3 

### TABLE OF CONTENTS
Page

I. Preliminary W ork Plan (PWP) 4

II. Fact Sheet 1 1

III. Summary of Data Gaps 16

________________________________________ Please Note
This Preliminary Work Plan and Fact Sheet summarize the Environmental Protection Agency's current position bas ed on the following documents:

1. Registration Review : Preliminary Problem Formula tion for Environmental Fate and Ecological Risk, Endangered Species and Drinking W ater Assessments for Halosulfuron

m ethyl , March 8 , 201 2

. 2. Halosulfuron

- m e thyl : Human Health Assessment Scoping Document in Support of Registration Review , March 6, 2012

. 3. Halosulfuron

- methyl : R eview of Human Incidents

. D ecember 8, 2011.

4. Halosulfuron

- methyl Screening Level Usage Analysis (SLUA) , June 3 , 201 1

. 5. BEAD Chemical Profile for R egistration Review: Halosulfuron

- methyl

. October 12 , 201 1

. 6. Appendix A: Food/Feed & Non

- Food/Non

- Feed Uses Considered in Registration Review Work Planning, August 2, 2011

. Additional sup porting documents for halosulfuron

- meth yl may be found in the registration review docket EPA

- HQ

- OPP

- 201 1

- 0 745 located on the internet at www.regulations.gov

.4 I. P reliminary W ork P lan

– Halosulfuron

- methyl

Introduction: The Food Quality Protection A ct (FQPA) of 1996 mandated a registration review program

. All pesticides sold or distributed in the United States generally must be registered by the E nvironmental P rotection A gency (EPA) , based on scientific data showing that they will not
cause unreason able risks to human health or the environment when used as directe d on product labeling. The registration review program is intended to make sure that, as the ability to assess risk evolves and as policies and practices change, all registered pesticides c ontinue to meet the statutory standard of no unreasonable adverse effects to human health or the environment

. Changes in science, public policy, and pesticide use practices will occur over time. Through the
r egistration review program, the Agency periodi cally reevaluates pesticides to make sure that as change occurs, products in the marketplace can be used safely. Information on this program is provided at: http://www.epa.gov/oppsrrd1/registration_review/. The Agency is implementing the registration re view program pursuant to Section 3(g) of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), and will review each registered pesticide every 15 years to determine whether it continues to meet the F IFRA standard for registration. The Agency wi ll consider benefits information and data as required by FIFRA. The public phase of registration review begins when the initial docket is opened for each case. The docket is the Agency’s opportunity to state what it knows about the pesticide and what add itional risk analyses and data or information it believes are needed to make a registration review decision. After reviewing and responding to comments and data received in the docket during this initial comment period, the Agency will develop and commit to a final work plan and schedule for the registration review of halosulfuron

- methyl

.

Halosulfuron

- methyl is a sulfonylurea herbicide that is primarily absorbed through the leaves of plants. Sulfonylurea herbicides disrupt the synthesis of amino acids in plants by inhibiting the enzyme acetolactate synthase (ALS). ALS inhibition in plants adversely affects plant growth and reproduction. Although the sulfonylurea herbicides all act upon the same enzyme system in plants, that system is not present in huma ns or other mammals. Halosulfuron

- methyl is registered for use on various crops including corn, cotton, nuts, rice, sorghum, soybeans, squash, sugarcane, and fruiting vegetables to control broadleaf weeds and annual and perennial sedges

. In addition to t he agricultural food uses, halosulfuron

- methyl is also registered for use on turfgrass, ornamentals, and a variety of non

- crop areas including, but not limited to, airports, cemeteries, fallow non

- crop areas, golf courses, landscaped areas, public recreati on areas, residential and commercial lawns, sod and turf farms, sports fields, tennis courts, race tracks, fairgrounds, and rights

- of

- way. Halosulfuron

- methyl was first registered in 19 94; therefore , it was not subject to the reregistration requirements o f FIFRA. In 1999, in conjunction with the establishment of new halosulfuron

- methyl tolerances ( 64 FR 25439) , EPA also completed the reassessment of the existing halosulfuron

- methyl tolerances as required by FQPA.
Anticipated Risk Assessment and Data Need s: The Agency anticipates requiring data to conduct a comprehensive ecological risk assessment, including an endangered species risk assessment, for all uses of halosulfuron

- methyl . The Agency also anticipates requiring additional data to conduct human e xposure risk assessments. Below is a summary of the issues relevant to the registration review of halosulfuron

- methyl

.5 Ecological Risk:

**•** The most recent ecological risk assessment for halosulfuron

- methyl w as completed in May 2010 for the registration of h alosulfuron

- methyl

- containing pesticides on dried shelled peas and beans (except soybeans), succulent shelled peas and beans, apples, rhubarb, bushberry, fruiting vegetables , and tuberous and corm vegetables

.

**•** The Agency has not conducted a risk assessme nt that supports a complete endangered species determination for halosulfuron

- methyl . The ecological risk assessment planned during registration review will allow the Agency to determine whether halosulfuron

methyl ’s use has “no effect” or “may affect” fe derally listed threatened or endangered species (listed species) or their designated critical habitats. When an assessment concludes that a pesticide’s use “may affect” a listed species or its designated critical habitat, the Agency will consult with the U.S. Fish and Wildlife Service and/or National Marine Fisheries Service (the Services), as appropriate.

**•** The Agency anticipates requir ing the following data for halosulfuron

- methyl in order to conduct a complete ecological risk assessment, including an end angered species assessment:

**•** GDLN 835.4100

– Aerobic Soil Metabolism (two additional soils)

**•** GDLN 835.4300

– Aerobic Aquatic Metabolism ( submitted study in review)

**•** GDLN 835.6100 (7)

– Terrestrial Field Dissipation 1

**•** GDLN 835.6200

– Aquatic Field Dissipation (including Environmental Chemistry Methods and Independent Laboratory Validation for Water) 2

**•** GDLN 850.1010

– Acute Toxicity Freshwater Invertebrates (TEP)

**•** GDLN 850.1075

– Acute Freshwater Fish Toxicity (TEP)

**•** NON

- GDLN

– Special Study for Non

- Target Plant R eproductive Toxicity

**•** NON

- GDLN

– Enhanced Aerobic Soil Metabolism Study

**•** NON

- GDLN

– Enhanced Hydrolysis Study

**•** The Agency anticipates requiring an enhanced aerobic soil metabolism study during registration review. Limited studies on halosulfuron

- methyl de cline in at least 10 soils
are expected to be needed because of discrepancies between available field and laboratory study results regarding halosulfuron

- methyl persistence. H alosulfuron

- methyl appears to be significantly more persistent than expected at some field sites based on the results of currently available aerobic soil metabolism studies. Once these studies are conducted in at least 10 soils, the Agency anticipate s requiring registrant s to conduct full aerobic soil metabolism studies (i.e., with c haracterization of the formation and decline of major degradates) on the two soils where halosulfuron

- methyl is most persistent.

1 See footnote 7 of 40 CFR 158.1300. EPA anticipates requiring only the environmental chemistry analytical method and independent laboratory validation portions of GDLN 835.6100

– Terrestrial Field Dissi pation. 2 The Agency has classified a previously

- submitted study (MRID 44437304) as supplemental , as it incompletely addressed the fate of halosulfuron

- methyl in flooded environments. Acceptance of this study is made conditional upon acceptance of a submi tted aerobic aquatic metabolism study (GDLN 835.4300) , which is currently in review. In addition, environmental chemistry methods and independent laboratory validation are still required for water under GDLN 835.6200 per footnote 7 of 40 CFR 158.1300

.6 **•** The Agency anticipates requiring an enhanced hydrolysis study for halosulfuron

- methyl during registration review due to the va riability in the hydrolysis rate of halosulfuron

methyl with changes in pH and temperature. Suggested parameters are expected to include : testing at pH s of 5, 7, and 9 and at temperatures of 10, 15, 20, and 25 C for 6 0 days ; testing at pHs of 4, 6, and 8 at 15 C ; and analysis for halo sulfuron

- methyl and potential major hydrolysis products.

**•** Please refer to Registration Review : Preliminary Problem Formulation for Environmental Fate and Ecological Risk, Endangered Species and Drinking Water Assessments for H alosulfuron

- methyl , March 8, 2012, located in the docket, for a detailed discussion of these anticipated risk assessment and data needs.

Human Health Risk:

**•** The most recent human health risk assessment , including a drinking water assessment, for halosulfu ron

- methyl was completed in April 2010 for the registration of use on dried shelled peas and beans (except soybeans), succulent shelled peas and beans, apples, rhubarb, bushberry, fruiting vegetables , and tuberous and corm vegetables.

**•** The Agency antici pates requiring the following data for halosulfuron

- methyl in order to conduct a complete human health risk assessment:

**•** GDLN 860.1650

– Submittal of Analytical Reference Standards

**•** GDLN 870.7800

– Immunotoxicity

**•** T he current uncertainty factor for halosulf uron

- methyl is 100X (1 X FQP A safety factor, 10X for inter

- species variation , 10X for intra

- speci es variation). However, the uncertainty/ safety factor s will be re

- evaluated for halosulfuron

- methyl a fter the additional toxicology stud y that is expected to b e required is submitted and reviewed.

**•** T he Agency does not anticipat e conducting updated dietary , residential, aggregate, or occupational risk assessment s dur ing registration review. The Agency plans to rely on the most recent comprehensive human health a ssessment in making its registration review decision, as there were no risks of concern at that time and changes in Agency models and policies that have occurred since that assessment are not expec ted to alter risk conclusions. If the results of the addit ional toxicity stud y that is expected to be required change s assessment endpoints or uncertainly/safety factors, the Agency will reconsider the need for updated risk assessments.

**•** The Agency anticipates updating the current halosulfuron

- methyl toleranc e expression in 40 CFR §180. 479 to be consistent with the Chemical Abstracts Service (CAS) nomenclature or the International Union of Pure and Applied Chemistry (IUPAC) nomenclature.

**•** For more information p lease refer to Halosulfuron

- methyl

. Human Healt h Assessment Scoping Document in Support of Registration Review , March 6, 2012, located in the docket

.7 Endocrine Disruptor Screening Program
As required by FIFRA and FFDCA, EPA reviews numerous studies to assess potential adverse outcomes from exposure to chemicals. Collectively, these studies include acute, subchronic and chronic toxicity, including assessments of carcinogenicity, neurotoxicity, developmental, reproductive, and general or sys temic toxicity. These studies include endpoints which may be susceptible to endocrine influence, including effects on endocrine target organ histopathology, organ weights, estrus cyclicity, sexual maturation, fertility, pregnancy rates, reproductive loss, and sex ratios in offspring. For ecological hazard assessme nts, EPA evaluates acute tests and chronic studies that assess growth, developmental and reproductive effects in different taxonomic groups. As part of its most recent halosulfuron

- methyl registration decision , EPA reviewed these data and selected the mos t sensitive endpoints for relevant risk assessment scenarios from the existing hazard database. However, as required by FFDCA section 408(p), halosulfuron

- methyl is subject to the endocrine screening part of the Endocrine Disruptor Screening Program (EDSP ). EPA has developed the EDSP to determine whether certain substances (including pesticide active and other ingredients) may have an effect in humans or wildlife similar to an effect produced by a “naturally occurring estrogen, or other such endocrine eff ects as the Administrator may designate.” The EDSP employs a two

- tiered approach to making the statu torily required determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a chemical substance to interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal systems. Chemicals that go through Tier 1 screening and are found to have the potential to interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP where EPA will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 testing is designed to identify any adverse endocrine

- related effects caused by the substance, and establish a dose

- response relationship between the dose and the E, A, o r T effect. Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Between October 2009 and February 2010, EPA issued test orders/data call

- ins for the first group of 67 chemicals, which contains 58 pesticide active ingredients and 9 inert ingredients. Halosulfuron

methyl is not among the group of 58 pesticide active ingredients on the initial list to be screened under the EDSP. Accordingly, as part of registration review, EPA will issue future EDSP orders/data call

- ins, requiring the submission of EDSP screening assays for halosulfuron

- methyl

. For further information on the status of the EDSP, the policies and procedures, the list of 67 chemicals, future lists, the test guidelines and the Tier 1 screening battery, please visit our website: http://www.epa.gov/endo/

.8 Timeline:

EPA has created the following estimated timeline for the completion of the halosulfuron

- methyl registration review

.

Registration Review for Halosulfuron

- met hyl

– Projected Registration Review Timeline Activities Estimated Date Opening the Docket Open Docket and Public Comment Period 201 2

– March Close Public Comment 201 2

– May Case Development Final Work Plan 201 2

– August Issue DCI 201 3

– April

– June Data Submission 201 7

– April

– June Open Public Comment Period for Draft Risk Assessments 201 8

– Oct.

– Dec. Close Public Comment Period 201 9

– Jan.

– March Registration Review Decision Open Public Comment Period for Proposed Registration Revi ew Decision 201 9

– April

– June

Close Public Comment Period 201 9

– July

– Sept. Registration Review Decision and Begin Post

- Decision Follow

- up 20 20 Total (years) 8

Guidance for Comment e rs : The public is invited to comment on EPA’s preliminary w ork plan and rationale. The Agency will carefully consider all comments as well as any additional information or data provided in a timely manner prior to issuing a Final Work P lan for halosulfuron

- methyl

. Trade Irritants: Through the registration review process, the Agency intends to solicit information on trad e irritants and, to the extent feasible, take steps toward facilitating irritant resolution. Growers and other stakeholders are asked to comment on any trade irritant issues resulting from lack of MRLs or disparities between U.S. tolerances and MRLs in key export markets, providing as much specificity as possible regarding the nature of the concern. Water Quality: Halosulfuron

- methyl is not identified as a cause of impairment for any water bodies listed as impaired under section 303(d) of the Clean Water Act 3

. In addition, n o Total Maximum Daily Load s (TMDL) have been developed for halosulfuron

- methyl 4 . More information on impaired water bodies and TMDLs can be found at the Agency’s website 5

3 . The Agency invites submission of water quality data for th is pesticide. To the extent possible, data should conform to the quality standards in Appendix A of the OPP Standard Operating Procedure: Inclusion of Impaired Water Body and Other Water Quality Data in OPP’s Registration Review Risk Assessment and

http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885 4 http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=885&p_pollutant_group_name=PEST ICIDES 5 http://www.epa.gov/owow/tmdl/9 Management Process 6 in order to ensure they can be used quantitatively or qualitatively in pesticide risk assessments.

Environmental Justice: EPA seeks to achieve environmental justice, the fair treatment and meaningful involvement of all people, regardless of race, color, national origin, or income, in the development, implementation, and enforcement of environmental laws, regulations, and policies. To help address potential environmental justice issues, the Agency seeks information on any groups or segments of the population who, as a result of their location, cultural practices, or other factors, may have atypical, unusually high exposure to halosulfuron

- methyl , compared to the general population. Plea se comment if you are aware of any sub

- populations that may have atypical, unusually high exposure compared to the general population.

Additional Information: Stakeholders are also specifically asked to provide information and data that will assist the Ag ency in refining its risk assessments, including any species

- specific ecological effects determinations. The Agency is interested in receiving the following information:

1. confirmation on the following label information
a. sites of application b. formulations
c. a pplication methods and equipment d. maximum application rates in units related to mass per unit area of treatment
zone e. frequency of application, application intervals and maximum number of applications per season f. geographic limitations on use 2. use or potential use distribution (e.g., acreage and geographical distribution of relevant crops) 3. use history 4. median and 90 th

5. application timing (date of first application and app lication intervals) by crop

– national, state and county percentile reported use rates (lbs. a.i./acre) from usage data

– national, state, and county

6. sub

- county crop location data 7. directly acquired county

- level usage data (not derived from state level data)
a. maximum reported use rate (lbs. a.i./acre) from usage data

– county b. percent crop treated

– county
c. median and 90 th d. total pounds per year

– county percentile number of applications

– county

e. the year the pesticide was last used in the county/sub

- county area f. the years in which the pesticide was applied in the county/sub

- county area 8. typical interval (days) 9. state or local use restrictions 10. ecological incidents (non

- target plant damage and avian, fish, reptilian, amphibian and mammalian mortalities) not already reported to the Agency 11. monitoring data

6 http://www.epa.gov/oppsrrd1/registration_review/water_quality_sop.htm10 12. d ata regarding the use of halosulfuron

- methyl on airpor ts, outdoor non

- agricultural
areas , fallow non

- crop areas , farm storage areas, tank farms, industrial/commercial/recreational areas, race tracks, fencerows, rights

- of

- way, roadsides, schools, and tennis courts.
Next Steps:

After the 6 0

- day comment perio d closes, the Agency will review and respond to any comments received in a timely manner , and expects to issue a Final Work Plan for halosulfuron

- methyl

.11 II. FACT SHEET
Background Information:

**•** Halosulfuron

- methy l re gistration review case number : 7233

**•** Halosulfuron

- methyl PC code: 1 28721.

**•** The first halosulfuron

- methyl

- containing pesticide was registered in the U.S. in 19 94; therefore, it was not subject to the reregistration process under FIFRA

. **•** Existing halosulfur on

- methyl tolerances were reassessed in 1999 in conjunction with the establishment of new halosulfuron

- methyl tolerances ( 64 FR 25439 )

. **•** There are currently 25 FIFRA Section 3 registrations for halosulfuron

- methyl

. **•** Technical registrants for halosulfuron

- met hyl include : Aceto Agricultural Chemicals Corp. and Canyon Group , LLC.

**•** Tolerances for residues of halosulfuron

- methyl in/on raw agricultural commodities exist under 40 CFR § 180.479.

**•** Pesticide Re

- evaluation Division (PRD) Chemical Review Manager (CRM): Kait lin Keller, keller.kaitlin@epa.gov

**•** Registration Division (RD) Product Manager (PM): Kable Bo Davis, davis.kable@epa.gov Use & Usage Information: For additional details, please refer to Appendix A: Food/Feed & Non

- Food/Non

- Feed Uses Considere d in Registration Review Work Planning, August 2, 2011; Halosulfuron

- methyl Screening Lev el Usage Analysis (SLUA), June 3 , 201 1; and BEAD Chemical Profile for Registration Review: Halosulfuron

- methyl ( PC Code: 128887 October 12 , 201 1 )

.

**•** Halosulfuron

- methyl is registered for use on various crops including corn, cotton, nuts, rice, sorghum, soybeans, squash, sugarcane, and fruiting vegetables to control broadleaf weeds and annual and perennial sedges

. In addition to the agricultural food uses, halosulfuron

- me thyl is also registered for use on turfgrass, ornamentals, and a variety of
non

- crop area s including, but not limited to, airports, cemeteries, fallow non

- crop area s , golf courses, landscaped areas, public recreation areas, residential and commercial lawns , sod and turf farms, sports field s, tennis courts, race tracks, fairgrounds, and rights

- of

way.

**•** According to the most recent usage data, approximately 30,000 pounds of halosulfuron

methyl active ingredient (a.i .) are applied per year to approximately one million acres for agricultural purposes

. Rice, corn, sugarcane, and green beans account for the highest agricultural usage (in pounds) of halosulfuron

- methyl. On average, the states with the most agricultural usage in terms of pounds a.i. applied are Arkansas, Louisiana, Texas, Florida, and Wisconsin. The majority of non

- agricultural usage is on turfgrass at golf courses, turf farms, and lawns. A pproximately 1,000 pounds a.i. is used on golf courses and 1,000 pounds a.i. is used on turf farms annual ly

. Additionally, l awn care operators use approximately 500 pounds a

. i

. per year.

**•** Halosulfuron

- methyl is formulated as water dispersible granules and emulsifiable, flowable, and soluble concen trates. End

- use product concentrations range from 0.32

– 75 .0 percent a .i

.12 **•** A pplication methods include aircraft, ground, soil in

- furrow , soil surface, and spot treatment s as well as backpack, handheld, band, and hooded sprayer s

. Recent Actions:

**•** During the development of the Preliminary Work Plan for halosulfu ron

- methyl , the Agency identified an erroneous single application rate of 0.47 lb a.i lb/ acre for field corn on EPA Reg. No. 81880

- 20. After contacting the registrant about this label error, the registrant requested voluntary cancellation of EPA Reg. No 81880

- 20 on February 28, 2012

. The Agency will process this cancellation request by publishing a notice in the Federal Register and taking the other steps required by FIFRA Section 6(f) relating to voluntary cancellations.

**•** On December 8, 2011, tolerances were proposed for h alosulfuron

- methyl and its metabolites and degradates in or on millet, proso, forage; millet, proso, hay; millet, proso, grain; millet, proso, straw; grass forage, fodder, and hay, crop group 17, forage; and grass forage, fodder, and ha y, crop group 17, hay (76 FR 76674)

. The Agency is currently conducting dietary and occupational risk assessments in 2012 to support the proposed
use s of halosulfuron

- methyl on millet and grass forage, fodder, and hay.

**•** A final rule for halosulfuron

- methy l was issued on August 4, 2010 ( 75 FR 46847 ), which established tolerances for residues of halosulfuron

- methyl, including its metabolites and degradates, in or on apple; bushberry, subgroup 13

- 07B ; okra ; pea and bean, succulent shelled, subgroup 6B ; rhubar b; vegetable, tuberous and corm, subgroup 1C ; and re moved
an existing tolerance for residues for halosulfuron

- methyl and its metabolites and degra dates in or on bean, snap, succulent as it was superseded by the new tolerance on pea and bean, succulent shel led, subgroup 6B.
Ecological Risk Assessment Status : The following are key findings of the most recent ecological risk assessments for halosulfuron

methyl . Please refer to Registration Review

– Preliminary Problem Formulation for the Environmental Fate , Ecological Risk, and Endangered Species and Drinking Water Assessments for Halosulfuron

- methyl , March 8 , 2012 , located in the docket, for a detailed discussion of the ecological risk assessments.

**•** The most rec ent ecological risk assessment for halosulfur on

- methyl was completed in May 2010 in support of the registration for use on dried shelled peas and beans (except soybeans), succulent shelled peas and beans, apples, rhubarb, bushberry, fruiting vegetables, and tuberous and corm vegetables.

**•** The Agency concluded that acute and chronic risk estimates for birds, mammals, freshwater fish, aquatic invertebrates, and estuarine/marine invertebrates did not exceed the Agency’s Level of Concern (LOC) for ecological effects

. **•** In the 20 10 ecological risk assessme nt, the Agency concluded that the LOCs were exceeded for aquatic and terrestrial plants (listed species and non

- listed species) from both the aerial and ground application of halosulfuron

- methyl.13 Human Health Risk Assessment Status: The following are ke y findings of the most recent human health risk assessments for halosulfuron

- methyl . Please refer to Halosulfuron

- methyl: Human Health Assessment Scoping Document in Support of Registration Review , March 6, 2012 located in the docket, for a detailed discu ssion of the human health risk assessment.

The most recent human health risk assessment for halosulfuron

- methyl was completed in April 2010 in support of the registration for use on dried shelled peas and beans (except soybeans), succulent shelled peas an d beans, apples, rhubarb, bushberry, fruiting vegetables, and tuberous and corm vegetables.
Hazard Characterization:

**•** The herbicidal activity of halosulfuron

- methyl, as with all sulfonylureas , is due to the inhibition of acetolactate synthase (ALS), an en zyme found only in plants and bacteria. This enzyme is part of the biosynthesis pathway leading to the formation of branched chain amino acids (e.g. , isoleucine, leucine, and valine) , which are required for growth. Animals lack AL S and this biosynthetic pathway, contribut ing to the relatively low toxicity of sulfonylurea herbicides in animals.

**•** Halosulfuron

- methyl has low acute to xicity via the oral , inhalation , and dermal routes of exposure. It is not a dermal or eye irritant or skin sensitizer.

**•** The A gency reduced the 10x FQPA Safety Factor to 1x in its most recent risk assessment

. Although the data indicated an increase in qualitative susceptibility in fetuses following prenatal exposure in rats and rabbits, the developmental effects were seen in the presence of maternal effects and clear N o Observed Adverse Effect Levels (NOAELs) and Lowest Observed Adverse Effect Levels ( LOAELs ) were established for both maternal and developmental effects. In addition, the developmental effects in rats were seen at doses approaching the limit dose (1000 mg/kg). The Agency concluded that the degree of concern was low and there was no residual uncertainty in either the rat or rabbit developmental toxicity study. In addition to a lack of residual concerns for suscept ibility, there was no evidence of neurotoxicity, and exposures were not considered to be underestimated.

**•** Halosulfuron

- methyl has been classified as “not likely to be carcinogenic to humans” because carcinogenicity studies in rats and mice showed no increa se in the incidence of treatment

- related tumor s . The results of acute and subchronic neurotoxicity studies show no neurotoxic effects. Genotoxicity studies did not demonstrate any evidence of mutagenic potential for halosulfuron

- methyl.
Dietary:

**•** Acute and chronic dietary (food and water) risk assessments were conducted for the general U.S. population and various population subgroups, with the major emphasis placed on the exposure estimates for infants and children. F or all supported registered commodit ies, a cute and c hronic dietary exposure to halosulfuron

- methyl did not exceed the Agency’s LOC for the general population and vulnerable population subgroups.14 Residential:

**•** In the 2010 risk assessment, short

- and intermediate

- term dermal and inhalation
r esidential handler risk estimates for all residential handler exposure scenarios were below the Agency’s target LOC. Based on the use pattern of halosulfuron

- methyl, long

term residential exposures were not expected and, therefore, not assessed

.

**•** For res idential post

- application exposure scenarios, all risk estimate s were below the Agency’s LOC. Post

- application e xposure risk estimates from lawn treatment were assessed for adults ’ and children’s post

- application dermal exposure, children’s incidental ing estion of pesticide residues on lawns from hand

- to

- mo u th exposure, children’s object

to

- mouth transfer from mouthing of pesticide

- treated turfgrass, and children’s incidental ingestion of soil from pesticide

- treated residential areas.
Aggregate:

**•** Acute, s hort

- , and intermediate

- term aggregate risk assessments were conducted as part of the 2010 human health risk assessment

. A cancer aggregate risk assessment was not performed because halosulfuron

- methyl has not been shown to be carcinogenic. All
a ggregate risk estimates were below the Agency’s LOC.
Occupational :

**•** Short

- and intermediate

- term o ccupational handler scenarios resulted in exposure s below the Agency’s LOC with the use of b aseline clothing (i.e., long

- sleeved shirt, pants, socks, and shoes)

. P ost

- application scenarios also resulted in dermal exposure below the Agency’s LOC at a restricted

- entry interval of 12 hours

.

**•** Based on Agency standards and policies at the time of the assessment, a quantitative post

- application inhalation exposure assess ment was not performed for halosulfuron

methyl

. Human Studies:

**•** Past halosulfuron

- methyl risk assessments rely in part on data from studies in which adult human subjects were intentionally exposed to a pesticide to determine their dermal and inhalation exposure. Many such studies, involving exposure to many different pesticides, comprise generic pesticide exposure databases such as the Pesticide Handlers Exposure Database (PHED) and the Agricultural Reentry Task Force (ARTF) Database. EPA has reviewed all the studies supporting these multi

- pesticide generic exposure databases, and has found no clear and convincing evidence that the conduct of any of them was either fundamentally unethical or significantly deficient relative to the ethical standards prev ailing at the time the research was conducted. All applicable requirements of EPA’s Rule for the Protection of Human Subjects of Research (40 CPR Part 26) have been satisfied, and there is no regulatory barrier to continued reliance on these studies.15 Cumulative:

**•** The Agency has not determined whether halosulfuron

- methyl shares a common mechanism of toxicity with other chemical substances. If, in the future, the Agency determines that new information on halosulfuron

- methyl is available that could poten tially impact a cumulative risk assessment, the Agency will revisit the need for one.

Incidents:

**•** The Office of Pesticide Programs (OPP) Incident Data System (IDS) was consulted for reports of halosulfuron

- methyl incidents. From 200 6 to November 2, 2 011 , fourteen cases were reported for halosulfuron

- methyl . Because the cases fall within the categories reported as minor, unknown, or no effects, there is no unique report that provides details about the incidents, and single chemical incidents are not d istinguished from multiple chemical incidents. B ased on the low severity of incident cases that occurred, there does not appear to be a concern at this time that would warrant further investigation.

**•** A preliminary review was made on September 6 , 2011 of t he Ecological Incident Information System (EIIS), which is maintained by OPP, and the Avian Monitoring Information System (AIMS), which is maintained by the American Bird Conservancy. No incidents involving halosulfuron

- methyl were found in EIIS or the AIM S database

. Tolerances and International Harmonization:

**•** T olerances are established for residues of halosulfuron

- methyl , including its metabolites and degradates , under 40 CFR §180.479(a)(2)

. Compliance with tolerances levels is determined by measurin g halosulfuron

- methyl, methyl 5

- [(4,6

- dimethoxy

- 2

- pyrimidinyl)amino]carbonylaminosulfonyl]

- 3

- chloro

- 1

- methyl

- 1 H

- pyrazole

- 4

- carboxylate

**•** The Agency anticipates updating the current halosulfuron

- methyl tolerance expression in 40 CFR §180. 479 to be consistent with the Chemical Abstracts Service (CAS) nomenclature ( methyl 3

- chloro

- 5

- [[[[(4,6

- dimethoxy

- 2

- pyrimidinyl)amino]carbonyl]amino]sulfonyl]

- 1

- methyl

- 1 H

- pyrazole

- 4

- carboxylate) or the International Union of Pure and Applied Chemistry (IUPAC) nomenclature (me thyl 3

- chloro

- 5

- (4,6

- dimethoxypyrimidin

- 2

- ylcarbamoylsulfamoyl)

- 1

- methylpyrazole

- 4

- carboxylate).

Data Call

- In Status

**•** No data call

- ins have been issued for halosulfuron

- methyl

. Labels :

**•** Halosulfuron

- methyl Section 3 product labels can be obtained from t he Pesticide Product Label System (PPLS) website: http://oaspub.epa.gov/pestlabl/ppls.hom16 III. Summary of Anticipated Data Requirements

– Halosulfuron

- methyl

1. The table below summarizes all anticipated dat a needs for halosulfuron

- methyl in Section I, of this document (Preliminary Work Plan), the Registration Review : Preliminary Problem Formulation for the Environmental F ate and Ecological Risk, Endangered Species and Drinking Water Assessments for Halosulfu ron
- methyl , March 8 , 2012 , and the Halosulfuron

- methyl : Human Health Assessment Scoping Document in Support of Registration Review , March 6, 2012

.

Guideline Number Anticipated Data Requirement Test Material Study Duration

835.4100 Aerobic Soil Metabol ism (two soils) TGAI 24

835.4300 Aerobic Aquatic Metabolism TGAI 24

835.6100 Terrestrial Field Dissipation 1 TGAI 12

8 35.6200 Aquatic Field Dissipation 2 T EP 24

850.1010 Acute Toxicity Freshwater Invertebrates TEP 24

850.1075 Acute Freshwater Fish Tox icity TEP 12

860.1650 Submittal of Analytical Reference Standards 3 PAI ; residue of

concern 24

870.7800 Immunotoxicity TGAI 12 NON

GDLN Enhanced Aerobic Soil Metabolism Study 4 TGAI 48
NON

GDLN Enhanced Hydrolysis Study 5 TGAI 12
NON

GDLN Special Study f or Non

- Target Plant Reproductive Toxicity TEP 4 24

1 See footnote 7 of 40 CFR 158.1300. EPA anticipates req uiring only the environmental chemistry analytical method and independent laboratory validation portion s of GDLN 835.6100

– Terrestrial Field Dissipation. 2 That Agency has classified a previously

- submitted study (MRID 44437304) as supplemental, as it inco mpletely addressed the fate of halosulfuron

- methyl in flooded environments. Acceptance of this study is made conditional upon acceptance of a submitted aerobic aquatic metabolism study (GDLN 835.4300), which is currently in review. In addition, environme ntal chemistry methods and independent laboratory validation are still required for water under GDLN 835.6200 per footnote 7 of 40 CFR 158.1300

. 3 Analytical reference standards are available for halosulfuron

- methyl and the 3

- CSA (3

- chlorosulfonamide acid) metabolite but not for the rearrangement ester (RRE) of halosulfuron

- methyl. An analytical reference standard for the RRE of halosulfuron

methyl is expected to be required to be submitted to the EPA National Pesticide Standards Repository. 4 The anticipa t ed DCI will require a protocol be submitted within 90 days of receipt of the DCI for review and approval by the Agency prior to initiation of this study. 5 The anticipated DCI will require the protocol for GDLN 835.2120

– hydrolysis be followed

. Suggeste d parameters include testing at pHs of 5, 7, and 9 and at temperatures of 10, 15, 20, and 25 C for 60 days (and additional ly pH 4, 6, and 8 at 15 C), and analysis for halosulfuron

- methyl and potential major hydrolysis products.