[Federal Register Volume 64, Number 96 (Wednesday, May 19, 1999)]
[Rules and Regulations]
[Pages 27186-27192]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-12247]



[[Page 27186]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 180

[OPP-300853; FRL-6078-4]
RIN 2070-AB78


Sulfosulfuron; Pesticide Tolerance

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: This regulation establishes a tolerance for residues of 
sulfosulfuron: 1-(4,6-dimethoxypyrimidin-2yl)-3-[(2-ethanesulfonyl-
imidazo[1,2-a]pyridine-3-yl)sulfonyl]urea and its metabolites converted 
to 2-(ethylsulfonyl)-imidazo[1,2-a]pyridine and calculated as 
sulfosulfuron in or on wheat grain at 0.02 parts per million (ppm), 
wheat straw at 0.1 ppm, wheat hay at 0.3 ppm, wheat forage at 4.0 ppm, 
milk at 0.006 ppm, fat and meat of cattle, goat, swine, horse, and 
sheep at 0.005 ppm, and meat by-products of cattle, goat, swine, horse, 
and sheep at 0.05 ppm. Monsanto Company requested this tolerance under 
the Federal Food, Drug, and Cosmetic Act, as amended by the Food 
Quality Protection Act of 1996.

DATES: This regulation is effective May 19, 1999. Objections and 
requests for hearings must be received by EPA on or before July 19, 
1999.

ADDRESSES: Written objections and hearing requests, identified by the 
docket control number, [OPP-300853], 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-300853], 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 be submitted electronically by sending electronic mail (e-
mail) to: [email protected]. Copies of objections and hearing requests 
must be submitted as an ASCII file avoiding the use of special 
characters and any form of encryption. Copies of objections and hearing 
requests will also be accepted on disks in WordPerfect 5.1/6.1 file 
format or ASCII file format. All copies of objections and hearing 
requests in electronic form must be identified by the docket control 
number [OPP-300853]. No Confidential Business Information (CBI) should 
be submitted through e-mail. Electronic copies of objections and 
hearing requests on this rule may be filed online at many Federal 
Depository Libraries.

FOR FURTHER INFORMATION CONTACT: By mail: Jim 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. 237, CM #2, 1921 
Jefferson Davis Hwy., Arlington, VA, (703) 305-5697, 
T[email protected].

SUPPLEMENTARY INFORMATION: In the Federal Register of December 23, 1998 
(63 FR 71126) (FRL-6047-7), 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) 7F4840 for 
tolerance by Monsanto Company. This notice included a summary of the 
petition prepared by the Monsanto Company, the registrant. There were 
no comments received in response to the notice of filing.
    The petition requested that 40 CFR part 180 be amended by 
establishing a tolerance for residues of the herbicide sulfosulfuron in 
or on wheat grain at 0.02 part per million (ppm), wheat straw at 0.1 
ppm, wheat hay at 0.3 ppm, wheat forage at 4.0 ppm, milk at 0.006 ppm, 
fat and meat of cattle, goat, swine, horse, and sheep at 0.005 ppm, and 
meat by-products of cattle, goat, swine, horse, and sheep at 0.05 ppm.

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 
Sulfosulfuron and to make a determination on aggregate exposure, 
consistent with section 408(b)(2), for a tolerance for residues of 1-
(4,6-dimethoxypyrimidin-2yl)-3-[(2-ethanesulfonyl-imidazo[1,2-
a]pyridine-3-yl)sulfonyl]urea and its metabolites converted to 2-
(ethylsulfonyl)-imidazo[1,2-a]pyridine and calculated as sulfosulfuron 
on wheat grain at 0.02 parts per million (ppm), wheat straw at 0.1 ppm, 
wheat hay at 0.3 ppm, wheat forage at 4.0 ppm, milk at 0.006 ppm, fat 
and meat of cattle, goat, swine, horse, and sheep at 0.005 ppm, and 
meat by-products of cattle, goat, swine, horse, and sheep at 0.05 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 sulfosulfuron are 
discussed in this unit.
    1. Several acute toxicity studies place technical sulfosulfuron in 
Toxicity Categories III or IV. Technical sulfosulfuron is not a dermal 
sensitizer.

[[Page 27187]]

    2. In a rat subchronic oral toxicity study, sulfosulfuron was 
administered in the diet for 13 weeks at a dose levels of 0, 20, 200, 
2,000, 6,000, or 20,000 ppm (equivalent to average daily intake of 0, 
1.2, 12.1, 123.2, 370.3 or 1,277.5 miligrams/kilograms/day (mg/kg/day) 
for males and 0, 1.5, 14.6, 144.3, 447.5 or 1,489.1 mg/kg/day for 
females). The systemic toxicity lowest observed adverse effect level 
(LOAEL) is 20,000 ppm (1,277.5 mg/kg/day), based on decreased body 
weight/weight gain in males, possible decreased weight gain in pregnant 
females during gestation days 14-21, and possible renal lesions related 
to formulation of calculi. The no observed adverse effect level (NOAEL) 
is 6,000 ppm (370.3 mg/kg/day).
    3. In a dog subchronic oral toxicity study, sulfosulfuron was 
administered by gelatin capsule at dose levels of 0, 30, 100, 300, or 
1,000 mg/kg/day for 90 days. The systemic toxicity LOAEL is 300 mg/kg/
day, based on lesions in the urinary bladder in females occurring 
subsequent to urinary crystal formation and on abnormal urinary 
crystals in males and females. The NOAEL for systemic toxicity is 100 
mg/kg/day.
    4. In a 28-day rat dermal study, sulfosulfuron was applied dermally 
at dose levels of 0,100, 300 or 1,000 mg/kg/day for 5 days/week for 4 
weeks. The NOAEL is  1,000 mg/kg/day the highest dose tested 
for males and females.
    5. In a 1-year dog chronic feeding study, sulfosulfuron was 
administered by gelatin capsule at dose levels of 0, 5, 20, 100 or 500 
mg/kg/day, 5 days/week, for 1 year. The LOAEL is 500 mg/kg/day based on 
the presence of abnormal urinary crystals and bladder pathology 
secondary to formation of urinary tract calculi in males. The NOAEL is 
100 mg/kg/day.
    6. In a rat chronic feeding/ carcinogenicity study, sulfosulfuron 
was administered in the diet at dose levels of 0, 50, 500, 5,000 and 
20,000 ppm (females only) for 22 months. Surviving males at 20,000 ppm 
were sacrificed on day 259 due to excessive mortality. The average 
daily intake of test material was 0, 2.4, 24.4 or 244.2 mg/kg/day(males 
up to 5,000 ppm); 1,178.3 mg/kg/day, males at 20,000 ppm until day 259) 
and 3.1, 30.4, 314.1 or 1,296.5 mg/kg/day for females. The LOAEL is 
5,000 ppm (244.2 mg/kg/day), based on increased incidence of urinary 
tract gross/microscopic lesions, mineralization in several tissues 
(males), abnormal urine crystals and possibly decreased albumin (males, 
termination). The NOAEL is 500 ppm (24.4 mg/kg/day) Transitional cell 
papilloma and carcinoma of the urinary bladder occurred at 1,296.5 mg/
kg/day (5,000 ppm) in females. These tumors were determined to be 
treatment related.
    7. In a mouse carcinogenicity study, sulfosulfuron was administered 
in the diet at dose levels of 0, 30, 700, 3,000, or 7,000 ppm (0, 4.0, 
93.4, 393.6 or 943.5 mg/kg/day to males or 0, 6.5 153.0 634.9 or 
1,388.2 mg/kg/day to females) for 18 months. The LOAEL is 3,000 ppm 
(393.6 mg/kg/day), based on gross and microscopic effects related to 
urinary calculus formation in the urinary bladder of males. The NOAEL 
is 700 ppm (93.4 mg/kg/day) Benign mesenchymal tumors of the urinary 
bladder occurred in males at 943.5 mg/kg/day (7,000 ppm). These tumors 
also occurred in one male at 393.6 mg/kg/day (3,000 ppm), one control 
female and one female at 1,388.2 mg/kg/day (7,000 ppm). Incidences of 
renal tubular adenoma were observed in one male and one female at 943.5 
and 1,388.2 mg/kg/day or 7,000 ppm. The mesenchymal tumors and adenoma 
in females were determined to be treatment related.
    8. In a 2-generation rat reproduction study, sulfosulfuron was 
administered in the diet at dose levels of 0, 50, 500, 5,000 or 20,000 
ppm during premating (equivalent to average daily intake for P adults 
of 0, 3.1, 31.6, 312.1 or 1,312.8 mg/kg/day, males and 0, 3.6, 36.2. 
363.2 or 1,454.1 mg/kg/day, females; for F1a adults, 0, 3.1, 31.1, 
315.8, 1,378.8 mg/kg/day, males and 0, 3.7, 37.7, 377.8 or 1,598.0 mg/
kg/day, females). The reproductive toxicity NOAEL is  20,000 
ppm (1,312.8 mg/kg/day) and the LOAEL is > 20,000 ppm. The parental 
systemic toxicity LOAEL is 20,000 ppm based on decreased parental body 
weight and/or weight gain during premating, gestation and lactation, 
mortality (males) and increased incidence of urinary tract pathology 
related calculus formation. The parental systemic NOAEL is 5,000 ppm 
(312.1 mg/kg/day). The offspring toxicity LOAEL is 20,000 ppm (1,312.8 
mg/kg/day) based on decreased body weight gain in postweaning 
adolescent rats, and the offspring NOAEL is 5,000 ppm (312.1 mg/kg/
day).
    9. In a rat developmental study, sulfosulfuron was administered by 
gavage at dose levels of 0, 100, 300, and 1000 mg/kg/day to females 
from day 6 through 15 of gestation. The NOAELs for maternal and 
developmental toxicity were greater than 1,000 mg/kg/day, the highest 
dose tested.
    10. In a rabbit developmental study, sulfosulfuron was administered 
by gavage at dose levels of 0, 50, 250, or 1,000 mg/kg/day from day 7 
through 19 of gestation. The NOAEL for maternal toxicity is greater 
than 1,000 mg/kg/day the highest dose tested. No LOAEL for 
developmental toxicity was observed in this study.
    11. In an acute rat oral neurotoxicity screening study, 
sulfosulfuron was administered by gavage at dose levels of 0, 125, 500, 
or 2,000 mg/kg/day. No treatment-related effects on clinical signs, 
body weight, food consumption, functional observational battery 
parameters, motor activity, gross pathology or neuropathology were 
observed. The NOAEL is  2,000 mg/kg/day. The LOAEL > 2,000 
mg/kg/day.
    12. In a rat subchronic neurotoxicity study, sulfosulfuron was 
administered in the diet at dose levels of 0, 200, 2,000, 20,000 ppm 
(corresponding to average daily doses of 0, 12, 122, or 1,211 mg/kg/day 
in males and 0, 14, 141, or 1,467 mg/kg/day in females). The NOAEL is 
20,000 ppm (1,211 mg/kg/day), based on marginal reductions in body 
weight/weight gain of males. The LOAEL is > 20,000 ppm (> 1,211 mg/kg/
day).
    13. Mutagenicity data included a gene mutation bacterial reverse 
gene mutation with Salmonella (negative for inducing reverse gene 
mutation); an in vitro mammalian forward gene mutation with Chinese 
hamster ovary cells ( negative for inducing forward gene mutations at 
the HGPRT locus in Chinese hamster ovary (CHO) with and without S9 
activation);  in vitro  chromosome aberration study on human 
lymphocytes (did not induce structural chromosome damage); and an in 
vivo structural chromosome aberration micronucleus test (negative).
    14. Based on the results of the rat metabolism study, more than 90% 
of the administered radioactivity was excreted by 72-hours post-dosing. 
Between 77% to 87% was excreted in the urine in all low dose groups. 
Feces was the major route of elimination at the high dose. In all dose 
groups minimal radioactivity was retained in the tissue. Metabolism of 
sulfosulfuron in all groups was minimal and most was excreted 
unmetabolized.

B. Toxicological Endpoints

    1. Acute toxicity. A dose and endpoint were not selected for the 
acute dietary risk assessment because there were no effects 
attributable to a single dose (exposure) observed in oral toxicity 
studies including developmental toxicity studies in the rat and rabbit 
(up to 1,000 mg/kg/day) and an acute neurotoxicity study in rat (up to 
2,000 mg/kg). The acute oral, dermal and inhalation toxicity of 
sulfosulfuron is very low.
    2. Short- and intermediate-term toxicity.  No short- or 
intermediate-term dermal or inhalation endpoints were

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identified. No dermal or systemic toxicity was seen following dermal 
applications in the 28-day dermal toxicity study with rats up to 1,000 
mg/kg/day.
    Based on the low acute inhalation toxicity (Toxicity Category IV, 
no mortality at 3.0 mg/liter (l), the formulation of the product as 
wettable granules and the low application rates from the proposed use 
patterns, there is minimal concern for potential inhalation exposure 
and risk.
    3.  Chronic toxicity. EPA has established the RfD for sulfosulfuron 
at 0.24 mg/kg/day. This Reference Dose (RfD) is based on the rat 
chronic toxicity/carcinogenicity study NOAEL of 24.0 mg/kg/day and an 
uncertainty factor of 100.
    4. Carcinogenicity. In accordance with the Agency's Proposed 
Guidelines for Carcinogenic Risk Assessment (April 10, 1996), the HED 
Cancer Assessment Review Committee (CARC) classified sulfosulfuron as a 
likely human carcinogen. The weight-of-evidence for this classification 
are as follows: (i) occurrence of rare transitional cell papilloma and 
carcinoma of the urinary bladder in female rats; (ii) occurrence of 
rare benign mesenchymal tumors of the urinary bladder in male as well 
as one renal adenoma in both male and female mice; and (iii) the 
relevancy of the observed tumors to human exposure. The Committee 
recommended that a linear low-dose approach (Q1*) for human 
risk characterization and extrapolation of risk should be based on the 
incidence of benign mesenchymal bladder tumors in male mice. The unit 
risk, Q1* (mg/kg/day), of sulfosulfuron based upon male 
mouse urinary bladder mesenchymal tumor rates is 1.03  x  
10-3 (mg/kg/day)-1 in human equivalents.

C. Exposures and Risks

    1. From food and feed uses. No tolerances have been established for 
sulfosulfuron. Risk assessments were conducted by EPA to assess 
exposures from sulfosulfuron 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. An acute risk from the proposed use is 
not expected because no effect attributed to a single dose (exposure) 
were observed in oral toxicology studies including developmental 
toxicity in the rat and the rabbit and an acute neurotoxicity study in 
the rat. The Agency concludes with reasonable certainly that 
sulfosulfusulfuron does not elicit an acute toxicological response.
    ii. Chronic exposure and risk. A chronic dietary exposure analysis 
was performed using the RfD of 0.24 mg/kg/day based on a chronic 
toxicity NOAEL of 24.0 mg/kg/day and an uncertainly factor of 100, 
assuming tolerance level residues and 100 % crop treated information to 
estimate the Theoretical Maximum Residue Contribution (TMRC) for the 
general population and 28 subgroups. The TMRC for the all population 
subgroups represent <1% of the RfD. This is a highly conservative risk 
estimate since no refinements for percent crop treated or anticipated 
residues were made.
    iii. Carcinogenicity exposure and risk. A cancer exposure analysis 
was performed (DEEM) software, USDA 1989-91 Nationwide Continuing 
Surveys for Food Intake by Individuals (CSFII) using tolerance level 
residues and 100% crop treated information to estimate the lifetime 
cancer risk for the general population. The lifetime risk was 8.45  x  
10-8 for a 70-year exposure. The lifetime risk was 1.05  x  
10-7 for infants, 2.55  x  10-7 for childern (1-
6) and 1.47  x  10-7 for childern (7-12). The Agency 
considers risks in the range of 1  x  10-6 as negligible 
risk. The cancer dietary risk associated with sulfosulfuron is below 
the Agency`s level of concern.
    2.  From drinking water.  Tier I estimated environmental 
concentrations (EEC) were calculated for both surface water ((Generic 
expected environmental concentration) GENEEC model) and ground water 
((Screening Concentration in GROund water) SCI-GROW). Tier I models 
represent the most conservative estimates of potential residues in 
drinking water. Drinking water levels of comparison (DWLOCs) for acute 
and chronic dietary risk from drinking water were calculated for both 
surface and ground water. Estimated environmental concentrations (EECs) 
for surface and ground water were 1.73 parts per billion (ppb) and 
0.295 ppb, respectively.
    A 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.
    i. Acute exposure and risk. An acute risk from the proposed use is 
not expected because no effect attributed to a single dose (exposure) 
were observed in oral toxicology studies including developmental 
toxicity in the rat and the rabbit and an acute neurotoxicity study in 
the rat.
    ii.  Chronic exposure and risk. The DWLOC s calculated for adults 
and children were 8,400 ppb and 2,400 ppb, respectively. These are 
higher than the EEC s of 1.73 ppb for surface water and 0.295 ppb for 
ground water.
    iii. For cancer exposure to sulfosulfuron, the adult DWLOC is 27 
ppb, which is above the EECs of 1.73 ppb for surface water and 0.0295 
ppb for ground water.
    3. From non-dietary exposure. Based on the proposed use of 
sulfosulfuron on turf at playgrounds, parks, and residential areas by 
professional applicators, potential for residential exposure exists, 
from post-application scenarios.
    i. Acute exposure and risk. An acute risk from the proposed use is 
not expected because no effects attributed to a single dose (exposure) 
were observed in oral toxicology studies including developmental 
toxicity in the rat and the rabbit and an acute neurotoxicity study in 
the rat.
    ii. Chronic exposure and risk. A chronic exposure is not expected 
for use of sulfosulfuron on agricultural, and non-agricultural areas, 
because exposure does not continuously (daily) occur more than 180 
days.
    iii. Short- and intermediate-term exposure and risk. No short-term 
or intermediate term dermal or inhalation endpoints were identified. 
The Agency concludes that exposures form residential uses of 
sulfosulfuron are not expected to pose undue risk.
    iv. Cancer exposure and risk. Post-application exposures resulting 
from the proposed application of sulfosulfuron to recreational areas, 
parks, and residential areas (lawns) are not expected to pose an undue 
cancer risk.
    A typical cancer risk for a residential adult was calculated for a 
Tc = 1,000 cm2/hr (high activity for 1 hr.) and for a Tc = 
500 cm2/hr (low activity for 1 hr.). An average is usually 
used for cancer assessments. This assessment is based on conservative 
assumptions (due to the assessment using 50 years of exposure, and 
utilizing an estimated 20% (default) of dislodgeable foliar residues 
(DFR) from the turf; which is

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derived from the maximum application rate). An average of 14 days of 
DFRs was used for this cancer assessment; this would be considered a 
10% decrease each day (from dilution by rain, and mowing of the grass) 
of the 20% residue for at least 14 days, and then taking the mean value 
of this 14 day exposure. The Life time Average Daily Dose (LADD) = 6.0 
x  10-5 mg/kg/day for a Tc = 1,000 cm2/hr (high 
activity for 1 hr.) and for a Tc = 500 cm2/hr (low activity 
for 1 hr.) is equal to 3.0  x  10-5 mg/kg/day. The cancer 
risks are 6.0  x  10-8 (for Tc =1,000 cm2/hr, 
high activity) and 3.0  x  10-8 (for Tc = 500 
cm2/hr (low activity for 1 hr.)). The highest residential 
calculated level of cancer risk on day zero for a Tc =1,000 
cm2/hr (high activity for 1 hr.) is equal to 1.2  x  
10-7, and for a Tc = 500 cm2/hr (low activity for 
1 hr.) is equal to 6.0  x  108. This risk is considered 
minimal.
    The cancer risk assessment for dermal post-application exposure for 
toddlers is based on conservative assumptions (due to the assessment 
using 12 years of exposure at maximum rate, for 14 days a year without 
a 10 % dissipation each day after day zero, and a high transfer 
coefficient (Tc); default for toddlers = 8,700 cm2/hr (high 
activity for 2 hrs, Tier I.). It also utilizes dislodgeable foliar 
residues (DFR) derived from the maximum application rate and an 
estimated 20 % (upper percentile, default) of this residue remaining on 
the turf). The calculated level of cancer risk is 1.0  x  
106. This is considered as a worst case scenario for 
toddlers, because the toddler default Tc = 8,700 cm22/hr 
(high activity for 2 hrs, Tier I.), and an average of exposure over 
time is usually used for cancer assessments (which would be considered 
much less due to a 10% decrease each day, from dilution by rain and 
mowing of the grass, of the 20% residue for at least 14 days, and then 
taking the mean value of this 14 day exposure). This risk is considered 
minimal.
    Although it is likely that toddlers also would be exposed to 
sulfosulfuron from incidental ingestion of grass, soil, or hand-to-
mouth transfer, no risk assessment was performed for these scenarios 
because no relevant oral toxicological endpoints have been identified. 
There was no acute dietary endpoint identified for sulfosulfuron.
    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 sulfosulfuron 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, 
sulfosulfuron 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 sulfosulfuron 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.  An acute risk from the proposed use is not expected 
because no effects attributed to a single dose (exposure) were observed 
in oral toxicology studies including developmental toxicity in the rat 
and the rabbit and an acute neurotoxicity study in the rat.
    2. Chronic risk. Using the theoretical maximum residue contribution 
exposure assumptions described in this unit, EPA has concluded that 
aggregate exposure to sulfosulfuron from food will utilize <1% 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 sulfosulfuron in drinking water and from non-
dietary, non-occupational exposure, EPA does not expect the aggregate 
exposure to exceed 100% of the RfD. EPA concludes that there is a 
reasonable certainty that no harm will result from aggregate exposure 
to sulfosulfuron 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.
    Short- term and intermediate-term dermal and inhalation is not a 
concern due to the lack of significant toxicological effects observed 
with sulfosulfuron under these exposure scenarios.
    4. Aggregate cancer risk for U.S. population. The cancer aggregate 
risk which includes food, water, and the lifetime average daily dose 
from post application exposure for the general population is 2.05  x  
10-7 which is lower than the Agency`s negligible risk of 1 
x  10-6.
    Aggregrate cancer risk for infants and childern. The aggregrate 
cancer risk for infants and childern which includes food, water, and 
lifetime average daily dose from post-application exposure is 1.1  x  
10-6 which is considered negibile risk.
    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 sulfosulfuron 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 Sulfosulfuron, 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

[[Page 27190]]

raise concerns regarding the adequacy of the standard MOE/safety 
factor.
    ii. Pre- and post-natal sensitivity. The developmental and 
reproductive toxicity data did not indicate increased susceptibility to 
in utero and/or postnatal exposure.
    iii. Conclusion. There is a complete toxicity database for 
Sulfosulfuron and exposure data is complete or is estimated based on 
data that reasonably accounts for potential exposures.
    Based on these data, there is no indication that the developing 
fetus or neonate is more sensitive than adult animals. Acceptable acute 
and subchronic neurotoxicity studies in rats have been submitted to the 
Agency. There were no data gaps for the assessment of the neurotoxic 
potential of sulfosulfuron. There was no evidence of neurotoxicity in 
other studies (including a rat 90-day feeding toxicity study, rat 2-
year chronic toxicity/carcinogenicity study, dog oral (capsule) 90-day 
study and a dog 1 year oral (capsule) toxicity study, conducted on 
sulfosulfuron. The Agency believes that reliable data support the use 
of the standard 100-fold uncertainly factor, and that a tenfold (10x) 
uncertainty factor to protect the safety of infants and children should 
not be retained.
    2. Acute risk. There are no acute toxicological endpoints for 
sulfosulfuron. The Agency concludes that establishment of the proposed 
tolerances would not pose an unacceptable aggregate risk.
    3. Chronic risk. Using the exposure assumptions described in this 
unit, EPA has concluded that aggregate exposure to Sulfosulfuron from 
food will utilize < 1% of the RfD for infants and children. EPA 
generally has no concern for exposures below 100% of the RfD because 
the RfD represents the level at or below which daily aggregate dietary 
exposure over a lifetime will not pose appreciable risks to human 
health. Despite the potential for exposure to Sulfosulfuron in drinking 
water and from non-dietary, non-occupational exposure, EPA does not 
expect the aggregate exposure to exceed 100% of the RfD.
    4. Short- or intermediate-term risk. Short-term and intermediate-
term dermal and inhalation risk is not a concern due to lack of 
significant toxicological effects observed with sulfosulfuron under 
these exposure scenarios.
    5. Aggregrate cancer risk for infants and childern. The aggregrate 
cancer risk for infants and childern which includes food, water, and 
lifetime average daily dose from post-application exposure is 1.1  x  
10-6 which is considered negibile risk.
    6. 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 Sulfosulfuron 
residues.

III. Other Considerations

A. Metabolism In Plants and Animals

    The guideline requirement for an animal metabolism study is 
satisfied. Sulfosulfuron is rapidly excreted, primarily unmetabolized. 
Excretion at low dose occurred primarily in the urine, whereas at high 
dose, a large percentage of the administered dose was excreted in the 
feces. Sulfosulfuron was not retained in tissues to any significant 
extent.
    The nature of the residue in plants is understood. The sulfonyl 
urea bond is cleaved in soil prior to uptake by wheat and Pd-
metabolites are taken up less readily than Im-metabolites. Metabolite 
formation appears to occur by demethylation and cleavage of sulfonyl 
urea bond.start

B. Analytical Enforcement Methodology

     An interim adequate enforcement methodology (example - gas 
chromatography) is available to enforce the tolerance expression. The 
method is undergoing modification to improve the method. The improved 
method, when available, may be requested from: Calvin Furlow, PIRIB, 
IRSD (7502C), Office of Pesticide Programs, Environmental Protection 
Agency, 401 M St., SW., Washington, DC 20460. Office location and 
telephone number: Rm. 101FF, CM #2, 1921 Jefferson Davis Hwy., 
Arlington, VA, (703) 305-5229. The interim method is available from the 
Analytical Chemistry Lab, BEAD (7503C), Office of Pesticide Programs, 
Environmental Protection Agency, 401 M St., SW., Washington, DC 20460, 
(703) 305-2905.

C. Magnitude of Residues

    Residues of 1-(4,6-dimethoxypyrimidin-2yl)-3-[(2-ethanesulfonyl-
imidazo[1,2-a]pyridine-3-yl)sulfonyl]urea and its metabolites that are 
converted to 2-(ethylsulfonyl)-imidazol[1,2-a]pyridine and calculated 
as sulfosulfuron are not expected to exceed on wheat grain 0.02 ppm, 
wheat straw 0.1 ppm, wheat hay 0.3 ppm, wheat forage 4.0 ppm, milk 
0.006 ppm, fat and meat of cattle, goat, swine, horse, and sheep 0.005 
ppm, and meat by-products of cattle, goat, swine, horse, and sheep at 
0.05 ppm.

D. International Residue Limits

    No Codex or Mexican MRLs are established for sulfosulfuron. 
Canadian MRLs exist for sulfosulfuron on wheat grain at 0.02 mg/kg; 
milk at 0.006 mg/kg, meat and fat of cattle, goat, swine, horse , sheep 
and poultry at 0.005 mg/kg, eggs at 0.0005 mg/kg; and meat by products 
of cattle, goat, swine, horse, sheep and poultry at 0.05 mg/kg. The 
Canadian MRLs are the same as the United States tolerances. No Canadian 
MRLs exist for wheat straw, wheat hay, and wheat forage. These 
tolerances are necessary to support use patterns in the United States.

E. Rotational Crop Restrictions

    Based on the results of the confined accumulation in rotational 
crops study, the appropriate plantback intervals are: 30 days for leafy 
and root crops. Limited rotational field trials are required to 
determine the appropriate rotation intervals for all other crops 
(except wheat).

IV. Conclusion

    Therefore, the tolerances are established for residues of 
sulfosulfuron, 1-(4,6-dimethoxypyrimidin-2yl)-3-[(2-ethanesulfonyl-
imidazo[1,2-a]pyridine-3-yl)sulfonyl]urea and its metabolites converted 
to 2-(ethylsulfonyl)-imidazo[1,2-a]pyridine and calculated as 
sulfosulfuron, in wheat grain at 0.02 ppm, wheat straw at 0.1 ppm, 
wheat hay at 0.3 ppm, wheat forage at 4.0 ppm, milk at 0.006 ppm, fat 
and meat of cattle, goat, swine, horse, and sheep at 0.005 ppm, and 
meat by-products of cattle, goat, swine, horse, and sheep at 0.05 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 July 19, 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

[[Page 27191]]

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 
regulation. 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, [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.

VI. Public Record and Electronic Submissions

    EPA has established a record for this regulation under docket 
control number [OPP-300853] (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:
    [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.
    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 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

[[Page 27192]]

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 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: May 6, 1999.

Susan B. Hazen,

Acting Director, 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), 346(a) and 371.

    2. Section 180.552 is added to subpart C to read as follows:


Sec. 180.552  Sulfosulfuron; tolerances for residues.

    (a) General. Tolerances are established for residues of the 
herbicide sulfosulfuron, 1-(4,6-dimethoxypyrimidin-2-yl)-3-[(2-
ethanesulfonyl-imidazo[1,2-a]pyridine-3-yl) sulfonyl]urea and its 
metabolites converted to 2-(ethylsulfonyl)-imidazo[1,2-a]pyridine and 
calculated as sulfosulfuron in or on the raw agricultural commodities.

 
------------------------------------------------------------------------
                                                                  Parts
                           Commodity                               per
                                                                 million
------------------------------------------------------------------------
Cattle, fat....................................................   0.005
Cattle, meat...................................................   0.005
Cattle, meat by-products.......................................   0.05
Goat, fat......................................................   0.005
Goat, meat.....................................................   0.005
Goat, meat by-products.........................................   0.05
Horse, fat.....................................................   0.005
Horse, meat....................................................   0.005
Horse, meat by-products........................................   0.05
Milk...........................................................   0.006
Sheep, fat.....................................................   0.005
Sheep, meat....................................................   0.005
Sheep, meat by-products........................................   0.05
Swine, fat.....................................................   0.005
Swine, meat....................................................   0.005
Swine, meat by-products........................................   0.05
Wheat, forage..................................................   4.0
Wheat, grain...................................................   0.02
Wheat, hay.....................................................   0.3
Wheat, straw...................................................   0.1
------------------------------------------------------------------------


    (b) Section 18 emergency exemptions. [Reserved]
    (c) Tolerances with regional registrations. [Reserved]
    (d) Indirect or inadvertent residues. [Reserved]

[FR Doc. 99-12247 Filed 5-18-99; 8:45 am]
BILLING CODE 6560-50-F