2

Propazine Preliminary Work Plan – Table of Contents 

Overview 3 

Anticipated Data Needs 4 

Statutory and Regulatory Authority 5 

Propazine Facts 5 

Use and Usage Information 6 

Recent Actions 7 

Anticipated Risk Assessments for Registration Review 8 

Timeline 10 

Next Steps 10 

Appendix – Additional Areas Considered in the Propazine Registration Review 11 

References:

This Preliminary Work Plan summarizes the Environmental Protection Agency's current position 

based on the following documents: 

1. Registration Review: Problem Formulation for Environmental Fate and Ecological Risk, 

Endangered Species, and Drinking Water Assessments for Propazine. B. Kiernan. May 8, 

2013. 

2. Atrazine, Propazine, and Simazine. Human Health Risk Scoping Document in Support of 

Registration Review. W. Donovan. June 4, 2013 

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

January 22, 2013. 

4. BEAD Chemical Profile for Registration Review: Propazine. B. Phillips. December 5, 

2012.

5. Propazine Screening Level Usage Analysis: Propazine. June 15, 2012

6. PRD Label Data Report: Food/Feed & Non-Food/Non-Feed Uses Considered in 

Registration Review Work Planning. July 5, 2012.
3

These and other supporting documents for the propazine registration review case may be found 

in the docket EPA-HQ-OPP-2013-0250 at http://www.regulations.gov. 
4

OVERVIEW

The docket for propazine is now open, initiating the first public comment period for this 

registration review (docket number EPA-HQ-OPP-2013-0250). Propazine is a triazine herbicide 

registered for use to control broadleaf and grass weeds. It is registered for use on grain sorghum 

and containerized ornamental plants grown in greenhouses. Propazine is a triazine herbicide and 

part of the triazine common mechanism group based on a common toxicity end-point and known 

mechanism of toxicity. The other members of the triazine common mechanism group are 

atrazine, simazine, and the three major chloro metabolites (DEA, DIA, and DACT for short).1

 

This Preliminary Work Plan (PWP) document explains what EPA's Office of Pesticide Programs 

knows about propazine, highlighting anticipated data and assessment needs, identifying the types 

of information that would be especially useful to the Agency in conducting the review, and 

providing an anticipated timeline for completing the registration review for propazine. 

 

The registration review process was designed to include a public participation component to 

solicit input from interested stakeholders. The Agency intends, by sharing this information in the 

docket, to inform the public of what it knows about propazine and what types of new data or 

other information would be helpful for the Agency to receive as it moves toward a decision on 

propazine. The Agency encourages all interested stakeholders to review the PWP and Appendix 

and to provide comments and additional information that will help the Agency’s decisionmaking process for propazine. In addition to general areas on which persons may wish to 

comment, there are some areas identified in the PWP and Appendix about which the Agency 

specifically seeks comments and information. Interested stakeholders could include: 

environmental non-profit or interest groups; pesticide manufacturers; agricultural labor or 

commodity groups; commercial, institutional, residential, and other users of pesticides; or the 

public at large. 

The Preliminary Work Plan begins by listing the anticipated data needs for propazine. Next, it 

discusses the statutory and regulatory authority for Registration Review. Then the document 

provides propazine facts, use and usage information, recent actions, the anticipated risk 

assessments, and a projected registration review timeline for propazine. Finally, the Appendix to 

this document includes identification and discussion of some areas that are considered generally 

in Registration Review along with some additional propazine case-specific information. 

 

 

1

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

triazine common mechanism group because they do not share the same toxicity profile. For additional 

information, see the triazine cumulative risk assessment at http://www.regulations.gov/#!docketDetail;D=EPAHQ-OPP-2005-0481. 
5

ANTICIPATED DATA NEEDS

Table 1 below summarizes anticipated data needs for propazine. For additional discussion of the 

anticipated data needs, see the Registration Review: Problem Formulation for Environmental 

Fate and Ecological Risk, Endangered Species, and Drinking Water Assessments for Propazine

and Atrazine, Propazine, and Simazine. Human Health Risk Scoping Document in Support of 

Registration Review.

Table 1: Anticipated Data Needs for the Propazine Registration Review 

Guideline 

Number2 Study Title Test Material 

Estimated 

Timeframe 

(Months from 

receipt of DCI) 

850.2100 Acute avian toxicity (passerine species) TGAI 12 

850.2300 Avian reproduction TGAI 24 

TGAI = technical grade active ingredient; 

 

 

2

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

– including renumbering and other designations or changes for some guideline studies. See “Final Test 

Guidelines; OCSPP 850 Series; Notice of Availability” 77 FR 38282, June 27, 2012. 

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0154-0028
6

STATUTORY AND REGULATORY AUTHORITY

The Food Quality Protection Act (FQPA) of 1996 mandated a registration review program. All 

pesticides distributed or sold in the United States (U.S.) generally must be registered by the 

Environmental Protection Agency (EPA or the Agency), based on scientific data showing that 

they will not cause unreasonable risks to human health or the environment when used as directed 

on product labeling. The registration review program is intended to make sure that, as the ability 

to assess risk evolves and as policies and practices change, all registered pesticides continue to 

meet the statutory standard of no unreasonable adverse effects to human health or the 

environment. Changes in science, public policy, and pesticide use practices will occur over time. 

Through the registration review program, the Agency periodically reevaluates pesticides to make 

sure that as change occurs, products in the marketplace can be used safely. Information on this 

program is provided on EPA’s website.3

The Agency is implementing the registration review program pursuant to Section 3(g) of the 

Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), and will review each registered 

pesticide every 15 years to determine whether it continues to meet the FIFRA standard for 

registration. The regulations governing registration review begin at 40 CFR 155.40. The 

Agency will consider benefits information and data as required by FIFRA. The public phase of 

registration review begins when the initial docket is opened for each case. The docket is the 

Agency’s opportunity to state what it knows about the pesticide and what additional risk analyses 

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

reviewing and responding to comments and data received in the docket during this initial 

comment period, the Agency will develop a Final Work Plan (FWP) and anticipated schedule for 

the registration review of propazine. 

PROPAZINE FACTS

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

Table 2: Chemical Facts for Propazine

PC code 080808 

Case Number 7278 

CAS Number 139-40-2 

Year first registered 1989 

Pesticide Type Herbicide 

Propazine class Triazine 

Reregistration Eligibility 

Decision (RED) 

Because it was registered after November 1984, propazine was not 

subject to reregistration 

Tolerance Reassessment 

Eligibility Decision 

(TRED) 

April 2006 

 

3

 http://www.epa.gov/oppsrrd1/registration_review/ 
7

Table 2: Chemical Facts for Propazine

Cumulative group Triazine. Propazine is a triazine herbicide and part of the triazine 

common mechanism group based on a common toxicity end-point 

and known mechanism of toxicity. The other members of the 

triazine common mechanism group are atrazine, simazine, and the 

three major chloro metabolites (DEA, DIA, and DACT for short). 

The most recent cumulative risk assessment for the triazine 

common mechanism group was completed March 28, 2006 . 

40 CFR Citation Tolerances for propazine are established in 40 CFR Part 180.243. 

Dual-use Propazine is registered for conventional pesticidal uses only and has 

no registered antimicrobial or biopesticidal uses. 

Non-pesticidal uses There are no identified non-pesticidal uses of propazine 

Pesticide Re-evaluation 

Division, Propazine 

Review Manager 

Molly Clayton 

clayton.molly@epa.gov

703-603-0522 

Registration Division, 

Product Manager 

Kable Bo Davis 

davis.kable@epa.gov

703-306-0415 

USE AND USAGE INFORMATION

Table 3 summarizes the use and usage information for propazine. Please see the BEAD 

Chemical Profile for Registration Review: Propazin in the registration review docket for more 

details. 

Table 3: Propazine Use and Usage Information

Summary of Use Propazine is a triazine herbicide registered for use to control broadleaf 

and grass weeds. It is registered for use on sorghum and containerized 

ornamental plants grown in greenhouses.

Use Sites There are only two registered uses for simazine: 

Agricultural: Sorghum (forage, grain, stover) 

Non-Agricultural: Greenhouses on ornamental plants grown in 

containers. 

Summary of Usage During the 2007-2011 timeframe, use of propazine on grain sorghum 

averaged approximately 74,000 pounds annually and was applied on 

average to 96,000 acres. No information on the containerized 

ornamental usage is available.

Formulation Type(s) Propazine is formulated as a flowable concentrate. 

Application Method(s) Products can be applied via aerial and ground 

spray applications, using flat fan-type nozzles for uniform broadcast 

applications and band treatments. Propazine is also applied through 

flood or drench nozzles in greenhouse applications.

Technical Registrant(s) Albaugh, Inc. 
8

Table 3: Propazine Use and Usage Information

No. of Registrations 1 Section 3 registration4

Restricted Use No 

Guidance for Commenters: Additional areas of use and usage related information

requested for this registration review, and of particular interest to EPA, are described below. 

 Information on typical propazine use in the non-agricultural sector, including but not 

limited to, application timing, application rate, application method, and application 

frequency. Confirmation of the following label information for all uses: sites of 

application; formulations; application methods and equipment; maximum application 

rates; frequency of application, application intervals, and maximum number of 

applications per season; and geographic limitations on use. 

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

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

and county. 

 Typical application timing (date of first application and application intervals) – national, 

state, and county. 

 Usage/use information for non-agricultural uses. 

 Typical application interval (days). 

 State or local use restrictions. 

 Foreign technical registrants not listed above who supply technical propazine to the US 

market. 

 PENDING ACTIONS 

The Agency is currently evaluating a tolerance petition for simazine (2F8006, 77 FR 50686) to 

establish crop group tolerances for stone fruit, pome fruit, citrus fruit, and tree nuts; to remove 

individual tolerances which would be replaced by the new crop groups; and for several other 

related actions. EPA is in the process of reviewing this request which will likely necessitate an 

updated assessment for the triazine cumulative group. 

ANTICIPATED RISK ASSESSMENTS FOR REGISTRATION REVIEW

The most recent comprehensive human health risk assessment for propazine was completed in 

2005 for the new sorghum use request for propazine. The most recent ecological and 

environmental fate risk assessment was completed in March 2006 for the same purpose. 

Findings and conclusions from these risk assessments are summarized in the Registration 

Review: Problem Formulation for Environmental Fate and Ecological Risk, Endangered 

Species, and Drinking Water Assessments for Propazine and Atrazine, Propazine, and 

Propazine: Human Health Risk Scoping Document in Support of Registration Review. 

 

4

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

(http://oaspub.epa.gov/pestlabl/ppls.home). 
9

During registration review, the Agency anticipates the need to conduct a comprehensive 

ecological risk assessment, including an endangered species assessment, for all uses of 

propazine. For human health, EPA anticipates the need to conduct revised dietary, residential, 

and occupational, and cumulative risk assessments during registration review. If toxicological 

endpoints or points of departure are revised based on the data that are anticipated to be required, 

or based on the results of literature reviewed during registration review, they will be considered 

in the new assessments, as well as any changes to the standard operating procedures or default 

exposure assumptions. 

Table 4 below summarizes the anticipated registration review risk assessments based on the 

EFED Problem Formulation and HED Scoping Document. 

Table 4: Anticipated Risk Assessments for the Propazine Registration Review 

Type of Risk Assessment Conduct? Notes 

Ecological and Environmental Fate 

Comprehensive ecological 

(species to be assessed 

include terrestrial and aquatic 

organisms), including 

endangered species 

Y The parent propazine will be considered the stressor 

of concern because it is expected to be protective for 

any non-target organisms that may be exposed to the 

parent and any of its degradates. 

Incidents Will check for 

updates 

For a discussion of reported ecological incidents for 

propazine, see page 15 of the Problem Formulation. 

Human Health 

Dietary 

Food Y During registration review, an updated dietary 

assessment may be conducted to include any updates 

to toxicological endpoints, dietary exposure estimates, 

and changes to assessment SOPs. 

Drinking water Y EPA anticipates updating the drinking water 

assessment for propazine during registration review. 

Occupational 

Handlers (mixers, loaders, 

applicators) 

Y In registration review, an up-to-date quantitative 

occupational risk assessment may be required to 

account for current registered application rates, unit 

exposures, transfer coefficients (TCs), and toxicity 

endpoints and safety factors. 

Post-application Y 

Residential 

Handlers N There are no registered residential uses of propazine. 

Post-application N 

Other 

Aggregate Y Evaluates the combined risk from dietary and 

residential exposures. Since there are no registered 

residential uses of propazine, its aggregate assessment 

consists of the dietary exposure assessment only. 
10

Cumulative Y An assessment of the triazine cumulative group is 

expected as part of registration review. 

Tolerances Y Tolerances are established under 40 CFR §180.243 

for residues of propazine in/on sorghum commodities. 

EPA anticipates updating the residue definition for 

the tolerance expression for propazine to be in 

accordance with current policy on tolerance 

definitions. 

Incidents Will check for 

updates 

For a discussion of reported human incidents for 

propazine, see page 12 of the Scoping Document and 

the Atrazine, Propazine, and Propazine: Review of 

Human Incident Reports.

TIMELINE

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

registration review in Table 5 below. 

Table 5: Projected Propazine Registration Review Timeline

Activities Estimated Date

Opening the Docket 

Open Docket and 60-day Public Comment Period 2013 – June 

Close Public Comment 2013 – August 

Case Development 

Final Work Plan 2013 – November 

Issue DCI 2014 July - September 

Data Submission 2016 July - September 

60-day Public Comment Period for Draft Risk 

Assessments5

2018 January – March 

Registration Review Decision 

60-day Public Comment Period for Proposed 

Registration Review Decision 

2018 October – December 

Registration Review Decision and Begin Post-Decision 

Follow-up 

2019 

Total (years) 6 

NEXT STEPS

After the 60-day public comment period closes, the Agency will review and respond to any 

comments received in a timely manner and then issue a Final Work Plan for the registration 

review of propazine. 

 

5

 The regulations governing Registration Review require the Agency to provide a public comment period of at least 

30 calendar days for draft risk assessments; see 40 CFR Part 155.53(c). The Agency plans to provide a 60 calendar 

day public comment period for draft risk assessments as a general standard of practice. 
11

Appendix – Additional Areas Considered in the Propazine Registration 

Review

PUBLIC COMMENTS AND FEEDBACK:

Guidance for Commenters: The areas below highlight topics of special interest to the Agency 

where your comments, data submissions, or reference to sources of additional information could 

be of particular use.

Trade Irritants: 

Through the registration review process, the Agency intends to solicit information on trade 

irritants and, to the extent feasible, take steps toward facilitating irritant resolution. The Agency 

will work to harmonize tolerances and international maximum residue limits (MRLs) and may 

modify tolerance levels to do so, when possible. Growers and other stakeholders are asked to 

comment on any trade irritant issues resulting from lack of MRLs or disparities between U.S. 

tolerances and MRLs in key export markets, providing as much specificity as possible regarding 

the nature of the concern. 

Water Quality: 

Propazine is not identified as a cause of impairment for any water bodies listed as impaired under 

section 303(d) of the Clean Water Act.6

 In addition, no Total Maximum Daily Loads (TMDL) 

have been developed for propazine.7 More information on impaired water bodies and TMDLs 

can be found at the Agency’s website.8 The Agency invites submission of water quality data 

for this pesticide. To the extent possible, data should conform to the quality standards in 

Appendix A of the OPP Standard Operating Procedure: Inclusion of Impaired Water Body and 

Other Water Quality Data in OPP’s Registration Review Risk Assessment and Management 

Process9 in order to ensure they can be used quantitatively or qualitatively in pesticide risk 

assessments. 

Environmental Justice: 

EPA seeks to achieve environmental justice, the fair treatment and meaningful involvement of all 

people, regardless of race, color, national origin, or income, in the development, implementation, 

and enforcement of environmental laws, regulations, and policies. To help address potential 

environmental justice issues, the Agency seeks information on any groups or segments of the 

population who, as a result of their location, cultural practices, or other factors, may have 

atypical, unusually high exposure to propazine compared to the general population. Please 

comment if you are aware of any sub-populations that may have atypical, unusually high 

exposure compared to the general population.

 

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

7

http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=885&p_pollutant_

group_name=PESTICIDES

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

9 http://www.epa.gov/oppsrrd1/registration_review/water_quality_sop.htm
12

ENDANGERED SPECIES:

A risk assessment that supports a complete endangered species determination has not been 

conducted for propazine. The ecological risk assessment planned during registration review will 

allow the Agency to determine whether use of propazine has “no effect” or “may affect” 

federally listed threatened or endangered species (listed species) or their designated critical 

habitats. When an assessment concludes that a pesticide’s use “may affect” a listed species or its 

designated critical habitat, the Agency will consult with the U.S. Fish and Wildlife Service 

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

ENDOCRINE DISRUPTOR SCREENING PROGRAM: 

As required by FIFRA and FFDCA, EPA reviews numerous studies to assess potential adverse 

outcomes from exposure to propazines. 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 decision for propazine, 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), propazine 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 

propazine 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. Propazine is 

not among the group of 58 pesticide active ingredients on the initial list to be screened under the 

EDSP. Accordingly, as part of registration review, EPA will issue future EDSP orders/data callins, requiring the submission of EDSP screening assays for propazine. For further information 
13

on the status of the EDSP, the policies and procedures, the list of 67 chemicals, future lists, the 

test guidelines and the Tier 1 screening battery, please visit our website.10

HUMAN STUDIES:

Past propazine risk assessments rely in part on data from studies in which adult human subjects 

were intentionally exposed to a pesticide to determine their dermal and inhalation exposure. 

Many such studies, involving exposure to many different pesticides, comprise generic pesticide 

exposure databases such as the Pesticide Handlers Exposure Database (PHED) and the 

Agricultural Reentry Task Force (ARTF) Database. EPA has reviewed all the studies supporting 

these multi-pesticide generic exposure databases, and has found no clear and convincing 

evidence that the conduct of any of them was either fundamentally unethical or significantly 

deficient relative to the ethical standards prevailing at the time the research was conducted. All 

applicable requirements of EPA’s Rule for the Protection of Human Subjects of Research (40 

CFR Part 26) have been satisfied, and there is no regulatory barrier to continued reliance on 

these studies. 

 

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