[Federal Register Volume 64, Number 159 (Wednesday, August 18, 1999)]
[Rules and Regulations]
[Pages 44829-44836]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-20869]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[OPP-300900; FRL-6092-8]
RIN 2070-AB78


Glufosinate Ammonium; Pesticide Tolerances for Emergency 
Exemptions

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes time-limited tolerances for 
combined residues of glufosinate ammonium (butanoic acid, 2-amino-4-
(hydroxymethylphosphinyl)-monoammonium salt and its metabolite, 3-
methylphosphinico-propionic acid in or on sweet corn (kernels and cob 
with husk removed), sweet corn forage, sweet corn stover, canola meal 
and canola seed. This action is in response to EPA's granting of 
emergency exemptions under section 18 of the Federal Insecticide, 
Fungicide, and Rodenticide Act authorizing use of the pesticide on 
sweet corn and canola. This regulation establishes a maximum 
permissible level for residues of glufosinate ammonium in these food 
commodities pursuant to section 408(l)(6) of the Federal Food, Drug, 
and Cosmetic Act, as amended by the Food Quality Protection Act of 
1996. These tolerances will expire and are revoked on December 1, 1999.

DATES: This regulation is effective August 18, 1999. Objections and 
requests for hearings must be received by EPA on or before October 18, 
1999.

ADDRESSES: Written objections and hearing requests, identified by the 
docket control number [OPP-300900], 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-300900], 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, 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 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-300900]. 
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: Barbara Madden, 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. 284, CM #2, 1921 
Jefferson Davis Hwy., Arlington, VA, (703) 305-6463; e-mail: 
[email protected].

SUPPLEMENTARY INFORMATION: EPA, on its own initiative, pursuant to 
section 408(l)(6) of the Federal Food, Drug, and Cosmetic Act (FFDCA), 
21 U.S.C. 346a, is establishing tolerances for combined residues of the 
herbicide glufosinate ammonium (butanoic acid, 2-amino-4-
(hydroxymethylphosphinyl)-monoammonium salt and its metabolite, 3-
methylphosphinico-propionic acid, in or on sweet corn (kernels and cob 
with husk removed) at 4.0 part per million (ppm), sweet corn forage at 
4.0 ppm, sweet corn stover at 6.0 ppm, canola meal at 1.1 ppm and 
canola seed at 0.4 ppm. These tolerances will expire and are revoked on 
December 1, 1999. EPA will publish a document in the Federal Register 
to remove the revoked tolerance from the Code of Federal Regulations.

I. Background and Statutory Findings

    The Food Quality Protection Act of 1996 (FQPA) (Public Law 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 in this preeamble 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

[[Page 44830]]

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 tolerances to set binding precedents for the 
application of section 408 and the new safety standard to other 
tolerances and exemptions.

II. Emergency Exemption for Glufosinate Ammonium on Sweet Corn and 
Canola and FFDCA Tolerances

    The Wisconsin Department of Agriculture, Trade, and Consumer 
Protection requested an emergency exemption for use of glufosinate 
ammonium on sweet corn to control weeds. The applicant states that only 
a limited number of broadleaf herbicides are registered for use in 
sweet corn. Traditionally, triazine herbicides have been widely used. 
However, Wisconsin's ground water law restricts the use of atrazine, 
and in sensitive areas, cyanazine and simazine may also contribute to 
problems and are best not used. Approximately 36,900 acres of 
Wisconsin's sweet corn production is located in ground water-sensitive 
areas. Additionally, approximately 24,700 acres of Wisconsin's cropland 
used to grow sweet corn are infested with triazine-resistant weeds. 
2,4-D, registered for use on sweet corn to control weeds, often injures 
sweet corn hybrids resulting in reduction of crop yields. Bentazon is 
also registered but fails to control the two most serious annual 
broadleaf weeds (common lambsquarters and pigweed species). Other 
alternatives such as ametryne, linuron or paraquat require specialized 
application equipment not available to most Wisconsin sweet corn 
growers. In addition, sweet corn is frequently infested by two 
difficult-to-control annual grasses, wild-proso millet and woolly 
cupgrass. Registered soil applied grass herbicides are largely 
ineffective against these species.
    Weather in North Dakota and Minnesota was responsible for serious 
losses in wheat due to disease and to serious losses due to water 
damage and to inability to harvest wet fields. Even good revenue years 
for wheat have netted less than those for canola. This use of Liberty 
on canola is needed to maintain grower solvency. The ``above-average'' 
returns from alternative crops such as canola are urgently needed to 
maintain economic viability for producers in North Dakota and 
Minnesota.
    EPA has authorized under FIFRA section 18 the use of glufosinate 
ammonium on sweet corn in Wisconsin and on canola in North Dakota and 
Minnesota for control of weeds. After having reviewed these 
submissions, EPA concurs that emergency conditions exist for these 
States.
    As part of its assessment of this emergency exemption, EPA assessed 
the potential risks presented by residues of glufosinate ammonium in or 
on sweet corn and canola. In doing so, EPA considered the 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 
safety standard and with FIFRA section 18. Consistent with the need to 
move quickly on the emergency exemption in order to address an urgent 
non-routine situation and to ensure that the resulting food is safe and 
lawful, EPA is issuing these tolerances without notice and opportunity 
for public comment under section 408(e), as provided in section 
408(l)(6). Although these tolerances will expire and are revoked on 
December 1, 1999, under FFDCA section 408(l)(5), residues of the 
pesticide not in excess of the amounts specified in the tolerance 
remaining in or on sweet corn and canola after that date will not be 
unlawful, provided the pesticide is applied in a manner that was lawful 
under FIFRA, and the residues do not exceed a level that was authorized 
by these tolerances at the time of that application. EPA will take 
action to revoke these tolerances earlier if any experience with, 
scientific data on, or other relevant information on this pesticide 
indicate that the residues are not safe.
    Because these tolerances are being approved under emergency 
conditions EPA has not made any decisions about whether glufosinate 
ammonium meets EPA's registration requirements for use on sweet corn 
and canola or whether permanent tolerances for these uses would be 
appropriate. Under these circumstances, EPA does not believe that these 
tolerances serve as a basis for registration of glufosinate ammonium by 
a State for special local needs under FIFRA section 24(c). Nor does 
these tolerances serve as the basis for any State other than Wisconsin, 
North Dakota, and Minnesota to use this pesticide on these crops under 
section 18 of FIFRA without following all provisions of EPA's 
regulations implementing section 18 as identified in 40 CFR part 166. 
For additional information regarding the emergency exemption for 
glufosinate ammonium, contact the Agency's Registration Division at the 
address provided under the ``ADDRESSES'' section.

III. Aggregate Risk Assessment and Determination of Safety

    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).
    Consistent with section 408(b)(2)(D), EPA has reviewed the 
available scientific data and other relevant information in support of 
these actions. EPA has sufficient data to assess the hazards of 
glufosinate ammonium and to make a determination on aggregate exposure, 
consistent with section 408(b)(2), for time-limited tolerances for 
combined residues of glufosinate ammonium (butanoic acid, 2-amino-4-
(hydroxymethylphosphinyl)-monoammonium salt and its metabolite, 3-
methylphosphinico-propionic acid on sweet corn (kernels and cob with 
husk removed ) at 4.0 ppm, sweet corn forage at 4.0 ppm, sweet corn 
stover at 6.0 ppm, canola meal at 1.1 ppm and canola seed at 0.4 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 glufosinate 
ammonium are discussed in this unit.

B. Toxicological Endpoint

    1. Acute toxicity. An acute reference dose (aRfD) of 0.50 
milligrams/kilograms/day (mg/kg/day) has been identified for females 
13+ years old. The aRfD is derived from a no observable adverse effect 
level (NOAEL) of 50 mg/

[[Page 44831]]

kg/day, based on developmental toxicity characterized as dilated renal 
pelvis and/or hydroureter, from a rat developmental toxicity study, and 
an uncertainty factor (UF) of 100 (10x for interspecies extrapolation 
and 10x for intraspecies variability). The 10x FQPA Safety factor to 
account for enhanced sensitivity of infants and children (as required 
by FFDCA section 408 (b)(2)(C)) was reduced to 3x for acute exposures. 
The acute Population Adjusted Dose (aPAD) is a modification of the aRfD 
to accommodate the FQPA Safety Factor. The aPAD is equal to the aRfD 
divided by the FQPA Safety Factor. Therefore, the dietary aPAD is 0.167 
mg/kg/day. The dietary aPAD applies only to the female 13+ years old 
subgroups since the endpoint of concern is based on developmental 
toxicity. No acute dietary endpoint was identified for the general 
population including infants and children.
    2. Short- and intermediate-term toxicity. For short- and 
intermediate-term exposure scenarios for dermal exposure, the dermal 
NOAEL of 100 mg/kg/day from the 21-day dermal toxicity study in rats, 
based on neurological clinical signs (hyperactivity, aggressive 
behavior, piloerection) at the lowest observed adverse effect level 
(LOAEL) of 300 mg/kg/day, has been identified as the endpoint for risk 
assessment. A margin of exposure (MOE) of 100 is required (10x for 
interspecies extrapolation and 10x for intraspecies variability). 
Short-term inhalation exposure should be converted to an oral 
equivalent dose (using 100% inhalation absorption) and compared to the 
NOAEL of 50 mg/kg/day from the oral rat developmental toxicity study. 
Intermediate-term inhalation exposure should be converted to an oral 
equivalent dose (using 100% inhalation absorption) and compared to the 
NOAEL of 2.1 mg/kg/day from the 2-year chronic feeding study in rats. 
MOEs of 100 are required to account for interspecies extrapolation 
(10x) and intraspecies variability (10x).
    3. Chronic toxicity. EPA has established the chronic RfD (cRfD) for 
glufosinate ammonium at 0.021 mg/kg/day. This RfD is derived from a 
NOAEL of 2.1 mg/kg/day, based on increases in absolute and relative 
kidney weights in males at the LOAEL of 7.6 mg/kg/day in a 2-year 
chronic feeding study in rats and an UF of 100 (10x for interspecies 
extrapolation and 10x for intraspecies variability). The 10x FQPA 
Safety factor to account for enhanced sensitivity of infants and 
children (as required by FFDCA section 408(b)(2)(C)) was reduced to 3x 
for chronic exposures. The chronic Population Adjusted Dose (cPAD) is a 
modification of the cRfD to accommodate the FQPA Safety Factor. The 
cPAD is equal to the cRfD divided by the FQPA Safety Factor. Therefore, 
the dietary cPAD is 0.007 mg/kg/day.
    4. Carcinogenicity. There is no cancer concern based on negative 
results observed in three guideline studies available for the 
carcinogenicity screen (the chronic feeding study in rats, 
carcinogenicity study in rats and the carcinogenicity study in mice).

C. Exposures and Risks

    1. From food and feed uses. Tolerances have been established (40 
CFR 180.473) for the combined residues of glufosinate ammonium 
(butanoic acid, 2-amino-4-(hydroxymethylphosphinyl)-monoammonium salt 
and its metabolite, 3-methylphosphinico-propionic acid, in or on a 
variety of raw agricultural commodities. Time-limited tolerances have 
also been established as a result of secondary residues in/on eggs and 
meat, fat, and meat byproducts of cattle, goats, hogs, horses, poultry, 
and sheep. Risk assessments were conducted by EPA to assess dietary 
exposures and risks from glufosinate ammonium 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 of 
Food Intake by Individuals (CSFII) and accumulated exposure to the 
chemical for each commodity. At the 95th percentile exposure level, 
assuming 100% crop treated and tolerance level residues for all 
commodities, 6% of the aPAD was utilized for females (13+ nursing), the 
subgroup with the highest exposure. The results of the acute analyses 
indicate that the acute dietary risk associated with the existing and 
proposed uses of glufosinate ammonium is below the Agency's current 
level of concern.
    ii. Chronic exposure and risk. The chronic DEEM analysis assumed 
tolerance level residues for all commodities except for milk. 
Anticipated residues were used for milk. Maximum percent crop treatment 
data were incorporated into the chronic dietary estimate. Percent crop 
treated (PCT) data for sweet corn was incorporated by determining the 
amount of sweet corn produced in Wisconsin versus that produced in the 
United States. Assuming tolerance level residues for all commodities 
except milk where anticipated residues were used and PCT values, 4% of 
the cPAD was utilized for the U.S. Population and 9% of the cPAD was 
utilized for non-nursing infants, the subgroup with the highest 
exposure. The results of this analysis indicate that the acute dietary 
risk associated with existing uses and the proposed use of glufosinate 
ammonium is below the Agency's level of concern.
    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.
    Section 408(b)(2)(F) states that the Agency may use data on the 
actual PCT for assessing chronic dietary risk only if the Agency can 
make the following findings: That the data used are reliable and 
provide a valid basis to show what percentage of the food derived from 
such crop is likely to contain such pesticide residue; that the 
exposure estimate does not underestimate exposure for any significant 
subpopulation group; and if data are available on pesticide use and 
food consumption in a particular area, the exposure estimate does not 
understate exposure for the population in such area. In addition, the 
Agency must provide for periodic evaluation of any estimates used. To 
provide for the periodic evaluation of the estimate of PCT as required 
by the section 408(b)(2)(F), EPA may require registrants to submit data 
on PCT.
    The Agency used PCT information as follows:
    A routine chronic dietary exposure analysis for glufosinate 
ammonium was based 1% of apples, 4% of field corn, and less than 1% of 
soybeans were treated. PCT data for sweet corn was incorporated by 
determining the amount of sweet corn produced in Wisconsin versus that 
produced in the United States. Based on this information the time-
limited tolerance for sweet corn only supports a section 18 for use in 
Wisconsin.

[[Page 44832]]

    The Agency believes that the three conditions, discussed in section 
408 (b)(2)(F) unit concerning the Agency's responsibilities in 
assessing chronic dietary risk findings, have been met. EPA finds that 
the PCT information is reliable and has a valid basis. Before the 
petitioner can increase production of product for treatment of greater 
than 30,000 acres of sweet corn, permission from the Agency must be 
obtained. The regional consumption information and consumption 
information for significant subpopulations is taken into account 
through EPA's computer-based model for evaluating the exposure of 
significant subpopulations including several regional groups. Use of 
this consumption information in EPA's risk assessment process ensures 
that EPA's exposure estimate does not understate exposure for any 
significant subpopulation group and allows the Agency to be reasonably 
certain that no regional population is exposed to residue levels higher 
than those estimated by the Agency. Other than the data available 
through national food consumption surveys, EPA does not have available 
information on the consumption of food bearing glufosinate ammonium in 
a particular area.
    2. From drinking water. The Agency lacks sufficient water-related 
exposure data to complete a comprehensive drinking water exposure 
analysis and risk assessment for glufosinate ammonium. Because the 
Agency does not have comprehensive and reliable monitoring data, 
drinking water concentration estimates must be made by reliance on some 
sort of simulation or modeling. To date, there are no validated 
modeling approaches for reliably predicting pesticide levels in 
drinking water. The Agency is currently relying on GENEEC and PRZM/
EXAMS for surface water, which are used to produce estimates of 
pesticide concentrations in a farm pond and SCI-GROW, which predicts 
pesticide concentrations in ground water. None of these models include 
consideration of the impact processing of raw water for distribution as 
drinking water would likely have on the removal of pesticides from the 
source water. The primary use of these models by the Agency at this 
stage is to provide a coarse screen for sorting out pesticides for 
which it is highly unlikely that drinking water concentrations would 
ever exceed human health levels of concern. Based on the GENEEC and 
SCI-GROW models, the acute drinking water concentration values are 
estimated to be 237 parts per billion (ppb) for surface water and 1.16 
ppb for ground water. The chronic drinking water concentration values 
are estimated to be 59.43 ppb for surface water and 1.16 pbb for ground 
water.
    In the absence of monitoring data for pesticides, drinking water 
levels of comparison (DWLOCs) are calculated and used as a point of 
comparison against the model estimates of a pesticide's concentration 
in water. DWLOCs are theoretical upper limits on a pesticide's 
concentration in drinking water in light of total aggregate exposure to 
a pesticide in food, drinking water, and residential uses. A DWLOC will 
vary depending on the toxic endpoint, with drinking water consumption 
and body weights. Different populations will have different DWLOCs. 
DWLOCs are used in the risk assessment process as a surrogate measure 
of potential exposure associated with pesticide exposure through 
drinking water. DWLOC values are not regulatory standards for drinking 
water. Since DWLOCs address total aggregate exposure to glufosinate 
ammonium, they are further discussed in the aggregate risk sections 
below.
    3. From non-dietary exposure. Glufosinate ammonium is currently 
registered for use on the following residential non-food sites: spot 
spraying around trees, shrubs, fences, walks, patios, driveways, 
sidewalks, in flower beds, around houses, buildings, wooded lots, 
storage and recreational areas, and for spot-kill weeds in lawns. The 
risk estimates indicate that the potential risks from the registered 
residential uses of glufosinate ammonium do not exceed the Agency's 
level of concern. These risk estimates are based on the Agency's Draft 
HED Standard Operating Procedures (SOPs) for Residential Exposure 
Assessments, December 18, 1998.
    i. Acute exposure and risk. Acute dietary exposure and risks are 
not expected from use of glufosinate ammonium as a result of non-
dietary, non-occupational exposure.
    ii. Chronic exposure and risk. Chronic-term residential exposures 
are not expected from the proposed section 18 use of glufosinate 
ammonium, therefore a risk assessment was not conducted.
    iii. Short- and intermediate-term exposure and risk. There are 
potential short-term exposures from the registered residential uses of 
glufosinate ammonium. Therefore, a risk assessment was conducted to 
estimate the potential risks from garden uses. The estimated MOEs from 
residential uses ranged from 190 (dermal exposures to homeowner/
handler) to 330,000 (inhalation exposures).
    4. Cumulative exposure to substances with a 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 glufosinate ammonium 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, 
glufosinate ammonium 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 glufosinate ammonium has a 
common mechanism of toxicity with other substances. For more 
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. An acute dietary endpoint was identified only for 
the females 13+ years old subpopulations. Using the exposure 
assumptions of 100% crop treated and tolerance level residues for all 
commodities, at the 95th percentile, 6% of the aPAD was utilized for 
females (13+, nursing) the subgroup with the highest exposure. EPA 
generally has no concern for exposures below 100% of the aPAD. Despite 
the potential for exposure to glufosinate ammonium in drinking water, 
after calculating a DWLOC (4730 ppb) for the females (13+ nursing) and 
comparing it to conservative model estimates of acute concentrations of 
glufosinate ammonium in surface and ground water (237 ppb and 1.16 pbb, 
respectively), EPA does not expect the aggregate exposure to exceed 
100% of the aPAD.
    2. Chronic risk. Using the exposure assumptions of tolerance level 
residues for all commodities except milk where anticipated residues 
were used and PCT values, 4% of the cPAD was utilized for the U.S. 
population. The major identifiable subgroup with the highest aggregate 
exposure is non-nursing infants. EPA generally has no concern for 
exposures below 100% of the cPAD because the cPAD represents the level 
at

[[Page 44833]]

or below which daily aggregate dietary exposure over a lifetime will 
not pose appreciable risks to human health. Despite the potential for 
chronic exposure to glufosinate ammonium in drinking water, after 
calculating a DWLOC (236 ppb) for the U.S. population and comparing it 
to conservative model estimates of concentrations of glufosinate 
ammonium surface and ground water (59.43 ppb and 1.16 pbb, 
respectively), EPA does not expect the aggregate exposure to exceed 
100% of the cPAD.
    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. There are registered residential uses for 
glufosinate ammonium. The estimated MOEs from residential uses ranged 
from 190 (dermal exposures to homeowner/handler) to 330,000 (inhalation 
exposures). These estimates indicate that the potential inhalation 
exposures will not be a significant contribution to the aggregate risk. 
The potential dermal exposures were not aggregated because the toxic 
effects for short- and intermediate-term exposure (neurological 
clinical signs) and chronic exposure (increases in absolute and 
relative kidney weights) are different. Therefore, based on the best 
available data and current policies, potential risks do not exceed the 
Agency's level of concern.
    4. Aggregate cancer risk for U.S. population. There is no cancer 
concern based on negative results observed in three guideline studies 
available for the carcinogenicity screen: the chronic feeding study in 
rats, carcinogenicity study in rats and the carcinogenicity study in 
mice.
    5. Determination of safety. Based on these risk assessments, EPA 
concludes that there is a reasonable certainty that no harm will result 
from aggregate exposure to glufosinate ammonium residues.

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 glufosinate ammonium, 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 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 prenatal-and postnatal toxicity and 
the completeness of the data base unless EPA determines that a 
different margin of safety will be safe for infants and children. 
Margins of safety are incorporated into EPA risk assessments either 
directly through use of a MOE analysis or through using uncertainty 
(safety) factors in calculating a dose level that poses no appreciable 
risk to humans. EPA believes that reliable data support using the 
standard MOE and uncertainty factor (usually 100 for combined 
interspecies and intraspecies variability) and not the additional 
tenfold MOE/uncertainty factor when EPA has a complete data base under 
existing guidelines and when the severity of the effect in infants or 
children or the potency or unusual toxic properties of a compound do 
not raise concerns regarding the adequacy of the standard MOE/safety 
factor.
    ii. Developmental toxicity studies. In the developmental study in 
rats, the maternal (systemic) NOAEL was 10 mg/kg/day, based on vaginal 
bleeding and hyperactivity at the LOAEL of 50 mg/kg/day. The 
developmental (fetal) NOAEL was 50 mg/kg/day, based on dilated renal 
pelvis and/or hydroureter at the LOAEL of 250 mg/kg/day.
    In the developmental toxicity study in rabbits, the maternal 
(systemic) NOAEL was 2 mg/kg/day, based on decreases in body weight, 
body weight gain and food consumption and increased kidney weight at 
the LOAEL of 6 mg/kg/day. The developmental (pup) NOAEL was 2 mg/kg/day 
based on absent/incomplete ossification, with fetal death at 20 mg/kg/
day.
    iii. Reproductive toxicity study. In the 2-generation reproductive 
toxicity study in rats, the parental (systemic) NOAEL was 2 mg/kg/day 
based on increased kidney weights in males and females ate 6 mg/kg/day. 
The reproductive/developmental NOAEL was 6 mg/kg/day based on decreased 
pup viability in all generations at 18 mg/kg/day.
    iv. Prenatal and postnatal sensitivity. The toxicological data base 
for evaluating prenatal and postnatal toxicity for glufosinate ammonium 
is complete with respect to current data requirements. There are no 
prenatal or postnatal susceptibility concerns for infants and children, 
based on the results of the rat and rabbit developmental toxicity 
studies and the 2-generation reproduction study.
    v. Conclusion. There is a complete toxicity data base for 
glufosinate ammonium and exposure data are complete or are estimated 
based on data that reasonably accounts for potential exposures. 
Although the data indicate that there is no additional sensitivity to 
young rats or rabbits following prenatal and/or postnatal exposure to 
glufosinate ammonium in the developmental and reproductive toxicity 
studies; the Agency has determined that the FQPA Safety Factor should 
not be removed but instead reduced to 3x due to the presence of 
neurotoxicity in several studies in the toxicology data base, and the 
absence of acute neurotoxicity data, subchronic neurotoxicity data, and 
developmental neurotoxicity data.
    2. Acute risk. An acute dietary RfD was not identified for any 
subpopulation other than female 13+ years old.
    3. Chronic risk. Using the exposure assumptions described in this 
unit, EPA has concluded that aggregate exposure to glufosinate ammonium 
from food will utilize 9% of the cPAD for non-nursing infants, the 
major identifiable subgroup with the highest aggregate exposure. EPA 
generally has no concern for exposures below 100% of the cPAD because 
the cPAD 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 chronic exposure to glufosinate 
ammonium in drinking water, after calculating a DWLOC (64 ppb) for non-
nursing infants and comparing it to conservative model estimates of 
concentrations of glufosinate ammonium in surface and ground water 
(59.43 ppb and 1.16 pbb, respectively), EPA does not expect the 
aggregate exposure to exceed 100% of the cPAD.
    4. Short- or 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 uses. There are registered residential uses for glufosinate 
ammonium, however, based on the use patterns (spot treatments), 
potential post application exposures to infants and children from these 
uses will not contribute significantly to the overall risks. The 
estimated MOE from post application exposures was 330 (based on 
conservative estimates). Therefore, the Agency concludes that there is 
a reasonable certainty that no harm will result to infants and children 
from short- and intermediate-term

[[Page 44834]]

aggregate exposures to residues of glufosinate ammonium.
    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 glufosinate ammonium 
residues.

IV. Other Considerations

A. Metabolism in Plants and Animals

    1. Plants. The nature of the residues of glufosinate ammonium is 
considered to be understood. The Agency has concluded that the residues 
of concern are glufosinate ammonium and its metabolites 2-acetamido-4-
methylphosphinico-butanoic acid and 3-methylphosphinico-propionic acid 
expressed as glufosinate free acid equivalents.
    2. Animals. The nature of the residues of glufosinate ammonium in/
on animals is considered to be understood. The Agency has concluded 
that the residues of concern in ruminants and hens are glufosinate 
ammonium and its metabolite 3-methylphosphinico-propionic acid 
expressed as glufosinate free acid equivalents.

B. Analytical Enforcement Methodology

    Method AE-24 is an adequate tolerance enforcement method for 
determination of glufosinate ammonium related residues. This method is 
a modification of the current enforcement Analytical Method HRAV-5A. 
Method AE-24, includes an additional post-extraction cation exchange 
procedure to allow for separate detection and measurement of each 
residue component. Final determination is made by gas chromatography 
with flame photometric detection (GC/FPD) operating in the phosphorus 
selective mode (P-mode). Residues are expressed as glufosinate-ammonium 
free acid equivalents.

C. Magnitude of Residues

    Residues of glufosinate ammonium are not expected to exceed 4.0 ppm 
in/on sweet corn (kernels and cob with husk removed), sweet corn forage 
at 4.0 ppm, sweet corn stover at 6.0 ppm, canola seed at 0.4 ppm and 
canola meal at 1.1 ppm as a result of these section 18 uses. Secondary 
residues in animal commodities are not expected to exceed the 
previously established tolerances as a result of this section 18 use.

D. International Residue Limits

    There are no Canadian or Mexican MRLs established for glufosinate 
ammonium in/on sweet corn.

E. Rotational Crop Restrictions

    A 120-day plant back interval is required for all crops.

V. Conclusion

    Therefore, the tolerance is established for combined residues of 
glufosinate ammonium (butanoic acid, 2-amino-4-
(hydroxymethylphosphinyl)-monoammonium salt and its metabolite, 3-
methylphosphinico-propionic acid in sweet corn (kernels and cobs with 
husk removed) at 4.0 ppm, sweet corn forage at 4.0 ppm, sweet corn 
stover at 6.0 ppm, canola seed at 0.4 ppm and canola meal at 1.1 ppm.

VI. 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 October 18, 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 the ``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, Crystal Mall #2, 1921 Jefferson Davis Hwy., Arlington, 
VA, (703) 305-5697, [email protected]. 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 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.

VII. Public Record and Electronic Submissions

    EPA has established a record for this regulation under docket 
control number [OPP-300900] (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 119 of the Public Information and Records 
Integrity Branch, Information Resources and Services Division (7502C), 
Office of Pesticide Programs, Environmental Protection Agency, Crystal 
Mall #2, 1921 Jefferson Davis Hwy., Arlington, VA.
    Objections and hearing requests may be sent by e-mail directly to 
EPA at:

    [email protected]

    E-mailed objections and hearing requests must be submitted as an 
ASCII file avoiding the use of special characters and any form of 
encryption.

[[Page 44835]]

    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.

VIII. Regulatory Assessment Requirements

A. Certain Acts and Executive Orders

    This final rule establishes a tolerance under section 408 of the 
FFDCA. 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) (Public Law 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(l)(6), 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 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.

IX. 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 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: July 29, 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. 321(q), 346a and 371.

    2. Section 180.473, is amended as follows:
    i. By redesignating (b)(1), and (b)(2) as paragraphs (a)(3) and 
(a)(4).
    ii. By adding a new paragraph (b).


Sec. 180.473   Glufosinate Ammonium; tolerances for residues.

*    *    *    *    *
    (b) Section 18 emergency exemptions. Time-limited tolerances are 
established for combined residues of the herbicide (butanoic acid, 2-
amino-4-(hydroxymethylphosphinyl)-monoammonium salt and its metabolite, 
3-methylphosphinico-propionic acid in connection with use of section 18 
emergency exemptions granted by EPA.

[[Page 44836]]

 The tolerances will expire and are revoked on the date specified in 
the following table.

------------------------------------------------------------------------
                                                     Parts   Expiration/
                     Commodity                        per     Revocation
                                                    million      date
------------------------------------------------------------------------
Canola, meal......................................  1.1          12/1/99
 
Canola, seed......................................  0.4          12/1/99
 
Corn, sweet, forage...............................  4.0          12/1/99
 
Corn, sweet, kernels and cobs with husks removed..  4.0          12/1/99
 
Corn, sweet, stover...............................  6.0          12/1/99
------------------------------------------------------------------------

*    *    *    *    *

[FR Doc. 99-20869 Filed 8-17-99; 8:45 am]
BILLING CODE 6560-50-F