2 

### Simazine Preliminary Work Plan – Table of Contents

Overview 3

Anticipated Data Needs 4

Statutory and Regulatory Authority 4

Simazine Facts 5

Use and Usage Information 5

Recent Actions 7

Anticipated Risk Assessments for Registration Review 7

Timeline 9

Next Steps 10

Appendix – Additional Areas Considered in the Simazine Registration Review 11

References:

This Preliminary Work Plan summarizes the En vironmental Protection Agency's current position based on the following documents:

1. Registration Review – Preliminary Problem Formulation for the Ecological Risk Assessment for Simazine. F. Farruggia. May 28, 2013.

2. Atrazine, Propazine, and Simazine. Human He alth Risk Scoping Document in Support of Registration Review . W. Donovan. June 4, 2013

3. Atrazine, Propazine, and Simazine: Review of Human Incident Reports . S. Recore. January 22, 2013.

4. BEAD Chemical Profile for Registration Review: Simazine. B. Phillips. February 1, 2013.

5. Simazine Screening Level Usage Analysis . March 16, 2012.

6. PRD Label Data Report: Food/Feed & N on-Food/Non-Feed Uses Considered in Registration Review Work Planning . January 14, 2013.

These and other supporting documents for the sim azine registration review case may be found in the docket EPA-HQ-OPP-2013-0251 at http://www.regulations.gov

.3 OVERVIEW

The docket for simazine is now open, initiati ng the first public comment period for this registration review (docket number EPA-HQ- OPP-2013-0251). Simazine is a non-selective systemic triazine herbicide registered for use fo r pre- and post-emergent applications to control annual and perennial grasses and broadleaf weed s on a variety of crops, such as oranges and corn; and non-agricultural use site s, such as residential turf. Fo r human health risk assessment, simazine is part of the tri azine common mechanism group based on a common toxicity end-point and known mechanism of toxicity. The triazi ne common mechanism group consists of the pesticide active ingredients atrazine, simazine, propazine, and the metabolites desethyl-s-atrazine (DEA), desisopropyl-s-atr azine (DIA), and diaminochlorotriazine (DACT). 1 This Preliminary Work Plan (PWP) document explains what EP A's Office of Pesticide Programs knows about simazine, highlighting anticipated data and assessment needs, identifying the types of information that would be especially useful to the Agency in conducting the review, and providing an anticipated timeline for comple ting the registration review for simazine.

The registration review process was designed to include a publi c participation component to solicit input from interested stake holders. The Agency intends, by sharing this information in the docket, to inform the public of what it knows about simazine and what types of new data or other information would be helpful for the Agency to receive as it moves toward a decision on simazine. The Agency encourages all interested stakeholders to review the PWP and Appendix and to provide comments and additional inform ation that will help the Agency’s decisionmaking process for simazine. In addition to general areas on which persons may wish to comment, there are some areas identified in the PWP and Appendix about which the Agency specifically seeks comments and information. Interested stakeholde rs could include: environmental non-profit or interest groups; pe sticide manufacturers; agricultural labor or commodity groups; commercial, institutional, reside ntial, and other users of pesticides; or the public at large.

The Preliminary Work Plan begins by listing the anticipated data needs for simazine. Next, it discusses the statutory and regul atory authority for Registration Review. Then the document provides simazine facts, use and usage info rmation, recent actions, the anticipated risk assessments, and a projected registration review timeline for simazine. Finally, the Appendix to

this document includes identification and discussion of some areas that ar e considered generally in Registration Review along with some a dditional simazine case-specific information.

1 There are other triazine pesticides, such as ametryn, prometryn, and prometon, but they are excluded from the

triazine common mechanis m group because they do not share the same toxicity profile. ( Triazine Cumulative

Risk Assessment . J. Morales. March 28, 2006.)4 ANTICIPATED DATA NEEDS

Table 1 below summarizes anticipa ted data needs for simazine. For additional discussion of the anticipated data needs, see the Registration Review – Preliminary Problem Formulation for the Ecological Risk Assessment for Simazine and Atrazine, Propazine and Simazine. Human Health Risk Scoping Document in Support of Registration Review

.

Table 1: Anticipated Data Needs for the Simazine Registration Review

Guideline

Number 1 Study Title 1
Test Material Estimated

Timeframe

(Months from receipt of DCI)

850.6100 Environmental chemistry methods (ECM) and associated independent laboratory validation (ILV) for soil 2 TGAI 12

TGAI = technical grade active ingredient

1 On June 27, 2012, EPA announced certain revisions in harmonized guideline series 850 – Ecological Effects Tests

– including renumbering and other designations or changes for some guideline studies. See “Final Test Guidelines; OCSPP 850 Series; Notice of Av ailability” 77 FR 38282 , June 27, 2012. http://www.regulations.gov/#!documen tDetail;D=EPA-HQ-OPPT-2009-0154-0028

2 ECM and ILVs are used in the testi ng and identification of chemicals.

STATUTORY AND REGULATORY AUTHORITY

The Food Quality Protection Act (FQPA) of 1996 mandated a registration review program. All pesticides distributed or sold in the United Stat es (U.S.) generally must be registered by the Environmental Protection Agency (EPA or the Ag ency), based on scientific data showing that they will not cause unreasonable ri sks to human health or the environment when used as directed on product labeling. The registration review program is intended to ma ke sure that, as the ability to assess risk evolves and as policies and practices change, all registered pesticides continue to meet the statutory standard of no unreasonabl e adverse effects to human health or the environment. Changes in science, public policy, and pesticide use practices will occur over time. Through the registration review prog ram, the Agency periodically r eevaluates pesticides to make sure that as change occurs, products in the mark etplace can be used safely. Information on this program is provided on EPA’s website. 2

The Agency is implementing the registration revi ew program pursuant to Section 3(g) of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), a nd will review each registered pesticide every 15 years to determine whether it continues to meet th e FIFRA standard for registration. The regulations governing regi stration review begin at 40 CFR 155.40. The Agency will 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 additional risk analyses

and data or information it believes are needed to make a registration review decision. After

2 http://www.epa.gov/oppsrrd1/registration_review/5 reviewing and responding to comments and data received in the docke t during this initial comment period, the Agency will develop a Final Work Plan (FWP) and anticipated schedule for the registration review of simazine.

SIMAZINE FACTS

Table 2 provides a summary of the chemical facts for simazine.

Table 2: Chemical Facts for Simazine

PC code 080807

Case Number 7280

CAS Number 122-34-9 Year first registered 1957 Pesticide Type Herbicide

Chemical class Triazine Reregistration Eligibility Decision (RED) April 2006

Tolerance Reassessment Eligibility Decision (TRED) N/A

Cumulative group Triazine. The most r ecent human health cumulative risk assessment was completed in March 2006. ( Triazine Cumulative

Risk Assessment . J. Morales. March 28, 2006.) 40 CFR Citation Tolerances for simazine are established in 40 CFR §180.213 Dual-use Simazine is registered for c onventional pesticidal uses only and has no registered antimicrobial or biopesticidal uses. Non-pesticidal uses There are no identi fied non-pesticidal uses of simazine

Pesticide Re-evaluation Division, Simazine Review Manager Molly Clayton clayton.molly@epa.gov

703-603-0522 Registration Division, Product Manager Kable Bo Davis davis.kable@epa.gov

703-306-0415

USE AND USAGE INFORMATION

Table 3 summarizes the use and usage information for simazine. Please see BEAD Chemical Profile for Registration Review: Simazine in the registration review docket for more details.

Table 3: Simazine Use and Usage Information

Summary of Use Simazine is a non-selective systemic triazine herbicide that can be applied postemergence to weeds as a foliar- applied herbicide; however since it is readily abso rbed through the root system, it i s primarily applied as a pre-plant incorporated or soil applied

herbicide. It is also registered for use on non-agricultu ral use sites.6 Table 3: Simazine Use and Usage Information

Use Sites Agricultural : Registered for u se on crops including but not limited

to p ome fruits, broccoli, brussel sprouts, cranberry, persimmon, strawberries, caneberries, grapes, citrus fruits, nut crops, stone fruits, artichokes, corn, asparagus, kale, cabbage , blueberries,

a l falfa, avocado, and olives

.

Non-a gricu l tura l : Registered use sites include but are not limited to

forest trees

, ornamenta l plants , ornamental ponds and aquaria, uncultivated agricultural areas, re sidential and golf course turf,

Chris t mas tree farms, nursery stock

, building perimeters, and shelterbelt p l an t ings. Summary of Usage Agricultural : During the time per io d of 1998

- 2011, the annual total agricultural usage of simazine averaged approximate l y 6 m illi on pounds active ingredient (a.i.) to treat approx i mately 4 million

acres. During this t i me frame, the crops with the highest use in

t erms of percent of total pounds of active ingredient app lied and

acres treated were co rn and oranges.

Non-agricultural : The most recent non-agricultural usage data available to the EPA (2002-2006) indicate approximately 400,000 pounds of simazine a.i. are applied to non-agricultural use sites per

year. Formulation Type(s) Simazine i s formu l ated e i th er as a liqu i d, emu l s i fiab l e concentrate, dry flowable or a flowable concentrate. Application Method(s) Applied by aerial and ground broadcast

, band application,

c h emigation, and spo t tr eat ment. Technical Registrant(s) Syngenta Crop Prot ection, LLC; Oxon Italia S.P.A.; Drexel Chemical Company No. of Registrations 22 Section 3 and 12 Sect ion 24c (special loca l needs) registrations 3

Restricted Use No

Guidance for Commenters: Additional areas of use and usage related information requested for this registration review, and of part icular interest to EPA, are described below.

 Certain simazine labels are uncl ear with respect to application parameters such as the size of the treated area, the extent of a treated “spot,” retreat ment intervals, or maximum annual application rates. In the lack of further information, EPA expects to use conservative assumptions to approximate th ese parameters in order to conduct a quantitative risk assessment. However, the Ag ency will work with registrants to clarify information on simazine product labels, especi ally the maximum annual application rates for non-agricultural uses incl uding golf courses, turf, and ornamental lawns.

3 Section 3 product labels can be obtained from th e Pesticide Product Label System (PPLS) website

(http://oaspub.epa.gov/pestlabl/ppls.home).7  Confirmation of the following label informati on: sites of application; formulations; application methods and equipment; maxi mum application rates; frequency of application, application intervals, and maxi mum number of applica tions per season; and geographic limitations on use.

 Use distribution ( e.g. , acreage and geographical distri bution of relevant use sites).

 Median and 90 th percentile reported use rates (lbs a i/A) from usage data – national, state, and county.

 Typical application timing (date of first applic ation and application in tervals) – national, state, and county.

 Usage/use information for non-agricultural uses.

 Typical application interval (days).

 State or local use restrictions.

 Foreign technical registrants not listed above who supply tech nical simazine to the US

market.

RECENT AND PENDING ACTIONS

The 2006 Simazine RED, which included a Memo randum of Agreement (MOA), and subsequent Data Call-In Notice (DCI), issu ed in 2007, required the registra nts to establis h an on-going drinking water monitoring program, called the Simazine Monitoring Program (SMP). The technical registrants for simazine are required to conduct an annua l review of all Safe Drinking Water Act (SDWA) data for simazine to determ ine if any community water systems (CWS) have a drinking water annual average concentration of simazine-based Total Chlorotriazine (TCT) concentration at 2.6 parts-per-billion ( μ g/L or ppb) or greater as a criterion for participation in the SMP. SMP monitoring samples are analyzed for simazine, atrazine, and their chlorinated degradates, as all are considered equally toxic to humans. Currently, 7 CWS are included in the SMP. More specific details concerning the SMP may be found in the simazine RED. As new data become available, EPA conducts reviews of the registrant-submitted water monitoring data and other water monitoring programs looking for si mazine, such as U.S. Geological Survey’s (USGS’s) National Water-Quality Assessmen t Program (NAWQA) and state monitoring

programs.

The Agency is currently reviewing a request , dated March 28, 2012, submitted by a technical registrant for simazine, Synge nta Crop Protection, LLC, to rem ove 5 of the 7 CWS from the SMP. The request states that these 5 sites are eligible for re moval from the SMP under the terms established by the MOA, since five consecutive years have passed wit hout any 90-day rolling average concentration of simazine and its two chlorinated degradates meeting or exceeding 37.5 ppb. EPA expects to complete its revi ew of this request in summer 2013.

The Agency is currently evaluating a toleran ce petition for simazine (2F8006, 77 FR 50686) to establish crop group tolerances for stone fruit, po me fruit, citrus fruit, and tree nuts, and to

remove individual tolerances which would be replaced by the new crop groups. EPA is in the process of reviewing this request which will likely necessitate an upda ted assessment for the triazine cumulative group.8 ANTICIPATED RISK ASSESSMENT S FOR REGISTRATION REVIEW

The most recent comprehensive human health risk assessment for simazine was completed in 2006 in preparation for the Reregistration Eligibility Decision. The most recent ecological and environmental fate risk assessment was completed in 2005 for the same purpose. Findings and

conclusions from these risk assessments are summarized in the Registration Review – Preliminary Problem Formula tion for the Ecological Ri sk Assessment for Simazine and Atrazine, Propazine, and Simazine; Human Health Risk Scoping Document in Support of Registration

Review.

During registration review, the Agency antici pates the need to conduct a comprehensive ecological risk assessment, including an endangered species assessment, for all uses of simazine. For human health, EPA anticipates the need to conduct revised diet ary, residential, and occupational, and cumulative risk assessments during registration review . If toxicological endpoints or points of departure are revised, they will be considered in the new assessments, as well as any changes to the standard operating procedures or default exposure assumptions.

Table 4 below summarizes the anticipated regi stration review risk assessments based on the

EFED Problem Formulation and HED Scoping Document.

Table 4: Anticipated Risk Assessments for the Simazine Registration Review

Type of Risk Assessment Conduct? Notes

Ecological and Environmental Fate Comprehensive ecological (species to be assessed include terrestrial and aquatic organisms), including endangered species Y The stressors of concern for terrestrial organisms are parent simazine and the de gradate DIA. The stressor of concern for aquatic organisms is parent simazine alone. For additional information, see page 23 of the

Problem Formulation.

Incidents Will check for updates For a discussion of reporte d ecological incidents for simazine, see page 21 of the Problem Formulation.

Human Health Dietary Food Y During registration review, an updated dietary assessment may be conducted to include any updates to toxicological endpoints, dietary exposure estimates, and changes to assessment SOPs.

Drinking water Y EPA intends to use the data collected in the SMP in its drinking water assessme nt for simazine during registration review. EPA also intends to use data

collected in the Atrazine Monitoring Program (AMP) in the drinking water assessment for simazine, as simazine is also detected in water samples analyzed

for the AMP.9 Occupational Handlers (mixers, loaders, applicators) Y Since the most recent occupational risk assessment for simazine was conducted, EPA finalized new occupational risk assessment standard operating procedures (SOPs), includi ng new potential exposure scenarios applicable to simazine that were not previously assessed (e.g. ha ndheld equipment for turf and ornamentals). During registration review, EPA anticipates updating all relevant occupational exposure scenarios, along with any changes to toxicity endpoints and/or safety factors. Post-application Y

Residential

Handlers Y Since the most rece nt residential assessment for simazine was conducted, new residential risk assessment procedures containing additional turf scenarios have been finalized. During registration review, EPA anticipates updating all relevant residential handler and po st-application assessments, along with any changes to toxicity endpoints and/or safety factors. Post-application Y

Other Aggregate Y Evaluates the combined risk from dietary and residential exposures. Cumulative Y An assessment of the triazine cumulative group is expected as part of registration review.

Tolerances Y Tolerances ar e established under 40 CFR §180.213

for the combined residues of simazine and its two chlorinated metabolites in/on a variety of crops and livestock commodities. EPA anticipates updating the

residue definition for the tolerance expression for simazine in accordance with current policy on

tolerance definitions.

Incidents Will check for updates For a discussion of reported human incidents for simazine, see page 12 of the Scoping Document and

the Atrazine, Propazine, and Simazine: Review of Human Incident Reports

.

TIMELINE

EPA has created the following estimated timeline for the completion of the simazine registration

review in Table 5 below.

Table 5: Projected Simazine Registration Review Timeline

Activities Estimated Date Opening the Docket Open Docket and 60-day Public Comment Period 2013 – June10 Table 5: Projected Simazine Registration Review Timeline

Activities Estimated Date Close Public Comment 2013 – August Case Development

Final Work Plan 2013 – November Issue DCI 2014 – July - September 60-day Public Comment Period for Draft Risk Assessments 4,5 2015 – April - June Data Submission 2016 – July - September Registration Review Decision 60-day Public Comment Period fo r Proposed Registration Review

Decision 2015 – Oct. - Dec.

Registration Review Decision and Begin Post-Decision Follow-up 2016 Total (years) 3

NEXT STEPS

After the 60-day public comment period closes , the Agency will review and respond to any comments received in a timely manner and then i ssue a Final Work Plan for the registration

review of simazine.

4 The registration review schedule for most conventional pesticides includes a 6 month period after the Final Work

Plan to issue a data call-in and then an appropriate time period for the required data to be submitted to EPA. However, because the one anticipated data requirement for simazine, Guideline 850.6100 (environmental chemistry methods and associated independent labor atory validation for soil), will not aff ect the preliminary risk assessments for simazine registration review, the schedule has been modified as appropriate.

5 The regulations governing Registration Review generally require the Agency to provide a public comment period

of at least 30 calendar days for draft risk assessments; see 40 CFR Part 155.53(c). For conventional pesticides, the Agency plans to provide a 60 calendar day public comment period for draft risk assessments.11 

### Appendix – Additional Areas Considered in the Simazine Registration Review

PUBLIC COMMENTS AND FEEDBACK:

Guidance for Commenters: The areas below highlight topics of special interest to the Agency where your comments, data submi ssions, or reference to sources of additional information could be of particular use.

Trade Irritants:

Through the registration review process, the Ag ency intends to solicit information on trade irritants and, to the extent feas ible, take steps toward facilitating irritant resolution. The Agency will work to harmonize tolerances and international maximum residue limits (MRLs) and may modify tolerance levels to do so, when possible. 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, provi ding as much specificity as possible regarding

the nature of the concern

Water Quality:

Simazine is identified as a cause of impairmen t, as defined under sec tion 303(d) of the Clean Water Act, for three water bodies in Califor nia, based on information provided at EPA’s

website. 6 Total Maximum Daily Loads (TMDLs) are needed for simazine for one impaired water body in Oregon and one in Michigan, ba sed on information provided at the website. 7
More information on impaired water bodies and TMDLs can be found at EPA’s website. 8 The Agency invites submission of wat er quality data for this pesticide. To the extent possible, data should conform to the quality standards in Appendix A of the OPP Standard Operating Procedure: Inclusion of Im paired Water Body and Other Water Quality Data in OPP’s Registration Review Risk A ssessment and Management Process 9 in order to ensure they can be used quantitatively or qualitativel y in pesticide risk assessments.

Environmental Justice:

EPA seeks to achieve environmenta l justice, the fair tr eatment and meaningful involvement of all people, regardless of race, color, national origi n, or income, in the deve lopment, implementation, and enforcement of environmental laws, regulati ons, 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 thei r location, cultural practices, or other factors, may have atypical, unusually high exposure to simazi ne compared to the general population. Please comment if you are aware of any sub-populations that may have atypical, unusually high exposure compared to the general population.

6 http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885

7 http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl _pollutant_detail?p_pollutant_group_id=885&p_pollutant_ group_name=PESTICIDES

8 http://www.epa.gov/owow/tmdl/

9 http://www.epa.gov/oppsrrd1/registration_review/water_quality_sop.htm12 ENDANGERED SPECIES:

A risk assessment that supports a complete endangered species determination has not been conducted for simazine. The ecological risk a ssessment planned during registration review will allow the Agency to determine whether use of sim azine has “no effect” or “may affect” federally listed threatened or endangered species (listed sp ecies) or their designate d critical habitats. When an assessment concludes that a pesticid e’s use “may affect” a listed species or its designated critical habitat, the Agency will c onsult with the U.S. Fish and Wildlife Service

and/or National Marine Fisheries Service (the Se rvices), as appropriate.

ENDOCRINE DISRUPTOR SCREENING PROGRAM :

As required by FIFRA and FFDCA, EPA reviews num erous studies to asse ss potential adverse outcomes from exposure to chemicals. Collectiv ely, these studies includ e acute, subchronic and chronic toxicity, including asse ssments of carcinogenicity, ne urotoxicity, developmental, reproductive, and general or systemic toxicity. These studies include endpoints which may be susceptible to endocrine influe nce, including effects on endocri ne target organ histopathology, organ weights, estrus cyclicity, sexual maturatio n, fertility, pregnancy rates, reproductive loss, and sex ratios in offspring. For ecological h azard assessments, EPA evaluates acute tests and chronic studies that assess gr owth, developmental and reprod uctive effects in different taxonomic groups. As part of its re registration decision for simazine, EPA reviewed these data and selected the most sensitive endpoints for relevant risk assessment scenarios from the existing hazard database. However, as required by FFDCA section 408(p), simazine is subject to the endocrine screening part of the Endocri ne Disruptor Screen ing Program (EDSP).

EPA has developed the EDSP to determine whet her 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 ot her such endocrine effect s as the Administrator may designate.” The EDSP employs a two-tiered approach to making th e statutorily required

determinations. Tier 1 consists of a battery of 11 scr eening assays to identify the potential of a chemical substance to interact with the estrog en, androgen, or thyroid (E, A, or T) hormonal systems. Chemicals that go th rough Tier 1 screening and are found to have the potential to interact with E, A, or T hormonal systems will proceed to the next stag e of the EDSP where EPA will determine which, if any, of th e Tier 2 tests are necessary base d on the available data. Tier 2 testing is designed to identify a ny adverse endocrine-related eff ects caused by the substance, and establish a dose-response relationship between the dose and the E, A, or 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 in gredients and 9 inert ingredients. Simazine was included on that list and has been issued an orde r to conduct the Tier 1 testing. Once all required

Tier 1 and Tier 2 data have been received and reviewed, the endpoints and safety factors used for risk assessment purposes will be examined and a new risk assessment performed if necessary.

For further information on the status of the ED SP, the policies and procedures, the list of 6713 chemicals, future lists, the test guidelines and the Tier 1 screening ba ttery, please visit our

website. 10

HUMAN STUDIES:

Occupational and Residential

Past simazine risk assessments rely in part on data from studies in which adult human subjects were intentionally exposed to a pesticide to de termine their dermal and inhalation exposure. Many such studies, involving exposur e to many different pesticides, comprise generic pesticide exposure databases such as the Pesticide Handl ers Exposure Database (PHED), the Agricultural Reentry Task Force (ARTF) Database, and th e Outdoor Residential Exposure Task Force (ORETF) Database. EPA has reviewed all the studies supporting these multi-pesticide generic exposure databases, and has found no clear and c onvincing evidence that the conduct of any of them was either fundamentally unethical or si gnificantly deficient relative to the ethical standards prevailing at the time the research wa s conducted. All applicab le requirements of EPA’s Rule for the Protection of Human Subject s of Research (40 CFR Part 26) have been satisfied, and there is no regulatory barri er to continued reliance on these studies.

AGRICULTURAL HEALTH STUDY:

Simazine is among several agricultural chemi cals included in the Agri cultural Health Study (AHS). The AHS began in 1993 and is a collaboration of the National Institute of Environmental Health Sciences (NIEHS), the Nati onal Cancer Institute (NCI), the EPA, and the National Institute for Occupational Safety and H ealth (NIOSH). Designe d as a large long-term epidemiological study, the AHS collects and analyzes data on the health and work practices of nearly 90,000 farmers and their families in Iowa and North Carolina who enrolled in the study before any disease developed. The study focu ses particularly on fa rmers' exposure to 50 chemicals including many of the most widely used pesticides. As data are collected over a period of years, scientists can compare overall he alth outcomes for people who differ in whether they have had exposure to various chemicals. While these comparisons cannot conclusively demonstrate how exposure affects health, they ca n show some statistical associations. More information on the AHS can be found at: http:/ /aghealth.nci.nih.gov. EPA is monitoring the results of the AHS and will consider this study in the registration review of simazine as appropriate.

10 http://www.epa.gov/endo/