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2,4-D Time-Limited Pesticide Tolerance 3/99

  


[Federal Register: March 10, 1999 (Volume 64, Number 46)]
[Rules and Regulations]               
[Page 11792-11799]
>From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr10mr99-13]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[OPP-300800; FRL-6065-3]
RIN 2070-AB78

 
2,4-D; Time-Limited Pesticide Tolerance

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes a time-limited tolerance for 
residues of 2,4-dichlorophenoxyacetic acid in or on soybeans. Industry 
Task Force II on 2,4-D Research Data requested this tolerance under the 
Federal Food, Drug, and Cosmetic Act, as amended by the Food Quality 
Protection Act of 1996. The tolerance will expire on December 31, 2001.

DATES: This regulation is effective March 10, 1999. Objections and 
requests for hearings must be received by EPA on or before May 10, 
1999.

ADDRESSES: Written objections and hearing requests, identified by the 
docket control number [OPP-300800], 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-300800], 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. 119, Crystal Mall 2 (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@epa.gov. Copies of electronic 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 
or ASCII file format. All copies of electronic objections and hearing 
requests must be identified by the docket control number [OPP-300800]. 
No Confidential Business Information (CBI) should be submitted through 
e-mail. Copies of electronic objections and hearing requests on this 
rule may be filed online at many Federal Depository Libraries.

FOR FURTHER INFORMATION CONTACT: By mail: Joanne I. Miller, 
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: Rm. 235, CM #2, 
1921 Jefferson Davis Hwy., Arlington, VA, 703-305-6224, 
miller.joanne@epa.gov.

SUPPLEMENTARY INFORMATION: In the Federal Register of December 11, 1998 
(63 FR 68455) (FRL-6043-3), EPA issued a notice pursuant to section 408 
of the Federal Food, Drug, and Cosmetic Act (FFDCA), 21 U.S.C. 346a, as 
amended by the Food Quality Protection Act of 1996 (FQPA) (Pub. L. 104-
170) announcing the filing of a pesticide petition (PP) for tolerance 
by Industry Task Force II on 2,4-D Research Data, McKenna & Cuneo, 1900 
K St., NW, Washington, DC 20006-1108. This notice included a summary of 
the petition prepared by Industry Task Force II on 2,4-D Research Data, 
the registrant. There were no comments received in response to the 
notice of filing.
    The petition requested that 40 CFR 180.142 be amended by 
establishing a time-limited tolerance for residues of the herbicide 
2,4-dichlorophenoxyacetic acid, in or on soybeans at 0.02 part per 
million (ppm). This tolerance will expire on December 31, 2001.

I. Background and Statutory Findings

    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. . . .''
    EPA performs a number of analyses to determine the risks from 
aggregate exposure to pesticide residues. For further discussion of the 
regulatory requirements of section 408 and a complete description of 
the risk assessment process, see the final rule on Bifenthrin Pesticide 
Tolerances (62 FR 62961, November 26, 1997) (FRL-5754-7).

II. 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 soybeans at 0.02 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 
in this unit.
    An oral LD<INF>50</INF> of 2,4-D acid is 699 miligrams/kilograms 
(mg/kg) in the rat.

[[Page 11793]]

 The dermal LD<INF>50</INF> in the rabbit is >2000 mg/kg. The acute 
inhalation LC<INF>50</INF> in the rat is >1.8 mg/liter. A primary eye 
irritation study in the rabbit showed severe irritation. A dermal 
irritation study in the rabbit showed moderate irritation. A dermal 
sensitization study in the guinea pig showed no skin sensitization. An 
acute neurotoxicity study in the rat produced a no observed advers 
effect level (NOAEL) of 227 mg/kg for systemic toxicity and a 
neurobehavioral NOAEL of 67 mg/kg with a lowest observed effect level 
(LOEL) of 227 mg/kg.
     Mutagenicity studies including gene mutation, chromosomal 
aberrations, and direct DNA damage tests were negative for mutagenic 
effects.
     A 2-generation reproduction study was conducted in rats with 
NOAELs for parental and developmental toxicity of 5 mg/kg/day. The 
LOELs for this study are established at 20 mg/kg/day based on 
reductions in body weight gain in F<INF>0</INF> and F<INF>2b</INF> 
pups, and reduction in pup weight at birth and during lactation. A 
teratology study in rabbits given gavage doses at 0, 10, 30, and 90 mg/
kg on days 6 through 18 of gestation was negative for developmental 
toxicity at all doses tested. A teratology study in rats given gavage 
doses at 0, 8, 25, and 75 mg/kg on days 6 through 15 of gestation was 
negative for developmental toxicity at all doses tested. A NOAEL for 
fetotoxicity was established at 25 mg/kg/day based on delayed 
ossification at the 75 mg/kg dose level. The effects on pups occurred 
in the presence of parental toxicity.
     A subchronic dietary study was conducted with mice fed diets 
containing 0, 1, 15, 100, and 300 mg/kg/day with a NOAEL of 15 mg/kg/
day. The LOEL was established at 100 mg/kg/day based on decreased 
glucose and thyroxine levels, increases in absolute and relative kidney 
weights, and histopathological lesions in the liver and kidneys. A 90-
day dietary study in rats fed diets containing 0, 1, 15, 100, or 300 
mg/kg/day resulted in a NOAEL of 15 mg/kg/day and an LOEL of 100 mg/kg/
day. The LOEL was based on decreases in body weight and food 
consumption, alteration in clinical pathology, changes in organ 
weights, and histopathological lesions in the kidney, liver, and 
adrenal glands of both sexes of rats. A 90-day feeding study was 
conducted in dogs fed diets containing 0, 0.3, 1, 3, and 10 mg/kg/day 
with a NOAEL of 1 mg/kg/day. The LOEL was established at 3 mg/kg/day 
based on histopathological changes in the kidneys of male dogs.
     A 1-year dietary study was conducted in the dog using doses of 0, 
1, 5, and 7.5 mg/kg/day. The NOAEL was 1 mg/kg/day and the LOEL was 5 
mg/kg/day based on clinical chemistry changes and histopathological 
lesions in the liver and kidney. A 2-year feeding/carcinogenicity study 
was conducted in mice fed diets containing 0, 1, 15, and 45 mg/kg/day 
with a NOAEL of 1 mg/kg/day. The systemic LOEL was established at 15 
mg/kg/day based on increased kidney and adrenal weights and homogeneity 
of renal tubular epithelium due to cytoplasmic vacuoles. No 
carcinogenic effects were observed under the conditions of the study at 
any dosage level tested. A second 2-year oncogenicity study was 
conducted in mice fed diets containing 0, 5, 62.5, and 125 mg/kg/day 
(males) and 0, 5, 150, and 300 mg/kg/day (females). No treatment-
related oncogenicity was observed. A 2-year feeding/carcinogenicity 
study was conducted in rats fed diets containing 0, 1, 15, and 45 mg/
kg/day with a NOAEL of 1 mg kg/day. Although there appeared to be a 
slight treatment-related incidence of benign brain tumors 
(astrocytomas) in male rats fed diets containing 45 mg/kg/ day, two 
different statistical evaluations found no strong statistical evidence 
of carcinogenicity in male rats. There were no carcinogenic effects 
observed in female rats. A second 2-year feeding/carcinogenicity study 
was conducted in rats fed diets containing 0, 5, 75, and 150 mg/kg/day. 
The NOAEL was 5 mg/kg/day and the LOEL was 75 mg/kg/day based on 
decreased body weight, body weight gain and food consumption; clinical 
chemistry changes; organ weight changes and histopathological lesions. 
No treatment-related carcinogenic effects or increased incidences of 
astrocytomas were observed.
     The metabolism of phenyl ring labeled <SUP>14</SUP>C-2,4-D was 
studied in the rat following a single intravenous or oral dose of 
approximately 1 mg/kg/day. At 48 hours after treatment, recovery of 
radioactivity in urine was in excess of 98%. Parent 2,4-D was the major 
metabolite (72.9% to 90.5%) found in the urine.

B. Toxicological Endpoints

    1. Acute toxicity. EPA has used an acute neurotoxicity study in 
rats for endpoint for acute toxicity. The NOAEL of 67 mg/kg/day was 
based on the increased incidence of incoordination, slight gait 
abnormalities, and decreased motor activity in both sexes at the lowest 
observed adverse effect (LOAEL) of 227 mg/kg/day. This risk assessment 
will evaluate acute dietary risk to all population subgroups.
    2. Short - and intermediate-term toxicity. For short-term dermal 
Margin of Exposure (MOE) calculations, EPA used the maternal NOAEL of 
30 mg/kg/day from an oral developmental toxicity study in rabbits. The 
MOE is a measure of how close the high end of exposure comes to the 
NOAEL (or LOAEL, as the case may be) and is calculated as the ratio of 
the NOAEL to the exposure. The LOAEL of 90 mg/kg/day was based on 
abortions, clinical signs (ataxia, decreased motor activity, and cold 
extremities during gestation), and decreased body weight gain. For 
acute toxicity, EPA decided that FQPA factor of 10 should be reduced to 
3 for females 13 years old and older (13+) and removed for all other 
population subgroups. As the short-term and acute endpoints are based 
on the oral developmental toxicity study, this decision is also 
applicable to the short-term, nonoccupational assessment. Therefore, 
based on this recommendation, the MOE needed for females 13+ is 300.
    For intermediate-term dermal MOE calculations, EPA used the NOAEL 
of 1.0 mg/kg/day from a 90-day oral toxicity study in dogs. The LOAEL 
of 3 mg/kg/day was based on clinical chemistry changes (increased BUN 
and creatinine levels) and lesions in the kidneys. An MOE of 100 is 
required.
    3. Chronic toxicity. EPA has established the RfD for 2,4-D at 0.01 
mg/kg/day. This RfD is based on a 1-year oral toxicity study in dogs 
with a NOAEL of 1 mg/kg/day and an uncertainty factor (UF) of 100, 
based on alterations in serum chemistry with corroborative 
histopathological lesions in the liver and kidneys.
    4. Carcinogenicity. EPA 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''.

C. Exposures and Risks

    1. From food and feed uses. Tolerances have been established (40 
CFR 180.142) for the residues of 2,4-dichlorophenoxyacetic acid, in or 
on a variety of raw agricultural commodities. A time limited tolerance 
of 0.1 ppm was previously established for residues of 2,4-D on soybeans 
resulting from the preplant use of 2,4-D ester or amine 40 CFR 
180.142(a)(11). In order for EPA to recommend favorably for the 
establishment of permanent tolerances on soybeans, additional field 
trial data and processing data were required. In response, the Industry 
Task Force II on

[[Page 11794]]

2,4-D Research Data (Task Force II) submitted field residue data on 
soybeans. EPA reviewed these data and concluded that a tolerance of 
0.02 ppm was appropriate for soybean seed. Task Force II has thus 
proposed to extend the soybean tolerance to December 31, 2001 at a 
level of 0.02 ppm. Risk assessments were conducted by EPA to assessed 
dietary exposures 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 1-day or single exposure. The Dietary Exposure Evaluation Model 
(DEEM ) analysis evaluated the individual food consumption as reported 
by respondents in the USDA 1989-91 Nationwide Continuing Surveys for 
Food Intake by Individuals (CSFII) and accumulated exposure to the 
chemical for each commodity. Each analysis assumes uniform distribution 
of 2,4-D in the commodity supply.
    The acute exposure analysis for all subgroup was performed using 
anticipated and tolerance-level residues and 100 percent crop treated. 
The high end MOE for the subgroup of Females (13+) was 399, and is no 
cause for concern given the need of a MOE of 300. The high end MOEs for 
the remaining populations ranged from 214 (infants less than one year 
old) to 321 (overall U.S. population, 48 states), and demonstrate no 
cause for concern given the need of a MOE of 100. Therefore, EPA does 
not consider the acute food risk to exceed the level of concern.
    ii. Chronic exposure and risk. A chronic dietary risk assessment 
was performed for 2,4-D using the RfD for the chronic dietary analysis 
of 0.01 mg/kg bwt/day. Chronic dietary exposure estimates (DEEM ) used 
mean consumption (3 day average) and anticipated or tolerance-level 
residues for all commodities. Exposure estimates used 25.6% of the RfD 
for the general U.S. population (48 states) and 49.2% of the RfD for 
the most exposed population of non-nursing infants (less than one year 
old). Since estimated exposures did not exceed the RfD for any 
subgroup, EPA does not consider the chronic food risk to exceed the 
level of concern.
    2. From drinking water. A Maximum Contaminant Level (MCL) of 0.07 
mg/L and Health Advisories (HAs) as follows are established for 2,4-D 
in drinking water: 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.
    Information in the Pesticides in Groundwater Database (EPA 734-12-
92-001, 9/92) indicates that 6,142 wells in 32 States were sampled for 
residues of 2,4-D during the period 1979-91. Detectable residues were 
reported (0.0079-57.1 g/L) in 2.3% (139) of those sampled wells.
    An FQPA water assessment was conducted by the Environmental Fate 
and Effects Division (EFED) to support an FQPA tolerance reassessment 
for the use of 2,4-D dimethylamine salt (DMA), 2,4-D ethylhexyl ester 
(EHE), and 2,4-D (acid) as a soybean burndown product. Since laboratory 
environmental fate data indicate that 2,4-D DMA and 2,4-D EHE degrade 
rapidly to form 2,4-D, the water assessment is focused on the 
environmental fate and transport of the 2,4-D. The strategy assumes 
that the 2,4-D DMA and 2,4-EHE are not persistent in the environment, 
and the environmental fate of these compounds is dependent on the fate 
properties of the degradate 2,4-D.
    It is noteworthy that water treatment processes affect the removal 
of 2,4-D from raw water (Versar, 1992). These treatments include 
granulated activated carbon (70-100% removal), packed tower aeration 
(0-29% removal), and ozone oxidation (30-69% removal).
    A review of the labels indicate that the highest single application 
rate in terrestrial environments (e.g., terrestrial noncrop and 
terrestrial crop use patterns) for 2,4-D occur at 3.74 pounds of active 
ingredient per acre (lbs ai/A), for 2,4-D EHE occur at 10 lbs ai/A, and 
for 2,4-D DMA occur at 2 lbs ai/A. These rates represent seasonal 
maximum application rates as part of 2,4-D exposure reduction agreement 
to support 2,4-D use on pasture/rangeland, forestry, and residential 
and turf (excluding sod farm) sites. It is noteworthy that the 10 lbs 
ai/A rate corresponds to a basal bark spot treatment. Since this type 
of application cannot be simulated from Tier 1 models, EFED conducted 
modeling on the label rate from the 2,4-D label.
     For groundwater, SCIGROW modeling indicates that the 2,4-D 
concentration in ground water is not likely to exceed 0.014 <greek-m>g/
L for both peak (acute) and annual average (chronic) concentration. 
Since this estimation was less than the actual monitoring 
concentrations noted above, the actual monitoring concentrations were 
used in the risk assessment.
    For surface water estimates were made using the generic expected 
environmental concentration (GENEEC) model. GENEEC modeling indicates 
that 2,4-D concentrations in raw surface water are not likely to exceed 
132 <greek-m>g/L for annual peak (acute) and 48 <greek-m>g/L for 56 day 
average (chronic) concentrations. Since Office of Pesticide Program 
(OPP) policy recommends that the 90/56-day GENEEC value be divided by 3 
to obtain a value for chronic risk assessment calculations, the surface 
water value for use in the chronic risk assessment would be 16 ppb or 
<greek-m>g/L.
    A Drinking Water Level of Comparison (DWLOC) is a theoretical upper 
limit on a pesticide's concentration in drinking water in light of 
total aggregate exposure to a pesticide in food, drinking water, and 
through residential uses. A DWLOC will vary depending on the toxic 
endpoint, with drinking water consumption, and body weights. Different 
populations will have different DWLOCs. OPP uses DWLOCs internally in 
the risk assessment process as a surrogate measure of potential 
exposure associated with pesticide exposure through drinking water. In 
the absence of monitoring data for pesticides, it is used as a point of 
comparison against conservative model estimates of a pesticide's 
concentration in water. DWLOC values are not regulatory standards for 
drinking water. They do have an indirect regulatory impact through 
aggregate exposure and risk assessments. Because EPA considers the 
aggregate risk resulting from multiple exposure pathways associated 
with a pesticide's uses, levels of comparison in drinking water may 
vary as those uses change. If new uses are added in the future, EPA 
will reassess the potential impacts of 2,4-D on drinking water as a 
part of the aggregate risk assessment process.
    i. Acute exposure and risk. EPA has calculated drinking water 
levels of comparison (DWLOCs) for acute exposure to 2,4-D in drinking 
water for the females (13+ years old, nursing) to be 1700 ppb. To 
calculate the DWLOC for acute exposure relative to an acute toxicity 
endpoint, the acute dietary food exposure (from the DEEM analysis) was 
subtracted from the RfD to obtain the acceptable acute exposure to 2,4-
D in drinking water. DWLOCs were then calculated using default body 
weights and drinking water consumption figures. EPA has determined that 
the maximum estimated concentrations of 2,4-D in surface and/or ground 
water is not likely to exceed EPA's levels of consideration for 2,4-D 
in drinking water as a contribution to acute exposure. EPA concludes 
with reasonable certainty that residues of 2,4-D in drinking water 
(when considered along with other sources of exposure for which EPA has 
reliable data) would not result in unacceptable levels of aggregate 
human health risk at this time.

[[Page 11795]]

    ii.  Chronic exposure and risk. For chronic (non-cancer), the 
drinking water levels of concern are 260 and 51 ppb for the U.S. 
population and non-nursing infants (less than 1 year old), 
respectively. To calculate the DWLOC for chronic (non-cancer, cancer) 
exposure relative to a chronic toxicity endpoint, the chronic dietary 
food exposure (from DEEM) was subtracted from the RfD to obtain the 
acceptable chronic (non-cancer) exposure to 2,4-D in drinking water. 
DWLOCs were then calculated using default body weights and drinking 
water consumption figures. EPA has determined that the maximum 
estimated concentrations of 2,4-D in surface and/or ground water is not 
likely to exceed EPA's levels of consideration for 2,4-D in drinking 
water as a contribution to chronic aggregate exposure. EPA concludes 
with reasonable certainty that residues of 2,4-D in drinking water 
(when considered along with other sources of exposure for which EPA has 
reliable data) would not result in unacceptable levels of aggregate 
human health risk at this time.
    Section 408(b)(2)(E) authorizes EPA to use available data and 
information on the anticipated residue levels of pesticide residues in 
food and the actual levels of pesticide chemicals that have been 
measured in food. If EPA relies on such information, EPA must require 
that data be provided 5 years after the tolerance is established, 
modified, or left in effect, demonstrating that the levels in food are 
not above the levels anticipated. Following the initial data 
submission, EPA is authorized to require similar data on a time frame 
it deems appropriate. As required by section 408(b)(2)(E), EPA will 
issue a data call-in for information relating to anticipated residues 
to be submitted no later than 5 years from the date of issuance of this 
tolerance.
    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. There are chemical-specific and site-specific 
data available to determine the potential risks associated with 
residential exposures from the registered uses of 2,4-D. Dislodgeable 
residues of 2,4-D taken during exposure sessions showed a rapid decline 
from 1 hour following application (8%) to 24 hours following 
applications (1%). No detectable residues were found in urine samples 
supplied by volunteers exposed to sprayed turf 24 hours following 
application. Intermediate-term postapplication exposure is thus not 
expected. The following assessments are based on the available chemical 
specific data.
    i. Chronic exposure and risk. Although a chronic endpoint was 
chosen, this risk assessment is not required because there is no 
chronic exposure scenario for this use.
    ii. Short- and intermediate-term exposure and risk. For short-term 
dermal MOE calculations, EPA used the maternal NOAEL of 30 mg/kg/day 
from the oral developmental toxicity study in rabbits. The LOAEL of 90 
mg/kg/day was based on abortions, clinical signs (ataxia, decreased 
motor activity, and cold extremities during gestation), and decreased 
body weight gain. For acute toxicity, EPA reduce the FQPA factor of 10 
to 3 for females 13+ and removed for all other population subgroups. As 
the short-term and acute endpoints are based on the oral developmental 
toxicity study, this decision is also applicable to the short-term, 
nonoccupational assessment. Therefore, based on this recommendation, 
the MOE needed for females 13+ is 300.
    For intermediate-term dermal MOE calculations, EPA used the NOAEL 
of 1.0 mg/kg/day from the 90-day oral toxicity study in dogs. The LOAEL 
of 3 mg/kg/day was based on clinical chemistry changes (increased BUN 
and creatinine levels) and lesions in the kidneys. An MOE of 100 is 
required.
    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.''
    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. For 
information regarding EPA's efforts to determine which chemicals have a 
common mechanism of toxicity and to evaluate the cumulative effects of 
such chemicals, see the final rule for Bifenthrin Pesticide Tolerances 
(62 FR 62961, November 26, 1997).

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

    1. Acute risk. The acute dietary MOE was calculated to be 321 for 
the U.S. population and 399 for females 13+ years/nursing (accounts for 
both maternal and fetal exposure). These MOE calculations were based on 
the acute neurotoxicity NOAEL of 67 mg/kg/day. This risk assessment 
assumed 100% crop-treated with anticipated (blended commodities) or 
tolerance-level residues on all treated crops consumed, resulting in a 
significant over estimation of dietary exposure. The acute dietary MOE 
calculated for the U.S. population and for females 13+ years/nursing 
provides assurance that there is a reasonable certainty of no harm for 
acute exposure to 2,4-D.
    The maximum estimated concentrations of 2,4-D in surface and ground 
water are less than EPA's DWLOCs for 2,4-D as a contribution to acute 
aggregate exposure. Therefore, EPA concludes with reasonable certainty 
that residues of 2,4-D in drinking water do not contribute 
significantly to the aggregate acute human health risk at the present 
time considering the present uses and uses proposed in this action.
    EPA bases this determination on a comparison of estimated 
concentrations of 2,4-D in surface waters and ground waters to levels 
of comparison for 2,4-D in drinking water. The estimates of 2,4-D in 
surface and ground waters are derived from water quality models that 
use conservative assumptions regarding the pesticide transport from the 
point of application to surface and ground water. Because EPA considers 
the aggregate risk resulting from multiple exposure pathways associated 
with a pesticide's uses, DWLOCs may vary as those uses change. If new 
uses are added in the future, EPA will reassess the potential impacts 
of 2,4-D on drinking water as a part of the aggregate acute risk 
assessment process.
    2. Chronic risk. Using the ARC exposure assumptions described in 
this unit, EPA has concluded that aggregate exposure to 2,4-D from food 
will utilize 26% of the RfD for the U.S. population. The major 
identifiable subgroup with the highest aggregate exposure is discussed 
below. EPA generally has no concern for exposures below 100% of the RfD 
because the RfD represents the level at or below which daily aggregate 
dietary exposure over a lifetime will not pose appreciable risks to 
human health. Despite the potential for exposure to 2,4-D in drinking 
water and from non-dietary, non-occupational exposure, EPA does not 
expect the aggregate

[[Page 11796]]

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.
    3. 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.
    The short-term NOAEL for dermal exposure is based on the maternal 
NOAEL of 30 mg/kg/day from the oral developmental toxicity study in 
rabbits. After factoring in residential exposure, the high end total 
MOE for females 13+ was 750, and does not exceed EPA's level of 
concern.
    The intermediate-term NOAEL for dermal exposure is based on the 
NOAEL of 1.0 mg/kg/day from the 90-day oral toxicity study in dogs. As 
homeowner use of 2,4-D is not expected to result in intermediate-term 
dermal exposure, only dietary and water exposures need to be considered 
in this assessment.
    There is a potential for short- and intermediate-term exposure from 
drinking water. However, as estimated average concentrations of 2,4-D 
in surface and ground water are less than EPA's levels of concern for 
drinking water as a contribution to chronic aggregate and acute 
aggregate exposures, contribution to short- and intermediate-term 
exposure should not exceed EPA's levels of concern.
    4. Aggregate cancer risk for U.S. population. EPA 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.'' Based on these risk assessments, EPA concludes 
that there is a reasonable certainty that no harm will result from 
aggregate exposure to 2,4-D residues.
    5. Determination of safety. Based on these risk assessments, EPA 
concludes that there is a reasonable certainity that no harm will 
result from aggregate exposure to residues of 2,4-D.

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 2,4-D, EPA considered data from developmental 
toxicity studies in the rat and rabbit and a 2-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 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 margin of exposure (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 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 a developmental toxicity 
study in rats, the maternal (systemic) NOAEL was >75 mg/kg/day at the 
highest dose tested (HDT). The developmental (fetal) NOAEL was 25 mg/
kg/day, based on delayed ossification at the developmental LOAEL of 75 
mg/kg/day. In a developmental toxicity study in rabbits, the maternal 
(systemic) NOAEL was 30 mg/kg/day, based on ataxia, decreased motor 
activity, cold extremities, and decreased body weight gain at the LOAEL 
OF 90 mg/kg/day. The developmental (fetal) NOAEL was 90 mg/kg/day 
(HDT).
    iii. Reproductive toxicity study. In the 2-generation reproductive 
toxicity study in rats, the parental (systemic) NOAEL of 5 mg/kg/day 
was based on degenerative effects in the kidneys of males and decreased 
body weight gain in females at the LOAEL of 20 mg/kg/day. The 
reproductive (pup) NOAEL was 5 mg/kg/day, based on decreased pup weight 
at the LOAEL of 20 mg/kg/day. The reproductive effects occurred in the 
presence of parental toxicity.
    iv. Pre- and post-natal sensitivity. The toxicological data base 
for evaluating pre- and post-natal toxicity for 2,4-D is complete with 
respect to current data requirements. There are pre-natal toxicity 
concerns for infants and children, based on the results of the rat 
developmental toxicity study in which developmental toxicity occurred 
in the absence of maternal toxicity. Based on the developmental and 
reproductive toxicity studies discussed above, for 2,4-D there does 
appear to be an extra sensitivity for pre-natal effects.
    EPA decided that the FQPA factor of 10 should be reduced to 3 for 
females 13+ and removed for all other population subgroups. The 
recommendation was based on the presence of developmental effects in 
the absence of maternal effects for 2,4 D in the rat developmental 
study. There was no indication of increased susceptibility in a rabbit 
developmental study or a multigeneration reproduction study in rats. 
Currently, the acute dietary risk assessment is based on the NOAEL 
results of the acute neurotoxicity study and applies to all population 
subgroups with an MOE requirement of 100. However, due to the FQPA 
concerns discussed above, females 13+ will require an MOE of 300 (100 x 
3 for FQPA), in contrast to the other population subgroups which will 
continue to require the usual MOE of 100 (FQPA does not apply). In 
practical terms, the acute dietary risk assessment will be performed 
for all population subgroups using the NOAEL from the acute 
neurotoxicity study. However, only females 13+ will require an MOE of 
300 and all other population subgroups will require an MOE of 100.
    v. Conclusion. There is a complete toxicity database for 2,4-D and 
exposure data is complete or is estimated based on data that reasonably 
accounts for potential exposures.
    2. Acute risk. The acute dietary MOE was calculated to be 214 for 
infants (less than 1 year old), and 399 for females 13+ years (accounts 
for both maternal and fetal exposure). These MOE calculations were 
based on the acute neurotoxicity NOAEL of 67 mg/kg/day. This risk 
assessment assumed 100% crop-treated with anticipated or tolerance-
level residues on all treated crops consumed, resulting in a 
significant over estimation of dietary exposure. The large acute 
dietary MOE calculated for females 13+ years and infants (less than 1 
year old) provides assurance that there is a reasonable certainty of no 
harm for both females 13+ years and the pre-natal development of 
infants or infants and children and post-natal exposure to 2,4-D.
    The maximum estimated concentrations of 2,4-D in surface and ground 
water are less than EPA's DWLOCs for 2,4-D as a contribution to acute 
aggregate exposure. Therefore, EPA concludes with reasonable certainty 
that residues of 2,4-D in

[[Page 11797]]

drinking water do not contribute significantly to the aggregate acute 
human health risk at the present time considering the present uses and 
uses proposed in this action.
    EPA bases this determination on a comparison of estimated 
concentrations of 2,4-D in surface waters and ground waters to levels 
of comparison for 2,4-D in drinking water. The estimates of 2,4-D in 
surface and ground waters are derived from water quality models that 
use conservative assumptions regarding the pesticide transport from the 
point of application to surface and ground water. Because EPA considers 
the aggregate risk resulting from multiple exposure pathways associated 
with a pesticide's uses, DWLOCs may vary as those uses change. If new 
uses are added in the future, EPA will reassess the potential impacts 
of 2,4-D on drinking water as a part of the aggregate acute risk 
assessment process.
    3. Chronic risk. Using the conservative exposure assumptions 
described in this unit, EPA has concluded that aggregate exposure to 
2,4-D from food will utilize from 11.4% of the RfD for nursing infants 
less than one year old up to 49.2% of the RfD for non-nursing infants 
less than one year old. EPA generally has no concern for exposures 
below 100% of the RfD because the RfD represents the level at or below 
which daily aggregate dietary exposure over a lifetime will not pose 
appreciable risks to human health. 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 to infants and children from aggregate exposure to 
2,4-D residues.
    4. Short- or intermediate-term risk. The short-term NOAEL for 
dermal exposure is based on the maternal NOAEL of 30 mg/kg/day from the 
oral developmental toxicity study in rabbits. After factoring in for 
residential exposure, the calculated MOE or the short-term aggregate 
risk of the most highly exposed subgroup (non-nursing infants (<1 year 
old)) is 560, and does not exceed EPA's level of concern.
    The intermediate-term NOAEL for dermal exposure is based on the 
NOAEL of 1.0 mg/kg/day from the 90-day oral toxicity study in dogs. As 
homeowner use of 2,4-D is not expected to result in intermediate-term 
dermal exposure, only dietary and water exposures need be considered in 
this assessment.
    There is a potential for short- and intermediate-term exposure from 
drinking water. However, as estimated average concentrations of 2,4-D 
in surface and ground water are less than EPA's levels of concern for 
drinking water as a contribution to chronic aggregate and acute 
aggregate exposures, contribution to short- and intermediate-term 
exposure should not exceed EPA's levels of concern either.
    5. Determination of safety. Based on these risk assessments, 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.

III. Other Considerations

A. Metabolism In Plants and Animals

    The nature of the residue in plants is adequately understood. The 
residue of concern is 2,4-D per se. The nature of the residue in 
animals is adequately understood based upon acceptable ruminant and 
poultry metabolism studies. The residues of concern in animals is 2,4-
D, per se.

B. Analytical Enforcement Methodology

    Adequate enforcement methodology is available (gas chromatography 
(GC) with electron capture detection (ECD), EN-CAS Method ENC-2/93. 
This GC/ECD method has undergone successful independent laboratory 
validation and is available to enforce the time-limited tolerance on 
soybean seed.

C. Magnitude of Residues

    Residues of 2,4-D are not expected to exceed 0.02 ppm in/on soybean 
seed as a result of this use. Secondary residues are expected in animal 
commodities as associated with this use. Meat/milk/poultry/egg 
tolerances have been established as a result of other 2,4-D uses.

D. International Residue Limits

    There are no Codex, Canadian or Mexican residue limits established 
for 2,4-D on soybeans.

E. Rotational Crop Restrictions

    The confined rotational crop data indicate that no plant-back 
intervals following 2,4-D application are needed.

IV. Conclusion

    Therefore, the tolerance is established for residues of 2,4-
dichlorophenoxyacetic acid in soybeans at 0.02 ppm.

V. Objections and Hearing Requests

    The new FFDCA section 408(g) provides essentially the same process 
for persons to ``object'' to a tolerance regulation 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 May 10, 1999, 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 under ``ADDRESSES'' section (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). EPA is authorized to waive any fee requirement 
``when in the judgement of the Administrator such a waiver or refund is 
equitable and not contrary to the purpose of this subsection.'' For 
additional information regarding tolerance objection fee waivers, 
contact James Tompkins, 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: Rm. 239, CM #2, 1921 Jefferson Davis Hwy., Arlington, VA, 
(703) 305-5697, tompkins.jim@epa.gov. Requests for waiver of tolerance 
objection fees should be sent to James Hollins, Information Resources 
and Services Division (7502C), Office of Pesticide Programs, 
Environmental Protection Agency, 401 M St., SW., Washington, DC 20460.
     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

[[Page 11798]]

the action requested (40 CFR 178.32). Information submitted in 
connection with an objection or hearing request may be claimed 
confidential by marking any part or all of that information as CBI. 
Information so marked will not be disclosed except in accordance with 
procedures set forth in 40 CFR part 2. A copy of the information that 
does not contain CBI must be submitted for inclusion in the public 
record. Information not marked confidential may be disclosed publicly 
by EPA without prior notice.

VI. Public Record and Electronic Submissions

    EPA has established a record for this regulation under docket 
control number [OPP-300800] (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 Rm. 119 of the Public Information and Records 
Integrity Branch, Information Resources and Services Division (7502C), 
Office of Pesticide Programs, Environmental Protection Agency, CM #2, 
1921 Jefferson Davis Hwy., Arlington, VA.
    Objections and hearing requests may be sent by e-mail directly to 
EPA at:
    opp-docket@epa.gov.


    E-mailed objections and hearing requests must be submitted as an 
ASCII file avoiding the use of special characters and any form of 
encryption.
    The official record for this regulation, as well as the public 
version, as described in this unit 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 record which 
will also include all comments submitted directly in writing. The 
official record is the paper record maintained at the Virginia address 
in ``ADDRESSES'' at the beginning of this document.

VII. Regulatory Assessment Requirements

A. Certain Acts and Executive Orders

    This final rule establishes a tolerance under section 408(d) of the 
FFDCA in response to a petition submitted to the Agency. 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 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 tolerances and exemptions that are established 
on the basis of a petition under FFDCA section 408(d), such as the 
tolerance/exemption 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 
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.

B. Executive Order 12875

    Under Executive Order 12875, entitled Enhancing the 
Intergovernmental Partnership (58 FR 58093, October 28, 1993), EPA may 
not issue a regulation that is not required by statute and that creates 
a mandate upon a State, local or tribal government, unless the Federal 
government provides the funds necessary to pay the direct compliance 
costs incurred by those governments. If the mandate is unfunded, EPA 
must provide to OMB a description of the extent of EPA's prior 
consultation with representatives of affected State, local, and tribal 
governments, the nature of their concerns, copies of any written 
communications from the governments, and a statement supporting the 
need to issue the regulation. In addition, Executive Order 12875 
requires EPA to develop an effective process permitting elected 
officials and other representatives of State, local, and tribal 
governments ``to provide meaningful and timely input in the development 
of regulatory proposals containing significant unfunded mandates.''
    Today's rule does not create an unfunded Federal mandate on State, 
local, or tribal governments. The rule does not impose any enforceable 
duties on these entities. Accordingly, the requirements of section 1(a) 
of Executive Order 12875 do not apply to this rule.

C. Executive Order 13084

    Under Executive Order 13084, entitled Consultation and Coordination 
with Indian Tribal Governments (63 FR 27655, May 19, 1998), EPA may not 
issue a regulation that is not required by statute, that significantly 
or uniquely affects the communities of Indian tribal governments, and 
that imposes substantial direct compliance costs on those communities, 
unless the Federal government provides the funds necessary to pay the 
direct compliance costs incurred by the tribal governments. If the 
mandate is unfunded, EPA must provide OMB, in a separately identified 
section of the preamble to the rule, a description of the extent of 
EPA's prior consultation with representatives of affected tribal 
governments, a summary of the nature of their concerns, and a statement 
supporting the need to issue the regulation. In addition, Executive 
Order 13084 requires EPA to develop an effective process permitting 
elected officials and other representatives of Indian tribal 
governments ``to provide meaningful and timely input in the development 
of regulatory policies on matters that significantly or uniquely affect 
their communities.''
    Today's rule does not significantly or uniquely affect the 
communities of Indian tribal governments. This action does not involve 
or impose any requirements that affect Indian tribes. Accordingly, the 
requirements of section 3(b) of Executive Order 13084 do not apply to 
this rule.

VIII. Submission to Congress and the Comptroller General

    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the Agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and the Comptroller General of the United 
States. EPA will submit a report containing this rule and other 
required information to the U.S. Senate, the U.S. House of 
Representatives and

[[Page 11799]]

the Comptroller General of the United States prior to publication of 
the rule in the Federal Register. This rule is not a ``major rule'' as 
defined by 5 U.S.C. 804(2).

List of Subjects in 40 CFR Part 180

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

    Dated: March 1, 1999.

Peter Caulkins,
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. In Sec. 180.142, by revising paragraph (a)(11) to read as 
follows:


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

    (a) General .   *    *    *    
    (11) A tolerance that expires on December 31, 2001 is established 
for residues of the herbicide 2,4-D (2,4-dichlorophenoxyacetic acid) 
resulting from the preplant use of 2,4-D ester or amine in or on the 
food commodity as follows:


------------------------------------------------------------------------
                 Commodity                        Parts per million
------------------------------------------------------------------------
soybean, seed.............................  0.02
------------------------------------------------------------------------

    *    *      *    *    *

[FR Doc. 99-5961 Filed 3-9-99; 8:45 am]
BILLING CODE 6560-50-F