[Federal Register Volume 62, Number 172 (Friday, September 5, 1997)]
[Rules and Regulations]
[Pages 46900-46907]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-23684]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Parts 180 and 186

[OPP-300536; FRL-5738-9]
RIN 2070-AB78


2,4-D; 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 2,4-
dichlorophenoxyacetic acid (2,4-D) in or on wild rice. 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 wild rice. This regulation 
establishes a maximum permissible level for residues of 2,4-D in this 
food

[[Page 46901]]

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 August 31, 1998.

DATES: This regulation is effective September 5, 1997. Objections and 
requests for hearings must be received by EPA on or before November 4, 
1997.

ADDRESSES: Written objections and hearing requests, identified by the 
docket control number, [OPP-300536], 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-300536], 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-300536]. 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: Daniel Rosenblatt, 
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) 308-9375, e-mail: 
[email protected].

SUPPLEMENTARY INFORMATION: EPA, on its own initiative, pursuant to 
section 408(e) and (l)(6) of the Federal Food, Drug, and Cosmetic Act 
(FFDCA), 21 U.S.C. 346a(e) and (l)(6), is establishing a tolerance for 
residues of the herbicide 2,4-dichlorophenoxyacetic acid, in or on wild 
rice at 0.1 parts per million (ppm). This tolerance will expire and is 
revoked on August 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 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 2,4-D on Wild Rice and FFDCA Tolerances

    The cultivation of wild rice involves flooding fields. Common 
waterplantain (Alisma plantage-aquatica) is an aquatic plant pest that 
has established itself in areas where wild rice is produced. There are 
no herbicides registered for use on wild rice. An analysis submitted in 
support of the FIFRA section 18 exemption for this use suggests that 
common waterplantain will reduce yields in Minnesota by approximately 
50% in certain areas. EPA considers that this loss lies outside the 
range of normal profitability fluctuation. Such loss would, therefore, 
represent a significant economic loss for growers. Therefore, EPA has 
authorized under FIFRA section 18 the use of 2,4-D on wild rice for 
control of common waterplantain in Minnesota. 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 2,4-D in or on wild rice. 
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 August 31,

[[Page 46902]]

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 
wild rice 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 2,4-D meets EPA's 
registration requirements for use on wild rice 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 2,4-D 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 Minnesota 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 2,4-D, 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% or less of the RfD) is 
generally considered acceptable by EPA. EPA generally uses the RfD to 
evaluate the chronic risks posed by pesticide exposure. For shorter 
term risks, EPA calculates a margin of exposure (MOE) by dividing the 
estimated human exposure into the NOEL from the appropriate animal 
study. Commonly, EPA finds MOEs lower than 100 to be unacceptable. This 
100-fold MOE is based on the same rationale as the 100-fold uncertainty 
factor.
    Lifetime feeding studies in two species of laboratory animals are 
conducted to screen pesticides for cancer effects. When evidence of 
increased cancer is noted in these studies, the Agency conducts a 
weight of the evidence review of all relevant toxicological data 
including short-term and mutagenicity studies and structure activity 
relationship. Once a pesticide has been classified as a potential human 
carcinogen, different types of risk assessments (e.g., linear low dose 
extrapolations or MOE calculation based on the appropriate NOEL) will 
be carried out based on the nature of the carcinogenic response and the 
Agency's knowledge of its mode of action.
    2. Differences in toxic effect due to exposure duration. The 
toxicological effects of a pesticide can vary with different exposure 
durations. EPA considers the entire toxicity data base, and based on 
the effects seen for different durations and routes of exposure, 
determines which risk assessments should be done to assure that the 
public is adequately protected from any pesticide exposure scenario. 
Both short and long durations of exposure are always considered. 
Typically, risk assessments include ``acute'', ``short-term'', 
``intermediate term'', and ``chronic'' risks. These assessments are 
defined by the Agency as follows.
    Acute risk, by the Agency's definition, results from 1-day 
consumption of food and water, and reflects toxicity which could be 
expressed following a single oral exposure to the pesticide residues. 
High end exposure to food and water residues are typically assumed.
    Short-term risk results from exposure to the pesticide for a period 
of 1-7 days, and therefore overlaps with the acute risk assessment. 
Historically, this risk assessment was intended to address primarily 
dermal and inhalation exposure which could result, for example, from 
residential pesticide applications. However, since enaction of FQPA, 
this assessment has been expanded to include both dietary and non-
dietary sources of exposure, and will typically consider exposure from 
food, water, and residential uses when reliable data are available. In 
this assessment, risks from average food and water exposure, and high-
end residential exposure, are aggregated. High-end exposures from all 
three 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

[[Page 46903]]

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 (infants less 
than a 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 2,4-D and 
to make a determination on aggregate exposure, consistent with section 
408(b)(2), for a time-limited tolerance for residues of 2,4-
dichlorophenoxyacetic acid on wild rice at 0.1 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 2,4-D are discussed 
below.
    1. Acute toxicity. For the purpose of the acute dietary risk 
assessment, EPA recommends use of a NOEL of 67 mg/kg/day from the rat 
acute neurotoxicity study. The effects observed at the LOEL of 227 mg/
kg/day were increased incidence of incoordination, slight gait 
abnormalities, and decreased motor activity. As neurotoxicity is the 
effect of concern, this risk assessment will evaluate acute dietary 
risk to all population subgroups.
     2. Short - and intermediate - term toxicity. For short-term MOE 
calculations, EPA supports use of the maternal NOEL of 30 mg/kg/day 
from the oral developmental toxicity study in rabbits. The Lowest 
Effect Level (LEL) was 90 mg/kg/day, based on abortions, ataxia, 
decreased motor activity, cold extremities during gestation, and 
decreased weight gain. For intermediate-term dermal MOE calculations, 
EPA recommended use of the NOEL of 1.0 mg/kg/day from the 90-day oral 
toxicity study in dogs. The LEL of 3 mg/kg/day was based on clinical 
chemistry changes and lesions in the kidneys. For short- and 
intermediate-term inhalation risk, EPA concludes that exposure by the 
inhalation route was of no concern and that this risk assessment was 
not required for any exposure duration.
    3. Chronic toxicity. EPA has established the RfD for 2,4-D at 0.01 
milligrams/kilogram/day (mg/kg/day). This RfD is based on a 1-year oral 
toxicity study in dogs with a NOEL of 1 mg/kg/day and an uncertainty 
factor of 100. The LEL of 5 mg/kg/day was based on alterations in serum 
chemistry with corroborative histopathological lesions in the liver and 
kidneys.
    4. Carcinogenicity. EPA's Cancer Peer Review Committee has 
classified 2,4-D as a Group D chemical (``not classifiable as to human 
carcinogenicity'') on the basis that, ``the evidence is inadequate and 
cannot be interpreted as showing either the presence or absence of a 
carcinogenic effect.''

B. Exposures and Risks

    1. From food and feed uses. Tolerances have been established (40 
CFR 180.142) for residues of 2,4-D as the acid or various of its salts 
and esters, in or on a variety of raw agricultural commodities, 
including rice. In addition, there are also tolerances for 2,4-D for 
meat, milk, and eggs. Risk assessments were conducted by EPA to assess 
dietary exposures and risks from 2,4-D as follows:
    i.  Acute exposure and risk. Acute dietary risk assessments are 
performed for a food-use pesticide if a toxicological study has 
indicated the possibility of an effect of concern occurring as a result 
of a one day or single exposure. Wild rice is not uniquely identified 
in the system which the Agency uses to calculate acute and chronic 
dietary risk. Therefore, the Agency must estimate the additional 
exposure to 2,4-D associated with this use. Based on the proposed 
tolerance level and the probable low average consumption of this 
commodity, the Agency believes it is likely that any incremental 
increase in acute dietary risk would be negligible. In addressing this 
area, the Agency assessed the potential acute dietary exposure from 
2,4-D based on all of the chemical's existing tolerances and uses. For 
this analysis, EPA assumed tolerance level residues and 100% crop-
treated. MOEs were calculated for all population subgroups. MOEs ranged 
from 112 for infants (less than 1 year old) to 558 for males and 
females 13 years and older. Although these MOEs do not represent a 
level of concern to EPA, if the analysis were to incorporate 
anticipated residue levels and actual percent crop-treated, the MOEs 
would be even larger. Therefore, this assessment should be viewed as 
conservative.
    ii. Chronic exposure and risk. As mentioned above, wild rice is not 
a commodity that is uniquely identified in the Agency's current food 
consumption data system. However, EPA has estimated that the 
incremental chronic dietary risk from this Section 18 use of 2,4-D on 
wild rice adds less than 1 percent to the RfD values for this chemical. 
For the purpose of assessing potential chronic dietary exposure from 
2,4-D, EPA assumed Anticipated Residue Contributions (ARCs) for major 
identifiable subgroups of consumers, including infants and children, 
from the

[[Page 46904]]

existing uses of 2,4-D. The RfD values range from 58% for non-nursing 
infants less than 1 year old to 31% for the U.S. population (48 
states).
    2. From drinking water. In examining aggregate exposure, FQPA 
directs EPA to consider available information concerning exposures from 
the pesticide residues in food and all other non-occupational 
exposures. The primary non-food sources of exposure the Agency looks at 
include drinking water (whether from ground or surface water), and 
exposure through pesticide use in gardens, lawns, or buildings 
(residential and other indoor uses). Based on data available to EPA, 
2,4-D is soluble in water. The average field half-life is 10 days. The 
chemical is potentially mobile, but rapid degradation in soil and 
removal by plant uptake minimizes leaching. A Maximum Contaminant Level 
(MCL) of 0.07 mg/L has been established. In addition, the following 
Health Advisories (HAs) have been established: for a 10-kg child, a 
range of 1 mg/L from 1-day exposure to 0.1 mg/L for longer-term 
exposure up to 7 years; for a 70 kg adult, a range of 0.4 mg/L for 
longer-term exposure to 0.07 mg/L for lifetime exposure.
    i. Acute exposure and risk. EPA developed acute exposure levels for 
adults and children assuming the high end residue value of 57.1 
micrograms/L in drinking water. Adult exposure was calculated to be 1.6 
 x  10-3 mg/kg/day. Child exposure was calculated to be 5.7 
x  10-3 mg/kg/day. The child exposure calculations assumed a 
body weight of 10 kg and all the drinking water consumed in the United 
States was assumed to contain the high end level of residues (57 
micrograms/L). The assessment is quite conservative since only just 
over 2% of all wells monitored from 1979-1991 contained detectable 
residues of 2,4-D. The adult calculations assumed a body weight of 70 
kg and the high end of residue (57 micrograms/L). The acute NOEL for 
2,4-D is 67 mg/kg/day. The acute MOE is thus calculated to be 42,000 
for adults and 12,000 for children.
    ii. Chronic exposure and risk. The RfD for 2,4-D is 0.01 mg/kg/day. 
Thus, the levels of adult and child exposure correspond to a chronic 
dietary (water only) exposure of 16% of the RfD for adults and 57% of 
the RfD for children.
    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 2,4-D 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 
2,4-D 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. 2,4-D is currently registered for use 
on the following residential non-food sites: ornamental turf, lawns, 
and grasses, golf course turf, recreational areas, and several other 
indoor and outdoor uses. This herbicide is widely used. By volume, 2,4-
D is among the top pesticides used in non-agricultural settings. EPA 
does not have data on hand upon which to base calculation of non-
dietary exposure of 2,4-D for purposes of inclusion in an aggregate 
risk assessment. However, there are several characteristics of 2,4-D 
which suggest the chemical presents a low risk from non-dietary, non-
occupational exposure, particularly the chemical's high acute toxicity 
NOEL, the short half life in soil, low dermal penetration and high 
acute dietary MOE. Further, EPA has concluded that for the purposes of 
short- and intermediate-term risk, the inhalation route was of no 
health 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 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 2,4-D 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, 2,4-D 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 
2,4-D has a common mechanism of toxicity with other substances.

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

    1. Acute risk. EPA calculates acute aggregate risks by taking into 
account MOEs from food and MOEs from water. As described above in this 
document,

[[Page 46905]]

for the subgroup U.S. population the MOE for food is 223, the MOE for 
water is 42,000. Taken together, the aggregate MOE is 222. This figure 
does not exceed the Agency's level of concern for acute dietary 
exposure.
    2. Chronic risk. Using the ARC exposure assumptions described 
above, EPA has concluded that aggregate exposure to 2,4-D from food and 
water will utilize 47% of the RfD for the U.S. population. The major 
identifiable subgroup with the highest aggregate exposure is infants 
and children. See below for a discussion of the analysis of the risks 
for that subgroup. 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 2,4-D 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 2,4-D residues.

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

    1. Safety factor for infants and children. i. In assessing the 
potential for additional sensitivity of infants and children to 
residues of 2,4-D, EPA considered data from developmental toxicity 
studies in the rat and rabbit and a two-generation reproduction study 
in the rat. The developmental toxicity studies are designed to evaluate 
adverse effects on the developing organism resulting from maternal 
pesticide exposure during gestation. Reproduction studies provide 
information relating to effects from exposure to the pesticide on the 
reproductive capability of mating animals and data on systemic 
toxicity.
    FFDCA section 408 provides that EPA shall apply an additional 
tenfold margin of safety for infants and children in the case of 
threshold effects to account for pre-and post-natal toxicity and the 
completeness of the database unless EPA determines that a different 
margin of safety will be safe for infants and children. Margins of 
safety are incorporated into EPA risk assessments either directly 
through use of a MOE analysis or through using uncertainty (safety) 
factors in calculating a dose level that poses no appreciable risk to 
humans. EPA believes that reliable data support using the standard 100-
fold safety factor (usually 100 for combined inter- and intra-species 
variability)) and not the additional tenfold safety factor when EPA has 
a complete data base under existing guidelines and when the severity of 
the effect in infants or children or the potency or unusual toxic 
properties of a compound do not raise concerns regarding the adequacy 
of the standard safety factor.
    ii. Developmental toxicity studies. In the rat developmental 
toxicity analysis, the maternal NOEL was greater than 75 mg/kg/day at 
the highest dose tested (HDT). The developmental (fetal) NOEL was 25 
mg/kg/day, based on delayed ossification at the developmental LOEL of 
75 mg/kg/day. In the rabbit developmental toxicity study, the maternal 
NOEL was 30 mg/kg/day, based on ataxia, decreased motor activity, cold 
extremities, and decreased body weight gain at the LOEL of 90 mg/kg/
day. The developmental (fetal) NOEL was 90 mg/kg/day.
    iii. Reproductive toxicity study. In the 2-generation reproductive 
toxicity study in rats, the parental (systemic) NOEL of 5 mg/kg/day was 
based on degenerative effects in the kidneys of males and decreased 
body weight gain in females at the LOEL of 20 mg/kg/day. The 
reproductive (pup) NOEL was 5 mg/kg/day, based on decreased pup weight 
at the LEL of 20 mg/kg/day. The reproductive effects occurred in the 
presence of parental toxicity.
    iv. Pre- and post-natal sensitivity. The pre and post-natal 
toxicology data base for 2,4-D is complete with respect to current data 
requirements. In the developmental toxicity study in rats, evidence of 
toxicity occurred in developing fetuses (NOEL of 25 mg/kg/day) in the 
absence of maternal toxicity. This finding suggests that extra pre-
natal sensitivity may be present in rat fetuses exposed to 2,4-D in the 
absence of maternal toxicity. However, the results from the 
developmental toxicity study in rabbits demonstrate that maternal 
toxicity occurred (NOEL of 30 mg/kg/day) in the absence of 
developmental toxicity (NOEL of 90 mg/kg/day), thus suggesting no extra 
pre-natal sensitivity. Since the developmental NOELs for rats (25-fold) 
and rabbits (90-fold) are greater than the RfD NOEL of 1 mg/kg/day from 
the 1-year oral toxicity study in dogs, an additional uncertainty 
factor to protect infants and children is not warranted.
    v. Conclusion. Based on the reproductive toxicity study in rats 
discussed above, there does not appear to be an increased sensitivity 
for pre- and post-natal effects. Based on these findings, EPA concludes 
that reliable data support use of the standard 100-fold margin of 
exposure/uncertainty factor and that an additional margin/factor is not 
needed for 2,4-D to protect the safety of infants and children.
    2. Acute risk. EPA has determined aggregate MOE calculations which 
incorporate exposure to 2,4-D from food and water. The aggregate MOEs 
for 2,4-D are: 111 for infants less than a year old, 147 for children 
1-6 years old, and 556 for females 13 and older. These MOEs do not 
exceed EPA's level of concern. Further, they were prepared using 
conservative risk estimates; data refinement would result in lower 
acute aggregate exposure estimates. Therefore, EPA concludes that there 
is a reasonable certainty that no harm will result to infants and 
children from aggregate exposure to 2,4-D residues.
    3. Chronic risk. Using the conservative exposure assumptions 
described above, EPA has concluded that aggregate exposure to 2,4-D 
from food and water will utilize 87% of the RfD for nursing infants, 
115% for non-nursing infants, 114% for children 1-6 years old, and 100% 
for children 7-12 years old. EPA notes that the food exposure estimate 
is partially refined while the water estimate is quite conservative. 
Further refinement using additional anticipated residue values in crops 
and percent crop-treated information, and well water monitoring data 
would result in lower chronic dietary (food) and chronic dietary 
(water) exposure estimates, thus reducing the aggregate risk estimate. 
Given these factors, along with the completeness and reliability of the 
toxicity data, EPA concludes that there is a reasonable certainty that 
no harm will result to infants and children from aggregate chronic 
exposure to 2,4-D residues.

V. Other Considerations

A. Metabolism in Plants and Animals

    The nature of the residue of 2,4-D is adequately understood. The 
regulable residue is 2,4-D per se, as established in 40 CFR 180.142. No 
livestock feed issues are raised by this action.

B. Analytical Enforcement Methodology

    EN-CAS Method ENC-2/93 is available to enforce this time-limited 
tolerance on wild rice.

C. Magnitude of Residues

    Adequate residue data are available to support a time-limited 
tolerance for residues of 2,4-D in/on wild rice at 0.1 ppm. Wild rice 
hulls, obtained from processing, have no recognized food or feed use. 
Secondary residues are not expected in meat, milk, poultry, or eggs 
from this use since no feed items are associated with wild rice. 
Further, the

[[Page 46906]]

label restricts against use of treated water to irrigate other crops or 
to water livestock.

D. International Residue Limits

    There are no Codex, Canadian, or Mexican maximum residue limits 
(MRLs) for use of 2,4-D on wild rice. Therefore, international 
harmonization is not an issue for this commodity. There is a Codex MRL 
of 0.05 ppm for 2,4-D on rice, a Mexican MRL of 0.1 ppm for 2,4-D on 
rice; and a Canadian MRL of 0.1 ppm for 2,4-D on cereal grains.

VI. Conclusion

    Therefore, the time limited tolerance is established for residues 
of 2,4-dichlorophenoxyacetic acid in wild rice at 0.1 ppm. Since the 
FQPA has eliminated the distinctions between processed food, feed, and 
raw agricultural commodities, the tolerance in Sec. 186.1450 is being 
renumbered and transfered to Sec. 180.142(a)(12). Therefore, 
Sec. 186.1450 is being removed.

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 November 4, 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 Record

    EPA has established a record for this rulemaking under docket 
control number [OPP-300536] (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 Highway, Arlington, VA.
    Electronic comments may be sent directly to EPA at:
    [email protected].


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

IX. Regulatory Assessment Requirements

    This final rule establishes a time-limited tolerance under FFDCA 
section 408(d). 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).
    In addition, since these tolerances and exemptions that are 
established on the basis of a petition under FFDCA section 408 (d), 
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

[[Page 46907]]

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 Parts 180 and 186

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

    Dated: August 25, 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 180.142 is amended as follows:
    i. By adding a heading to paragraph (a), by redesignating 
paragraphs (a)(1) and (a)(2) as paragraphs (a)(1)(i) and (a)(1)(ii), 
respectively, by designating the introductory text of paragraph (a) as 
paragraph (a)(1), and by adding new paragraph (a)(12).
    ii. By redesignating the introductory text of paragraph (b) as the 
introductory text of paragraph (a)(2), and paragraphs (b)(1), 
(b)(1)(i), (b)(1)(ii), and (b)(2) as paragraphs (a)(2)(i), 
(a)(2)(i)(A), (a)(2)(i)(B), and (a)(2)(ii), respectively.
    iii. By redesignating paragraphs (c) through (k) as paragraphs 
(a)(3) through (a)(11), respectively.
    iv. By adding a new paragraph (b).
    v. By adding and reserving paragraphs (c) and (d) with headings.


Sec. 180.142  2,4-D; tolerances for residues.

    (a) General. *    *    *
    (12) The following tolerances are established for residues of 2,4-D 
(2,4-dichloro-phenoxyacetic acid) in the following processed feeds. 
Such residues may be present therein only as a result of application to 
the growing crop of the herbicides identified in this section:
    (i) 5 parts per million in sugarcane bagasse and sugarcane 
molasses.
    (ii) 2 parts per million in the milled fractions derived from 
barley, oats, rye, and wheat to be ingested as animal feed or converted 
into animal feed.
    (b) Section 18 emergency exemptions. A time-limited tolerance is 
established for 2,4-dichlorophenoxyacetic acid (2,4-D) in or on wild 
rice in connection with use of the pesticide under a section 18 
emergency exemption granted by EPA. The tolerance will expire on the 
dates specified in the following table.

                                                                        
------------------------------------------------------------------------
                                                          Expiration/   
            Commodity              Parts per million    Revocation Date 
------------------------------------------------------------------------
Wild rice.......................  0.1 ppm             August 31, 1998   
------------------------------------------------------------------------

    (c)  Tolerances with regional registrations. [Reserved]
    (d) Indirect or inadvertent residues. [Reserved]
    2. In part 186:
    a. The authority citation for part 186 continues to read as 
follows:
    Authority: 21 U.S.C. 342, 348, and 701.


Sec. 186.1450  [Removed]

    b. Section 186.1450 is removed.

[FR Doc. 97-23684 Filed 9-4-97; 8:45 am]
BILLING CODE 6560-50-F