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maleic hydrazide (Royal MH-30) Pesticide Tolerances for Emergency Exemptions 11/97

 

[Federal Register: December 5, 1997 (Volume 62, Number 234)]
[Rules and Regulations]               
[Page 64287-64294]
>From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr05de97-15]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 180 and 185

[OPP-300587; FRL-5754-5]
RIN 2070-AB78

 
Maleic hydrazide; Pesticide Tolerances for Emergency Exemptions

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes time-limited tolerances for 
residues of maleic hydrazide (1,2-dihydro-3,6-pyridazinedione) in or on 
rice commodities as well as tolerances for secondary residues in animal 
commodities. 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 rice 
in Louisiana. This regulation establishes a maximum permissible level 
for residues of maleic hydrazide in these food commodities 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 tolerances will 
expire and are revoked on September 30, 1998.

DATES: This regulation is effective December 5, 1997. Objections and 
requests for hearings must be received by EPA on or before February 3, 
1998.
ADDRESSES: Written objections and hearing requests, identified by the 
docket control number, [OPP-300587], 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-300587], must also be submitted to: Public 
Information and Records Integrity Branch, Information Resources and 
Services Division (7502C), Office of Pesticide Programs, Environmental 
Protection Agency, 401 M St., SW., Washington, DC 20460. In person, 
bring a copy of objections and hearing requests to Rm. 1132, CM #2, 
1921 Jefferson Davis Hwy., Arlington, VA.
    A copy of objections and hearing requests filed with the Hearing 
Clerk may also be submitted electronically by sending electronic mail 
(e-mail) to: 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 5.1/6.1 
file format or ASCII file format. All copies of objections and hearing 
requests in electronic form must be identified by the docket control 
number [OPP-300587]. 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 tolerances for 
residues of the herbicide maleic hydrazide (1,2-dihydro-3,6-
pyridazinedione), in or on rice, grain at 105 part per million (ppm); 
rice, straw at 75 ppm; rice, hulls at 240 ppm; and rice, bran at 180 
ppm. Additionally, the Agency is establishing tolerances for secondary 
residues in milk at 1.0 ppm; at 2.5 ppm in meat, 7 ppm in liver, 32 ppm 
in kidney, and 3 ppm in fat of cattle, goats, hogs, horses, and sheep; 
at 0.5 ppm in meat, liver, and fat of poultry; 1.4 ppm in poultry meat 
byproducts; and 0.5 ppm in eggs. These tolerances will expire and are 
revoked on September 30, 1998. EPA will publish a document in the 
Federal Register to remove the revoked tolerances from the Code of 
Federal Regulations.

I. Background and Statutory Authority

    The Food Quality Protection Act of 1996 (FQPA) (Pub. L. 104-170) 
was signed into law August 3, 1996. FQPA amends both the Federal Food, 
Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 301 et seq., and the Federal 
Insecticide, Fungicide, and Rodenticide Act (FIFRA), 7 U.S.C. 136 et 
seq. The FQPA amendments went into effect immediately. Among other 
things, FQPA amends FFDCA to bring all EPA pesticide tolerance-setting 
activities under a new section 408 with a new safety standard and new 
procedures. These activities are described below and discussed in 
greater detail in the final rule establishing the time-limited 
tolerance associated with the emergency exemption for use of 
propiconazole on sorghum (61 FR 58135, November 13, 1996)(FRL-5572-9).
    New section 408(b)(2)(A)(i) of the FFDCA allows EPA to establish a 
tolerance (the legal limit for a pesticide chemical residue in or on a 
food) only if EPA determines that the tolerance is ``safe.'' Section 
408(b)(2)(A)(ii) defines ``safe'' to mean that ``there is a reasonable 
certainty that no harm will result from aggregate exposure to the 
pesticide chemical residue, including all anticipated dietary exposures 
and all other exposures for which there is reliable information.'' This 
includes exposure through drinking water and in residential settings, 
but does not include occupational exposure. Section 408(b)(2)(C) 
requires EPA to give special consideration to exposure of infants and 
children to the pesticide chemical residue in establishing a tolerance 
and to ``ensure that there is a reasonable certainty that no harm will 
result to infants and children from aggregate

[[Page 64288]]

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 Maleic Hydrazide on Rice and FFDCA 
Tolerances

    On June 19, 1997, the Louisiana Department of Agriculture and 
Forestry availed of itself the authority to declare the existence of a 
crisis situation within the State, thereby authorizing use under FIFRA 
section 18 of maleic hydrazide on rice to control red rice. Red rice is 
normally controlled by flood water management and rotating the rice 
crop to soybeans, where soybean herbicides are used that control red 
rice but are also phytotoxic to commercial rice. Over the last 5 years, 
farm land to be rotated into rice in 1997 has experienced three 
consecutive soybean seasons with poor control of red rice. This has 
resulted in increasing red rice infestations in the two intervening 
rice crop seasons, and a buildup of red rice seed in the soil. This 
situation gives rise to the possibility of an unprecedentedly high red 
rice infestation in 1997. Economic loss due to red rice occurs both 
through reductions in the yield of the rice crop and through reductions 
in the quality of the harvested crop. Because red rice and cultivated 
rice are closely related, there are few selective herbicides available; 
those that are have limited efficacy against red rice. The use of 
maleic hydrazide would not only increase yield and quality of the 
harvested crop this year, but would reduce red rice seed in the soil 
and therefore reduce the level of red rice infestation in the next rice 
crop. EPA has authorized under FIFRA section 18 the use of maleic 
hydrazide on rice for control of red rice in Louisiana. 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 maleic hydrazide in or on 
rice. In doing so, EPA considered the new safety standard in FFDCA 
section 408(b)(2), and EPA decided that the necessary tolerances 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 these tolerances without notice and opportunity 
for public comment under section 408(e), as provided in section 
408(l)(6). Although these tolerances will expire and are revoked on 
September 30, 1998, under FFDCA section 408(l)(5), residues of the 
pesticide not in excess of the amounts specified in the tolerances 
remaining in or on rice grain, bran, hulls and straw or in meat, milk, 
poultry or eggs 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 these tolerances earlier if any experience with, 
scientific data on, or other relevant information on this pesticide 
indicate that the residues are not safe.
    Because these tolerances are being approved under emergency 
conditions EPA has not made any decisions about whether maleic 
hydrazide meets EPA's registration requirements for use on rice or 
whether permanent tolerances for this use would be appropriate. Under 
these circumstances, EPA does not believe that these tolerances serve 
as a basis for registration of maleic hydrazide by a State for special 
local needs under FIFRA section 24(c). Nor do these tolerances serve as 
the basis for any State other than Louisiana 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 maleic hydrazide, 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 hundredfold MOE is based on the same rationale as 
the hundredfold uncertainty factor.

[[Page 64289]]

    Lifetime feeding studies in two species of laboratory animals are 
conducted to screen pesticides for cancer effects. When evidence of 
increased cancer is noted in these studies, the Agency conducts a 
weight of the evidence review of all relevant toxicological data 
including short-term and mutagenicity studies and structure activity 
relationship. Once a pesticide has been classified as a potential human 
carcinogen, different types of risk assessments (e.g., linear low dose 
extrapolations or MOE calculation based on the appropriate NOEL) will 
be carried out based on the nature of the carcinogenic response and the 
Agency's knowledge of its mode of action.
    2. Differences in toxic effect due to exposure duration. The 
toxicological effects of a pesticide can vary with different exposure 
durations. EPA considers the entire toxicity data base, and based on 
the effects seen for different durations and routes of exposure, 
determines which risk assessments should be done to assure that the 
public is adequately protected from any pesticide exposure scenario. 
Both short and long durations of exposure are always considered. 
Typically, risk assessments include ``acute,'' ``short-term,'' 
``intermediate term,'' and ``chronic,'' risks. These assessments are 
defined by the Agency as follows.
    Acute risk, by the Agency's definition, results from 1-day 
consumption of food and water, and reflects toxicity which could be 
expressed following a single oral exposure to the pesticide residues. 
High end exposure to food and water residues are typically assumed.
    Short-term risk results from exposure to the pesticide for a period 
of 1-7 days, and therefore overlaps with the acute risk assessment. 
Historically, this risk assessment was intended to address primarily 
dermal and inhalation exposure which could result, for example, from 
residential pesticide applications. However, since enaction of FQPA, 
this assessment has been expanded to include both dietary and non-
dietary sources of exposure, and will typically consider exposure from 
food, water, and residential uses when reliable data are available. In 
this assessment, risks from average food and water exposure, and high-
end residential exposure, are aggregated. High-end exposures from all 3 
sources are not typically added because of the very low probability of 
this occurring in most cases, and because the other conservative 
assumptions built into the assessment assure adequate protection of 
public health. However, for cases in which high-end exposure can 
reasonably be expected from multiple sources (e.g. frequent and 
widespread homeowner use in a specific geographical area), multiple 
high-end risks will be aggregated and presented as part of the 
comprehensive risk assessment/characterization. Since the toxicological 
endpoint considered in this assessment reflects exposure over a period 
of at least 7 days, an additional degree of conservatism is built into 
the assessment; i.e., the risk assessment nominally covers 1-7 days 
exposure, and the toxicological endpoint/NOEL is selected to be 
adequate for at least 7 days of exposure. (Toxicity results at lower 
levels when the dosing duration is increased.)
    Intermediate-term risk results from exposure for 7 days to several 
months. This assessment is handled in a manner similar to the short-
term risk assessment.
    Chronic risk assessment describes risk which could result from 
several months to a lifetime of exposure. For this assessment, risks 
are aggregated considering average exposure from all sources for 
representative population subgroups including infants and children.

B. Aggregate Exposure

    In examining aggregate exposure, FFDCA section 408 requires that 
EPA take into account available and reliable information concerning 
exposure from the pesticide residue in the food in question, residues 
in other foods for which there are tolerances, residues in groundwater 
or surface water that is consumed as drinking water, and other non-
occupational exposures through pesticide use in gardens, lawns, or 
buildings (residential and other indoor uses). Dietary exposure to 
residues of a pesticide in a food commodity are estimated by 
multiplying the average daily consumption of the food forms of that 
commodity by the tolerance level or the anticipated pesticide residue 
level. The Theoretical Maximum Residue Contribution (TMRC) is an 
estimate of the level of residues consumed daily if each food item 
contained pesticide residues equal to the tolerance. In evaluating food 
exposures, EPA takes into account varying consumption patterns of major 
identifiable subgroups of consumers, including infants and children. 
The TMRC is a ``worst case'' estimate since it is based on the 
assumptions that food contains pesticide residues at the tolerance 
level and that 100% of the crop is treated by pesticides that have 
established tolerances. If the TMRC exceeds the RfD or poses a lifetime 
cancer risk that is greater than approximately one in a million, EPA 
attempts to derive a more accurate exposure estimate for the pesticide 
by evaluating additional types of information (anticipated residue data 
and/or percent of crop treated data) which show, generally, that 
pesticide residues in most foods when they are eaten are well below 
established tolerances.
    Percent of crop treated estimates are derived from Federal and 
private market survey data. Typically, a range of estimates are 
supplied and the upper end of this range is assumed for the exposure 
assessment. By using this upper end estimate of percent of crop 
treated, the Agency is reasonably certain that exposure is not 
understated for any significant subpopulation group. Further, regional 
consumption information is taken into account through EPA's computer-
based model for evaluating the exposure of significant subpopulations 
including several regional groups, to pesticide residues. For this 
pesticide, the most highly exposed population subgroup non-nursing 
infants less than 1 year 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 maleic 
hydrazide and to make a determination on aggregate exposure, consistent 
with section 408(b)(2), for time-limited tolerances for residues of 
maleic hydrazide (1,2-dihydro-3,6-pyridazinedione) on rice, grain at 
105 ppm; rice, straw at 75 ppm; rice, hulls at 240 ppm; rice, bran at 
180 ppm; time-limited tolerances are set at 2.5 ppm in meat, 7.0 ppm in 
liver, 32.0 ppm in kidney, and 3.0 ppm in fat of cattle, goats, hogs, 
horses, and sheep; 1.0 ppm in milk; 0.5 ppm in meat, liver, and fat of 
poultry; 1.4 ppm in poultry meat byproducts (except liver), and 0.5 ppm 
in eggs. 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 maleic hydrazide 
are discussed below.

[[Page 64290]]

    1. Acute toxicity. The Agency has determined that an acute dietary 
risk assessment is not required for this chemical.
     2. Short - and intermediate - term toxicity. Based on the 
available data base, the Agency has concluded that determination of 
short-term Margin of Exposure (MOE) calculations is not required. For 
intermediate-term MOE calculations, the Agency recommends use of the 
NOEL of 29 milligrams/kilogram/day (mg/kg/day) from the 1-year feeding 
study in dogs. Decreased weight gain and reduced heart weight are the 
effects observed at the Lowest Effect Level (LEL) of 87 mg/kg/day.
    3. Chronic toxicity. EPA has established the RfD for maleic 
hydrazide at 0.25 mg/kg/day. This RfD is based on a NOEL of 25 mg/kg/
day taken from a 2-year feeding study in rats in which decreased weight 
gain in males was the effect observed at the LEL of 500 mg/kg/day. An 
uncertainty factor of 100 was assigned to allow for inter- and intra-
species variability.
    4. Carcinogenicity. Maleic hydrazide has been classified as a Group 
E--evidence of non-carcinogenicity for humans in two species--chemical 
by the Agency. A carcinogenic risk assessment is not required.

B. Exposures and Risks

    1. From food and feed uses. Tolerances have been established (40 
CFR 180.175) for the residues of maleic hydrazide (1,2-dihydro-3,6-
pyridazinedione), in or on dry bulb onions, potatoes and cranberries. 
Risk assessments were conducted by EPA to assess dietary exposures and 
risks from maleic hydrazide as follows:
    i.  Acute exposure and risk. Acute dietary risk assessments are 
performed for a food-use pesticide if a toxicological study has 
indicated the possibility of an effect of concern occurring as a result 
of a 1 day or single exposure. The Agency has determined that this risk 
assessment is not required.
    ii. Chronic exposure and risk. Refined residue and percent of crop 
treated information were used in the chronic exposure analysis to 
calculate the Anticipated Residue Contribution (ARC) from published and 
proposed uses of maleic hydrazide. The use of tolerance level residues 
for potatoes and dry bulb onions as well as the use of high end 
anticipated residues for animal commodities results in overestimation 
of chronic dietary risk.
    2. From drinking water. Review of available data indicate that 
maleic hydrazide is neither mobile nor persistent. There is no 
established Maximum Contaminant Level for residues of maleic hydrazide 
in drinking water. Health advisory levels for maleic hydrazide in 
drinking water have been established at the following levels: for a 10 
kg child, 10 mg/liter (1-day and 10-day levels) and 5 mg/liter (long 
term level); for a 70 kg adult, 20 mg/liter (long term level).
     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 maleic hydrazide 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 maleic hydrazide 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. Maleic hydrazide is currently 
registered for use on the following residential non-food sites: outdoor 
non-food sites such as non-bearing citrus and ornamentals.
    i. Chronic exposure and risk. Based on the uses registered, a 
chronic, non-dietary exposure scenario is not expected.
    ii. Short- and intermediate-term exposure and risk.  Maleic 
hydrazide is currently registered for use on outdoor non-food sites 
such as non-bearing citrus, ornamental shade trees and plants, turf, 
lawns, utility and highway rights of way, industrial areas and 
airports. There are no indoor uses.
    4. Cumulative exposure to substances with common mechanism of 
toxicity. Section 408(b)(2)(D)(v) requires that, when considering 
whether to establish, modify, or revoke a tolerance, the Agency 
consider ``available information'' concerning the cumulative effects of 
a particular pesticide's residues and ``other substances that have a 
common mechanism of toxicity.'' The Agency believes that ``available 
information'' in this context might include not only toxicity, 
chemistry, and exposure data, but also scientific policies and 
methodologies for understanding common mechanisms of toxicity and 
conducting cumulative risk assessments. For most pesticides, although 
the Agency has some information in its files that may turn out to be 
helpful in eventually determining whether a pesticide shares a common 
mechanism of toxicity with any other substances, EPA does not at this 
time have the methodologies to resolve the complex scientific issues 
concerning common mechanism of toxicity in a meaningful way. EPA has 
begun a pilot process to study this issue further through the 
examination of particular classes of pesticides. The Agency hopes that 
the results of this pilot process will increase the Agency's scientific 
understanding of this question such that EPA will be able to develop 
and apply scientific principles for better determining which chemicals 
have a common mechanism of toxicity and evaluating the cumulative 
effects of such chemicals. The Agency anticipates, however, that even 
as its understanding of the science of common mechanisms increases, 
decisions on specific classes of chemicals will be heavily dependent on 
chemical specific data, much of which may not be presently available.
    Although at present the Agency does not know how to apply the 
information in its files concerning common mechanism issues to most 
risk assessments, there are pesticides as to which the common mechanism 
issues can be resolved. These pesticides include pesticides that are 
toxicologically dissimilar to existing chemical substances (in which 
case the Agency can conclude that it is unlikely that a pesticide 
shares a common mechanism of activity with other substances) and 
pesticides that produce a common toxic metabolite (in which case common 
mechanism of activity will be assumed).
    Maleic hydrazide is a member of the hydrazide class of pesticides; 
another member of this class is Alar (daminozide). EPA does not have, 
at this time, available data to determine whether maleic hydrazide 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

[[Page 64291]]

risk approach based on a common mechanism of toxicity, maleic hydrazide 
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 maleic hydrazide 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 in 
Unit IV.B. of this preamble, EPA has concluded that aggregate exposure 
to maleic hydrazide from food will utilize 14% 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 in Unit 
IV.E. of this preamble). 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 maleic hydrazide 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 maleic 
hydrazide 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. Data to quantify intermediate-term exposure from 
non-occupational, non-dietary uses are not available at this time. In 
the absence of a quantitative estimate of exposure, the Agency believes 
that the large MOEs calculated for mixers, loaders and applicators of 
the product (1,000 to 1,800, where 100 is considered to be the level at 
which the Agency has reasonable certainty of no harm resulting from 
occupational exposure to the chemical) demonstrate that intermediate 
aggregate risk from non-occupational uses of maleic hydrazide is below 
the Agency's level of concern.

D. Aggregate Cancer Risk for U.S. Population

     Maleic hydrazide has been classified as a Group E chemical. A 
carcinogenic risk assessment is not required for this chemical.

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 maleic hydrazide, 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 developmental toxicity 
study in rats, the maternal (systemic) NOEL was 1,600 mg/kg/day, the 
highest dose tested (HDT). The developmental NOEL was 1,200 mg/kg/day, 
based on minor skeletal variations at the LOEL of 1,600 mg/kg/day. In a 
second developmental toxicity study in rats, the maternal and 
developmental NOELs were greater than 1,000 mg/kg/day, the HDT. The 
Agency concluded that skeletal variations observed in the first study 
occurred at doses above 1 mg/kg/day, the limit dose, and therefore were 
of minimal concern. In the developmental toxicity study in rabbits, the 
maternal and developmental NOELs were 1,000 mg/kg/day, the HDT.
    iii. Reproductive toxicity study. In the 2-generation reproductive 
toxicity study in rats, the maternal NOEL was 500 mg/kg/day, based on 
decreased body weight at the LOEL of 1,500 mg/kg/day. The reproductive/
developmental NOEL was 500 mg/kg/day, based on post-natal decrease in 
body weight of pups during lactation at the LOEL of 1,500 mg/kg/day.
    iv. Pre- and post-natal sensitivity. The toxicity data base for 
evaluating pre- and post-natal toxicity for maleic hydrazide is 
complete with respect to current data requirements. There are no pre- 
or post-natal toxicity concerns for infants and children, based on the 
results of the rat and rabbit developmental toxicity studies and the 2-
generation rat reproductive toxicity study.
    v. Conclusion. Based on review of the required studies, EPA 
concludes that reliable data support use of the standard hundredfold 
MOE/uncertainty factor and that an additional margin/factor is not 
needed to protect infants and children.
    2. Chronic risk. Using the conservative exposure assumptions 
described above, EPA has concluded that aggregate exposure to maleic 
hydrazide from food will utilize between 14 and 54% 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 maleic hydrazide 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 maleic hydrazide 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 maleic hydrazide (as specified in 40 CFR 
180.175). The nature of the residue in animals is adequately understood 
for this section 18. The residue of concern is maleic hydrazide .

B. Analytical Enforcement Methodology

    Adequate enforcement methodology (with spectrophotometric 
detection) for plants is available in PAM II to enforce the tolerance 
expression. An enforcement method has not been validated for animal 
commodities. However, a method for animal commodities is available, see 
Wood,

[[Page 64292]]

P.R., ``Determination of Maleic Hydrazide Residues in Plant and Animal 
Tissue,'' Analytical Chemistry, 25, 1879 (1953).

C. Magnitude of Residues

    Residues of maleic hydrazide at a 14-day PHI are not expected to 
exceed 105.0 ppm on rice grain, 75.0 ppm on rice straw, 240.0 ppm on 
rice hulls, 180.0 ppm on rice bran, and 75.0 on the processed commodity 
polished rice as a result of this section 18 use. Time-limited 
tolerances should be established for rice grain, straw, bran, and hulls 
at these levels.
    No tolerances on animal commodities have been established for 
maleic hydrazide. Secondary residues in animal commodities resulting 
from this use on rice and the registered use on potatoes are not 
expected to exceed 2.5 ppm in meat, 7.0 ppm in liver, 32.0 ppm in 
kidney, and 3.0 ppm in fat of cattle, goats, hogs, horses, and sheep; 
1.0 ppm in milk; 0.5 ppm in meat, liver, and fat of poultry; 1.4 ppm in 
poultry meat byproducts (except liver), and 0.5 ppm in eggs.

D. International Residue Limits

    There are currently no Codex, Canadian, or Mexican limits for 
residues of maleic hydrazide in or on rice or animal commodities. 
Therefore, establishment of time-limited tolerances will not pose a 
concern for international harmonization.

E. Rotational Crop Restrictions.

    There are no rotational crop restrictions in the section 18 or 
Federal label.

VI. Conclusion

    Therefore, tolerances are established for residues of maleic 
hydrazide (1,2-dihydro-3,6-pyridazinedione) in rice, grain at 105 ppm, 
rice, straw at 75 ppm, rice, hulls at 240 ppm, and rice, bran at 180 
ppm. Additionally, tolerances are established for secondary residues of 
maleic hydrazide at 2.5 ppm in meat, 7 ppm in liver, 32 ppm in kidney, 
and 3 ppm in fat of cattle, goats, hogs, horses, and sheep; 1 ppm in 
milk; 0.5 ppm in meat, liver and fat of poultry; 1.4 ppm in poultry 
meat byproducts; and 0.5 ppm in eggs.
    In addition because FQPA has eliminated the distinctions between 
tolerances for raw and processed food, OPP is transferring the food 
additive tolerances now found in Sec. 185.3900 to Sec. 180.175, and is 
removing Sec. 185.3900.Therefore, to accomplish the transfer, and for 
the convenience of the user, OPP is revising Sec. 180.175 in its 
entirety, although only paragraph (b) of Sec. 180.175 is new.

VII. Objections and Hearing Requests

    The new FFDCA section 408(g) provides essentially the same process 
for persons to ``object'' to a tolerance regulation issued by EPA under 
new section 408(e) and (l)(6) as was provided in the old section 408 
and in section 409. However, the period for filing objections is 60 
days, rather than 30 days. EPA currently has procedural regulations 
which govern the submission of objections and hearing requests. These 
regulations will require some modification to reflect the new law. 
However, until those modifications can be made, EPA will continue to 
use those procedural regulations with appropriate adjustments to 
reflect the new law.
    Any person may, by February 3, 1998, file written objections to any 
aspect of this regulation and may also request a hearing on those 
objections. Objections and hearing requests must be filed with the 
Hearing Clerk, at the address given above (40 CFR 178.20). A copy of 
the objections and/or hearing requests filed with the Hearing Clerk 
should be submitted to the OPP docket for this rulemaking. The 
objections submitted must specify the provisions of the regulation 
deemed objectionable and the grounds for the objections (40 CFR 
178.25). Each objection must be accompanied by the fee prescribed by 40 
CFR 180.33(i). If a hearing is requested, the objections must include a 
statement of the factual issues on which a hearing is requested, the 
requestor's contentions on such issues, and a summary of any evidence 
relied upon by the requestor (40 CFR 178.27). A request for a hearing 
will be granted if the Administrator determines that the material 
submitted shows the following: There is genuine and substantial issue 
of fact; there is a reasonable possibility that available evidence 
identified by the requestor would, if established, resolve one or more 
of such issues in favor of the requestor, taking into account 
uncontested claims or facts to the contrary; and resolution of the 
factual issues in the manner sought by the requestor would be adequate 
to justify the action requested (40 CFR 178.32). Information submitted 
in connection with an objection or hearing request may be claimed 
confidential by marking any part or all of that information as 
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 and Electronic Submissions

    EPA has established a record for this rulemaking under docket 
control number [OPP-300587] (including any comments and data submitted 
electronically). A public version of this record, including printed, 
paper versions of electronic comments, which does not include any 
information claimed as CBI, is available for inspection from 8:30 a.m. 
to 4 p.m., Monday through Friday, excluding legal holidays. The public 
record is located in Room 1132 of the Public Information and Records 
Integrity Branch, Information Resources and Services Division (7502C), 
Office of Pesticide Programs, Environmental Protection Agency, Crystal 
Mall #2, 1921 Jefferson Davis Highway, Arlington, VA.
    Electronic comments may be sent directly to EPA at:
    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 action finalizes a tolerance requirement under FFDCA section 
408(e). 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). In 
addition, 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

[[Page 64293]]

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 special OMB 
review in accordance with Executive Order 13045, entitled Protection of 
Children from Environmental Health Risks and Safety Risks (62 FR 19885, 
April 23, 1997).
    In addition, under the Regulatory Flexibility Act (RFA) (5 U.S.C. 
601 et seq.), the Agency 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

40 CFR Part 180

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

40 CFR Part 185

    Environmental protection, Food additives, Pesticides and pests, 
Reporting and recordkeeping requirements.

    Dated: November 21, 1997.

Linda A. Travers,

Acting Director, Office of Pesticide Programs.
    Therefore, 40 CFR chapter I is amended as follows:

PART 180--[AMENDED]

    1. In part 180:
    i. The authority citation for part 180 continues to read as 
follows:

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

    ii. Section 180.175 is revised to read as follows:


Sec. 180.175  Maleic hydrazide; tolerances for residues.

    (a) General.  (1) Tolerances for residues of the herbicide and 
plant regulator maleic hydrazide (1,2-dihydro-3,6-pyridazinedione) are 
established in or on the following raw agricultural commodities:

------------------------------------------------------------------------
                                                               Parts per
                          Commodity                             million 
------------------------------------------------------------------------
Onions, dry bulb.............................................       15.0
Potatoes.....................................................       50.0
------------------------------------------------------------------------

    (2) A food additive known as maleic hydrazide (1,2-dihydro-3,6-
pyridazinedione) may be present in potato chips when used in accordance 
with the following conditions:
    (i) The food additive is present as a result of the application of 
a pesticide formulation containing maleic hydrazide to the growing 
potato plant in accordance with directions registered by the U.S. 
Environmental Protection Agency.
    (ii) The label of the pesticide formulation containing the food 
additive conforms to labeling registered by the U.S. Environmental 
Protection Agency.
    (iii) The food additive is present in an amount not to exceed 160 
parts per million by weight of the finished food.
    (b) Section 18 emergency exemptions. Time-limited tolerances are 
established for residues of the herbicide maleic hydrazide (1,2-
dihydro-3,6-pyridazinedione) in connection with use of the pesticide 
under section 18 emergency exemptions granted by EPA. The tolerances 
will expire and are revoked on the dates specified in the following 
table.

                                                                        
------------------------------------------------------------------------
                                                          Expiration/   
            Commodity              Parts per million    Revocation Date 
------------------------------------------------------------------------
Cattle, fat.....................  3                   9/30/98           
Cattle, liver...................  7                   9/30/98           
Cattle, kidney..................  32                  9/30/98           
Cattle, meat....................  2.5                 9/30/98           
Eggs............................  0.5                 9/30/98           
Goats, fat......................  3                   9/30/98           
Goats, liver....................  7                   9/30/98           
Goats, kidney...................  32                  9/30/98           
Goats, meat.....................  2.5                 9/30/98           
Hogs, fat.......................  3                   9/30/98           
Hogs, liver.....................  7                   9/30/98           
Hogs, kidney....................  32                  9/30/98           
Hogs, meat......................  2.5                 9/30/98           
Horses, fat.....................  3                   9/30/98           
Horses, liver...................  7                   9/30/98           
Horses, kidney..................  32                  9/30/98           
Horses, meat....................  2.5                 9/30/98           
Milk............................  1                   9/30/98           
Poultry, fat....................  0.5                 9/30/98           
Poultry, liver..................  0.5                 9/30/98           
Poultry, meat...................  0.5                 9/30/98           
Poultry, meat byproducts (except  1.4                 9/30/98           
 liver).                                                                
Rice, bran......................  180                 9/30/98           
Rice, grain.....................  105                 9/30/98           
Rice, hulls.....................  240                 9/30/98           
Rice, straw.....................  75                  9/30/98           
Sheep, fat......................  3                   9/30/98           

[[Page 64294]]

                                                                        
Sheep, liver....................  7                   9/30/98           
Sheep, kidney...................  32                  9/30/98           
Sheep, meat.....................  2.5                  9/30/98          
------------------------------------------------------------------------

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

PART 185--[Amended]

    2. In part 185:
    i. The authority citation for part 185 continues to read as 
follows:
    Authority: 21 U.S.C. 348.

Sec. 185.3900 [Removed]

    ii. Section 185.3900 is removed.

[FR Doc. 97-31553 Filed 12-4-97; 8:45 am]
BILLING CODE 6560-50-F