UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C., 20460 

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION 

MEMORANDUM 

DATE: September 19,2014 

SUBJECT: MCPA: PRD Response to Comments on Registration Review Preliminary Work 

Plan //

11 

Thomas 

Khue Nguyen, 

Moriarty, 

Chemical 

Team Leader 

Review Manager {~ 

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Risk Management and Implementation Branch 1 

FROM: 

Pesticide Re-evaluation Division (7508P) 

_ 12 fl M _S:( .{ _#.~Ls.- THROUGH: Neil Anderson, Branch Chief 1'-vr.--. \( · \.-. Risk Management and Implementation Branch 1 

Pesticide Re-evaluation Division (7508P) 

TO: MCPA Registration Review Docket 

Docket Number: EPA-HQ-OPP-2014-0180 

www.regulations.gov 

On March 28, 2014, EPA opened a 60-day public comment period on the preliminary work plan 

(PWP) for the registration review ofMCPA. The comment period ended on May 27,2014. During 

the public comment period the Agency received 5 submissions. Comments were submitted by the 

MCPA Task Force Three, the Center for Biological Diversity, the Central Valley Regional Water 

Quality Control Board (of California), the FIFRA Endangered Species Task Force (FESTF), and a 

private citizen. 

Below are PRD's responses to those comments pertaining to the preliminary work plan for MCPA, the 

use and usage of MCPA, or pertaining to the general MCPA registration review program. Comments 

regarding the environmental fate or effects of MCPA have been addressed by the Environmental Fate 

and Effects Division's (EFED) document, EFED Response to Public Comments on: Preliminary 

Problem Formulation for Environmental Fate and Ecological Risk, Endangered Species, and Drinking 

Water Assessments/or MCPA, dated August 14, 2014. Comments regarding the human health 

assessment or human health data requirements have been addressed by the Health Effects Division's 

(HED) document, MCPA. Response to Comments Received Regarding Scoping Document in Support 

of Registration Review, dated September 4, 2014. 

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Comments from the MCPA Task Force Three in EPA-HQ-OPP-2014-0180-0022 

MCP A Task Force Comment: The Agency indicates that the registration review case for MCP A will 

include PC code 030506, the isooctyl ester of MCPA that is generally considered an obsolete form. 

Only one MCPA product is currently identified as containing PC code 030563: Bromoxynil + MCPA 

Herbicide, EPA registration number 66222-1 20. The Task Force believes that this product is 

erroneously classified and should be corrected to PC code 030564, the 2-ethylhexyl esterform of 

MCPA. 

EPA Response: The Agency originally included PC code 030506 (MCPA isooctyl ester) in the 

registration review case for MCP A because the label for registr:ation number 66222-120 (Bromoxynil 

+ MCP A Herbicide) lists this PC code as the active ingredient. Upon closer examination of the 

documentation for registration number 66222-120, the Agency agrees that this product is erroneously 

classified and should be registered under PC code 030564, the 2-ethylhexyl ester form. The label for 

this product incorrectly lists MCP A isooctyl ester as the active ingredient and should be amended to 

reflect MCPA 2-ethylhexyl ester as the active ingredient. The statement on the label for number of 

pounds ae/gal should also be corrected. The basic CSF for this product should also be updated with 

the correct source registration number to reflect the correct active ingredient. The registrant, ADAMA 

(formerly Makhteshim Agan ofNorth America), should ensure that all cited/submitted data used to 

support registration number 66222-120 were conducted with the correct active ingredient. Once these 

changes are made, the Agency will ensure that PC code 030506 will not be included in the registration 

review case for MCP A. 

MCPA Task Force Comment: The summaries ofthe MCPA use sites listed in the Agency 's 

registration review documents are incomplete. The MCP A RED Appendix A, Use Patterns Subject to 

Reregistration for MCP A accurately list the comprehensive list of use sites. 

EPA Response: The Agency intended the summaries ofMCPA use sites to be a high level summary 

and not a complete comprehensive list of MCPA use sites. 

MCPA Task Force Comment: The Agency referenced MCPB and MR1Ds 45524105 and 47374801 

in the MCP A problem formulation in connection with its rational for requesting additional information 

on dioxin!furan impurities in MCP A products. The Task Force believes that EPA has access to more 

recent MCPA-specific information/rom MCPA technical registrants regarding this issue. EPA should 

make specific requests to technical registrants for additional data. 

EPA Response: The Task Force is correct, recent data on dioxin/furan impurities in MCPB products 

has prompted the Agency to require these data on MCP A products. The Agency is modifying its list of 

data requirements to include guideline 830.1700 preliminary analysis in order to confirm the 

presence/level of dioxin/furan impurities in MCPA products using the most up-to-date analytical 

methods. 

MCP A Task Force Comment: The preliminary work plan states that MCP A was first registered in 

1973. The Task Force notes that forms of MCPA were registered as early as 1952. 

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EPA Response: The Agency listed 1973 as the date of first registration for MCPA in error. EPA's 

records show that the first MCPA dimethylamine salt product was registered on May 13, 1953 

(Weedone MCP A concentrate, EPA registration number 11685-19). The Agency could not find record 

of any MCP A product registered in 1952. 

MCP A Task Force Comment: In the preliminary work plan and BEAD chemical profile, EPA 

requested additional information on use of MCPA and its importance in non-agricultural use sites. 

EPA did not know why use on turf, golf courses, and institutional turf have increased so substantively. 

The Task Force provided information on why customers in certain sectors prefer broadleaf herbicide 

mixtures not based on 2,4-D, information on other herbicides typically combined with MCPA, and 

information on which specific target weeds each combination is meant to target. 

EPA Response: The Agency thanks the MCPA Task Force for this information and will consider it 

during the registration review of MCP A. 

Comments from the Center for Biological Diversity in EPA-HQ-OPP-2014-0180-0020 

Center for Biological Diversity 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 MCP A 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 MCPA on endangered and threatened (listed) species and their designated critical habitat for 

the MCP A registration review. 

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

opening for MCPA 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 MCPA in connection with the development of its final registration review decision 

for this pesticide. 

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. The Interim Approaches were developed jointly by the agencies in response to theN AS 

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. 

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 workshop in April 2014, allowing additional 

opportunities for stakeholders to comment on the Interim Approaches. Additional workshops are 

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planned to enhance stakeholder involvement; the next workshop is scheduled for October 2014. 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. The details of the joint Interim Approaches are contained in the white 

~' 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. 

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 Final Work Plan for MCPA 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 MCPA, EPA described the screening-level risk assessment to determine the 

potential effects of MCPA 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 MCPA. 

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 MCP A 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 MCP A as part of completing this registration review. 

Comments from the FIFRA Endangered Species Task Force (FESTF) in EPA-HQ-OPP-2014-

0180-0019 

FESTF Comment: FESTF commented that the MCP A technical registrants, Albaugh, Inc., Dow 

AgroSciences LLC, Nufarm UK Limited, Nufarm Platte PTY Ltd, and Nufarm Americas, Inc. are all 

FESTF members and are entitled to rely on FESTF data for endangered species assessment. 

EPA Response: The Agency thanks FESTF for this information and will consider it during the 

registration review of MCP A. 

Comments from. an anonymous private citizen in EPA-HQ-OPP-2014-0180-0018 

Citizen Comment: A private citizen commented in favor of banning MCP A and similar herbicides 

because of potential for bioaccumulation in the fatty tissues and possible endocrine disruption in 

animals and humans. 

EPA Response: The Agency is considering the potential for bioaccumulation and endocrine 

disruption of MCPA during registration review. The Agency is requiring guideline 850.1730 aquatic 

organisms bioavailability, biomagnification, toxicity (fish bioconcentration factor) as part of the data 

requirements for the registration review of MCP A. 

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