PMEP Home Page --> Pesticide Active Ingredient Information --> Herbicides, Growth Regulators, and Desiccants --> Herbicides, N to R --> Primisulfuron-Methyl --> Primisulfuron-Methyl - Pesticide Tolerances for Emergency Exemptions 11/97

Primisulfuron-Methyl - Pesticide Tolerances for Emergency Exemptions 11/97

[Federal Register: December 17, 1997 (Volume 62, Number 242)]
[Rules and Regulations]
[Page 66014-66020]
From the Federal Register Online via GPO Access []



40 CFR Part 180

[OPP-300573; FRL 5753-6]
RIN 2070-AB78

Primisulfuron-methyl; Pesticide Tolerances for Emergency

Agency: Environmental Protection Agency (EPA).

ACTION: Final Rule.


SUMMARY: This regulation establishes a time-limited tolerance for
residues of primisulfuron-methyl in or on bluegrass grown for seed.
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 bluegrass grown for seed. This
regulation establishes a maximum permissible level for residues of
primisulfuron-methyl 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 October 31, 1998.

DATES: This regulation is effective December 17, 1997. Objections and
requests for hearings must be received by EPA on or before February 17,

ADDRESSES:  Written objections and hearing requests, identified by the
docket control number, [OPP-300573], 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-300573], must also be submitted to: Public
Information and Records Integrity Branch, Information Resources and
Services Division (7502C), 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 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: 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 5.1/6.1
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-300573]. 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 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) 308-9357; e-mail:

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 primisulfuron-methyl, in or on bluegrass
grown for seed at 0.10 parts per million (ppm). This tolerance will
expire and is revoked on October 31, 1998. EPA will publish a document
in the Federal Register to remove the revoked tolerance from the Code
of Federal Regulations.

[[Page 66015]]

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 Primisulfuron-methyl on Bluegrass Grown
for Seed and FFDCA Tolerances

    The applicant asserts that recent growing conditions and
curtailment of burning, a cultural weed control method, by the federal,
state, and/or county Clean Air Act requirements have created
unacceptable levels of weedy grasses proliferating in Kentucky
bluegrass fields. There are no effective registered pesticides or
alternative control practices available which will provide adequate
control of the weeds. EPA has authorized under FIFRA section 18 the use
of primisulfuron-methyl on bluegrass grown for seed for control of
quackgrass, windgrass, downey brome, wild oat, and other weeds in
Washington and Idaho. After having reviewed the submission, EPA concurs
that emergency conditions exist for these states.
    As part of its assessment of this emergency exemption, EPA assessed
the potential risks presented by residues of primisulfuron-methyl in or
on bluegrass grown for seed. 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 October 31, 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 bluegrass grown for seed 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 primisulfuron-methyl meets
EPA's registration requirements for use on bluegrass grown for seed 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 primisulfuron-methyl by a State for special
local needs under FIFRA section 24(c). Nor does this tolerance serve as
the basis for any States other than Washington and Idaho 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
primisulfuron-methyl, 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. 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

[[Page 66016]]

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 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 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 non-nursing
infants <1 year 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
primisulfuron-methyl and to make a determination on aggregate exposure,
consistent with section 408(b)(2), for a time-limited tolerance for
residues of primisulfuron-methyl on bluegrass grown for seed at 0.10
ppm. EPA's assessment of the dietary

[[Page 66017]]

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 primisulfuron-
methyl are discussed below.
    1. Acute toxicity. For acute dietary risk assessment, the Agency
used a NOEL of 100 mg/kg/day, based on delayed or absent ossification
effects in fetuses at the LEL of 500 mg/kg/day, from the oral
developmental study in rats. This risk assessment will evaluate acute
dietary risk to the population subgroup of concern, females 13+ years
of age.
    2. Chronic toxicity. EPA has established the RfD for primisulfuron-
methyl at 0.006 milligrams/kilogram/day (mg/kg/day). This RfD is based
on an 80-week mouse feeding study with a LOEL of 1.7 mg/kg/day based on
increased absolute and relative liver weights. An uncertainty factor of
300 was used because a NOEL was not achieved.
    3. Carcinogenicity. Primisulfuron-methyl has been classified as a
Group D chemical incomplete evidence based on liver tumors in mice.

B. Exposures and Risks

    1. From food and feed uses. Tolerances have been established (40
CFR 180.452) for the residues of primisulfuron-methyl, in or on the raw
agricultural commodities fresh corn and corn forage and fodder.
Tolerances are also established on cattle, goat, hog, horse, sheep, and
poultry commodities as well as milk and eggs. Risk assessments were
conducted by EPA to assess dietary exposures and risks from
primisulfuron-methyl as follows:
    i.  Acute exposure and risk. 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. The acute dietary food only risk
assessment used tolerance level residues for all commodities with
primisulfuron-methyl tolerances. Therefore, the resulting exposure
estimates should be viewed as conservative; further refinement using
anticipated residues and/or Monte Carlo and percent of crop-treated
would result in lower dietary exposure estimates. Since the acute
dietary effect is based on delayed or absent ossification effects in
fetuses, the subgroup of concern is females 13+ years of age. For
females 13+ years of age, an MOE value of 71,000 was calculated using
the high-end exposure value of 0.0014 mg/kg/day.
    ii. Chronic exposure and risk. Because there are no human food
items associated with bluegrass and existing meat/milk/poultry/egg
tolerances are adequate to cover secondary residues, a new chronic
Dietary Risk Evaluation System (DRES) run was not performed for this
section 18 request. The latest chronic DRES run was performed in
conjunction with the registration of primisulfuron-methyl on corn. The
chronic dietary exposure estimates were not refined using anticipated
residues and percent crop treated data. The existing primisulfuron-
methyl tolerances result in a Theoretical Maximum Residue Contribution
(TMRC) that is equivalent to the following percentages of the RfD:

                                            TMRCfood  Value(mg/
              Subpopulation                       kg/day)         % RfD
U.S. Population..........................              0.000571      10%

Nursing Infants..........................              0.000484       8%

Non-Nursing Infants < 1 year old.........              0.001732      29%

Children 1-6 years old...................              0.001327      22%

Children 7-12 years old..................              0.000876      15%

Hispanics................................              0.000723      12%
Non-Hispanic Others......................              0.000644      11%

    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 available to the
Agency, primisulfuron-methyl is moderately persistent and highly
mobile. There is no established Maximum Concentration Level for
residues of primisulfuron-methyl in drinking water. No health advisory
levels for primisulfuron-methyl in drinking water have been
established. Based on "Pesticides in Groundwater Database" (EPA 734-
12-92-001, Sept 1992), primisulfuron-methyl has not been analyzed for
in water.
    3. 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 primisulfuron-
methyl 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 primisulfuron-methyl 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.
    4. From non-dietary exposure. Primisulfuron-methyl is not
registered for uses that would be expected to result

[[Page 66018]]

in indoor or outdoor residential exposure.
    5. 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 primisulfuron-methyl 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,
primisulfuron-methyl 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 primisulfuron-methyl has a
common mechanism of toxicity with other substances.

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

    1. Acute risk. The acute aggregate risk assessment takes into
account exposure from dietary food and water only. As noted earlier,
the MOE for females 13+ years of age was calculated to be 71,000.
Therefore, EPA does not have an acute aggregate risk concern.
    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 calculated that dietary
exposure to primisulfuron-methyl from food will utilize 10% of the RfD
for the U.S. population. The Agency 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 primisulfuron-methyl in drinking water, 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 from chronic
aggregate exposure to primisulfuron-methyl residues.

D. 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 primisulfuron-methyl, 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 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 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 MOE
and uncertainty factor (usually 100 for combined inter- and intra-
species variability)) and not the additional tenfold MOE/uncertainty
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 MOE/safety factor.
    ii. Developmental toxicity studies. From the rat developmental
study, the maternal (systemic) NOEL was less than 100 mg/kg/day, based
on decreased weight gain during dosing at the LOEL of 100 mg/kg/day.
The developmental (fetal) NOEL was 100 mg/kg/day, based on delayed or
absent ossification at the LOEL of 500 mg/kg/day.
    From the rabbit developmental study, the maternal (systemic) NOEL
was 10 mg/kg/day, based on abortions, decreased weight gain and loose
stool at the LOEL of 300 mg/kg/day. The developmental (fetal) NOEL was
600 mg/kg/day highest dose tested.
    iii. Reproductive toxicity study. From the rat reproductive study,
the parental (systemic) NOEL was 50 mg/kg/day, based on decreased
weight gain at the LOEL of 250 mg/kg/day. The developmental (pup) NOEL
was 50 mg/kg/day, based on decreased pup body weight findings at the
LOEL of 250 mg/kg/day. The reproductive NOEL was 50 mg/kg/day, based on
decrease in testicular/spermatic function at the LOEL of 250 mg/kg/day.
    iv. Pre- and post-natal sensitivity. In rats, although the
developmental and maternal NOELs and LOELs were at the same dose
levels, the finding of developmental effects [absent ossification]
required that an acute dietary risk assessment be performed for females
13+ years of age. The calculated MOE of 71,000 demonstrated that acute
pre-natal developmental risks were below EPA's level of concern. There
were no pre-natal developmental concerns in rabbits, since the
developmental NOEL was greater than 600 mg/kg/day (HDT).
    Similarly, there were no post-natal rat reproductive study findings

[[Page 66019]]

required additional safety factors, since the maternal and pup NOEL and
LOEL of 50 and 250 mg/kg/day, respectively, occurred at the same dose
levels and both adult and pup animals had similar toxic effects
(decreased weight gain).
    v. Conclusion. The pre- and post-natal toxicology data base for
primisulfuron-methyl is complete with respect to current toxicological
data requirements. The Agency concludes that reliable data support use
of the standard 100-fold margin of exposure/uncertainty factor and that
an additional margin/factor is not needed to protect infants and
    2. Acute risk. The finding of developmental effects in the rat
study absent ossification required that an acute dietary risk
assessment be performed for females 13+ years of age. The calculated
MOE of 71,000 demonstrated that acute pre-natal developmental risks
were below EPA's level of concern.
    3. Chronic risk. Using the conservative exposure assumptions
described above, EPA has concluded that aggregate exposure to
primisulfuron-methyl from food will utilize from 8% of the RfD for
nursing infants up to 29% of the RfD for non-nursing infants < 1 year
old. 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.

V. Other Considerations

A. Metabolism In Plants and Animals

    The nature of the residue in corn and animals is adequately
understood. The residue of concern is the parent compound only, as
specified in 40 CFR 180.452.

B. Analytical Enforcement Methodology

    Adequate enforcement methodology (HPLC) has been submitted for
inclusion in PAM Vol. II to enforce the tolerance expression. Method I
of PAM II (Method AG-499A) has been validated on corn commodities and
Method II (Method AG-506) has been validated on livestock commodities.
Method A of PAM II is a confirmation method for plant commodities.

C. Magnitude of Residues

    Residues of primisulfuron-methyl are not expected to exceed 0.10
ppm in/on bluegrass hay as a result of this section 18 use. A time-
limited tolerance will be established at this level. Secondary residues
in animal commodities are not expected to exceed existing tolerances as
a result of this section 18 use.

D. International Residue Limits

    No Codex (MRLs) have been established for residues of
primisulfuron-methyl on grasses.

VI. Conclusion

    Therefore, the tolerance is established for residues of
primisulfuron-methyl in bluegrass grown for seed at 0.10 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 February 17, 1998, 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 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-300573] (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 (7502C),
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:

    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 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

[[Page 66020]]

not contain any information collections subject to OMB approval under
the Paperwork Reduction Act (PRA), 44 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 actions 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: November 18, 1997.

James Jones,

Acting Director, Registration Division, Office of Pesticide Programs.

    Therefore, 40 CFR chapter I is amended as follows:


    1. The authority citation for part 180 continues to read as

    Authority: 21 U.S.C. 346a and 371.

    2. Section 180.452, is amended as follows:
    i. By designating the existing text as paragraph (a) and adding a
    ii. By adding new paragraph (b).
    iii. By adding and reserving new paragraphs (c) and (d) with
headings to read as follows.

Sec. 180.452  Primisulfuron-methyl; tolerances for residues.

    (a)  General. * * *
    (b)  Section 18 emergency exemptions. Time-limited tolerances are
established for residues of the herbicide primisulfuron-methyl in
connection with use of the pesticide under section 18 emergency
exemptions granted by EPA. These tolerances will expire and are revoked
on the dates specified in the following table.

            Commodity              Parts per million    revocation date
Bluegrass hay...................  0.10                10/31/1998

    (c) Tolerances with regional registrations. [Reserved]
    (d) Indirect or inadvertent residues. [Reserved]

[FR Doc. 97-32937 Filed 12-16-97; 8:45 am]