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INTRODUCTION

This is the Environmental Protection Agency’s (EPA or the Agency) Final Work Plan (FWP) for 

the registration review of MCPP-p. This work plan addresses public comments received 

concerning the Preliminary Work Plan (PWP), which was posted in the MCPP-p registration 

review docket (EPA-HQ-OPP-2014-0361). This case includes the following active ingredients: 

mecoprop-p acid (MCPP-p), MCPP-p dimethylamine salt (MCPP-p DMAS), and MCPP-p 

potassium salt. The PC codes included in this case are: 129046, 031520, and 119046. These 

compounds are collectively referred to as MCPP-p. Products containing racemic mecoprop 

(MCPP) and its salts have been reformulated to the enriched isomer formulation MCPP-p. 

Therefore, registration review will focus solely on MCPP-p and its salts. MCPP-p is a nonselective herbicide in the chlorophenoxy class of herbicides that is registered for non-agricultural 

use to control a variety of weeds on commercial and residential lawns; turfgrass, golf courses,

sod farms, and outdoor residential areas. It is registered for noxious weed and brush control use 

on uncultivated, non-agricultural areas such as rights-of-way, roadsides, and airports. There are 

no registered food or feed uses, and MCPP-p products are used primarily in residential, 

commercial, institutional, and industrial areas.

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

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

Information on this program is provided on the Agency’s website.

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The FWP begins with any updates since the PWP was issued. Next is a summary of substantive 

comments received during the public comment period for the PWP concerning anticipated data 

needs, expected risk assessments, or the estimated timeline identified in the PWP, and a 

summary of the Agency’s responses to those comments. This section is followed by registration 

review planned data needs, risk assessments expected to be conducted, and the projected

registration review timeline for MCPP-p. Lastly, there is a discussion of next steps.

UPDATES SINCE THE PWP WAS ISSUED

The honey bee larvae chronic oral toxicity study (non-guideline) was identified as a data need in 

the Problem Formulation, but was inadvertently left out of the MCPP-p PWP. Table 1: Planned 

Data Needs for the MCPP-p Registration Review has been updated to include this data need.

SUMMARY OF COMMENTS AND AGENCY RESPONSES

During the 60-day public comment period on the MCPP-p Preliminary Work Plan, which opened 

on June 25, 2014 and closed on August 25, 2014, the Agency received 5 sets of public 

comments. Comments were submitted by the Center for Biological Diversity, the FIFRA 

 

1 http://www.epa.gov/oppsrrd1/registration_review/
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Endangered Species Task Force, the MCPP-p Task Force, the San Francisco Bay Regional 

Water Quality Control Board, and the Central Valley Regional Water Quality Control Board. 

The comments do not address the timeline described in the PWP, but they do address the planned 

ecological and human health risk assessments and data requirements. In the PWP, EPA also 

solicited comments on the specific topics of environmental justice, water quality concerns, and 

trade irritants, but no comments or information were received on those issues.

This section does not capture every comment made about the PWP nor all of the Agency’s 

responses. Summarized below are public comments that are of a broader regulatory nature. 

Comments and Agency responses related to the anticipated ecological risk assessment or data 

needs are in the EFED Response to Public Comments the EFED Problem Formulation for the 

Environmental Fate and Ecological Risk, Endangered Species, and Drinking Water Assessments 

(DP Barcode: 416759) in Support of the Registration Review of Mecoprop-p (MCPP-p). Public 

comments and EPA responses in their entirety are located in the docket, EPA-HQ-OPP-2014-

0361. 

Comment submitted by Brett Hartl, Endangered Species Policy Director, Center for 

Biologic Diversity in EPA-HQ-OPP-2014-0361-0010:

Comment: The Center for Biological Diversity’s (CBD) comments focus on the EPA’s duty 

to consult with the U.S. Fish and Wildlife Service and the National Marine Fisheries Service 

(the Services) on the registration review of MCPP-p in accordance with the Endangered 

Species Act (ESA). The CBD comments mention various aspects of the risk assessment 

process, including use of the best available data to develop endangered species risk 

assessments, and evaluation of effects on endangered and threatened species and their 

designated critical habitat. CBD also expresses concern regarding the rigor of the Agency’s 

preliminary determinations regarding the effects of MCPP-p on endangered and threatened 

(listed) species and their designated critical habitat for the MCPP-p registration review. 

 

Response: EPA has reviewed the comments from CBD on the registration review docket 

opening for MCPP-p and plans to address many of the concerns raised by CBD 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. EPA will 

address concerns specific to MCPP-p in connection with the development of its final 

registration review decision for MCPP-p. 

In November 2013, the EPA, along with the Services and the USDA, released a summary of 

their joint interim approaches for assessing risks to endangered and threatened (listed) 

species from pesticides in the white paper Interim Approaches for National-Level Pesticide 

Endangered Species Act Assessments Based on the Recommendations of the National 

Academy of Sciences April 2013 Report, dated November 1, 2013. The Interim Approaches

were developed jointly by the agencies in response to the National Academy of Sciences’ 

(NAS) recommendations and reflect a common approach to risk assessment shared by the 

agencies as a way of addressing scientific differences between the EPA and the Services. 

The NAS report outlines recommendations on specific scientific and technical issues related 

to the development of pesticide risk assessments that EPA and the Services must conduct in 

connection with their obligations under the ESA and FIFRA. 
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The joint Interim Approaches were released prior to a stakeholder workshop held on 

November 15, 2013. In addition, the EPA presented the joint Interim Approaches at the 

December 2013 Pesticide Program Dialogue Committee (PPDC) and State-FIFRA Issues 

Research and Evaluation Group (SFIREG) meetings. The agencies also held a stakeholder 

workshops in April 2014 and October 2014, allowing additional opportunities for 

stakeholders to comment on the Interim Approaches. Additional workshops are planned to 

enhance stakeholder involvement. As part of a phased, iterative process for developing the 

Interim Approaches, the agencies will also consider public comments on the Interim 

Approaches in connection with the development of upcoming Registration Review decisions. 

Given that the agencies are continuing to develop and work toward implementation of the 

Interim Approaches to assess the potential risks of pesticides to listed species and their 

designated critical habitat, the ecological problem formulation supporting this FWP for 

MCPP-p does not describe the specific ESA analysis, including effects determinations for 

specific listed species or designated critical habitat, to be conducted during registration 

review. In the ecological problem formulation document for MCPP-p, EPA described the 

screening-level risk assessment to determine the potential effects of MCPP-p on all taxa of 

non-target wildlife and plants, which will assume that listed species and their designated 

critical habitats may be present in the vicinity of the application of MCPP-p. This 

screening-level assessment will allow 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. While the agencies continue to develop a common 

method for ESA analysis, the planned screening-level risk assessment for the registration 

review of MCPP-p will describe the level of ESA analysis completed for this particular 

registration review case. Once the agencies have fully developed and implemented the 

scientific methods necessary to complete risk assessments for endangered and threatened 

(listed) species and their designated critical habitats, these methods will be applied to 

subsequent analyses for MCPP-p as part of completing this registration review.

Comment submitted by Dan Campbell, chair, Administrative Committees, Syngenta on 

behalf of FIFRA Endangered Species Task Force (FESTIF) in EPA-HQ-OPP-2014-0361-

0014:

Comment: The technical registrants for MCPP-p, as identified on the fact sheet included in 

the PWP, are Nufarm Americas, Inc., and PBI/Gordon Corp., which are FESTF members 

and are entitled to rely on FESTF data.

Response: EPA will consider this comment during registration review of MCPP-p. 
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Comments submitted by C.M. Schofield, Chair, Technical Committee, MCPP-p Task 

Force in EPA-HQ-OPP-2014-0361-0011:

Comment: The MCPP-p Task Force makes several comments clarifying that the technical 

registrants are only supporting MCPP-p (PC codes 031520, 119046, and 129046) for 

Registration Review.

Response: The Agency concurs that this Registration Review case includes only the active 

ingredients mecoprop-p acid (MCPP-p), MCPP-p dimethylamine salt (MCPP-p DMAS), and

MCPP-p potassium salt; collectively referred to as MCPP-p. At the time of the PWP, certain 

MCPP-p registrations were coded with incorrect PC codes, but have since been corrected. 

The PC Codes that are part of the MCPP-p registration review are 031520, 119046, and 

129046.

Comment: The MCPP-p Task Force requests a number of DERs for studies cited within 

Registration Review documents.

Response: The Agency will provide the available DERs for the requested studies to the 

MCPP-p Task Force. 

Comment: The MCPP-p Task Force comments that the Scoping Document and PWP state 

that there are no food uses or tolerances for MCPP-p at this time, however Canadian MRLs 

have been established.

Response: The Agency acknowledges the MCPP-p Task Force’s comment, and clarifies that 

there are no registered food or feed uses or established tolerances in the United States.

Comment: The MCPP-p Task Force provided several comments on the Bead Chemical 

Profile (BCP) and Screening Level Usage Analysis (SLUA) to clarify pasture application

practices.

Response: The Agency acknowledges and thanks the Task Force for this information and 

will consider it during registration review.

Comment: The MCPP-p Task Force comments that BEAD has requested updated usage 

information and that Task Force member registrants expect to develop updated use and 

usage information during Registration Review, but it is not currently available.

Response: The Agency will consider this information once received. 
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PLANNED DATA NEEDS

Table 1 below summarizes the planned data needs for MCPP-p based on the Problem 

Formulation for the Environmental Fate and Ecological Risk, Endangered Species, and 

Drinking Water Assessments in Support of the Registration Review of Mecoprop-p, MCPP, 

MCPP-p (Acid), MCPP-p DMAS, and MCPP-p Potassium Salt Human Health Assessment 

Scoping Document in Support of Registration Review. The honey bee larvae chronic oral toxicity 

study (non-guideline) was identified as a data need in the Problem Formulation, but was 

inadvertently left out of the MCPP-p PWP. The table below has been updated to include this data 

need.

Table 1: Planned Data Needs for the MCPP-p Registration Review

Guideline 

Number2 Study Title2

Test Material

Estimated 

Timeframe

(Months from 

receipt of DCI)

850.2100 Avian oral toxicity (passerine species) TGAI 12

850.2300 Avian reproduction (waterfowl species) TGAI 24

870.3465 90-day inhalation toxicity TGAI 12

NONGDLNHoney bee adult acute oral toxicity TGAI 12

NONGDLNHoney bee larvae acute oral toxicity TGAI 12

NONGDLNHoney bee adult chronic oral toxicity TGAI 12

NONGDLNHoney bee larvae chronic oral toxicity TGAI 12

TGAI = technical grade active ingredient; TEP = typical end-use product;

RISK ASSESSMENTS FOR REGISTRATION REVIEW

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

ecological risk assessment, including an endangered species assessment, for all uses of MCPP-p. 

For human health, EPA anticipates the need to conduct revised dietary (drinking water only), 

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

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

for registration review, they will be considered in the new assessments, as well as any changes to 

the standard operating procedures or default exposure assumptions.

 

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
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Table 2 below summarizes the planned registration review risk assessments based on the EFED 

Problem Formulation and HED Scoping Document. The planned assessments have not changed 

from what was included in the PWP.

Table 2: Planned Risk Assessments for the MCPP-p 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

Incidents Will check for 

updates

For a discussion of reported ecological incidents for 

MCPP-p, see page 16 and Appendix B of the Problem 

Formulation.

Human Health

Dietary

Food N MCPP-p is not currently registered for use on food or 

feed.

Drinking water Y Updated dietary (drinking water only) risk assessments 

may be needed during registration review to consider 

newly estimated drinking water concentrations and/or 

changes in the toxicological endpoints.

Occupational

Handlers (mixers, loaders, 

applicators)

Y Updated occupational exposure assessments may be 

needed during registration review to consider new 

exposure estimates based on current science policies or if 

there are changes in the toxicological endpoints.

Post-application N There is no evidence of systemic toxicity from dermal 

exposure. Appropriate re-entry intervals (REIs) are 

currently on product labels, thus significant dermal 

exposure from recently treated areas is not anticipated.

Residential

Handlers Y Updated residential exposure assessments may be needed 

during registration review to consider new exposure 

estimates based on current science policies or if there are 

changes in the toxicological endpoints. 

Post-application Y

Other

Aggregate Y Evaluates the combined risk from dietary (drinking water 

only) and residential exposures.

Cumulative N MCPP-p has not been identified as a member of a 

cumulative group that shares a common mechanism of 

toxicity.

Tolerances N Tolerances are not established for MCPP-p since it is not 

registered for use on food or feed in the U.S. at this time. 

Incidents Will check for 

updates

For a discussion of reported human incidents for MCPPp, see page 9 of the Scoping Document and the MCPP 

(Mecoprop): Tier 1 Review of Human Incidents.
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TIMELINE

EPA has created the following estimated timeline for the completion of the MCPP-p registration

review in Table 3 below. The projected timeline has not changed since the PWP.

Table 3: Registration Review for MCPP-p – Projected Registration Review Timeline

Activities Estimated Date

Opening the Docket

Open Docket and 60-day Public Comment Period June 2014 – Completed

Close Public Comment June 2014 – Completed

Case Development

Final Work Plan December 2014 – Completed

Issue DCI 2015 – Jan.- March

Data Submission 2017 – Jan.- March

60-day Public Comment Period for Draft Risk Assessments3 2018 – July - Sept.

Registration Review Decision

60-day Public Comment Period for Proposed Registration Review 

Decision

2019 – April - June

Registration Review Decision and Begin Post-Decision Follow-up 2020

Total (years) 6

NEXT STEPS

As noted previously, the Agency plans to require several environmental fate, ecological effects, 

and human health studies for MCPP-p through a Data Call-In Notice, expected to be issued in 

March 2015. 

 

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

of at least 30 calendar days for draft risk assessments; see 40 CFR Part 155.53(c). For conventional pesticides, the 

Agency plans to provide a 60 calendar day public comment period generally for draft risk assessments.