[Federal Register Volume 62, Number 163 (Friday, August 22, 1997)]
[Rules and Regulations]
[Pages 44558-44565]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-22377]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[OPP-300533; FRL-5738-6]
RIN 2070-AB78


Sethoxydim; Pesticide Tolerances for Emergency Exemptions

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes a time-limited tolerance for 
residues of sethoxydim and its metabolites containing the 2-cyclohexen-
1-one moiety in or on horseradish. This action is in response to EPA's 
granting of an emergency exemption under section 18 of the Federal 
Insecticide, Fungicide, and Rodenticide Act authorizing use of the 
pesticide on horseradish in Illinois. This regulation establishes a 
maximum permissible level for residues of sethoxydim in this food 
commodity pursuant to section 408(l)(6) of 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 September 30, 1998.

DATES: This regulation is effective August 22, 1997. Objections and 
requests for hearings must be received by EPA on or before October 21, 
1997.

ADDRESSES: Written objections and hearing requests, identified by the 
docket control number, [OPP-300533], 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 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-300533], must also be submitted to: Public 
Information and Records Integrity Branch, Information Resources and 
Services 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

[[Page 44559]]

requests to Rm. 1132, CM #2, 1921 Jefferson Davis Hwy., 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: [email protected]. 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 control 
number [OPP-300533]. 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: Virginia Dietrich, 
Registration Division 7505C, Office of Pesticide Programs, 
Environmental Protection Agency, 401 M St., SW., Washington, DC 20460. 
Office location, telephone number, and e-mail address: Crystal Mall #2, 
1921 Jefferson Davis Hwy., Arlington, VA, (703) 308-9359, e-mail: 
[email protected].

SUPPLEMENTARY INFORMATION: EPA, on its own initiative, 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 sethoxydim, in or on horseradish at 4 part 
per million (ppm). This tolerance will expire and is revoked on 
September 30, 1998. EPA will publish a document in the Federal Register 
to remove the revoked tolerance 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 FR 58135, November 13, 1996)(FRL-5572-9).
    New section 408(b)(2)(A)(i) of the FFDCA 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 and in residential settings, 
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) of the FFDCA 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. Such tolerances can be established without providing notice 
or period for public comment.
    Because decisions on section 18-related tolerances must proceed 
before EPA reaches closure on several policy issues relating to 
interpretation and implementation of the FQPA, EPA does not intend for 
its actions on such tolerance to set binding precedents for the 
application of section 408 and the new safety standard to other 
tolerances and exemptions.

II. Emergency Exemption for Sethoxydim on Horseradish and FFDCA 
Tolerances

    Unprecedented flooding events in the horseradish production areas 
in Illinois in the last few years have transported seeds and vegetative 
propagules to previously uninfested fields. Currently registered 
herbicides, as well as cultural practices (mechanical and hand 
weeding), do not provide adequate control. Of particular concern was 
infestation by Johnsongrass. Johnsongrass causes losses by competing 
with the crop thereby reducing yields. Losses were also realized at the 
packing houses because of the similarity of horseradish roots to 
Johnsongrass rhizomes. After having reviewed the submission, EPA 
concurs that emergency conditions exist for this state. EPA has 
authorized under FIFRA section 18 the use of sethoxydim on horseradish 
for control of grass weeds in Illinois.
    As part of its assessment of this emergency exemption, EPA assessed 
the potential risks presented by residues of sethoxydim in or on 
horseradish. In doing so, EPA considered the new safety standard in 
FFDCA section 408(b)(2), and EPA decided that the necessary tolerance 
under FFDCA section 408(l)(6) would be consistent with the new safety 
standard and with FIFRA section 18. Consistent with the need to move 
quickly on the emergency exemption in order to address an urgent non-
routine situation 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 in section 
408(l)(6). Although this tolerance will expire and is revoked on 
September 30, 1998, under FFDCA section 408(l)(5), residues of the 
pesticide not in excess of the amounts specified in the tolerance 
remaining in or on horseradish after that date will not be unlawful, 
provided the pesticide is applied in a manner that was lawful under 
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.
    Because this tolerance is being approved under emergency conditions 
EPA has not made any decisions about whether sethoxydim meets EPA's 
registration requirements for use on horseradish or whether a permanent 
tolerance for this use would be appropriate. Under these circumstances, 
EPA does not believe that this tolerance serves as a basis for 
registration of sethoxydim by a State for special local needs under 
FIFRA section 24(c). Nor does this tolerance serve as the basis for any 
State other than Illinois to use this pesticide 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 exemption for sethoxydim, contact the Agency's Registration 
Division at the address provided above.

[[Page 44560]]

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. Second, 
EPA examines exposure to the pesticide through the diet (e.g., food and 
drinking water) and through exposures that occur as a result of 
pesticide use in residential settings.

A. Toxicity

    1. Threshold and non-threshold effects. For many animal 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% or less of the RfD) is 
generally considered acceptable by EPA. EPA generally uses the RfD to 
evaluate the chronic risks posed by pesticide exposure. For shorter 
term risks, EPA calculates a margin of exposure (MOE) by dividing the 
estimated human exposure into the NOEL from the appropriate animal 
study. Commonly, EPA finds MOEs lower than 100 to be unacceptable. This 
100-fold MOE is based on the same rationale as the 100-fold uncertainty 
factor.
    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 
relationship. Once a pesticide has been classified as a potential human 
carcinogen, different types of risk assessments (e.g., linear low dose 
extrapolations or 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.
    2. Differences in toxic effect due to exposure duration. The 
toxicological effects of a pesticide can vary with different exposure 
durations. EPA considers the entire toxicity data base, and based on 
the effects seen for different durations and routes of exposure, 
determines which risk assessments should be done to assure that the 
public is adequately protected from any pesticide exposure scenario. 
Both short and long durations of exposure are always considered. 
Typically, risk assessments include ``acute'', ``short-term'', 
``intermediate term'', and ``chronic'' risks. These assessments are 
defined by the Agency as follows.
    Acute risk, by the Agency's definition, results from 1-day 
consumption of food and water, and reflects toxicity which could be 
expressed following a single oral exposure to the pesticide residues. 
High end exposure to food and water residues are typically assumed.
    Short-term risk results from exposure to the pesticide for a period 
of 1-7 days, and therefore overlaps with the acute risk assessment. 
Historically, this risk assessment was intended to address primarily 
dermal and inhalation exposure which could result, for example, from 
residential pesticide applications. However, since enaction of FQPA, 
this assessment has been expanded to include both dietary and non-
dietary sources of exposure, and will typically consider exposure from 
food, water, and residential uses when reliable data are available. In 
this assessment, risks from average food and water exposure, and high-
end residential exposure, are aggregated. High-end exposures from all 3 
sources are not typically added because of the very low probability of 
this occurring in most cases, and because the other conservative 
assumptions built into the assessment assure adequate protection of 
public health. However, for cases in which high-end exposure can 
reasonably be expected from multiple sources (e.g. frequent and 
widespread homeowner use in a specific geographical area), multiple 
high-end risks will be aggregated and presented as part of the 
comprehensive risk assessment/characterization. Since the toxicological 
endpoint considered in this assessment reflects exposure over a period 
of at least 7 days, an additional degree of conservatism is built into 
the assessment; i.e., the risk assessment nominally covers 1-7 days 
exposure, and the toxicological endpoint/NOEL is selected to be 
adequate for at least 7 days of exposure. (Toxicity results at lower 
levels when the dosing duration is increased.)
    Intermediate-term risk results from exposure for 7 days to several 
months. This assessment is handled in a manner similar to the short-
term risk assessment.
    Chronic risk assessment describes risk which could result from 
several months to a lifetime of exposure. For this assessment, risks 
are aggregated considering average exposure from all sources for 
representative population subgroups including infants and children.

B. Aggregate Exposure

    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, residues in groundwater 
or surface water that is consumed as drinking water, and other non-
occupational exposures through pesticide use in gardens, lawns, or 
buildings (residential and other indoor uses). 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. In evaluating food 
exposures, EPA takes into account varying consumption patterns of major 
identifiable subgroups of consumers, including infants and children.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% 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

[[Page 44561]]

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.
    Percent of crop treated estimates are derived from 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 of crop 
treated, the Agency is reasonably certain that exposure is not 
understated for any significant subpopulation group. Further, regional 
consumption information is taken into account through EPA's computer-
based model for evaluating the exposure of significant subpopulations 
including several regional groups, to pesticide residues. For this 
pesticide, the most highly exposed population subgroup (children from 
one to six years old) was not regionally based.

IV. Aggregate Risk Assessment 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, EPA has sufficient data to assess the hazards of 
sethoxydim and to make a determination on aggregate exposure, 
consistent with section 408(b)(2), for a time-limited tolerance for 
residues of sethoxydim and its 2-cyclohexen-1-one moiety on horseradish 
at 4 ppm. EPA's assessment of the dietary exposures and risks 
associated with establishing the tolerance follows.

A. Toxicological Profile

    EPA has evaluated the available toxicity data and considered its 
validity, completeness, and reliability as well as the relationship of 
the results of the studies to human risk. EPA has also considered 
available information concerning the variability of the sensitivities 
of major identifiable subgroups of consumers, including infants and 
children. The nature of the toxic effects caused by sethoxydim are 
discussed below.
    1. Acute toxicity. 180 mg/kg/day. For acute dietary risk 
assessment, the Office of Pesticide Programs selected the developmental 
NOEL of 180 mg/kg/day from the developmental study in rats. At the 
developmental lowest observed effect level (LOEL) of 650 mg/kg/day, 
there were decreased fetal weights, filamentous tail, lack of tail, and 
delayed ossification. Acute dietary risk will be evaluated for the 
population subgroup of concern, females 13+ years.
    2. Short - and intermediate - term toxicity. For short- and 
intermediate-term Margin of Exposure (MOE) calculations, the Office of 
pesticide Programs concluded that this risk assessment is not required, 
based on the lack of any observable effects in a 21-day dermal toxicity 
study in rabbits at the limit dose (1000 mg/kg/day) and the observation 
of no adverse effects in a developmental toxicity study in rabbits at 
400 mg/kg/day, the highest dose tested (HDT).
    3. Chronic toxicity. EPA has established the RfD for sethoxydim at 
0.09 milligrams/kilogram/day (mg/kg/day). This RfD is based on a 1-year 
feeding study in dogs (MRID# 00152669) with a NOEL of 8.86 mg/kg/day 
and an uncertainty factor of 100 based on equivocal anemia in male dogs 
at the lowest effect level (LEL) of 17.5 mg/kg/day.
    4. Carcinogenicity. Sethoxydim has not been classified with concern 
to carcinogenicity by the Office of Pesticide Programs. However, no 
positive tumor findings have been reported at this time.

B. Exposures and Risks

    1. From food and feed uses. Tolerances have been established (40 
CFR 180.412) for combined residues of sethoxydim and its metabolites 
containing the 2-cyclohexen-1-one moiety (calculated as the herbicide) 
in or on a variety of raw agricultural commodities (RACs) at levels 
ranging from 0.2 ppm to 50 ppm. Among them are tolerances on several 
RACs of the root and tuber vegetables crop group, of which horseradish 
is a member: artichoke (3 ppm), carrots (1 ppm), potatoes (4 ppm), 
sweet potatoes (4 ppm), and sugar beet roots (1 ppm). Various food (40 
CFR 185.2800) and feed (40 CFR 186.2800) additive tolerances are also 
established, at levels up to 75 ppm (peanut soapstock). Risk 
assessments were conducted by EPA to assess dietary exposures and risks 
from sethoxydim as follows:
    i.  Acute exposure and risk. The acute dietary (food only) risk 
assessment used tolerance level residues for all crops with sethoxydim 
tolerances and assumed 100% crop-treated. A Margin of Exposure (MOE) of 
960 was calculated for females aged 13+ years, the population subgroup 
of concern. That acute dietary (food only) MOE should be viewed as a 
conservative risk estimate; refinement using percent crop-treated and 
anticipated residue levels or Monte Carlo analysis would result in a 
lower dietary exposure estimate. 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 one day or single exposure.
    ii. Chronic exposure and risk. In conducting this chronic dietary 
risk assessment, the Office of Pesticide Programs has made very 
conservative assumptions which result in a conservative over-estimate 
of human dietary exposure; 100% of horseradish and all other 
commodities having tolerances for the regulable residue of sethoxydim 
will contain residues of same, and at the level of the tolerance. 
Refinement using anticipated residue values and percent crop-treated 
data would result in a lower chronic dietary exposure estimate.
    The existing sethoxydim regulable residue tolerances (published, 
pending, and this Section 18 proposed tolerance) result in a 
Theoretical Maximum Residue Contribution (TMRC) that is equivalent to 
the following percentages of the RfD:

----------------------------------------------------------------------------------------------------------------
                 Population Subgroup                      TMRCfood (mg/kg/day)                   %RfD           
----------------------------------------------------------------------------------------------------------------
U.S. population (48 states).........................                      0.033266                           37%
Nursing infants.....................................                      0.020447                           23%
Non-nursing infants (<1 year old)...................                      0.057129                           63%
Children (1-6 years old)............................                      0.067039                           74%
Children (7-12 years old)...........................                      0.049618                           55%
Southern Region.....................................                      0.033782                           38%
Western Region......................................                      0.034829                           39%
Hispanics...........................................                      0.039524                           44%
Males (13-19 years old).............................                      0.033837                           38%
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[[Page 44562]]

    The subgroups listed above are: (1) the U.S. population (48 
states); (2) those for infants and children; and, (3) the other 
subgroups for which the percentage of the RfD occupied is greater than 
that occupied by the subgroup U.S. population (48 states).
    2. From drinking water. Based on information in OPP files, 
sethoxydim is a non-persistent, but highly mobile compound in soil and 
water environments. There are no Maximum Contaminant Levels or Health 
Advisories established for sethoxydim residues in drinking water.
    Limited monitoring data of ground water and surface water are 
available for sethoxydim. Exposure estimates using these data are 
listed below.
    Adult Exposure: Groundwater
Sethoxydim Exposure (highest concentration detected in public supply 
wells) = (1 g/L) * (10-3 mg/g)  
(70 kg body weight) * (2 L/day) = 2.85 x 10-5 mg/kg/day.
Sethoxydim Exposure (highest concentration detected in ground water) = 
(42 g/L) * (10-3 mg/g)  (70 kg 
body weight) * (2 L/day) = 1.2 x 10-3 mg/kg/day
    Children's Exposure: Groundwater
Sethoxydim Exposure (highest concentration detected in public supply 
wells) = (1 g/L) * (10-3 mg/g)  
(10 kg body weight) * (1 L/day) = 1 x 10-4 mg/kg/day.
Sethoxydim Exposure (highest concentration detected in ground water) = 
(42 g/L) * (10-3 mg/g)  (10 kg 
body weight) * (1 L/day) = 4.2 x 10-3 mg/kg/day
    Estimates of Exposure: Surface Water. The highest concentration of 
sethoxydim residues detected in a surface water sample was 0.87 
g/L. The same calculations as above for ground water were used 
to estimate the exposure of adults (2.49 x 10-5 mg/kg/day) 
and children (0.9 x 10-4 mg/kg/day) to sethoxydim residues 
in surface water.
    i. Acute exposure and risk. The Office of Pesticide Programs 
calculates a margin of exposure (MOE) to estimate the acute risk for 
drinking water, as follows:
Acute MOE = Acute NOEL (mg/kg/day)  Exposure (mg/kg/day)
    The acute dietary endpoint is based on the developmental NOEL of 
180 mg/kg/day from the developmental study in rats. Using the exposure 
estimates calculated above, the acute MOEs for adults and children are 
calculated to be > 40,000.
Using the surface water exposure estimates calculated above, the acute 
MOEs for adults and children are calculated to be > 1.8 million.
    ii. Chronic exposure and risk. 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 
exposure from contaminated water, the ranges the Agency is continuing 
to examine are all below the level that would cause sethoxydim to 
exceed the RfD if the tolerance being considered in this document were 
granted. The Agency has therefore concluded that the potential 
exposures associated with sethoxydim 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.
    Using the surface water exposure estimates calculated above, the 
chronic risks are calculated to be < 1% of the RfD for both adults and 
children.
    3. From non-dietary exposure. Sethoxydim is currently registered 
for use on the following residential non-food sites: flowering plants, 
recreational areas, and buildings/structures (non-agricultural - 
outdoor). These residential uses comprise a short- and intermediate-
term exposure scenario, but do not comprise a chronic exposure 
scenario. Since the TESC did not identify a short-term, intermediate-
term, or chronic toxicity non-dietary endpoint, a short- and 
intermediate-term aggregate risk assessment is not required for this 
Section 18 action.
    Short- and intermediate-term exposure and risk.  The Office of 
Pesticide Programs determined that a risk assessment for short- and 
intermediate term exposure is not appropriate since no adverse effects 
were noted in toxicity studies conducted for this duration of exposure
    4. 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 sethoxydim 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, 
sethoxydim does not appear to produce

[[Page 44563]]

a toxic metabolite produced by other substances. For the purposes of 
this tolerance action, therefore, EPA has not assumed that sethoxydim 
has a common mechanism of toxicity with other substances.

C. Aggregate Risks and Determination of Safety for U.S. Population

    1. Acute risk. The aggregate (food + water) MOE value is and is 
935, based on an MOEfood of 960 and a conservative 
MOEwater of 40,000. This aggregate MOE value does not exceed 
the Agency's level of concern for acute dietary exposure.
    2. Chronic risk. Using the conservative TMRC exposure assumptions 
described above, and taking into account the completeness and 
reliability of the toxicity data, EPA has concluded that chronic 
aggregate dietary exposure (food + water) to sethoxydim will utilize 
38% (37% from food +  1% from water) of the RfD for the U.S. 
population. EPA generally has no concern for exposures below 100% 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. Residential (outdoor) usage of sethoxydim does 
not comprise a chronic exposure scenario. EPA concludes that there is a 
reasonable certainty that no harm will result from chronic aggregate 
exposure to sethoxydim residues.
    3. Short- and intermediate-term risk. Short- and intermediate-term 
aggregate exposure takes into account chronic dietary food and water 
(considered to be a background exposure level) plus short- and 
intermediate-term exposure scenarios from indoor and outdoor 
residential uses. Since the Office of Pesticide Programs did not 
identify a short-term, intermediate-term, or chronic toxicity non-
dietary endpoint, a short- and intermediate-term aggregate risk 
assessment was not conducted for this duration of exposure.

D. Aggregate Cancer Risk for U.S. Population

    Sethoxydim has not been classified by the Agency's Cancer Peer 
Review Committee. However, no positive tumor findings have been 
reported at this time in the evaluation of the cancer study in mice or 
the preliminary evaluation of the rat study.

E. Aggregate Risks and Determination of Safety for Infants and Children

    1. Safety factor for infants and children-- i. In general. In 
assessing the potential for additional sensitivity of infants and 
children to residues of sethoxydim, EPA considered data from 
developmental toxicity studies in the rat and rabbit and a two-
generation reproduction study in the rat. The developmental toxicity 
studies are designed to evaluate adverse effects on the developing 
organism resulting from maternal pesticide exposure during gestation. 
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 MOE analysis or through using uncertainty (safety) 
factors in calculating a dose level that poses no appreciable risk to 
humans. EPA believes that reliable data support using the standard 100-
fold safety factor (usually 100 for combined inter- and intra-species 
variability)) and not the additional tenfold safety factor when EPA has 
a complete data base 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 safety factor.
    ii. Developmental toxicity studies-- a. Rats. In the developmental 
toxicity study in rats, the maternal (systemic) NOEL was 180 mg/kg/day, 
based on irregular gait, decreased activity, excessive salivation and 
anogenital staining at the LOEL of 650 mg/kg/day. The developmental 
(pup) NOEL was 180 mg/kg/day, based on decreased fetal weights, 
filamentous tail, lack of tail, and delayed ossification at the LOEL of 
650 mg/kg/day.
    b. Rabbits. In the developmental toxicity study in rabbits, the 
maternal (systemic) NOEL was 320 mg/kg/day, based on a 37% reduction in 
body weight gain without significant differences in group mean body 
weights and food consumption at the LOEL of 400 mg/kg/ day. The 
developmental (pup) NOEL was  400 mg/kg/day (HDT).
    iii. Reproductive toxicity study-- Rats. In the 2-generation 
reproductive toxicity study in rats, the maternal (systemic) and 
reproductive (pup) NOEL was  150 mg/kg/day (HDT). There were 
no indications of toxicity, dose-related effects on fertility or 
difficult deliveries in either parental generation.
    iv. Pre- and post-natal sensitivity. The toxicological data base 
for evaluating pre- and post-natal toxicity for sethoxydim is complete 
with respect to current data requirements.
    The available data indicate that no developmental toxicity was 
observed in the rabbit study at the highest dose tested (400 mg/kg/
day). Maternal toxicity was observed in the rabbit at the highest dose 
tested, and consisted of significant reductions in body weight gain and 
food consumption.
    In the developmental study in rats, developmental toxicity was 
observed in the presence of significant maternal toxicity at a high 
dose level (650 mg/kg/day).
    There was no parental or reproductive toxicity observed in a multi-
generation reproductive toxicity study in rats at doses up to 150 mg/
kg/day (HDT).
    These data, taken together, suggest minimal concern for 
developmental or reproductive toxicity and do not indicate any extra 
pre- or post-natal sensitivity. Thus, these data support use of the 
standard uncertainty factor of 100. An additional safety factor is not 
needed to protect infants and children.
    v. Conclusion. These data, taken together, suggest minimal concern 
for developmental or reproductive toxicity and do not indicate any 
extra pre- or post-natal sensitivity. Thus, these data support use of 
the standard uncertainty factor of 100. An additional safety factor is 
not needed to protect infants and children.
    2. Acute risk. As calculated above, the acute dietary (food + 
water) MOE for females 13+ years (accounts for both maternal and fetal 
exposure) is 935, based on an MOEfood of 960 and a 
conservative MOEwater of 40,000. This dietary MOE does not 
exceed the Agency's level of concern. Further, this MOE should be 
viewed as a conservative risk estimate; data refinement and the use of 
Monte Carlo analysis would result in a lower acute aggregate exposure 
estimate. HED concludes that there is a reasonable certainty that no 
harm will result to infants and children from acute aggregate exposure 
to sethoxydim regulable residue.
    3. Chronic risk. Using the conservative exposure assumptions 
described above, EPA has calculated that the percentage of the RfD that 
will be utilized by dietary (food only) exposure to the sethoxydim 
regulable residue ranges from 23% for nursing infants < 1 year old, up 
to 74% for children 1-6 years old. As calculated above, the percentage 
of the RfD that will be utilized by dietary (water) exposure ranges 
from < 1 to 5% from

[[Page 44564]]

ground water and <1% from surface water. Thus, the chronic aggregate 
(food + water) risk ranges from  24-29% for nursing infants 
< 1 year old, to  75-80% for children 1-6 years old. It has 
been determined by HED that residential uses do not comprise a chronic 
exposure scenario, and thus will not contribute to chronic aggregate 
risk. EPA generally has no concern for exposures below 100% 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 sethoxydim in 
drinking water and from non-dietary, non-occupational exposure, EPA 
does not expect the 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 aggregate exposure to sethoxydim residues.

V. Other Considerations

A. Metabolism In Plants and Animals

    The nature of the residue in plants and animals is adequately 
understood. The residue of concern is the combined residues of 
sethoxydim and its metabolites containing the 2-cyclohexen-1-one moiety 
(calculated as the herbicide), as specified in 40 CFR 180.412.

B. Analytical Enforcement Methodology

    Adequate enforcement methodology (GLC/FPD-S) is available (Method 
I, Pesticide Analytical Manual, Vol. II) to enforce the tolerance 
expression.

C. Magnitude of Residues

    Combined residues of sethoxydim and its regulated metabolites are 
not expected to exceed 4 ppm in/on horseradish as a result of this 
Section 18 use. A time-limited tolerance should be established for the 
regulable residue in/on horseradish at 4 ppm. There are no processed 
commodities from horseradish. Secondary residues are not expected in 
animal commodities as a result of this Section 18 use, as no livestock 
feed items are associated with horseradish.

D. International Residue Limits

    There are no Codex residue limits established for sethoxydim, and 
no Canadian or Mexican residue limits for sethoxydim use on 
horseradish. Harmonization is thus not an issue for this Section 18 
action.

E. Rotational Crop Restrictions.

    There are no rotational crop restrictions associated with this use, 
and none are required As stated previously, sethoxydim is a non-
persistent, highly mobile compound in soil and water environments.

VI. Conclusion

    Therefore, the tolerance is established for residues of sethoxydim 
and its metabolites containing the 2-cyclohexen-1-one moiety in or on 
horseradish at 4 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 October 21, 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

    EPA has established a record for this rulemaking under docket 
control number [OPP-300533] (including any comments and data submitted 
electronically). A public version of this record, including printed, 
paper versions of electronic comments, which does not include any 
information claimed as CBI, is available for inspection from 8:30 a.m. 
to 4 p.m., Monday through Friday, excluding legal holidays. The public 
record is located in Room 1132 of the Public Information and Records 
Integrity Branch, Information Resources and Services Division (7506C), 
Office of Pesticide Programs, Environmental Protection Agency, Crystal 
Mall #2, 1921 Jefferson Davis Hwy., Arlington, VA.
    Electronic comments may be sent directly to EPA at:
    [email protected].

    Electronic comments must be submitted as an ASCII file avoiding the 
use of special characters and any form of encryption.
    The official record for this rulemaking, as well as the public 
version, as described above will be kept in paper form. Accordingly, 
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 which 
will also include all comments submitted directly in writing. The 
official rulemaking record is the paper record maintained at the 
Virginia address in ``ADDRESSES'' at the beginning of this document.

IX. Regulatory Assessment Requirements

    This final rule establishes a time-limited tolerance under FFDCA 
section 408(l)(6). The Office of Management and Budget (OMB) has 
exempted these types of actions from review under Executive Order 
12866, entitled Regulatory Planning and Review (58 FR 51735, October 4, 
1993). This final rule does not contain any information collections 
subject to OMB approval under the Paperwork Reduction Act (PRA), 44

[[Page 44565]]

U.S.C. 3501 et seq., or impose any enforceable duty or contain any 
unfunded mandate as described under Title II of the Unfunded Mandates 
Reform Act of 1995 (UMRA) (Pub. L. 104-4). Nor does it require any 
prior consultation as specified by Executive Order 12875, entitled 
Enhancing the Intergovernmental Partnership (58 FR 58093, October 28, 
1993), or special considerations as required by Executive Order 12898, 
entitled Federal Actions to Address Environmental Justice in Minority 
Populations and Low-Income Populations (59 FR 7629, February 16, 1994), 
or require OMB review in accordance with Executive Order 13045, 
entitled Protection of Children from Environmental Health Risks and 
Safety Risks (62 FR 19885, April 23, 1997).
    In addition, since these tolerances and exemptions that are 
established under FFDCA section 408 (l)(6), such as the tolerance in 
this final rule, do not require the issuance of a proposed rule, the 
requirements of the Regulatory Flexibility Act (RFA) (5 U.S.C. 601 et 
seq.) do not apply. Nevertheless, the Agency has previously assessed 
whether establishing tolerances, exemptions from tolerances, raising 
tolerance levels or expanding exemptions might adversely impact small 
entities and concluded, as a generic matter, that there is no adverse 
economic impact. The factual basis for the Agency's generic 
certification for tolerance acations published on May 4, 1981 (46 FR 
24950), and was provided to the Chief Counsel for Advocacy of the Small 
Business Administration.

X. Submission to Congress and the General Accounting Office

    Under 5 U.S.C. 801(a)(1)(A), as added by the Small Business 
Regulatory Enforcement Fairness Act of 1996, the Agency has 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 this rule in 
today's Federal Register. This is not a ``major rule'' as defined by 5 
U.S.C. 804(2).

List of Subjects in 40 CFR Part 180

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

    Dated: August 15, 1997.
Peter Caulkins,
Acting 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. In Sec. 180.412, by adding text to paragraph (b) to read as 
follows:


Sec. 180.412  Sethoxydim: tolerance for residues.

* * * * *
    (b) Section 18 emergency exemptions. A time-limited tolerance is 
established for combined residues of the herbicide sethoxydim and its 
metabolites containing the 2-cyclohexen-1-one moiety, calculated as the 
herbicide in connection with use of the pesticide under section 18 
emergency exemptions granted by EPA. This tolerance will expire and is 
revoked on the date specified in the following table:

                                                                        
------------------------------------------------------------------------
                                                          Expiration/   
            Commodity              Parts per million    revocation date 
------------------------------------------------------------------------
Horseradish.....................  4                   September 30, 1998
------------------------------------------------------------------------

* * * * *

[FR Doc. 97-22377 Filed 8-21-97; 8:45 am]
BILLING CODE 6560-50-F