[Federal Register Volume 62, Number 168 (Friday, August 29, 1997)]
[Rules and Regulations]
[Pages 45735-45741]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-23098]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 180
[OPP-300534; FRL-5738-7]
RIN 2070-AB78
Cyromazine; 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
combined residues of cyromazine (N-cyclopropyl-1,3,5-triazine-2,4,6-
triamine) and its metabolite, melamine (1,3,5-triazine-2,4,6-triamine)
in or on dry bulb onions. 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
onion seed in California. This regulation establishes a maximum
permissible level for residues of cyromazine 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 July 31, 1998.
DATES: This regulation is effective August 29, 1997. Objections and
requests for hearings must be received by EPA on or before October 28,
1997.
ADDRESSES: Written objections and hearing requests, identified by the
docket control number, [OPP-300534], 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-300534], 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 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: opp-docket@epamail.epa.gov. 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-300534]. 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: Stephen Schaible,
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) 308-9362, e-mail:
schaible.stephen@epamail.epa.gov.
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
combined residues of the insecticide cyromazine (N-cyclopropyl-1,3,5-
triazine-2,4,6-triamine) and its metabolite, melamine (1,3,5-triazine-
2,4,6-triamine), in or on dry bulb onions at 0.3 part per million
(ppm). This tolerance will expire and is revoked on July 31, 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
[[Page 45736]]
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 Cyromazine on Onion Seed and FFDCA
Tolerances
On February 6, 1997, the California Environmental Protection
Agency, Department of Pesticide Regulation, availed itself of the
authority to declare the existence of a crisis situation within the
state, thereby authorizing use under FIFRA section 18 of cyromazine on
onion seed to control onion maggots (Delia antiqua). Onion maggots
damage onion plants by tunneling and feeding on the growing
(underground bulbs and stems; several generations of onion maggots can
mature within a single season, thereby increasing the magnitude of
losses to growers. The Applicant claims that resistance to
chlorpyrifos, the most effective registered alternative control agent,
has developed in the onion maggot. Utilization of alternative cultural
practices, such as crop rotation, has not successfully controlled the
onion maggot without the use of chemical control agents. Onion growers
in the states receiving seed are expected to experience up to a 36%
yield loss without the use of cyromazine. EPA has authorized under
FIFRA section 18 the use of cyromazine on onion seed for control of
onion maggot in California. After having reviewed the submission, EPA
concurs that emergency conditions exist for this state.
As part of its assessment of this emergency exemption, EPA assessed
the potential risks presented by residues of cyromazine in or on dry
bulb onions as a result of treatment of onion 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 July 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 dry bulb onions 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 cyromazine meets EPA's
registration requirements for use on onion 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 cyromazine 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 California 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 cyromazine, 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 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
[[Page 45737]]
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 less than one 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
cyromazine and to make a determination on aggregate exposure,
consistent with section 408(b)(2), for a time-limited tolerance for
combined residues of cyromazine (N-cyclopropyl-1,3,5-triazine-2,4,6-
triamine and its metabolite, melamine (1,3,5-triazine-2,4,6-triamine on
dry bulb onions at 0.3 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 cyromazine are
discussed below.
1. Acute toxicity. OPP has determined that an acute dietary risk
assessment is not required for this chemical.
2. Short - and intermediate - term toxicity. For short- and
intermediate-term MOE calculations, the Agency recommends use of the
systemic NOEL of 0.75 mg/kg/day from the 6-month dog feeding study. At
the Lowest Effect Level (LEL) of 7.5 mg/kg/day, there were changes in
hematological parameters.
3. Chronic toxicity. EPA has established the RfD for cyromazine at
0.0075 milligrams/kilogram/day (mg/kg/day). This RfD is based on the
NOEL of 0.75 mg/kg/day, taken from the 6-month dog feeding study.
Pronounced effects on hematological parameters were observed at the LEL
of 7.5 mg/kg/day.
[[Page 45738]]
An uncertainty factor of 100 was applied to account for both
interspecies and intraspecies variability.
4. Carcinogenicity. Cyromazine has been classified as a Group E
(evidence of non-carcinogenicity for humans) chemical by the Agency.
Melamine, a metabolite of cyromazine, has been evaluated by the
Carcinogenicity Peer Review Committee (CPRC). The CPRC concluded that
melamine was not amenable to classification using the current Agency
guidelines and chose to describe the weight-of-the-evidence using a
narrative form. Based on mechanistic evaluation of the only tumors
seen, those that occurred at exceptionally high doses in the bladder of
male rats, it appears that humans are not likely to be exposed to doses
of melamine that produce the urinary tract toxicity that precedes and
seems to lead to the carcinogenic response in rats. The CPRC concluded
that it is unlikely that melamine exposure would pose a carcinogenic
hazard to humans from pesticidal usage of cyromazine.
B. Exposures and Risks
1. From food and feed uses. Tolerances have been established (40
CFR 180.414) for the combined residues of cyromazine (N-cyclopropyl-
1,3,5-triazine-2,4,6-triamine) and its metabolite, melamine (1,3,5-
triazine-2,4,6-triamine), in or on a variety of raw agricultural
commodities. Though tolerances exist for residues of cyromazine in or
on animal commodities, there are no animal feed items associated with
the proposed use, and no secondary residues in meat, milk, poultry or
eggs are expected. Risk assessments were conducted by EPA to assess
dietary exposures and risks from cyromazine as follows:
Chronic exposure and risk. Chronic dietary exposure was calculated
assuming tolerance level residues for published and proposed uses and
percent of crop treated refinements for several commodities. While
percent of crop treated refinements were incorporated into these ARC
exposure estimates, chronic risk is still overestimated due to the use
of tolerance level residues.
2. From drinking water. Review of available data indicates that
cyromazine and its metabolite, melamine, are persistent and mobile.
There is no established Maximum Concentration Level (MCL) for residues
of cyromazine in drinking water, nor have there been drinking water
Health Advisory Levels issued for cyromazine. The ``Pesticides in
Groundwater Database'' has no information concerning cyromazine.
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 cyromazine 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 cyromazine 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.
3. From non-dietary exposure. Cyromazine is currently registered
for outdoor use on ornamentals. There are no lawn or indoor residential
uses.
i. Chronic exposure and risk. There are residential uses of
cyromazine and the Agency acknowledges that there may be chronic, non-
occupational exposure scenarios. EPA has identified toxicity endpoints
for chronic residential risk assessment. However, no acceptable,
reliable exposure data to assess this potential risk are available at
this time. Based on the low percentage of the RfD occupied by aggregate
dietary exposure and in the best scientific judgement of the Agency,
chronic exposure from residential uses will not cause the aggregate
risk from cyromazine to exceed the Agency's level of concern.
ii. Short- and intermediate-term exposure and risk. There are
residential uses of cyromazine and the Agency acknowledges that there
may be short- and intermediate-term, non-occupational exposure
scenarios. EPA has identified toxicity endpoints for short- and
intermediate-term residential risk assessment. However, no acceptable,
reliable exposure data to assess these potential risks are available at
this time. Based on the low percentage of the RfD occupied by aggregate
dietary exposure and in the best scientific judgement of the Agency,
short- and intermediate-term exposure from residential uses will not
cause the aggregate risk from cyromazine to exceed the Agency's level
of concern.
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
[[Page 45739]]
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 cyromazine 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,
cyromazine 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 cyromazine has a common mechanism of toxicity
with other substances.
C. Aggregate Risks and Determination of Safety for U.S. Population
1. Chronic risk. Using the ARC exposure assumptions described
above, EPA has concluded that aggregate exposure to cyromazine from
food will utilize 32% of the RfD for the U.S. population. The major
identifiable subgroup with the highest aggregate exposure is non-
nursing infants less than 1 year old (discussed below). 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 cyromazine 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 from aggregate
exposure to cyromazine residues.
2. 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 indoor and outdoor
residential exposure.
For short term MOE calculations, the Agency recommended use of the
systemic NOEL of 0.75 mg/kg/day from the 6-month dog feeding study.
The Agency typically considers aggregate MOEs of greater than 100
to be acceptable. Using ARC exposure estimates and making conservative
assumptions for exposure from water and residential routes of exposure,
short term aggregate MOEs were acceptable for the U.S. and all
population groups evaluated. EPA concludes that there is reasonable
certainty that no harm to the U.S. population will result from short
term aggregate exposure to cyromazine residues.
D. Aggregate Cancer Risk for U.S. Population
Cyromazine has been classified as a Group E (evidence of non-
carcinogenicity for humans) chemical by the Agency. No risk assessment
for cancer effects was performed.
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 cyromazine, 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. In the rabbit developmental
study, the maternal (systemic) NOEL was 10 mg/kg/day, the highest dose
tested. In the rat developmental study, the developmental NOEL was
identified at 300 mg/kg/day, while the maternal NOEL was 100 mg/kg/day.
Although there were developmental findings at 600 mg/kg/day in rat
fetuses, these findings were not severe effects and only occurred in
the presence of maternal toxicity.
iii. Reproductive toxicity study. In the rat reproduction study,
the parental (systemic) and reproductive/developmental NOELs were both
established at 50 mg/kg/day. A detailed analysis of the study indicates
that slight pup effects (decreased pup growth, decreased number of pups
per litter, and increased fetotoxicity) occurred in the presence of
slight maternal toxicity (body weight loss).
iv. Pre- and post-natal sensitivity. The results of the rat and
rabbit developmental studies did not demonstrate any potential for
additional pre-natal sensitivity. In the rat reproduction study, the
parental and reproductive/developmental NOELs were both established at
50 mg/kg/day, which suggests that there is no special post-natal
sensitivity to cyromazine.
v. Conclusion. Based on detailed analysis of the toxicological data
base for cyromazine, the Agency concludes that aggregate exposure to
cyromazine resulting from registered uses plus the emergency exemption
use does not represent an unacceptable pre- or post-natal risk to
infants and children. The data support use of the standard uncertainty
factor of 100; an additional uncertainty factor of 10 is not necessary
to be protective of infants and children.
2. Chronic risk. Using the conservative exposure assumptions
described above, EPA has concluded that aggregate exposure to
cyromazine from food will utilize 50% of the RfD for infants and
children. 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 cyromazine
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 cyromazine residues.
3. Short- or intermediate-term risk. For short term MOE
calculations, the Agency recommended use of the systemic NOEL of 0.75
mg/kg/day from the 6-month dog feeding study.
The Agency typically considers aggregate MOEs of greater than 100
to be acceptable. Using ARC dietary exposure estimates and making
conservative assumptions for exposure from water and residential routes
of exposure, short term aggregate MOEs were acceptable for all infant
and children population groups evaluated. EPA concludes that there is a
reasonable certainty that no
[[Page 45740]]
harm will result to infants and children from short term aggregate
exposure to cyromazine residues.
V. Other Considerations
A. Metabolism In Plants and Animals
The nature of the residue in plants is adequately understood. The
residue of concern is cyromazine (N-cyclopropyl-1,3,5-triazine-2,4,6-
triamine) and its metabolite, melamine (1,3,5-triazine-2,4,6-triamine).
B. Analytical Enforcement Methodology
An adequate analytical method, HPLC/UV method AG-408, has been
validated by the Agency and published in PAM II.
C. Magnitude of Residues
Residues of cyromazine are not expected to exceed 0.3 ppm in dry
bulb onions grown from onion seed treated with cyromazine under the
proposed use.
D. International Residue Limits
There are currently no Codex, Canadian or Mexican limits for
residues of cyromazine in or on onions. Therefore, establishment of a
time-limited tolerance will not pose a concern for international
harmonization.
E. Rotational Crop Restrictions.
Tolerances are not yet established for sweet corn and radishes as
rotational crops (a decision regarding petition PP#6F3332 is currently
pending with the Agency). Until such tolerances are established,
rotation to sweet corn and radishes is not permitted.
VI. Conclusion
Therefore, the tolerance is established for combined residues of
cyromazine (N-cyclopropyl-1,3,5-triazine-2,4,6-triamine) and its
metabolite, melamine (1,3,5-triazine-2,4,6-triamine) in dry bulb onions
at 0.3 ppm. In addition to amending Sec. 180.414 to establishing a
tolerance for use in dry bulb onions, since the FQPA has eliminated the
distinctions between processed food and feed commodities, Sec. 180.414
is also being revised to restructure the existing tolerances.
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 28, 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-300534] (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:
opp-docket@epamail.epa.gov.
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.
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 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).
[[Page 45741]]
In addition, since these tolerances and exemptions that are
established under FFDCA section 408 (1), 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: August 17, 1997.
James Jones,
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. Section 180.414 is revised to read as follows:
Sec. 180.414 Cyromazine; tolerances for residues.
(a) General. (1) Tolerances are established for combined residues
of the insecticide cyromazine (N-cyclopropyl-1,3,5-triazine-2,4,6-
triamine) and its metabolite melamine (1,3,5-triazine-2,4,6-triamine)
in or on the following food commodities:
------------------------------------------------------------------------
Parts per
Commodity million
------------------------------------------------------------------------
Celery..................................................... 10.0
Cucurbit vegetables........................................ 2.0
Eggs....................................................... 0.25
Leafy vegetables (except Brassica)......................... 10.0
Lettuce, head.............................................. 5.0
Mushrooms.................................................. 10.0
Peppers.................................................... 4.0
Tomato..................................................... 1.0
------------------------------------------------------------------------
(2) Tolerances are established for residues of the cyromazine
metabolite melamine (1,3,5-triazine-2,4,6-triamine) in or on the
following food commodities:
------------------------------------------------------------------------
Part per
Commodity million
------------------------------------------------------------------------
Fat, poultry (from chicken layer hens and chicken breeder
hens only)................................................ 0.05
Meat, poultry (from chicken layer hens and chicken breeder
hens only)................................................ 0.05
Meat byproducts (from chicken layer hens and chicken
breeder hens only)........................................ 0.05
------------------------------------------------------------------------
(3) Tolerances are established for residues of the insecticide
cyromazine (N-cyclopropyl-1,3,5-triazine-2,4,6-triamine) in or on the
following food commodities:
------------------------------------------------------------------------
Part per
Commodity million
------------------------------------------------------------------------
Fat, poultry (from chicken layer hens and chicken breeder
hens only)................................................ 0.05
Meat, poultry (from chicken layer hens and chicken breeder
hens only)................................................ 0.05
Meat byproducts (from chicken layer hens and chicken
breeder hens only)........................................ 0.05
------------------------------------------------------------------------
(b) Section 18 emergency exemptions. Time-limited tolerances are
established for the combined residues of the insecticide cyromazine (N-
cyclopropyl-1,3,5-triazine-2,4,6-triamine) and its metabolite, melamine
(1,3,5-triazine-2,4,6-triamine), in connection with use of the
pesticide under section 18 emergency exemption granted by EPA. The
tolerances are specified in the following table. These tolerances
expire and are revoked on the date specified in the table.
------------------------------------------------------------------------
Expiration/
Commodity Parts per million revocation date
------------------------------------------------------------------------
Onion, dry bulb................. 0.3 July 31, 1998
------------------------------------------------------------------------
(c) Tolerances with regional registrations. Tolerances with
regional registration, as defined in Sec. 180.1(n), are established for
the combined residues of the insecticide cyromazine (N-cyclopropyl-
1,3,5-triazine-2,4,6-triamine) and its metabolite melamine (1,3,5-
triazine-2,4,6-triamine), calculated as cyromazine, in or on the
following food commodities:
------------------------------------------------------------------------
Parts per
Commodity million
------------------------------------------------------------------------
Cabbage, Chinese........................................... 3.0
Mustard, Chinese........................................... 3.0
------------------------------------------------------------------------
(d) Indirect or inadvertent residues. [Reserved]
[FR Doc. 97-23098 Filed 8-28-97; 8:45 am]
BILLING CODE 6560-50-F
