Docket Number EP A-HQ-OPP-2013-0251
www.regulations. gov

Simazine
Proposed Interim Registration Review Decision
Case Number 0070
December 2019
Approved by:
Elissa Reaves, Ph.D.
Acting Director
Pesticide Re-evaluation Division
Date:	12-18-2019

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Table of Contents
I.	INTRODUCTION	3
A.	Summary of Simazine Registration Review	4
B.	Summary of Public Comments on the Draft Risk Assessments and Agency Responses	6
II.	USE AND USAGE	8
III.	SCIENTIFIC ASSESSMENTS	8
A.	Human Health Risks	8
1.	Risk Summary and Characterization	9
2.	Human Incidents and Epidemiology	13
3.	Tolerances	14
4.	Human Health Data Needs	15
B.	Ecological Risks	16
1.	Risk Summary and Characterization	16
2.	Ecological Incidents	19
3.	Ecological and Environmental Fate Data Needs	19
C.	Benefits Assessment	19
IV.	PROPOSED INTERIM REGISTRATION REVIEW DECISION	21
A.	Proposed Risk Mitigation and Regulatory Rationale	21
1.	Proposing Cancellation of Simazine Residential Turf Use	21
2.	Risk Mitigation for Occupational Handlers	22
4.	Non-target Organism Advisory Statement	23
5.	Herbicide Resistance Management	24
6.	Additional Label Changes	24
B.	Status of Simazine Water Monitoring Program and Proposed Changes	24
C.	Expected Impacts of Proposed Mitigation	25
D.	Tolerance Actions	31
E.	Proposed Interim Registration Review Decision	31
F.	Data Requirements	32
V.	NEXT STEPS AND TIMELINE	32
A.	Proposed Interim Registration Review Decision	32
B.	Implementation of Mitigation Measures	32
Appendix A: Summary of Proposed Actions for Simazine	34
Appendix B: Proposed Labeling Changes for Simazine Products	35
Appendix C: Endangered Species Assessment	41
Appendix D: Endocrine Disruptor Screening Program	43
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I. INTRODUCTION
This document is the Environmental Protection Agency's (the EPA or the agency) Proposed
Interim Registration Review Decision (PID) for simazine (PC Code 080807, case 0070), and is
being issued pursuant to40CFR§§ 155.56 and 155.58. A registration review decision is the
agency's determination whether a pesticide continues to meet, or does not meet, the standard for
registration in the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). The agency may
issue, when it determines it to be appropriate, an interim registration review decision before
completing a registration review. Among other things, the interim registration review decision
may require new risk mitigation measures, impose interim risk mitigation measures, identify data
or information required to complete the review, and include schedules for submitting the
required data, conducting the new risk assessment and completing the registration review.
Additional information on simazine, can be found in the EPA's public docket (EPA-HQ-OPP-
2013-0251) at www.regulations.gov.
FIFRA, as amended by the Food Quality Protection Act (FQPA) of 1996, mandates the
continuous review of existing pesticides. All pesticides distributed or sold in the United States
must be registered by the EPA based on scientific data showing that they will not cause
unreasonable risks to human health or to the environment when used as directed on product
labeling. The registration review program is intended to make sure that, as the ability to assess
and reduce risk evolves and as policies and practices change, all registered pesticides continue to
meet the statutory standard of no unreasonable adverse effects. Changes in science, public
policy, and pesticide use practices will occur over time. Through the registration review
program, the agency periodically re-evaluates pesticides to make sure that as these changes
occur, products in the marketplace can continue to be used safely. Information on this program is
provided at http://www.epa.gov/pesticide-reevaluation. In 2006, the agency implemented the
registration review program pursuant to FIFRA § 3(g) and will review each registered pesticide
every 15 years to determine whether it continues to meet the FIFRA standard for registration.
The EPA is issuing a PID for simazine so that it can (1) move forward with aspects of the
registration review that are complete and (2) implement interim risk mitigation (see Appendices
A and B). The agency is currently working with the U.S. Fish and Wildlife Service and the
National Marine Fisheries Service (collectively referred to as, "the Services") to develop
methodologies for conducting national threatened and endangered (listed) species assessments
for pesticides in accordance with the Endangered Species Act (ESA) § 7. Therefore, although the
EPA has not yet fully evaluated risks to federally-listed species, the agency will complete its
listed species assessment and any necessary consultation with the Services for simazine prior to
completing the simazine registration review. Likewise, the agency will complete endocrine
screening for simazine, pursuant to the Federal Food, Drug, and Cosmetic Act (FFDCA) §
408(p), before completing registration review. See Appendices C and D, respectively, for
additional information on the endangered species assessment and the endocrine screening for the
simazine registration review.
Simazine is an herbicide with products registered for use to control broadleaf and grassy weeds.
Simazine is a member of the triazine chemical class (Class 5), which includes atrazine and
propazine and the three major chloro metabolites: desethyl-s-atrazine (DEA), desisopropyl-s-
atrazine (DIA), and diaminochlorotriazine (DACT). The EPA has determined that the triazines
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and their three chlorinated metabolites share a common mechanism of toxicity, and as such,
human health risks were assessed together through a triazine cumulative risk assessment.
Pesticide products containing simazine are registered for use on several agricultural crops, most
common of which are corn and citrus. Simazine products are also registered for several non-
agricultural use sites, including residential and recreational settings. Common non-agricultural
uses include turf, nurseries, greenhouse and ornamentals. The first product containing simazine
was registered in 1958, and therefore simazine was subject to reregistration. There are three
technical product registrants for simazine: Drexel Chemical Company, Oxon Italia, and Syngenta
Crop Protection, LLC.
This document is organized in five sections: the Introduction, which includes this summary and a
summary of public comments and the EPA's responses; Use and Usage, which describes how
and why simazine is used and summarizes data on its use; Scientific Assessments, which
summarizes the EPA's risk and benefits assessments, updates or revisions to previous risk
assessments, and provides broader context with a discussion of risk characterization; the
Proposed Interim Registration Review Decision, which describes the mitigation measures
proposed to address risks of concern and the regulatory rationale for the EPA's PID; and, lastly,
the Next Steps and Timeline for completion of this registration review.
A. Summary of Simazine Registration Review
Pursuant to 40 CFR § 155.50, the EPA formally initiated registration review for simazine with
the opening of the registration review docket for the case. The following summary highlights the
docket opening and other significant milestones that have occurred thus far during the
registration review of simazine.
•	June 2013- The following documents were posted to the docket for a 60-day public
comment period
o Simazine Preliminary Work Plan (PWPj
o Registration Review - Preliminary Problem Formulation for the Ecological Risk
Assessment for Atrazine, Propazine, and Simazine
o Human Health Risk Scoping Document in Support of Registration Review
o Atrazine, Propazine, and Simazine: Review of Human Incidents
o BEAD Chemical Profile for Registration Review: Simazine (080807) Screening
Level Usage Analysis (SLUA)
o PRD Label Data Report: Food/Feed & Non-Food/Non-Feed Uses Considered in
Registration Review Work Planning
•	January 2014 - The Final Work Plan (FWP), for simazine was issued, 14 sets of public
comments were received concerning the PWP. The comments did not change the
schedule, risk assessment needs, or anticipated data requirements in the FWP.
•	May 2014 - A Generic Data Call-in (GDCI) 080807-1384 for simazine was issued for
data needed to conduct the registration review risk assessments. All data have been
submitted and accepted.
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•	June 2016 - The agency announced the availability of the Preliminary Ecological Risk
Assessment for Simazine for a 60-day public comment period. 119 comments were
received as well as another 88 that were posted on the shared trazine docket. These
comments and the agency's responses are summarized below. The comments resulted in
the correction of some minor errors, which are discussed in the Simazine—Environmental
Fate and Effects Division's Response to Public ("omments but did not impact the overall
conclusions of the risk assessment.
•	July 2018-The agency announced the availability of the Chlorotriazines: Cumulative
Risk Assessment - Atrazine, Propazine, and Simazine and Simazine Human Health Risk
Assessment for Registration Review to Support the Registration of Proposed Uses on
Citrus Fruit (Crop Group 10-10), Pome Fruit (Crop Group 11-10), Stone Fruit (Crop
Group 12/12), Tree Nuts (Crop Group 14-12), and tolerance Amendment for Almond
Hulls along with the supporting documents specified below. The comment period
opened on July 23, 2018 and was extended until November 23, 2018. During that time
sixteen public comments were received related to simazine.
o Chlorotriazines: Cumulative Risk Assessment - Atrazine, Propazine, and Simazine
o Cumulative Triazine (Atrazine, Simazine, Propazine) Drinking Water Assessment
o Chlorotriazines. Toxicology Systematic Literature Review- Atrazine, Simazine
and Propazine.
o Simazine Human Health Risk Assessment for Registration Review to Support the
Registration of Proposed Uses on Citrus Fruit (Crop Group 10-10), Pome Fruit
(Crop Group 11-10), Stone Fruit (Crop Group 12/12), Tree Nuts (Crop Group
14-12), and tolerance Amendment for Almond Hulls
o Simazine Occupational and Residential Exposure and Risk Assessment for
Registration Review and to Support the Registration of Proposed Uses Citrus
Fruit (Crop Group 10-10), Pome Fruit (Crop Group 11-10), Stone Fruit (Crop
Group 12-12), Tree Nuts (Crop Group 14-12), and Tolerance Amendment for
Almond Hulls
o Simazine. Acute 4-Day, Background, and Chronic Dietary (Food Only) Exposure
and Risk Assessments for Registration Review
•	December 2018 - A Generic Data Call-in (GDCI) for simazine was issued for
multiresidue data that was identified as a deficiency in the human health risk assessments.
The required data are currently under development and due to be submitted to EPA by
December 20, 2020. These data are not expected to impact the agency's ability to make a
risk managment finding.
•	December 2019 - The agency has completed the PID for simazine. Soon EPA will
announce the availability of the PID in the simazine docket and open a 60-day public
comment period. Along with the PID, the following documents are also posted to the
simazine docket: https//www.reeulations.aov/docke	-QPP-2013-0251
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o Simazine—Environmental Fate and Effects Division's Response to Public
Comments. November 25, 2019.
o Atrazine, Simazine, Propazine: Response to Public Comments on Registration
Review Human Health Risk Assessments. November 25, 2019.
o Atrazine and Simazine Use on Sweet Corn: Response to Comments, Usage,
Benefits, and Impacts of Potential Mitigation; PC Codes (080803 and 080807).
November 25, 2019.
o Atrazine and Simazine Use on Field Corn: Response to Comments, Usage,
Benefits, and Impacts of Potential Mitigation; PC Codes (080803 and 080807).
November 25, 2019.
o Atrazine and Simazine Use in Forestry, Rights of Way, Turf grass, and Nursery:
Response to Comments, Usage, and Benefits. November 25, 2019.
o Simazine Response to Comments, Usage, Benefits, and Impacts of Potential
Mitigation on Orchards, Vineyards, Caneberries, Strawberries, and Christmas
Trees. November 25, 2019
B. Summary of Public Comments on the Draft Risk Assessments and Agency
Responses
During the 120-day public comment period for the I'reliminary Ecological Risk Assessment for
Simazine, which opened on June 6, 2016 and closed on October 5, 2016, the agency received
public comments from 207 sources. The majority of these comments were part of a mass mailer
campaign in support of continued registration of simazine, including 52 post cards sent by
individual growers describing their use of simazine products. Other comments expressing
support of continued registration of simazine came from industry, various non-government
agencies and crop and agricultural associations. In addition, some individual comments
supported discontinuing registration of the triazines collectively, including simazine.
During the public comment period for the Simazine. Draft Human Health Risk Assessment for
Registration Review and the Chlorotriazines: Cumulative Human Health Risk Assessment -
Atrazine, Propazine, and Simazine, which opened on July 26, 2018 and closed on November 23,
2018, the agency received public comments from sixteen sources. These sources included
industry, various non-government agencies, and crop and agricultural associations, along with a
few individual citizens. Most of the comments were in support of continued simazine registration
but some, including the City of Sacramento Department of Utilities, were concerned about
simazine detections in public drinking supplies.
Comments that were technical in nature and specific to the Ecological Risk Assessment for
Simazine are addressed in the Simazine—Environmental Fate and Effects Division's Response to
Public Comments.
Technical comments related to the Simazine. Draft Human Health Risk Assessment for
Registration Review and the Chlorotriazines: Cumulative Human Health Risk Assessment -
Atrazine, Propazine, and Simazine are addressed in the Atrazine, Simazine, Propazine: Response
to Public Comments on Registration Review Human Health Risk Assessments.
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Comments related to simazine use and usage, benefits, and potential impacts of mitigation are
discussed in the following agency documents: (1 )Atrazine and Simazine Use on Sweet Corn:
Response to Comments, Usage, Benefits, and Impacts of Potential Mitigation; PC Codes
(080803 and 080807), (2) Atrazine and Simazine Use on Field Corn: Response to Comments,
Usage, Benefits, and Impacts of Potential Mitigation; PC Codes (080803 and 080807), (3)
Atrazine and Simazine Use in Forestry, Rights of Way, Turf grass, and Nursery: Response to
Comments, Usage, and Benefits, and (4) Simazine Response to Comments, Usage, Benefits, and
Impacts of Potential Mitigation on Orchards, Vineyards, Caneberries, Strawberries, and
Christmas Trees. These documents are available in the simazine registration review docket
through www.regulations. gov at docket identification number EPA-HQ-OPP-2013-0251. The
agency thanks all commenters for their comments and has considered them in developing this
PID.
Comments Submitted by Center for Biological Diversity (C I?I)) (Docket ID: EPA-HQ-
QPP-2013-0251-0103)
Comment: CBD's comments focus on the EPA's duty to consult with the Services on the
registration review of atrazine in accordance with the Endangered Species Act (ESA). The CBD
comments mention various aspects of the risk assessment process, specifically use of the best
available data, including all necessary data and studies, particularly to develop listed species risk
assessments, and evaluation of effects on listed species and their designated critical habitat. CBD
also expressed concern regarding the rigor of the agency's preliminary determinations regarding
the effects of the triazines (atrazine, simazine and propazine) on listed species and their
designated critical habitat for the triazines registration review. In addition, CBD expressed
concern about effects on pollinators and other beneficial insects, effects on human health or
environmental safety concerning endocrine disruption, and any additive, cumulative or
synergistic effects of the use of the pesticide.
EPA Response: The EPA has reviewed CBD's comments and plans to address many of the
concerns regarding listed species as part of the implementation plan for assessing the risks of
pesticides to listed species based on the recommendations of the April 2013 National Academy
of Sciences (NAS) report. See Endangered Species Assessment in Appendix C of this document
for more information. The EPA will address concerns specific to simazine particularly with
regard to pollinators, ESA, and endocrine disruption, in connection with the development of its
final registration review decision for this pesticide. See Endocrine Disruptor Screening Program
in Appendix D of this document for more information regarding endocrine disruption. The EPA
is currently developing an agency policy on how to consider claims of synergy being made by
registrants in their patents. The EPA intends to release this policy for public comment. After the
agency has received and considered public comment on the proposed policy, and once that
policy has been finalized, the EPA will consider its implications on the EPA's final decision for
simazine.
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H. USE AND USAGE
Simazine is a selective herbicide that prevents grass and broadleaf weeds from emerging.
Simazine products are registered for agricultural use sites such as caneberries, grapes,
strawberries, citrus fruits, nut crops, pome fruits, stone fruits, artichokes, corn, asparagus,
uncultivated agricultural areas, kale, cabbage, kohlrabi, Brussel sprouts, blueberries, alfalfa,
avocado, and olives. Products containing simazine are also registered for use on non-agricultural
sites such as forest trees, ornamental herbaceous plants, ornamental lawns and turf, ornamental
woody shrubs and vines, ornamental trees, Christmas tree farms, nursery stock, farm buildings,
golf course turf' and shelterbelt plantings. Simazine is registered in liquid, dry flowable (DF),
and water dispersible granule (WDG) formulations. Simazine can be applied via ground,
chemigation, and handheld application equipment; aerial application is prohibited.
An average of 3 million pounds of simazine are applied to 2.6 million acres of agricultural
cropland per year. Although simazine is not used extensively on major row crops (e.g., corn),
these type of use sites do account for the majority of agricultural use in terms of pounds applied
and acres treated. Approximately 3% of corn acres in the U.S. are treated with simazine each
year and this accounts for 76% of simazine use. Less than 1% of sweet corn acres are treated
with simazine, or about 3,600 acres annually.
Simazine is used extensively in orchard, vineyard, and berry crop sites. On average, over
650,000 pounds, or approximately 20%, of simazine is applied in agricultural settings to these
sites. The crops with the highest percent crop treated (PCT) with simazine are caneberries (32%),
blueberries (20%), raisin grapes (17%), hazelnuts (16%), oranges (12%), and peaches (10%). All
the orchard, vineyard, and berry crops surveyed typically received one to two applications of
simazine per year on average. Citrus fruit (i.e. oranges, lemons, and grapefruit) typically have the
highest reported average simazine application rates, around 2.2 lbs a.i./acre or higher.
In the most recent year with data available (2013-2016), thousands of pounds of simazine were
applied to various non-agricultural use sites: nursery/ornamental (400,000 lbs), turf-sod farms
(26,000 lbs), non-residential turfgrass [e.g., golf courses] (237,000 lbs) and forestry (less than
5,000 lbs).
in. SCIENTIFIC ASSESSMENTS
A. Human Health Risks
A summary of the agency's human health risk assessments is presented below. The agency used
the most current science policies and risk assessment methodologies to prepare a risk assessment
in support of the registration review of simazine. In addition, EPA has made a determination of a
common mechanism of toxicity for atrazine, simazine, propazine, and their chlorinated
metabolites. Therefore, in addition to assessing potential risk from simazine, EPA evaluated the
potential cumulative risk from combined exposure to the triazines and their three major
chlorinated metabolites, desethyl-s-atrazine (DEA), desisopropyl-s-atrazine (DIA), and
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diaminochlorotriazine (DACT). For additional details on the human health assessments, seethe
Simazine. Human Health Risk Assessment for Registration Review and to Support Registration of
Proposed Uses on Citrus Fruit, Pome Fruit, Stone Fruit, Tree Nuts, and Tolerance Amendment
for Almond Hulls, the Chlorotriazines: Cumulative Human Health Risk Assessment - Atrazine,
Propazine, and Simazine, and Cumulative Triazine (Atrazine, Simazine, Propazine) Drinking
Water Assessment, which are available in the public docket.
For registration review, the predominant adverse health effect of concern for triazines is
suppression of the luteinizing hormone (LH) surge leading to neuroendocrine effects. This effect
was observed in rat studies after four days of exposure, therefore potential risk was assessed
using a 4-day duration of exposure rather than EPA's typical short-or intermediate-term duration
of exposure. Disruptive hormonal effects related to the LH surge are different for different age
groups and sexes, and the downstream adverse effects vary considerably. Exposures during early
life may lead to effects later in life including delays in sexual maturation, inflammation of the
prostate, effects related to development of the genitalia, and/or irregular menstrual cycles.
Therefore, this endpoint is relevant for males and females, and all life-stages.
For the acute assessment for simazine and its chlorinated metabolites, the toxicological endpoint
is increased incidence of unossified teeth, head, centra vertebrae, and sternebrae, and also
rudimentary ribs, which is only applicable to females 13-49 years old. For the 4-day assessment
for simazine and its chlorinated metabolites, the toxicological endpoint is attenuation of LH
surge, which is applicable to all life-stages. The hydroxy metabolites of simazine are major
metabolites in plants but not in livestock. Dermal and inhalation exposures are not expected for
the hydroxy metabolites of simazine; however, chronic dietary exposures are expected. The
chronic endpoint (kidney effects) is applicable to all life-stages.
1. Risk Summary and Characterization
Dietary (Food + Water) Risks
EPA's dietary risk assessments did not identify any potential acute, 4-day, chronic, or cancer
risks of concern associated with dietary exposure to simazine and its chlorinated metabolites or
to the hydroxy metabolites of simazine. Simazine has been classified as "Not likely to be
carcinogenic to humans"; therefore, a quantitative cancer dietary risk assessment was not
conducted.
Residential Handler Risks
Simazine products are registered for use in residential areas (e.g., residential lawns and
playgrounds). Although all simazine labels require that handlers wear specific clothing (e.g.,
long sleeved shirt, long pants) and/or use personal protective equipment (PPE), one label is
specifically labeled "for residential use" of simazine on residential turf Therefore, a residential
handler assessment was conducted for simazine application to residential turf There were no
residential handler combined (dermal + inhalation) risks of concern; combined (dermal +
inhalation) Margins of Exposure (MOEs) ranged from 44 to 180 (Level of Concern (LOC)=30).
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Residential Post-Application Risks
Residential post-application exposure is expected via the dermal route for adults, children 11 to
16 years old, children 6 to 11 years old, and children 1 to < 2 years old; and via incidental oral
exposure (i.e., hand-to-mouth or object to mouth) for children 1 to < 2 years old as a result of
being in an environment that was previously treated with simazine (e.g., lawns, golf courses,
playgrounds, recreational areas, etc).
Since dermal and incidental oral exposure routes share a common toxicological endpoint, risk
estimates have been combined for those routes for children 1 to < 2 years old. Chemical-specific
predicted day zero turf transferable residues were adjusted in the post-application assessment for
any differences between the study application rate and the registered application rates for
simazine. Then, a 4-day average residue was used to estimate risk from contact with treated turf
because the point of departure (POD) is based on decreased LH surge and available toxicity data
indicate that the decrease occurs after a 4-day exposure. EPA's assessment of these exposure
pathways demonstrated potential post-application risks of concern (i.e., Margins of Exposure
(MOEs) 30) using either the
maximum air concentration data from application site monitoring or using the average air
concentration from all ambient air monitoring.
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Aggregate Risks
There is the potential for aggregate risks of concern following exposure to simazine and its
chlorinated metabolites (DEA, DIA, and DACT). EPA evaluated acute and 4-day aggregate
exposure to simazine (dietary and residential), and chronic aggregate exposure to the hydroxy
metabolites of simazine. The acute and chronic aggregate assessments include dietary (food-
only) and drinking water. The 4-day aggregate assessment includes dietary (food-only), drinking
water, and residential exposures.
EPA used a drinking water level of comparison (DWLOC) approach to evaluate aggregate risk.
This approach determines acceptable levels of exposure in the total "risk cup" for drinking water,
after accounting for exposures from food/residential uses. DWLOCs are then compared to
estimated drinking water concentrations (EDWC) to determine whether there are aggregate risk
concerns once exposure from drinking water is added in. The DWLOC approach is useful when
there are multiple EDWCs, as is the case for simazine or when there are potential aggregate risk
estimates of concern.
There were no acute risks of concern for simazine and its chlorinated metabolites, and no chronic
aggregate risks of concern for the hydroxy metabolites of simazine. For the 4-day aggregate
assessment, the maximum application rate on residential turf (2.0 lb ai/A) would need to be
reduced to 0.65 lb ai/A to be not of concern for all subpopulations.
Cumulative Risks
EPA has determined that simazine shares a common mechanism of toxicity (neuroendocrine
effects in rats that can cause developmental and reproductive toxicity) with the other triazine
herbicides, atrazine and propazine, and their chlorinated metabolites. EPA assessed cumulative
risk from the triazines and their chlorinated metabolites in the July 10, 2018 Chlorotriazines:
Cumulative Risk Assessment - Atrazine, Propazine, and Simazine, which is available in the
public docket.
There were no risks of concern identified for the chlorotriazine 4-day cumulative dietary (food
only) exposure and risk assessment, or for the 4-day dietary cumulative aggregate (food +
drinking water) exposure and risk assessment. There were also no cumulative risks of concern
for the chronic dietary (food only) or screening-level aggregate (food + drinking water)
assessment for the hydroxytriazines.
However, there were some 4-day cumulative aggregate (food + drinking water + residential)
exposures that resulted in risks of concern at the maximum labeled rates for simazine spray
application to residential turf at the maximum application rate (2.0 lb ai/A). However, if the
application rate is reduced to 0.65 lb ai/A for turf, there are no cumulative aggregate risks of
concern.
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Occupational Handler Risks
There is potential for occupational handler risk from combined dermal and inhalation exposure
to simazine, with dermal exposure driving the risk estimates. EPA calculated risk estimates
based on combined dermal and inhalation exposure for various levels of PPE; label-specified
PPE (i.e., long sleeves, pants and socks and chemical resistant gloves), and any additional PPE or
engineering controls required to result in risk estimates that are not of concern. The occupational
handler scenarios evaluated resulted in potential risks of concern with MOEs ranging from 2.7 to
1,400 (LOC = 30) assuming label-specified PPE. Uses with potential occupational risks of
concern are:
•	Mixing/loading/applying dry flowable/water dispersible granule (DF/WDG) and liquid
formulations for backpack application to grapefruit, oranges and landscape turf
•	Mixing/loading/applying DF/WDG and liquid for mechanically pressurized handgun
application to:
o Citrus (Grapefruit, Oranges, Lemons)
o Pome Fruits (Apples, Pears)
o Stone Fruits (Cherries [sweet and tart], peaches, Plums, Nectarines)
o Tree Nuts (Pecans, Walnuts, Filberts, Almonds, Macadamia Nuts
o Berry and Small Fruit (Blueberries, Blackberries, Loganberries, Raspberries,
Grapes, Lowbush Blueberries, Cranberries)
o Tropical and Sub-tropical Fruits (Avocado, Olive)
o Nursery/Ornamentals
o Sweet corn
o Strawberries
Based on EPA's risk assessment, a requirement of additional PPE could eliminate potential risk
for some but not all scenarios.
The scenarios for which potential occupational risks of concern remain (i.e., MOEs remain
below the LOC of 30) assuming the highest possible level of PPE and/or engineering controls
include:
•	Mixing/loading/applying DF/WDG and liquid formulations for broadcast backpack
sprayer applications to landscape turf (MOE assuming a double layer of clothing, gloves,
and a particulate filtering facepiece or elastomeric particulate respirator = 27).
•	Mixing/loading/applying DF/WDG and liquid formulations for mechanically pressurized
handgun applications to:
o grapefruit and oranges (MOE assuming a double layer of clothing, gloves, and a
particulate filtering facepiece or elastomeric particulate respirator =4.4);
o lemons, apples, pears, tart cherries, avocadoes, filberts, grapes, olives, peaches,
plums, sweet cherries, pecans, walnuts (MOE assuming a double layer of
clothing, gloves, and a particulate filtering facepiece or elastomeric particulate
respirator =8.7);
o almonds, peaches, nectarines, macadamia nuts, blueberries, blackberries,
loganberries, raspberries (MOE assuming a double layer of clothing, gloves, and a
particulate filtering facepiece or elastomeric particulate respirator = 18);
o nursery ornamentals (MOE assuming a double layer of clothing, gloves, and a
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particulate filtering facepiece or elastomeric particulate respirator =12);
o lowbush blueberries (MOE assuming a double layer of clothing, gloves, and a
particulate filtering facepiece or elastomeric particulate respirator = 18);
o cranberries (MOE assuming a double layer of clothing, gloves, and aPF 10
respirator =8.7); and,
o sweet corn (MOE assuming a double layer of clothing, gloves, and a particulate
filtering facepiece or elastomeric particulate respirator = 14).
The occupational handler exposure assessment relied on maximum registered application rates,
generic handler data in absence of chemical-specific unit exposure data, standard area/amount
treated assumptions. Registered simazine labels vary with respect to required attire and PPE.
The DF/WDG labels require mixer/loaders for groundboom applications; and/or mixer/loaders,
cleaners of equipment or spills, or other handlers otherwise exposed to the concentrate to wear
baseline attire (long sleeved shirts, long pants, shoes, and socks), chemical resistant gloves, and a
dust/mist respirator. Some labels also require mixer/loaders to wear a double layer of clothing or
coveralls. All other handlers of DF/WDG products must wear baseline attire and chemical
resistant gloves. All of the registered liquid labels require handlers to wear baseline attire and
waterproof or chemical resistant gloves. Therefore, results were presented for "baseline attire,"
(long sleeved shirt, long pants, shoes plus socks), protective gloves, and no respirator; as well as
baseline, gloves, and various levels of PPE as necessary (e.g., double layer of clothing,
respirator, etc.).
Occupational Post-Application Risks
Using atrazine dislodgeable foliar residue (DFR) and simazine turf transferable residue (TTR)
data, there are no occupational post-application MOEs of concern for the registered and proposed
uses of simazine on the day of application, except for hand-set irrigation for highbush and
lowbush blueberries (MOE = 24; LOC=30). One day after application there are no risks of
concern (MOE = 43). The agency does not consider this a risk of concern because there is an
existing restricted entry interval (REI) of 12 hours and the risk calculated at the maximum label
rate of 4 lb ai/A is much lower than the typical use rate of 1.6 lb ai/A. All other registered uses
had MOEs above the LOC.
2. Human Incidents and Epidemiology
Four minor severity incidents were reported in the OPP Incident Data System (IDS) between
January 1, 2012 and January 12, 2017 involving simazine. A National Pesticide Information
Center (NPIC) query from 2012 to 2017 found one minor severity incident involving simazine.
A query of California Pesticide Illness Surveillance Program incidents from 2010 to 2014 found
one incident involving simazine. Lastly, a query of Sentinel Event Notification System for
Occupational Risk-Pesticides from 2010 to 2013 identified three cases involving simazine. Two
cases were moderate in severity and one case was low in severity. All three cases were
occupational exposures.
The agency will continue to monitor the incident information. Additional analyses will be
conducted if ongoing human incident monitoring indicates a concern.
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Hie agency recently conducted an updated epidemiology systematic literature revKW to
investigate evidence about the bttooan heath effects potentially associated with exposure to
airaziue, aimazine, and/or propaaie. Ninety-three publications torn 1990 to 2017 were
identified for inclusion in the epidemiology literature review. These piibieatioiis investigated
cardiogenic aixi ooncarcmoaenie eSects (43% and 58°o. respectively; not mutually exclusive).
Most (88°o) reported an efleet estimate for afrazine, 14°-o reported an effect estimate for simaane
(not mutually exclusive. some articles reported estimates for lx>tii chemicals. wliie otlier articles
reported estanates for only oik). No publications reported an effect estimte tor propamine.
Additional detais can be found in Chlorotriazines, Toxicology Systematic Literature Review-
Atrozine, Simozitie and Propazine.
3. Tolerances
Tolerances are established under 40 CFR §180,213 for the coinbmed residues of sinoozine and
its two clibrkiated metabolites iifea a variety of crops arid .livestock commodities. The agency
intends to propose that die residue definition for the tolerance expression fcrsiaaziae be
modified ai accordance with current policy to read:
"Tolerances ore established for residues qf the herbicide smiaznie, including its
metabolites and degradates, in or on the commodities in the table below. Compliance
with the tolerance levels specified below is to be determined by measuring only the sum
ofsfmazme, 6-chloro-.\'.S '-diethyl-1. J.5-niazinc-2.4-diamine, its descthyl metabolite 2-
ammo-4-chloro-6-etbylammo-s-triazine (G-2S2"<>} (DM}, and tis diantino metabolite
2,4-diomino-6-chloro-s-triazme (G-2S273) tDACTi. calculated as the stoichiometric
equivalent ofsimazine. in or on the commodity.
A summary of the tolerance revisions and revocations that the agency intends to propose for
siroazroe is feted below.
1: ^nmiiwi \ <>I l'l oinsfii [uti-i .mri -vioii-. foi Siiii;i/iiii' i.4fi I I'K ^ISn.21.'!
( nt'ict ' ( iiirtiinxtih 1 >fHin(ii>!i
IMmI.IMu.I
Tolerance
(H«n)
i demure
•Mwnt
( i'lnmciifs
AllUutods, liulU
0.25

Donovan, 26-IUN-2013)
Awcado
0,20
0.2
OECD rounding class consistency
BlackU-rry
0,20
0.2
Blueberry
0.20
0.2
Cattle. meat
0.03
remove
40CFR§lS0.6iaX3>
D442S22. W. Donovan. 12-JUN-201S
Cattle, meat byproducts
0.03
remove
Corn, Held, forage
0.20
0.2
OECD rtmndmg class consistency
Corn, field, grain
0.20
0.2
Corn, pop, grain
0.20
0.2
Corn, sweet, forage
0.20
0.2
Corn, sflwt, kernel plus cob with busks
mmwd
0.25
0.2
D442825. W. Donovan. 10-JUL-2018
OECD rounding class consistency
IfeR
0.03
remove
40 CFR §1S0 6(a)(3)
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Docket Number EPA-fIQ-OPP-20I3-0251
n \v\v.reiail»rious. >20 v
!:iii!f 1 ^nifii!i;ii v .>( t'l <1 I cli-l :iiu ¦¦ Kfi ¦ f-iiis i< =i" iii.'./i li<- i 40 I t !\ i: i S".2 1 3 i
t ninmoitm

Crf):»l. llk>:U h>S»'Oifuc1S
003
remove
Fi'iiit. citrus. group 10 10
.
0.04
Establishment of crop group tolerance
Grapefruit
0.25
renm e
Lemon
0.25
remove
Orange
0.25
remove
Fruit. ]w>3ne. sump 11 1(1
.
0.03
Establishment of crop group tolerance
Apple
0.20
relieve
Pear
0.25
remove
Fruit, stone. group 12-5 2
.
0,1
Establisluneut ot crop group tolerance
Ctieiw
0.25
remove
Peach
0.20
remove
Phtni
0.25
reo»ve

0.20
0.2
OECD rounding class consistency
Horse, input
0.03
remove
40CFR y80.6faH3»
D442S22. W. Donovan. 12-JUN-201S
Horse, Hif;H hypifxhu' ts
0.03
remove
IjOKiin berry
0.20
02
OECD rounding class consistency
Afiik
0.03
remove
40 CFR §im.6{a)(i)
D442822. W, Donovau. 12-JUN-201S
Niit. tree, group i4 12
.
0.05
Establishment of crop group tolerance
Almond
0.25
i drove
Hazelnut
0.20
remove
Nut. lincadamia
0.20
remove
Pecan
0.20
remove
Walnut
0.2
remove
CMiw
0.20
0.2
OECD rounding class consistency
Raspberry
0.20
0
1	j
Sheep infill
0.03
remove
40 CFR $180.6ia}|.3)
D442S22. W, Donovan. 12-JUN-2018
Sheep. meat tfyprotiiie rs
003
remove
S trawl letrv
0.25
0.03
D442825. V Donovan. 10-JUL-2018
The agency will use as Federal Food. Drug, and Cosiiielic (FFDC'A'i rulemaking antliority lo
undertake nit) needed tolerance changev
4. Human Health Data Needs
The hi n nan health risk assessment identified mult ires id no method testing Jesuits tOCSPP
860.1360) tor the chtorioated njetaboltes ofatraziie, propaztne, and sitinane (desethylafrazine
!I)L A}. de^isopropyhtrnzinc (DI.A<. ami diammocliloroatrazuie (DACTt* as a data de&ieuey.
These data rue needed to detennine file suitahiliH of mult ire ski ue methodology for quantification
oi'sinsazine and ils 1 emulated metabolites. The agency issued a GDC"I to require these data on
December 12, 2018. These data are wider development nad due to be submitted to the agency by
December 20. 2020. Pending review and. acceptability oftlas study, the agency does not
anticipate any fiatliei human health data needs tor the siuaziiie registration review.
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B. Ecological Risks
A summary of the agency's ecological risk assessment is presented below. The agency used the
most current science policies and risk assessment methodologies to prepare a risk assessment in
support of the registration review of simazine. For additional details on the ecological assessment
for simazine, seethe Preliminary Ecological Risk Assessment for Simazine, which is available in
the public docket.
The EPA is currently working with its federal partners and other stakeholders to implement an
interim approach for assessing potential risk to listed species and their designated critical
habitats. Once the scientific methods necessary to complete risk assessments for listed species
and their designated critical habitats are finalized, the agency will complete its endangered
species assessment for simazine. See Appendix C for more details. As such, potential risks for
non-listed species only are described below.
1. Risk Summary and Characterization
EPA estimated risks associated with simazine use to non-target birds, mammals, reptiles,
freshwater fish, amphibians, and aquatic invertebrates; terrestrial invertebrates, including
honeybees and other insect pollinators; and plants. Risk estimates (risk quotients, orRQs) were
compared with EPA's LOCs. For ecological risk, RQs below the LOC are not of concern to the
agency. For all taxa in the terrestrial assessment, except for plants, the LOC for acute exposure is
0.5 and the LOC for chronic exposure is 1.0. The LOC for plants is 1.0. In the draft risk
assessment, the agency identified potential chronic risk concerns for mammals, birds, freshwater
fish, amphibians, reptiles, and aquatic invertebrates. In addition, available information suggests
potential risk to terrestrial invertebrates. The draft risk assessment assessed the maximum-
labelled and typical application rates.
Terrestrial Risks
Mammals
The ecological risk assessment did not identify acute risks of concern for mammals; however,
chronic risk estimates exceed the agency's LOC of 1 for all uses. At maximum application rates,
chronic risk quotients (RQs) range from 1 - 869. The toxicity endpoint is based on decreased
body weight and body weight gains. In addition, chronic LOCs for mammals are exceeded up to
distances of 1,000 feet off field depending on the method of application and application rate.
Birds, Reptiles, and Terrestrial-Phase Amphibians
The ecological risk assessment did not identify acute risks of concern for birds; however, chronic
levels of concern (LOC = 1) are exceeded for birds for all simazine uses. Birds serve as
surrogates for reptiles and terrestrial-phase amphibians in the absence of taxa-specific data.
Chronic RQs range from 0.2 to 11.2. The chronic endpoint is based on reproduction impacts
observed in the most sensitive species, bobwhite quail.
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Terrestrial Invertebrates (honeybees)
Available toxicity data kxbcate that sinazme is practically uoir-toxic to bees on an acute oral
exposure basis. Based on these data, the agency calculated an RQ of 0.11. which is below the
agency's LOC of 0.4 for acute exposure. However, there is uncertainty about potential risks to
terrestrial invertebrates because a M Her I suite of terrestrial invertebrate toxicity studies is not
available at this tune.
Given the uncertainty surrounding potential risks to terrestrial invertebrates due to lack of data,
the EPA believes that additional data nay be necessary to fifty evaluate risks to non-target
terrestrial invertebrates, especially poUtiafors. The EPA is currently determining whether
additional poinator data are needed for sinazuie. If the agency determines that additioual
pollinator exposure and effects data are necessary to help nuke a final registration review
decision for simzine, then the EPA wl issue a DCI to obtain these data. Hie poinator studies
that could be required are feted k Table 2 below and based on the EPA's June 2014 Guidance
for Assessing Pesticide Risks to Bees1.
1 abic 1: Pnh-iithil I'nllinalni Data RtuiiiivmriiK
(.imklillf
Miulv
Tier 1
850.3020
Acute contact toxicity study will adult honey tees
850.3030
Honey bee toxicity of residues on folia ee
Non-Qudeline (OECD 213)
Honey bee adult acute oral toxicity
Non-Guideline i OFCD 237)
Honey bee larvae acute oral toxicity
Non-Guideline
Honey bee adult chronic oral toxicity
Mon-CjUttdeine
Honey tee larvae chronic oral toxicity
Tier 2f
Non-Guideline
Field trial of residues in pollen and nectar
Non-Guideline (OECD 75)
Semi-field testing for pollinators
Tier 3'
8503040
FuI-FieM testing for paBmators
t The need for higher tier tests for pollinators will be determined based upon the results of fewer tiered tests and/or
other lines of evidence and the need for a refined pollinator risk assessment.
Terrestrial Plants
Consistent with its herbicidal nude of action, snnazine is highly toxic tomonocot and dicot
terrestrial plant species. As such, non-target terrestrial plant specks si areas adjacent to tieated
fields are likely to be impacted by exposure to sitnazine. At the maximum single application rate,
RQs associated with exposwe via spray drift, as wei as the combination ofrunoff and spray drift
exposure to dry areas and semi-aquatic habitats exceed the LOC of 1. RQs for spray drift-only
exposure range from 0.5 to 8.9, RQs for runoff and spray drift deposition to dry areas ranee from
1.0 to 10,7, and RQs for runoff and spray drift deposition to semi-aquatic areas range- from 5.5 to
48.9, Hie adverse effect endpoint is based on impacts to seedling emergence.
1 Avaiable at hitp¥//ww,ga.8ffv^te/gro4iiaipB/ite^2W4-
PC*	—tv*K——,i~l pdl
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For characterization, EPA evaluated potential risks to terrestrial plants at reduced application
rates and developed species vegetative vigor and seedling emergence sensitivity distributions
(SSDs); however, risks to terrestrial plants remain of concern.
Aquatic Risks
Freshwater Fish and Aquatic-Phase Amphibians
EPA's chronic LOC of 1 is exceeded for freshwater fish and aquatic-phase amphibians through
runoff and spray drift deposition into waterways following labeled applications for many
simazine uses (including corn, orchard, and berries), with RQs ranging from 0.1 to 5.7. The
chronic fish endpoint is based on decreased egg production in the freshwater Japanese medaka
fish; this endpoint is from a study conducted with atrazine, as no such study is available for
simazine. With aquatic-phase amphibian data unavailable, freshwater fish data is considered as
surrogate data for aquatic phase amphibians, and therefore chronic risks to aquatic-phase
amphibians are the same as freshwater fish. While there are amphibian-specific data for atrazine
which indicate potential sublethal effects at low exposure concentrations, it is unclear to what
degree those data represent simazine.
Estuarine/Marine Fish
Acute and chronic RQs did not exceed the LOC for estuarine/marine fish.
Freshwater Invertebrates
The ecological risk assessment did not identify acute risks of concern for freshwater
invertebrates; however, chronic risk estimates exceed the agency's LOC of 1, with RQs ranging
from 0.2 to 9.
Estuarine/Marine Invertebrates
The ecological risk assessment did not identify acute risks of concern for estuarine/marine
invertebrates; however, chronic risk estimates exceed the agency's LOC of 1 for
estuarine/marine invertebrates, with RQs ranging from 0.1 to 5.7.
Aquatic Vascular and Non-Vascular Plants
Risk estimates exceed the Agency's LOC for aquatic vascular and non-vascular plants for nearly
all uses. RQs range from 0.8 - 46.4 for vascular plants, and 0.1 - 5.5 for non-vascular plants.
Aquatic Plant Communities
Simazine does not have an extensive body of research on micro and mesocosms like atrazine
does. However, because atrazine and simazine share a common mechanism of action and similar
potency in plants and coupled with their propensity to move into aquatic ecosystems and their
persistence in water, these chemicals both pose a potential risk to aquatic plant communities.
Based on the toxicity data, there are risks to non-vascular plants for all simazine uses and risks to
vascular plants for many uses.
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2.	Ecological Incidents
A review of the Ecological Incident Information Systems (EIIS) database for ecological incidents
involving simazine was completed on January 25,2015. The Avian Monitoring System (AIMS)
is a database administered by the American Bird Conservancy and are included in the EIIS
summary. The EES search resulted in three incidents involving terrestrial animals, four for
plants, and ten freshwater incidents involving fish kills.
The Aggregate Incident Summary report in the IDS shows six simazine related incidents,
including two involving plant damage and the others were single reports involving moderate
property damage, minor to moderate effects on domestic animals, fatal domestic animal event
and one unspecified human event.
The agency will continue to monitor ecological incident information as it is reported to the
agency. Detailed analyses of these incidents are conducted if reported information indicates
concerns for risk to non-target organisms.
3.	Ecological and Environmental Fate Data Needs
Except for the potential pollinator data requirements described previously, the ecological and
environmental fate database for simazine is complete.
C. Benefits Assessment
Simazine is a chlorinated triazine herbicide and is classified as a Weed Science Society of
America (WSSA) Group 5 herbicide. Simazine is applied before the weed emerges to control
broadleaf and grass weeds, and it can be applied in the fall for winter weed control. Simazine is a
commonly used preemergence, soil residual herbicide in orchards, vineyard, berry crops,
nurseries/ornamentals, and Christmas tree farms. There is also usage of simazine in non-
agricultural sites, including turfgrass and forestry sites. It is an important herbicide for these use
sites because it is economical, has a flexible use pattern, has a long residual period, has good
crop safety, and is highly effective against a broad spectrum of weeds.
Field Corn
Infield corn, simazine provides residual control and offers control of a broad-spectrum of
broadleaf weeds and grasses. It has a flexible use pattern in that it can be applied before planting,
before crop emergence, or as a fall application after harvest. The Corn Belt states (Illinois,
Indiana, Iowa, Missouri, Ohio) account for approximately 76% of simazine's total acre
treatments, followed by the Southern/Seaboard states (Kentucky, Maryland, North Carolina,
Virginia) with about 18% of total area treatments and Northeast/Lakes states (Delaware,
Michigan, Pennsylvania, Wisconsin) with about 7% of total acre treatments. Application timing
varies by region, but nationally about 48% of simazine is applied during the previous fall (after
the harvest primarily in the Corn Belt for winter weed control), and the remaining 52% is applied
before corn emerges. In the absence of simazine, in the Corn Belt and Northeast/Lakes states, the
EPA estimates a loss of approximately 4% in net revenue ($7 per acre) for applications made
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prior to crop emergence using the next best alternative herbicide. For the Southern/Seaboard
states, the EPA estimates that growers may choose to use atrazine in the absence of simazine,
which is slightly cheaper than simazine per acre, so no net revenue losses are expected.
For more information refer to Atrazine and Simazine Use on Field Corn: Response to
comments, Usage, Benefits, and Impacts of Potential Mitigation; PC Codes (080803 and
080807) in the docket
Orchards, Vineyards, Berries and Christmas Trees
In perennial crop settings such as orchards, vineyards, and berries, simazine is used for residual
control of grasses and broadleaf weeds that occur in row middles and around the base of crops or
trees. Simazine is typically applied in the late fall or early spring months to provide weed control
in perennial cropping systems. It is the top pre-emergent option used in caneberry production. In
strawberries, simazine may be important for operations that do not use fumigation or for residual
control after harvest, especially in the Pacific Northwest strawberry production areas. In
Christmas tree production, simazine is a preemergence herbicide that can provide residual
control with winter applications.
For more information refer to Simazine Response to Comments, Usage, Benefits, and Impacts of
Potential Mitigation on Orchards, Vineyards, Caneberries, Strawberries, and Christmas Trees;
PC Code (080807) in the docket.
Sweet Corn
Simazine provides residual control and offers control of a broad-spectrum of broadleaf weeds
and grasses in sweet corn. It has a flexible use pattern in that it can be applied before planting, at
plant, before crop emergence or as a fall application after harvest. Growers in the North Central /
Northeastern (Indiana, Illinois, Michigan, Minnesota, New Jersey, New York, Ohio,
Pennsylvania, Wisconsin) region account for nearly all of the simazine usage in sweet corn, even
though simazine is recommended by university extension in other regions. Without simazine, the
agency estimates an increase in production costs of $11 per acre in the North Central /
Northeastern region using the next best alternative herbicide. Simazine is more expensive than
atrazine and used less frequently; however, it is still less expensive than many other herbicides
that can be used to target the similar suite of broadleaf weeds and grasses.
For more information refer to Atrazine and Simazine Use on Sweet Corn: Response to
Comments, Usage, Benefits, and Impacts of Potential Mitigation; PC Codes (080803 and
080807) in the docket.
Turfgrass and Nursery/Ornamental
Simazine is atop preemergence herbicide for a few non-agricultural use sites (i.e., certain types
of turfgrass and nursery/ornamental sites). Herbicides are applied to turfgrass at golf courses,
homes, parks, and professionally maintained turfgrass sites to control annual broadleaf and grass
weeds which may impact yield and/or seed/turf quality, playability, or it may be primarily driven
by aesthetics. According to the most recent data (2013) available to the agency, simazine was the
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third most used preemergence herbicide on turf-sod farms, and the second most used
preemergence herbicide on golf courses in terms of pounds applied. Simazine can be used on
many ornamental species without causing damage to the species. Simazine was the second-most
used herbicide overall in nursery/ornamental sites in 2013.
For more information refer to Atrazine and Simazine Use in Forestry, Rights of Way, Turfgrass,
and Nursery: Response to Comments, Usage, and Benefits; PC Codes (080803 and 080807) in
the docket.
IV. PROPOSED INTERIM REGISTRATION REVIEW DECISION
A. Proposed Risk Mitigation and Regulatory Rationale
The currently registered uses of simazine pose potential human health risks of concern, including
residential post application, aggregate, and cumulative risk associated with simazine use on
residential turf and potential occupational risk to handlers from mixing, loading, and applying
simazine. In addition, simazine use poses potential ecological risks to mammals, birds, reptiles,
amphibians, fish, aquatic invertebrates, terrestrial plants and aquatic plant communities.
The EPA is describing the proposed mitigation based on the risks to be addressed and
subsequently discusses the expected impacts by use site (unless otherwise noted). By describing
the mitigation in this way, the agency seeks to clarify the specific mitigation proposed, that may
impact each specific simazine user group.
To address the potential residential post-application aggregate, and cumulative risk concerns, the
EPA is proposing to cancel simazine use on residential turf In addition, EPA is proposing to
require additional PPE or engineering controls to address potential occupational handler risk
concerns associated with various simazine uses, as discussed in more detail below. EPA is also
proposing to update spray drift reduction language, herbicide resistance management language,
and require some additional label updates for consistency with generic labeling requirements.
In evaluating potential risk mitigation for simazine, the EPA considered the risks, the benefits,
and the use pattern of this compound. Although there are potential risks of concern associated
with the use of simazine, with the adoption of the mitigation measures discussed in this section,
the potential risks are outweighed by the benefits associated with the use of this compound.
1. Proposing Cancellation of Simazine Residential Turf Use
As discussed in the Risk Summary and Characterization section of this document (Section III.
A. 1.), the human health risk assessment indicates potential post-application, aggregate, and
cumulative triazine risks of concern for adults from dermal exposures to treated residential turf
and children 1 to <2 years old from combined dermal and incidental oral exposures to treated
residential turf Acceptable MOEs could be reached if the application rate was reduced from 2.0
lb ai/A to 0.65 lb ai/A, but that rate is below an efficacious level. As a result, EPA is proposing
cancellation of the residential and recreational turf use, which would mean that simazine could
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not be used to treat turf around homes, daycare facilities, schools, playgrounds, parks,
recreational areas, or sports fields. Use on golf courses and sod-production fields, however,
would not be affected.
For information about the impacts of the proposed mitigation, please refer to Section IV.A.7,
Impacts of Mitigation.
2. Risk Mitigation for Occupational Handlers
The human health risk assessment identifies several scenarios that result in potential risks of
concern to occupational handlers who mix, load, and apply simazine. Additional PPE is
necessary to address these potential risks. Therefore, EPA is proposing to require the following
additional PPE to include a respirator in some cases and, for pesticides covered by the Worker
Protection Standard2 (WPS), the associated fit test, training, and medical evaluation:
•	The agency is proposing to require that occupational handlers wear a double layer of clothing
for the uses listed below. A double layer of clothing will bring the MOEs to above the LOC
and remove any potential risks of concern.
o Dry flowable and Water Dispersible Granule (DF/WDG) - backpack application -
grapefruit, oranges
o Liquid - backpack application- grapefruit, oranges
•	The agency is proposing to require that occupational handlers wear a double layer of clothing
or to apply via spot treatment only for the uses listed below. Either action will bring the
MOEs to above the LOC and remove any potential risks of concern.
o DF/WDG - mechanically pressurized handgun - strawberries
o Liquid - mechanically pressurized handgun - strawberries
•	The agency is proposing to restrict mechanically pressurized handgun applications of DF,
WDG, and liquid formulations of simazine to spot treatment only for the following uses
because these uses do not reach acceptable MOEs with additional PPE.
o Citrus (Grapefruit, Oranges, Lemons)
o Pome Fruits (Apples, Pears)
o Stone Fruits (Cherries [sweet and tart], peaches, Plums, Nectarines)
o Tree Nuts (Pecans, Walnuts, Filberts, Almonds, Macadamia Nuts
o Berry and Small Fruit (Blueberries, Blackberries, Loganberries, Raspberries, Grapes,
Lowbush Blueberries, Cranberries)
o Tropical and Sub-tropical Fruits (Avocado, Olive)
o Nursery/Ornamentals
o Sweet corn
For information about the impacts of the proposed mitigation, please refer to Section IV.A.7,
Impacts of Mitigation.
2 40 CFR 170
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3. Spray Drift Reduction Language
In the 2006 Reregistration Eligibility Decision for Simazine (RED), mandatory and advisory
spray drift language was specified. The agency is proposing to update existing label language to
the latest spray drift mitigation language on all simazine product labels for products applied by
liquid spray application. The proposed spray drift language is intended to consist of mandatory,
enforceable statements and supersede any existing language already on product labels (either
advisory or mandatory) covering the same topics. The agency is proposing standardized advisory
language on simazine product labels. Registrants must ensure that any existing advisory
language left on labels does not contradict or modify the new mandatory spray drift statements
proposed in this PID, once effective.
•	Applicators must not spray during temperature inversions.
•	For ground boom applications, apply with the release height no more than 4 feet above
the ground or crop canopy.
•	For ground applications, do not apply when wind speeds exceed lOmphatthe
application site.
•	For ground applications, select nozzle and pressure that deliver coarse or coarser droplets
as indicated in nozzle manufacturers' catalogues and in accordance with American
Society of Agricultural & Biological Engineers Standard 572.1 (ASABE S572.1).
In addition to including the spray drift restrictions on simazine labels, all references to
volumetric mean diameter (VMD) information for spray droplets are proposed to be removed
from all simazine labels where such information currently appears. The proposed new language
above, which cites ASABE S572.1, eliminates the need for VMD information.
4. Non-target Organism Advisory Statement
The agency is also proposing the addition of a non-target organism advisory statement. The
protection of pollinating organisms is a priority for the agency. Risk to pollinators from the use
of simazine is uncertain. It is possible that pollinators may be exposed to simazine from residues
in pollen or nectar through spray drift. This may negatively impact forage and habitat of
pollinators and other non-target organisms. It is the agency's goal to reduce spray drift whenever
possible and to educate growers on the potential for indirect effects on the forage and habitat of
pollinators and other non-target organisms. Therefore, the EPA is proposing the following non-
target organism advisory language to be placed in the Environmental Hazards section of
simazine labels to address this potential concern:
"NON-TARGET ORGANISM ADVISORY STATEMENT: This product is toxic to
plants and may adversely impact the forage and habitat of non-target organisms,
including pollinators, in areas adjacent to the treated site. Protect the forage and habitat
of non-target organisms by following label directions intended to minimize spray drift."
For information about the impacts of the proposed mitigation, please refer to Section IV.A.7,
Impacts of Mitigation.
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5. Herbicide Resistance Management
On August 24, 2017, the EPA finalized a Pesticide Registration Notice (PRN) on herbicide
resistance management.3 Consistent with the Notice, the EPA is proposing the implementation of
herbicide resistance measures for existing chemicals during registration review, and for new
chemicals and new uses at the time of registration. In registration review, herbicide resistance
elements will be included in every herbicide PID.
The development and spread of herbicide resistant weeds in agriculture is a widespread problem
that has the potential to fundamentally change production practices in U.S. agriculture. While
herbicide resistant weeds have been known since the 1950s, the number of species and their
geographical extent, has been increasing rapidly. Currently there are over 250 weed species
worldwide with confirmed herbicide resistance. In the United States, there are over 155 weed
species with confirmed resistance to one or more herbicides.
Management of herbicide resistant weeds, both in mitigating established herbicide resistant
weeds and in slowing or preventing the development of new herbicide resistant weeds, is a
complex problem without a simple solution. Coordinated efforts of growers, agricultural
extension, academic researcher, scientific societies, pesticide registrants, and state and federal
agencies are required to address this problem.
The EPA is requiring measures for the pesticide registrants to provide growers and users with
detailed information and recommendations to slow the development and spread of herbicide
resistant weeds. This is part of a more holistic, proactive approach recommended by crop
consultants, commodity organizations, professional/scientific societies, researchers, and the
registrants themselves.
6. Additional Label Changes
In addition to the above-mentioned proposed mitigation, the EPA is also proposing the following
label changes to address generic labeling requirements for all simazine products and uses:
•	Updated Glove and Respirator Label Language: see Appendix B
•	Non-target Organism Advisory Label Statement: see Appendix B
•	Directions for Mixing/Loading Water Soluble Packages (WPS) Label Language : see
Appendix B
B. Status of Simazine Water Monitoring Program and Proposed Changes
A drinking water monitoring program was required through a 2008 simazine Generic Data Call-
in (GDCI-080807-26466) (2008) and the Simazine RED (2006). The simazine drinking water
monitoring program, which is conducted in conjunction with a similar monitoring program for
atrazine, monitors community drinking water systems, primarily in the midwest United States in
areas of high simazine use, to assesses simazine levels in drinking water sources.
3 PRN 2017-2, "Guidance for Herbicide Resistance Management Labeling, Education, Training, and Stewardship".
Available at https://www.epa.gov/pesticidejggistratioii/pesticide-registration-notices-year
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The EPA recognizes that the totality of available triazine monitoring data, including data
collected through the simazine drinking water monitoring programs, is robust and
comprehensive. The availability of robust triazine monitoring data enabled the EPA to refine and
characterize its draft human health risk assessments. While having monitoring data specific to
community water systems is useful, given the conclusions of the 2018 draft triazine human
health risk assessments, the EPA is proposing to discontinue the requirements for simazine
drinking water monitoring. Model-estimated triazine concentrations, as well as measured
concentrations for community water systems, are well below the drinking water level of concern
(DWLOC). The vast majority of samples from the simazine monitoring program were below 1
ppb, while the highest triazine concentration ever measured was 227 ppb, which is well below
the triazine DWLOC of 580 ppb. Therefore, the agency does not see value in continuation of the
simazine drinking water monitoring program. For these reasons, EPA will suspend the
requirements for the simazine drinking water monitoring program for calendar year 2020, during
which time the agency will accept and evaluate comments on the triazine PIDs and any
comments specific to the proposal to permanently discontinue the simazine drinking water
monitoring program. After comments are evaluated, EPA will make a final decision about the
future of the simazine drinking water monitoring requirements.
C. Expected Impacts of Proposed Mitigation
Impact of Spray Drift Reduction Language Update
The agency recognizes that the 2006 Reregistration Eligibility Decision for Simazine (RED)
specified mandatory spray drift language; however, not all components of that language were
incorporated on all product labels, including frequently used products (e.g., EPA Reg# 100-526).
Therefore, the agency is evaluating the impacts of each component of the spray drift language
update.
Impacts of Inversion Restriction
This requirement could reduce the amount of time users have to apply triazines. Users may
switch to other products that only have advisory language for this restriction if they encounter
temperature inversions when needing to treat a field.
Impacts of Mandatory Maximum Spray Release Height Requirement for Ground Applications
For ground boom applications, apply with the release height no more than 4 feet above the
ground or crop canopy. This currently exists as mandatory label language; therefore, there will
be no impact.
Impacts of Windspeed Restrictions for Ground Applications
The agency is aware that low wind speeds reduce the number of available hours a grower would
have to make an application. However, a restriction of 10 miles per hour for ground applications
currently exists as mandatory label language; therefore, there will be no impact.
Impacts of Droplet Size
The agency is ensuring that a restriction on droplet size is specified as mandatory label language
because coarser or coarser droplets have been demonstrated to decrease spray drift, and
therefore, reduce potential risks to non-target species. The current droplet size language specified
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in the simazine RED is advisory; through registration review, the agency is proposing to adjust
the language to clarify the droplet size restrictions are mandatory.
Because chemical-specific data for the performance of droplet sizes is limited, EPA is not able to
evaluate the effects of medium or coarser droplet sizes (as defined by ASABE S572.1)
specifically for simazine. Therefore, the EPA does not know the effect this requirement will have
on the performance of simazine across various use patterns, especially regarding tank mix
partners that require a finer droplet size. In general, potential negative impacts to growers from
requiring larger droplets could include: reductions in efficacy, increased selection pressure for
the evolution of herbicide resistance due to a decrease in lethal dose delivered to target weeds,
increased application rates used by growers, increased costs associated with reduced yield,
additional herbicide applications, purchase of alternative products, or an inability to use tank mix
or premix products. The EPA encourages comments on any potential impacts to growers from
specifying a mandatory minimum droplet size on product labels.
Impacts of Interaction of Individual Components of Spray Drift Mitigation
The agency acknowledges the impacts of multiple mitigation measures could be compounded
and further reduce the time in which applicators could apply herbicides. For instance, applicators
may deal with wind restrictions by spraying early in the morning/late evenings when winds are
calmer; however, temperature inversions are more likely to occur several hours before sunset and
can persist until 1-2 hours after sunrise. As the window of application gets smaller, growers may
be forced to switch to products without these restriction on short notice. Therefore, the
alternative may be based on availability and not cost and/or performance, which could be costly
and reduce weed control. Additionally, growers may have situations where a tank is loaded and
ready to spray, but they are not able to spray due to prolonged weather conditions that prevent
application due mandatory multi- layered restrictions. In rare situations, there could be scenarios
where applicators cannot spray what is mixed in the tank for a long period of time and would
need to dispose of a large quantity of mixed herbicides in order to switch to an alternative
mixture. There may be additional concerns (e.g., tank clean-out when products settle out) when a
loaded tank sits hours, and possibly days.
Impacts of Mitigation by Use Site
Turfgrass
Cancellation of Residential and Recreational Turfgrass
The agency is proposing the cancellation of the residential and recreational turf use, which would
mean that simazine could not be used to treat turf around homes, daycare facilities, schools,
playgrounds, parks, recreational areas, or sports fields. Current simazine users would have to
select another herbicide or a combination of herbicides to control the weeds present in their site
(simazine has over 50 weeds on the label). Selecting a different herbicide or combination of
herbicides could lead to higher prices for users and/or poorer weed control. Simazine usage has
declined in residential and recreational turfgrass use sites, so this potential mitigation may have
decreasing impacts over time if current usage trends continue.
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Spray Drift Management
Given that this use site is being proposed to be cancelled, the impacts from spray drift mitigation
could be minimal. However, golf course and sod-production uses will be retained; these uses
could have impacts. For the mandatory spray droplet size of coarse or coarser, a maximum four-
foot boom height, and maximum wind speed restrictions, the impacts are as described above.
Impacts of Inversion Restriction
This component does not appear on all labels. However, the agency assumes that applications to
golf course would be made during normal work hours when temperature inversions are unlikely.
Therefore, the agency assumes that requiring that applications be made when temperature
inversions were not likely to occur would not impact golf course and recreational uses. For sod-
production fields, there could be a reduction in hours when applications could be made (impacts
of the spray drift mitigation, see above).
For more information refer to Atrazine and Simazine Use in Forestry, Rights of Way, Turfgrass,
and Nursery: Response to Comments, Usage, and Benefits in the docket
Field Corn
Spray Drift Management
For impacts of the spray drift mitigation, see above.
For more information refer to Atrazine and Simazine Use on Field Corn: Response to
comments, Usage, Benefits, and Impacts of Potential Mitigation; PC Codes (080803 and
080807) in the docket
Sweet Corn
Restrict Mechanically Pressurized Handgun Applications of DFZWDG/L Formulations to Spot
Treatments Only
The agency anticipates that mechanically pressurized handguns would be used for spot
treatments to small areas, not for broadcast treatments over large acreages in sweet corn. In some
instances, applicators may use a mechanically pressurized handgun attached to small ground
boom sprayers to treat around an obstruction (e.g., telephone pole) or the perimeter of a field
(e.g., fencerows). Therefore, the impact of limiting mechanically pressurized applications to spot
treatments is likely to be low in terms of acres impacted. However, if there are growers who use
mechanically pressurized handguns for broadcast applications of simazine, they would have to
make an application using a different herbicide, which may be more expensive and possibly less
effective. The agency invites public comments to better inform impacts if their practices differ
from our assumption that most applications with mechanically pressurized hand guns are used
primarily for spot treatment.
Spray Drift Management
For impacts of the spray drift mitigation, see above.
For more information refer to Atrazine and Simazine Use on Sweet Corn: Response to
Comments, Usage, Benefits, and Impacts of Potential Mitigation; PC Codes (080803 and
080807) in the docket.
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Citrus (Grapefruit Oranges. Lemons)
Double-layers and Gloves for Grapefruit and Oranges for DF/WDG/L Formulations Applied Via
Backpack Sprayers
Requiring double-layer coveralls and gloves for users applying via backpack will not likely
impact the overall use of simazine since it is likely that applications via backpack sprayers are
infrequent. However, users who apply with backpack equipment may incur some additional costs
or burdens. For example, the use ofPPE(e.g., wearing double layers when applying pesticides)
can reduce productivity of workers because of the physiological stress when working in high
temperatures and/or humid conditions. Workers may need to take more frequent breaks in certain
situations than if extra PPE were not required. Individuals will respond differently depending on
many factors, such as fitness level, hydration, acclimatization, etc. The requirement of additional
PPE when individuals are applying simazine with a backpack applicator could decrease
productivity, which will increase the time required for an application to be made, and likely
increase costs. Alternatively, applicators may choose to use a different herbicide, which could be
more expensive and potentially less effective than simazine.
Restrict Mechanically Pressurized Handgun Applications of DF/WDG/L Formulations to Spot
Treatments Only (Grapefruit, Oranges, Lemons)
The agency assumes that mechanically pressurized handguns would be used for spot treatments
to small areas, not for broadcast treatments over large acreages in citrus groves. In some
instances, applicators may use a mechanically pressurized handgun attached to small ground
boom sprayers to treat around an obstruction (e.g., telephone pole) or the perimeter of a field
(e.g., fencerows). Therefore, limiting mechanically pressurized applications to spot treatments is
likely to be low in terms of acres impacted. However, if there are growers who use mechanically
pressurized handguns for broadcast applications of simazine, they would have to make an
application using a different herbicide, which may be more expensive and possibly less effective.
The agency invites public comments to better inform impacts if their practices differ from our
assumption that most applications with mechanically pressurized hand guns are used primarily
for spot treatment.
Spray Drift Management
For impacts of the spray drift mitigation to Grapefruit, Oranges, and Lemons, see above.
Pome Fruits (Apples. Pears)
Restrict Mechanically Pressurized Handgun Applications of DF/WDG/L Formulations to Spot
Treatments Only
The agency assumes that mechanically pressurized handguns would be used for spot treatments
to small areas, not for broadcast treatments over large acreages in in orchards. In some instances,
applicators may use a mechanically pressurized handgun attached to small ground boom sprayers
to treat around an obstruction (e.g., telephone pole) or the perimeter of afield (e.g.,
fencerows). Therefore, limiting mechanically pressurized applications to spot treatments is likely
to be low in terms of acres impacted. However, if there are growers who use mechanically
pressurized handguns for broadcast applications of simazine, they would have to make an
application using a different herbicide, which may be more expensive and possibly less effective.
The agency invites public comments to better inform impacts if their practices differ from our
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assumption that most applications with mechanically pressurized hand guns are used primarily
for spot treatment.
Spray Drift Management
For impacts of the spray drift mitigation for Pome fruit, see above.
Stone Fruits (Cherries rsweet and tart! Peaches. Plums. Nectarines)
Restrict Mechanically Pressurized Handgun Applications ofDF/WDG/L Formulations to Spot
Treatments Only
The agency assumes that mechanically pressurized handguns would be used for spot treatments
to small areas, not for broadcast treatments over large acreages in orchards. In some instances,
applicators may use a mechanically pressurized handgun attached to small ground boom sprayers
to treat around an obstruction (e.g., telephone pole) or the perimeter of afield (e.g.,
fencerows). Therefore, limiting mechanically pressurized applications to spot treatments is likely
to be low in terms of acres impacted. However, if there are growers who use mechanically
pressurized handguns for broadcast applications of simazine, they would have to make an
application using a different herbicide, which may be more expensive and possibly less effective.
The agency invites public comments to better inform impacts if their practices differ from our
assumption that most applications with mechanically pressurized hand guns are used primarily
for spot treatment.
Spray Drift Management
For impacts of the spray drift mitigation to Stone Fruit, see above.
Tree Nuts (Pecans, Walnuts, Filberts, Almonds, Macadamia Nuts)
Restrict Mechanically Pressurized Handgun Applications ofDF/WDG/L Formulations to Spot
Treatments Only
The agency assumes that mechanically pressurized handguns would be used for spot treatments
to small areas, not for broadcast treatments over large acreages in orchards. In some instances,
applicators may use a mechanically pressurized handgun attached to small ground boom sprayers
to treat around an obstruction (e.g., telephone pole) or the perimeter of afield (e.g.,
fencerows). Therefore, limiting mechanically pressurized applications to spot treatments is likely
to be low in terms of acres impacted. However, if there are growers who use mechanically
pressurized handguns for broadcast applications of simazine, they would have to make an
application using a different herbicide, which may be more expensive and possibly less effective.
The agency invites public comments to better inform impacts if their practices differ from our
assumption that most applications with mechanically pressurized hand guns are used primarily
for spot treatment
Spray Drift Management
For impacts of the spray drift mitigation to Tree Nuts, see above.
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Berry and Small Fruit (Blueberries. Blackberries. Loganberries. Raspberries. Grapes. Lowbush
Blueberries, Strawberries, Cranberries)
Double-layers and Glovesfor DF/WDG/L Formulations Applied Via Mechanically Pressurized
Handguns (Strawberries)
Requiring double-layer coveralls and gloves for users applying via mechanically pressurized
handguns will not likely impact the overall use of since it is likely that applications via
mechanically pressurized handguns are infrequent. However, users who apply with
mechanically pressurized handguns, may incur some additional costs or burdens. For example,
the use of aPPE (e.g., wearing double layers when applying pesticides) can reduce productivity
of workers because of the physiological stress when working in high temperatures and/or humid
conditions. Workers may need to take more frequent breaks in certain situations than if extra
PPE were not required. Individuals will respond differently depending on many factors, such as
fitness level, hydration, acclimatization, etc. Alternatively, applicators may choose to use a
different herbicide, which could be more expensive and potentially less effective than simazine.
Restrict Mechanically Pressurized Handgun Applications of DF/WDG/L Formulations to Spot
Treatments Only (Blueberries, Blackberries, Loganberries, Raspberries, Grapes, Lowbush
Blueberries, Cranberries)
The agency assumes that mechanically pressurized handguns would be used for spot treatments
to small areas, not for broadcast treatments over large acreages in orchards. In some instances,
applicators may use a mechanically pressurized handgun attached to small ground boom sprayers
to treat around an obstruction (e.g., telephone pole) or the perimeter of afield (e.g.,
fencerows). Therefore, limiting mechanically pressurized applications to spot treatments is likely
to be low in terms of acres impacted. However, if there are growers who use mechanically
pressurized handguns for broadcast applications of simazine, they would have to make an
application using a different herbicide, which may be more expensive and possibly less effective.
The agency invites public comments to better inform impacts if their practices differ from our
assumption that most applications with mechanically pressurized hand guns are used primarily
for spot treatment.
Spray Drift Management
For impacts of the spray drift mitigation to Berries and Small Fruit, see above.
Tropical and Sub-tropical Fruits (Avocado, Olive)
Restrict Mechanically Pressurized Handgun Applications of DF/WDG/L Formulations to Spot
Treatments Only
The agency assumes that mechanically pressurized handguns would be used for spot treatments
to small areas, not for broadcast treatments over large acreages in orchards. In some instances,
applicators may use a mechanically pressurized handgun attached to small ground boom sprayers
to treat around an obstruction (e.g., telephone pole) or the perimeter of afield (e.g.,
fencerows). Therefore, limiting mechanically pressurized applications to spot treatments is likely
to be low in terms of acres impacted. However, if there are growers who use mechanically
pressurized handguns for broadcast applications of simazine, they would have to make an
application using a different herbicide, which may be more expensive and possibly less effective.
The agency invites public comments to better inform impacts if their practices differ from our
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assumption that most applications with mechanically pressurized hand guns are used primarily
for spot treatment.
Spray Drift Management
For impacts of the spray drift mitigation to Avocado and Olives, see above.
For more information refer to Simazine Response to Comments, Usage, Benefits, and Impacts of
Potential Mitigation on Orchards, Vineyards, Caneberries, Strawberries, and Christmas Trees in
the docket
Nursery and Ornamentals
Restrict Mechanically Pressurized Handgun Applications ofDF/WDG/L Formulations to Spot
Treatments Only
The agency assumes that mechanically pressurized handguns would be used for spot treatments
to small areas, not for broadcast treatments over large acreages in nursery and ornamental
operations. In some instances, applicators may use a mechanically pressurized handgun attached
to small ground boom sprayers to treat around an obstruction (e.g., telephone pole), the perimeter
of a field (e.g., fencerows), or for small groups of nursery or ornamental crops in small acreage
sites. Therefore, limiting mechanically pressurized applications to spot treatments is likely to be
low in terms of acres impacted. However, if there are growers who use mechanically pressurized
handguns for broadcast applications of simazine, they would have to make an application using a
different herbicide, which may be more expensive and possibly less effective. The agency invites
public comments to better inform impacts if their practices differ from our assumption that most
applications with mechanically pressurized hand guns are used primarily for spot treatment.
Spray Drift Management
Nursery and ornamental users generally have mixtures of many plant species and are therefore
careful about off-site movement. Therefore, impacts of the spray drift mitigation relevant to
maximum droplet size, boom height, and maximum windspeed should be minimal, see above.
For more information refer to Atrazine and Simazine Use in Forestry, Rights of Way, Turfgrass, and
Nursery: Response to Comments, Usage, and Benefits, in the docket
D.	Tolerance Actions
EPA is proposing the establishment and revocation, as well as amendment of tolerances for
several commodities. Refer to Section m.A.3 for details. The agency will use its FFDCA
rulemaking authority to make the needed changes to the tolerances.
E.	Proposed Interim Registration Review Decision
In accordance with 40 CFR §§ 155.56 and 155.58, the agency is issuing this PID. Except for the
Endocrine Disruptor Screening Program (EDSP), the Endangered Species Act (ESA), and
pollinator components of this case, the agency has made the following PID:
(1) no additional data are required at this time; and (2) changes to the affected registrations and
their labeling are needed at this time, as described in Section IV. A and Appendices A and B.
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In this PID, the agency is making no human health or environmental safety findings associated
with the EDSP screening of simazine, nor is it making a complete endangered species finding or
a complete assessment of effects to pollinators. Although the agency is not making a complete
endangered species finding at this time, the proposed mitigation described in this document is
expected to reduce the extent of environmental exposure and may reduce risk to listed species
whose range and/or critical habitat co-occur with the use of simazine. The agency's final
registration review decision for simazine will be dependent upon the result of the agency's ESA
assessment and any needed § 7 consultation with the Services, and an EDSP FFDCA § 408(p)
determination.
F. Data Requirements
The EPA issued a GDCI requiring multiresidue method testing results (OCSPP 860.1360) for
simazine and its chlorinated metabolites (desethylatrazine (DEA), desisopropylatrazine (DIA),
and diaminochloroatrazine (DACT) on December 12, 2018. These data are needed to determine
the suitability of multiresidue methodology for quantification of simazine and its regulated
metabolites. These data are under development and are required to be submitted to the agency by
December 20, 2020.
No additional data are anticipated to be needed to be called-in for this registration review at this
time. The EPA will consider requiring submission of pollinator data as a separate action.
The analytical reference standard for desisopropylatrazine (DIA), and diaminochloroatrazine
(DACT) have expired and must be submitted to the EPA's National Pesticide Standards
Repository (see https://www.epa.gov/pesticide-analytical-methods/national-pesticide-standard-
repository).
V. NEXT STEPS AND TIMELINE
A.	Proposed Interim Registration Review Decision
A Federal Register Notice will announce the availability of this PID for simazine and will allow
a 60-day comment period on the PID. If there are no significant comments or additional
information submitted to the docket during the comment period that leads the agency to change
its PID, the EPA may issue an interim registration review decision for simazine. However, a final
decision for simazine may be issued without the agency having previously issued an interim
decision. A final decision on the simazine registration review case will occur after: (1) an EDSP
FFDCA § 408(p) determination, and (2) an endangered species determination under the ESA and
any needed § 7 consultation with the Services.
B.	Implementation of Mitigation Measures
Once the Interim Registration Review Decision is issued, the simazine registrants must submit
amended labels that include the label changes described in Appendices A and B. The revised
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labels and requests for amendment of registrations must be submitted to the agency for review
within 60 days following issuance of the Interim Registration Review Decision in the docket.
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Appendix A: Summary of Proposed Actions for Simazine
Registration Review Case#: 0070
PC Code: 080807
Chemical Type: Herbicide
Chemical Family: Triaziue
Mechanism of Action: 5
Affected Populations)
Source of Exposure
Route of Exposure
Equation of
Exposure
Potential Risk(s) of
Concern
Proposed Actions
Comment (use to
briefly clarify or
elaborate on risk or
initiation)
Occupational handler (applicator
of simazine via mechanically-
pressurized handgun on
numerous uses)
» Air (e.g. respirable
particles at/on site
while mixing loading)
» Residues (e.g.. at on
site while
mixing'loading)
Combined dermal and
inhalation
4-day and longer
LH surge suppression
Limit ap p licat ion t o sp ot
treatment only

Occupational handler (applicator
of simazine via backpack spraya
on oranges and grapefruit)
> Air (e.g. respirable
particles at/on site
while mixing loading)
» Residues (e.g.. at on
site while
mixing loading)
Combined dermal and
inhalation
4-day and longer
LH surge suppression
Require additional PPE
(double layer)

Post-Application Residential and
Recreational
• Chlorotriazine
cumulative aggregate
exposure (food
+vvat er + res ident ial
post-application
exposure to treated
residential turf)
•	Dietary (food)
•	Combined dermal and
incidental oral (residential
post-application to treated
residential turf)
4-day and longer
LH surge suppression
Prohibit residential and
recreational turf use

Avian
Dietary and spray drift
Ingestion
Chronic
Growth
Enforceable spray drift
management measures
Label clarification
Mammals
Dietary and spray drift
Ingestion
Chronic
Reproductive and Growth
Enforceable spray drift
management measures
Label clarification
T errestrial Plants
Spray drift
Direct contact
Acute
Chronic
Growth
Enforceable spray drift
management measures
Label clarification
Aquatic plants (nonvascular)
Spray drift and runoff
Direct contact
Acute
Chronic
Growth
Enforceable spray drift
management measures
Label clarification

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Docket Number hPA-HQ-OPP-2013-Ul!5 i
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Appendix B: Proposed f nbelinu < lianm s lor Simazine Products
I li-- l l ipiil'll
i'l n|mst'(| i I iKi^tiiiuc '"1 -¦iiiiii/iiif i'i-.nhii i\
i'Ult lH itil I ;iU-l
PFE ReCJuiiillKIH
For backpack
application of DF,
WDG. and liquid
fomxilatkms oil
Grapefruit and
Oranges
Mixer loader applicators for backpack application to grapefruit and oranges are inquired to wear double layer clothing

I'se Restrictions for
mechanically
pressurized handguns
ofDF. WDG and
liquid foimifetions
• Applications made by mechanically pressurized handguns are restricted to spot treatment only for the following
uses
o Citrus (Q-apefinil. Oranges. Lemons)
o Ponie Fruits (Apples. Pears"!
o Stone Fruits ^Cherries [sweet and tart], peaches.Plums, Nectarines >
o Tree Nuts (Pecans. Walnuts. Filberts. Almonds. Maeadanaa Nuts
o Beny and Small Fruit (Blnebenies. Blackberries, Loganberries. Raspberries. Grapes, Lowbush
Blueberries. Cranberries)
o Tropical and Sub-tropical Fruits (Avocado, Olive)
o Nursery •'Ornamentals
>;• Sweet Cora
• Applications made by mechanically pressurized handguns to strawberries are restricted to either spot
treatment only or nixer'loaderapplicators are required to wear double layer of clothing.


End Use Products

Mechanism of
Action Cioup
Nuafcer
Note to registrant:
•	Include the unme of ihe ACTIVE INGREDIENT m she column
•	Include die word "GROt1?1 ii the second cokanu
•	Include the MODE/MECHANISM OF ACTION CODE hi the thsd cokniw (for
herbickWs thiN t, the Mechanism of" Action, lot timeicides this is the FRAC ("ode. ami joi
in^eetie de s tins is the Primary Sire of Action')
•	Include the type of pesticide (i.e. HERBICIDE or FUNGICIDE or INSECTICIDE) ii
the fourth echinm.
Front Panel, upper right
quadrant.
All tea should be black,
bold face and all caps
on a white background.
except the nuJe of
action code, which
should be white, bold
face and all caps on a
black background; all
test and columns should
35

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Docket Numbei EPA-HQ-OPP-20! >-025 J
www.iegiiht io its. gov
1 )< • I 1 iplltlf!
t')-i|i1i-.id ( :iU j 1 fur SiilU/illv 5'l .idlit Is
Phu i'liu iii i'ii I :ils'l


Siiiu/iHt*
GROUP
In
bl
suiroundedby a
ick rectangle.
For products
registered for use
on surf
Use is. p emit fed on golf course rutf and sod farms only, Do not use on residential tiirfoi lawns, institutional t«if,
parks or recreational fields.
Directions for Use
Updated (.linrs
SrnU'llKMl!
Update the glove statements to be consistent with Chapter 10 of the Label Review Manual
In the Personal
Protective Equipment
(PPE) within the
Precautionary
Statements and
Agricultural Use
Requirements, if
applicable
1 ixlited Respirator
{.migua^c
[Note to registrant: If your end-use product only requires protection from particulates only (low volatility), use the
following language:}
"We.ii a nmuniim of a NIOSH-approved particulate filtering face piece respirator with any N*. R or P filter: OR a
NIOSH-approved ekstonieric particulate respirator with any N*. RorP filter: OR a NIOSH-approved powered air
purifying respirator with 'HE libel's ."
*Drop the "N" option if there k oil in the product's foraiilation and. or the product is labeled for tiiang with oil-
contaiiiiig products.
[Note to registrant: For respirator)' protection from organic vapor and particulates for aerosols.), use the following
language:]
"Wear a umriniim of a NIOSH-appro\ ed efastoineric half mask respirator with organic vapor i OV) cartridges and
conization N*. R. or P filters. QR a NIOSH-approved gas n»sk with OV canisters;Q& a MOSH-approved powered
air purifying respirator with OV cartridges and combination HE filters,"
[Note to resistraut; For products requaite urotection lor oraanic vapor onh*. use the following language:]
"Wenra nanmmn of a MOSH-approved elastonieiic half mask respirator with organic vapor (OV) cartridges: OR a
MOSH-approvetl fiti face respirator with OV cartridges: OR a gas mask with OV canisters: OE a powered air
purifying respiratoi with OV cartridges."
In the Personal
Protective Equipment
(PPE) within the
Precautionary
Statements
36

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Docket Number IIPA-HQ-OPP-2013-025 1
wwwjepihtioiB. gov
Hi-m i ipiiuii
Pi ( .il* i i .iiliiiil.me inl- Silll;l/illi- i'i 'stisst K
1'lateiniUl I HI

~Drop the **N" option if there is oi in the product's fomulaliba and/or the product is labeled for nihdng with, oft-
containing products.

Non -largol
Orgsiniwn A«hisory
StilttMllfllt
"NON-TARGET ORGANISM ADVISORY STATEMENT: This product is toxic to plants and may adveisefy itnpaci
the forage and habitat of non^argetoiganisns. including pollinators, in areas adjacent to the treated site. Protect the
forage and habitat of non-target organisms by following libel directions intended to rninimze spray drift."
Gavaomsentat Hazards
HERBICIDE
RESISTANCE
MANAGEMENT:
Weed Resistance
Management
Include resistance management label language for herbicides from PRN 201"-1 and PEN 201 "-2
Directions for Use, prior
to dkections tor specific
crops under the heading
"\fo FJiD
RESISTANCE-
MANAGEMENT"
Affefilionai
Required 1 ng
Action
Applies (o ail
products (HhertMl
u:i liquid spray
agitations
Renx>\ e information about volmnetrk mean diameter troin all labels where sudiinfbnretion currently appeal's.
Directions for Use
Direction-. for
mixing loading
|*\KhK'lS JKU'kagMt
in w»ter soluble
teigs
Instructions foi Introducing Water Soluble Packages Directly into Spray tanks:
"Soluble Packages (WSPs) are designed to dissolve in water. Agitation nay be used, if necessary, to help dissolve the
WSP. Failure to follow handling and nixing ins mictions c«u increase your e.^ostire to the pesticide product?, in
WSPs. WSPs. when used properly, qualify as a closed niune loading system under the Agricultural Worker
Protection Standard [40 GFR 170.607(d)]. *
Hand hug Instructions
Follow these steps when handling pesticide products in WSPs,
l.Mix in spray tank only.
2 Handle the WSP m a manner thatprotects package from breakage aii&or unintended release of contents. If package
is broken, put on PPE required for clean-up and then continue with nixing instiucnons.
3.Keep the WSP in outer packaging until just before use.
4 Keep the WSP thy prior to adding to the spray tank,
5,Handle rath dry gloves and according to the label ins mictions for PPE.

37

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Docket Number KPA-lIQ-OPP- jO) 3-025 i
www.regiilatioiis- go v
Pi - lTi|!ii!H i

?.Re&eal the WSP outer packaging to protect any unused WSPfs).
Mixing Instructions
Follow the steps below when iriraag this product, iiic hiding if it is tank-nixed with other pesticide products.. If being
tank-nixed, the mixing directions 1 through 9 below take precedence over the tncdng directions of the other tank nix
products. WSP* amy. in some cases.be nisil with other pesticide products so long as, the directions for use of all the
pesticide product components do not conflict. Do not tank-nix this product with products that prohibit tank-nixing or
have conflicting nixing directions.
i.If a basket or strainer is present in the tank hatch, remove prior to adding the WSP to the tank.
2.FilI tank with water to approximately one-third to one-half of the desired final volume of spray.
3.Stop adding water and stop any agitation.
-l.Place mtaci.'unopened WSP into the tank.
5,Do not spray water horn a hose or fill pipe to break or dissolve the WSP.
6.Start mechanical and recirculation agitation from the bottom of tank without using any overhead recirculation, if
possible. If overhead recirculation cannot be turned off. close the hatch before stalling agitation.
".Dissolving the WSP may take up to 5 iiinutes or longer, depending on water temperature. water hardness and
infelicity of agitation.
S.Stop agitation before tank M is. opened.
9 Open the lid to the tank, tHssrcising caution to avoid contact with dusts or spray nix to verify that the W SP has fully
dissolved and the contents have been thoroughly rami into the solution,
lO.Do not add other allowed products or coup lete filling the tank until the bats have fully dissolved and pesticide is
thoroughly meed.
11 .Once the WSP has fully dissolved and any other products have been added to the tank, resume filling the tank with
water to the desired level close the tank lid, and resune agitation.
12.Use the spray solution when nixing is complete.
1 .^Maintain agitation of the diluted pesticide nix dtuing transport and application.
14.It is unlawful to use any registered pesticide, including WSPs. in a manner inconsistent with its label.
ENGINEERING CONTROLS
Water soluble packets, wheu used coirectly. qualify as a closed nixing 'loading system under the Worker Protection
Standard [40 GFR ITO.QPfdi]. Misers and loaders handling this pioduct while it b enclosed in intact water-soluble
packets nay elect to wear reduced PPE of long-sleeved shirt, long pants, shoes, socks, a ehenical-resistaut apron, and
cheiiical-resisiant glov es. When reduced PPE is worn because a closed system k being used, handlers oust be
provided all PPE specified above for "applicators and other handlers" and have such PPE immediately available for use
m an emergency, such as in case of a spill or equipment break-down."

38

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Docket N umber IIP A-lTQ-OPP-201 -0251
www.regulatio ib. go v

iV-ijaiM'ii .';!!«. ! ! I'm siuni/iiii- lY'idiu K
PJ.st <:llu r.i 1:] 1 i ;i!s !
Miiiiiigfiwm
Application
Restrictions ibi
products that arc
applied as liquids
and alow ground
boom applications
^ Mi\IH
Ground Boom Aimliciitiom:
•	User must only apply with the release height recommended by (tie manufacturer, but no more than 4 feet above the
ground or crop canopy,
•	Applicators are required to use a coarse or coarser droplet size (ASABE S5"2.! 1
•	Do not apply when mid speeds e steed 10 miles per hour at the application site,
•	Do not apply during temp era hire inversions
box titled "Spray Drift"
under the heading
"Ciound Boom
Applications "
AAisorj Spray
Drift \taageiwnt
LiUtgiiage tor ail
products delivered
via liquid spray
application
"SPRAY DRIFT ADVISORIES
THE APPLICATOR IS EESPCNSTRT .F FOR AVOIDING OFF-SITE SPRAY DRIFT.
BE AWARE OF NEARBY NON-TARGET SriTES AND ENVIRONMENTAL CONDmONS.
IN [PORTA N CK OF DROPIJFT SIZE
An effective way to reduce spxay drift is to apply large droplets. Use the largest droplets that provide target pest
control. While applying lager droplets will reduce spray drift, the potential for drift will be greater if applications are
nude iqjfoperty or oilier unfavorable em tronn*mtal conditions
Coiurolliug Droplet Size - Ground Boom malt'to reghtrmiH: tvitm e ifground boom) s prohibited on product
labels)
•	Volume - Increasing the spray volume so that larger droplets are produced wiH reduce spray drift. Use the highest
practical spray vohmie for the application, if a greater spray vohnw is needed, coimderusiug a nozzle with a higher
flow rate,
•	Pressure-Use the lowest spray pressure recomiEnded tor the no^fe to produce the target spray volume and droplet
SIZE
•	Spray Nozzle -Use a spray nozzle that is designed for the intended application Consider using nozzles designed to
reduce dnft
BOOM HEIGHT - Ground Boom mote to registrants; remove ifground boom is prohibited on product labels)
For ground equipment, the boom should remain level with the crop and have itiiiinal bounce.
SHIELD ID sPRAYms
Shielding the boom or individual nozzles can reduce spray drift. Consider using shielded sprayers. Verity that the
shields are not interfering with the uniform deposition of the spray on the target area,
I I MPKR A! IRE \M> HIM 11)1 I V
When nuking applications in hot and dry conditions, use larger droplets to reduce effects of evaporation.
TEMPERATURE IMTRSIONS
Directions for Use, just
below the Spray Dnft
box, under the heading
"Spray Drift
Advisories"
39

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Docket Number EPA-HQ-OPP-2013-0251
wmvjisfjpkitiGiB, gov
Dom-i ijxion
i'i i .,li>i S i 1>>1 N1 lii.l/1III- 1*1 "dill' i\
I'hlCvlllflll ¦ HI (;|UI

Drift potentials Mgfa during .1 te;i4>eramre inversion T?ii|rcramruiid soutceorao akcrafi smoke
generator. Smoke that layers and moves laterallyin a concentrated cloud (under low wmd couditio&s) indicates an
inversion. ihJe smoke that moves upward and lapidiy dissipates .indicates good vertical air iiastig. Avoid
applications during teinpercitiue inversions.
WIND
Drift potential generally increases with wind speed. AVOID APPLICATIONS DURING GUSTY WIND
CONDITIONS
Applicators need to be faailiar with local wmd patterns and terrain thai could afiect spray dntt"

Athisory Spmy
Drift Management
Language for all
products that allow
liquid applications
with handheld
feclittologies
"SPRAY DRIFr \D\lsORIES
Handheld Technology Assjlicitioiis:
* Take precautions to naninaze spray drift."
Directions for Use. just
below the Spray Dntr
box, under the heading
"Spray Drift
Advisories"
40

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Docket Number EPA-HQ-OPP-2013-0251
www. regulations, gov
Appendix C: Endangered Species Assessment
This Appendix provides general background about the Agency's assessment of risks from
pesticides to endangered and threatened (listed) species under the Endangered Species
Act. Additional background specific to simazine appears at the conclusion of this Appendix.
In 2013, the EPA, along with the Fish and Wildlife Service (FWS), the National Marine
Fisheries Service (NMFS), and the United States Department of Agriculture (USDA) released a
summary of their joint Interim Approaches for assessing risks to endangered and threatened
(listed) species from pesticides4. These Interim Approaches were developed jointly by the
agencies in response to the National Academy of Sciences' (NAS) recommendations that
discussed specific scientific and technical issues related to the development of pesticide risk
assessments conducted on federally threatened and endangered species.
Since that time, EPA has conducted biological evaluations (BEs) on three pilot chemicals
representing the first nationwide pesticide consultations. These initial consultations were pilots
and were envisioned to be the start of an iterative process. The agencies are continuing to work
to improve the consultation process. For example, advancements to the initial pilot interim
methods have been proposed based on experience conducting the first three pilot BEs. Public
input on those proposed revisions is currently being considered.
Also, a provision in the December 2018 Farm Bill included the establishment of a FIFRA
Interagency Working Group to provide recommendations for improving the consultation process
required under section 7 of the Endangered Species Act for pesticide registration and
Registration Review and to increase opportunities for stakeholder input. This group includes
representation from EPA, NMFS, FWS, USDA, and the Council on Environmental Quality
(CEQ). Given this new law and that the first nationwide pesticide consultations were envisioned
as pilots, the agencies are continuing to work collaboratively as consistent with the congressional
intent of this new statutory provision. EPA has been tasked with a lead role on this group, and
EPA hosted the first Principals Working Group meeting on June 6, 2019.
Given that the agencies are continuing to develop and work toward implementation of
approaches to assess the potential risks of pesticides to listed species and their designated critical
habitat, the ecological risk assessment supporting this PID for simazine does not contain a
complete ESA analysis that includes effects determinations for specific listed species or
designated critical habitat. Although the EPA has not yet completed effects determinations for
specific species or habitats, for this PID, the EPA's evaluation assumed, for all taxa of non-target
wildlife and plants, that listed species and designated critical habitats may be present in the
vicinity of the application of simazine. This will allow the EPA to focus its future evaluations on
the types of species where the potential for effects exists once the scientific methods being
developed by the agencies have been fully vetted. Once that occurs, these methods will be
applied to subsequent analyses for simazine as part of completing this registration review.
4 https://www.epa.g-ov/endangered-species/draft-revised-niethod-national-level-endangered-species-nsk-assessnient-
process
41

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Docket Number EPA-HQ-OPP-2013-0251
www. regulations, gov
Simazine is one of the chemicals in stipulated partial settlement agreement in the case of Center
for Biological Diversity et. al., v. United States Environmental Protection Agency etal., No. 3:11
cv 0293 (N.D. Cal.). Among other provisions, this agreement sets an August 14, 2021, deadline
for EPA to complete nationwide ESA section 7(a)(2) effects determination for simazine and, as
appropriate, request initiation of any ESA section 7(a)(2) consultations with the Services that
EPA may determine to be necessary as a result of those effects determinations.
42

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Docket Number EPA-HQ-OPP-2013-0251
www. regulations, gov
Appendix D: 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 systemic 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 assessments, EPA evaluates acute tests and
chronic studies that assess growth, developmental and reproductive effects in different
taxonomic groups. As part of its most recent registration review 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 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 effects as the Administrator
may designate." The EDSP employs a two-tiered approach to making the statutorily 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, 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 ingredients and 9 inert ingredients. A second list of
chemicals identified for EDSP screening was published on June 14, 20135 and includes some
pesticides scheduled for registration review and chemicals found in water. Neither of these lists
should be construed as a list of known or likely endocrine disruptors.
Simazine is on List 1 for which EPA has received all of the required Tier 1 assay data. The
Agency has reviewed all of the assay data received for the appropriate List 1 chemicals and the
conclusions of those reviews are available in the chemical-specific public dockets (see Docket #
EPA-HQ-OPP-2013-0251).
5 See https://www regulations.gov/docunient?D:=EPA.-HO-OPPT-2009-0477-0074 for the final second list of
chemicals.
43

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Docket Number EPA-HQ-OPP-2013-0251
www. regulations, gov
For further information on the status of the EDSP, the policies and procedures, the lists of
chemicals, future lists, the test guidelines and the Tier 1 screening battery, please visit our
website6.
6 https://www.epa.gov/endocnne-dismption
44

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