although the developmental findings in
the rat were severe effects, the developmental NOEL of 18 mg/kg/day is
greater than the rabbit developmental NOEL of 10 mg/kg/day used to
calculate acute dietary MOEs. Therefore, the acute dietary risk
estimates calculated from the rabbit developmental NOEL are lower than
acute dietary MOEs which could be calculated for the more severe
effects occurring in rats above the NOEL of 18 mg/kg/day. By basing the
acute dietary MOEs on the NOEL in the most sensitive species (rabbit),
pregnant women are protected against both types of pre-natal toxicity
effects as seen in the rat and rabbit developmental toxicity studies.
Therefore, there are no
[[Page 20110]]
significant pre-natal toxicity concerns for infants and children due to
the high MOE for pregnant women 13+ years old. In the 2-generation
reproductive toxicity study in rats used to assess the post-natal
toxicity potential of infants and children, the NOEL and LOEL of 20 mg/
kg/day and 80 mg/kg/day, respectively, for developmental/reproductive
and systemic toxicity demonstrated that there are no pup toxicity
effects in the absence of parental toxicity (NOEL and LOEL are the same
for pups and parental animals). Therefore, there are no special post-
natal sensitivities in infants and children which can be attributed to
the findings of the 2-generation reproductive toxicity study in rats.
Additionally, the developmental/reproductive NOEL of 20 mg/kg/day
[which is the NOEL for decreased litter size at birth as well as
decreased pup body weight] and the parental systemic NOEL of 20 mg/kg/
day is 66 times greater than the NOEL of 0.3 mg/kg/day used to
calculate the RfD.
Based on the above, EPA concludes that reliable data support use of
the standard hundredfold margin of exposure/uncertainty factor and that
an additional margin/factor is not needed to protect the safety of
infants and children.
1. Chronic risk. Using the partially refined, conservative exposure
assumptions described above and taking into account the completeness
and reliability of the toxicity data, EPA has concluded that aggregate
dietary exposure to oxyfluorfen will utilize 1% of the RfD for infants
and 1.4% of the RfD for children. EPA generally has no concern for
exposures below 100 percent of the RfD because the RfD represents the
level at or below which daily aggregate dietary exposure over a
lifetime will not pose appreciable risks to human health. Despite the
potential for exposure to oxyfluorfen in drinking water and from non-
dietary, non-occupational exposure, EPA does not expect the chronic
aggregate exposure to exceed 100% of the RfD. EPA concludes that there
is a reasonable certainty that no harm will result to infants and
children from chronic aggregate exposure to oxyfluorfen residues.
2. Acute risk. As mentioned above, the acute dietary exposure
endpoint of concern for oxyfluorfen is fused sternebrae in developing
pups which was observed in the rabbit developmental study. The
population subgroup of concern is females 13+ years old (women of
childbearing age). For this subgroup, the calculated MOE at the high
end exposure is 5,000. The Agency considers dietary (food) MOEs of
greater than 100 to be acceptable for oxyfluorfen. Acute dietary
exposure (food only) was calculated using the TMRC (worst case)
assumptions.
In the absence of data for drinking water exposure, the ranges of
exposure being considered by the Agency for consumption of contaminated
water will be reserved for drinking water. Based on the ranges under
consideration, the aggregate MOE level of concern for dietary plus the
addition of drinking water is not likely to raise the MOE above the
Agency's level of concern. The large MOE calculated for this use of
oxyfluorfen provides assurance that there is a reasonable certainty of
no harm for infants and children.
V. Other Considerations
There is a practical analytical method for detecting and measuring
levels of oxyfluorfen in or on food with a limit of detection that
allows monitoring of food with residues at or above the levels set in
these tolerances. EPA has provided information on this method to FDA.
The method is available to anyone who is interested in pesticide
residue enforcement from: By mail, Calvin Furlow, Public Response and
Program Resources Branch, Field Operations Division (7506C), Office of
Pesticide Programs, Environmental Protection Agency, 401 M St., SW.,
Washington, DC 20460. Office location and telephone number: Crystal
Mall #2, Rm. 1128, 1921 Jefferson Davis Highway, Arlington, VA, 703-
305-5805.
VI. Conclusion
Therefore, a tolerance in connection with the FIFRA section 18
emergency exemptions is established for residues of oxyfluorfen in/on
strawberries at 0.05 ppm.
VII. Objections and Hearing Requests
The new FFDCA section 408(g) provides essentially the same process
for persons to ``object'' to a tolerance regulation issued by EPA under
new section 408(e) and (l)(6) as was provided in the old section 408
and in section 409. However, the period for filing objections is 60
days, rather than 30 days. EPA currently has procedural regulations
which govern the submission of objections and hearing requests. These
regulations will require some modification to reflect the new law.
However, until those modifications can be made, EPA will continue to
use those procedural regulations with appropriate adjustments to
reflect the new law.
Any person may, by June 24, 1997, file written objections to any
aspect of this regulation and may also request a hearing on those
objections. Objections and hearing requests must be filed with the
Hearing Clerk, at the address given above (40 CFR 178.20). A copy of
the objections and/or hearing requests filed with the Hearing Clerk
should be submitted to the OPP docket for this rulemaking. The
objections submitted must specify the provisions of the regulation
deemed objectionable and the grounds for the objections (40 CFR
178.25). Each objection must be accompanied by the fee prescribed by 40
CFR 180.33(i). If a hearing is requested, the objections must include a
statement of the factual issues on which a hearing is requested, the
requestor's contentions on such issues, and a summary of any evidence
relied upon by the requestor (40 CFR 178.27). A request for a hearing
will be granted if the Administrator determines that the material
submitted shows the following: There is genuine and substantial issue
of fact; there is a reasonable possibility that available evidence
identified by the requestor would, if established, resolve one or more
of such issues in favor of the requestor, taking into account
uncontested claims or facts to the contrary; and resolution of the
factual issues in the manner sought by the requestor would be adequate
to justify the action requested (40 CFR 178.32). Information submitted
in connection with an objection or hearing request 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. A copy of the information 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.
VIII. Public Docket
A record has been established for this rulemaking under docket
number [OPP-300478]. A public version of this record, 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 Room 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 Highway, Arlington, VA.
Electronic comments may be sent directly to EPA at:
opp-docket@epamail.epa.gov.
[[Page 20111]]
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 rulemaking, as well as the public
version, as described above, is kept in paper form. Accordingly, in the
event there are objections and hearing requests, EPA will transfer any
copies of objections and hearing requests received electronically into
printed, paper form as they are received and will place the paper
copies in the official rulemaking record. The official rulemaking
record is the paper record maintained at the address in ``ADDRESSES''
at the beginning of this document.
IX. Regulatory Assessment Requirements
Under Executive Order 12866 (58 FR 51735, October 4, 1993), this
action is not a ``significant regulatory action'' and, since this
action does not impose any information collection requirements as
defined by the Paperwork Reduction Act, 44 U.S.C. 3501 et seq., it is
not subject to review by the Office of Management and Budget. This
action does not impose any enforceable duty, or contain any ``unfunded
mandates'' as described in Title II of the Unfunded Mandates Reform Act
of 1995 (Pub. L. 104-4), or require prior consultation as specified by
Executive Order 12875 (58 FR 58093, October 28, 1993), entitled
Enhancing the Intergovernmental Partnership, or special consideration
as required by Executive Order 12898 (59 FR 7629, February 16, 1994).
Because FFDCA section 408(l)(6) permits establishment of this
regulation without a notice of proposed rulemaking, the regulatory
flexibility analysis requirements of the Regulatory Flexibility Act, 5
U.S.C. 604(a), do not apply. Nonetheless, the Agency has previously
assessed whether establishing tolerances or exemptions from tolerance,
raising tolerance levels, or expanding exemptions adversely impact
small entities and concluded, as a generic matter, that there is no
adverse impact. (46 FR 24950, May 4, 1981).
Under 5 U.S.C. 801(a)(1)(A) of the Small Business Regulatory
Enforcement Fairness Act of 1996 (Title II of Pub. L. 104-121, 110
Stat. 847), EPA submitted a report containing this rule and other
required information to the U.S. Senate, the U.S. House of
Representatives and the Comptroller General of the General Accounting
Office prior to publication of the rule in today's Federal Register.
This rule is not a ``major rule'' as defined by 5 U.S.C. 804(2) of the
APA as amended.
List of Subjects in 40 CFR Part 180
Environmental protection, Administrative practice and procedure,
Agricultural commodities, Pesticides and pests, Reporting and
recordkeeping requirements.
Dated: April 16, 1997.
Stephen L. Johnson,
Director, Registration Division, Office of Pesticide Programs.
Therefore, 40 CFR Chapter I is amended as follows:
PART 180-- [AMENDED]
1. The authority citation for part 180 continues to read as
follows:
Authority: 21 U.S.C. 346a and 371.
2. Section 180.381 is amended as follows:
i. In paragraph (a) by adding the heading ``General.''
ii. By redesignating paragraph (b) as paragraph (c), and adding a
new paragraph (b).
iii. In newly designated paragraph (c) by adding a paragraph
heading ``Tolerances with regional registrations.''
iv. By adding and reserving new paragraph (d) with the heading
``Indirect or inadvertent residues.''
v. By revising the phrase ``raw agricultural'', to read ``food''
throughout the section.
Sec. 180.381 Oxyfluorfen; tolerances for residues.
(a) General. * * *
(b) Section 18 emergency exemptions. Tolerances are established for
residues of the herbicide oxyfluorfen [2-chloro-1-(3-ethoxy-4-
nitrophenoxy)-4-(trifluoromethyl)benzene] in or on the following food
commodities:
------------------------------------------------------------------------
Expiration/
Commodity Parts per Revocation
million Date
------------------------------------------------------------------------
Strawberries.................................. 0.05 April 15,
1998
------------------------------------------------------------------------
(c) Tolerances with regional registrations. * * *
(d) Indirect or inadvertent residues. [Reserved]
[FR Doc. 97-10724 Filed 4-24-97; 8:45 am]
BILLING CODE 6560-50-F