[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: [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-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: 
[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 
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:
    [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 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