UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C., 20460 

APR 2 4 2013 OFFICE OF 

CHEMICAL SAFETY AND POLLUTION 

PREVENTION 

MEMORANDUM 

SUBJECT: BEAD's response to The Center For Food Safety comment on the 2,4-D BEAD 

Chemical Profile. (DP# 409912) 

FROM: Bill Phillips, II,, Ph.D., Agronomist Ay 

THRU: 

Biological Analysis Branch '}::(!1'1 J 

Sepehr 

Science 

Haddad, 

Information 

Environmental 

and Analysis 

Protection 

Branch 

Specialist /'It~ ., .. ~ 

Derek Berwald, Ph.D., Economist 

Economic Analysis Branch 

Biological and Economic Analysis Division (7503P) 

Arnet Jones, Chief 

Biological Analysis Branch 

DiannSims 

Science Information 

~~ and Analysis Branch 

Economic 

Timothy Kiely," 

Analysis 

Chief 

Branch ~ \MJ ~ \ 

Biological an~ Economic Analysi Division 75 3P) 

TO: Garland Waleko 

Risk Management and Implementation Branch 2 

Pesticide Re-evaluation Division 

PRODUCT REVIEW PANEL: March 27,2013 

Summary 

On February 12, 2013, The Center for Food Safety submitted to the Environmental Protection 

Agency (EPA) comments in response to all docketed EPA documents regarding the 

registration review of the herbicide 2,4-D. Within The Center for Food Safety comment 

document (see Appendix A) there were statements specific to BEAD's chemical profile 

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(BCP) 1 (see Appendix B). The focus of the statements was on the analysis of2,4-D use data 

and its interpretation. BEAD would like to thank The Center for Food Safety for their 

comments related to the BEAD BCP for 2,4-D. 

Below are the BEAD responses to the comments provided by The Center for Food Safety. 

The Center for Food Safety Comment: 

"BEAD also fails to provide any agronomic explanation for past changes in 2, 4-D use that it 

does record. For instance, BEAD data (Fable 2, p. 5) show substantial increases in 2,4-D use 

(both pounds applied and total acres treated) on soybeans, cotton and to a lesser extent corn 

from the 2001-2005 period to the 2006-2010 period. Since 2,4-D is .frequently recommended 

to control glyphosate-resistant (GR)weeds, and GR weeds have expanded dramatically over 

this time period in precisely those three crops, these increases are very likely attributable to 

farmers making increasing use of 2, 4-D to control GR weeds. Agronomically informed 

assessments of2,4-D use patterns are criticalfor estimatingfuture use, for instance ifthe 

requested new use applications are granted." 

BEAD Response: 

BEAD agrees that agronomic assessments are important to future uses and new uses of any 

pesticide. However, within the scope of the BEAD BCP the intent is to present information 

on the use of a pesticide in an effort to draw some inferences as to the importance of the role 

that a pesticide has played in pest control. In addition to evaluating the role of a pesticide the 

BCP is also intended to inform the environmental and human health assessments of currently 

labeled pesticide uses. 

As for past uses of2,4-D specifically, The Center for Food Safety is correct that there was an 

increase in 2,4-D use in soybeans and cotton between the 2001-2005 and .2006-2010 

timeframes. It's also important to note that the average total pounds and average total area 

treated for all uses actually decreased from the 2001-2005 timeframe (30 million pounds acid 

equivalent (a.e.) applied on 58 million acres) to (28 million pounds a.e. applied on 54 million 

acres) the 2006-2010 timeframe as was provided in a footnote to Table 2 of the document. 

While there were increases in 2,4-D use in soybean and cotton there are other crops for which 

use had increased minimally or had decreased. 

In recent years the increase in the number ofbiotypes and the size of each population of 

glyphosate resistant weeds has led growers and applicators to look for herbicides that can take 

over where glyphosate has failed. It is certainly plausible that one of the herbicides selected 

to fit such a role would be 2,4-D. However, complicating the issue of determining whether all 

or a major portion of the national increase in 2,4-D use in some crops over the past is a direct 

result of a single need is difficult due to the uncertainties with which herbicide decisions are 

1 BEAD Chemical Profile for Registration Review: 2,4-D Chemical Case, Biological and Economic Analysis. June 

27,2012 

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made. Any future evaluations of2,4-D use will need to look closely at such complexities in an 

attempt to conduct such an evaluation. 

BEAD did not address future uses in the BCP because those uses for 2,4-D, in particular the 

Enlist herbicide/GE crop technology, as discussed in the comments are new uses for the 

choline salt of2,4-D. The proposed decision on the label amendment for these new uses will 

be going through a public process whereby environmental and human health assessments will 

be conducted and will focus on the new uses of 2,4-D choline. The Agency appreciates the 

details that were provided by The Center for Food Safety and an opportunity to provide 

additional information and comments will be made available during the public comment 

period for the 2,4-D choline salt herbicide label amendment. 

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Appendix A 

II. EPA'S ANALYSIS OF 2,4-D USAGE 

EPA provides an extremely brief and inadequate analysis of 2,4-D use in "BEAD: Chemical 

Profile for Registration Review: 2,4-D Chemical Case," hereinafter referred to as "BEAD." 

As noted above, BEAD made no attempt to assess the changes in 2,4-D use that would be 

enabled by the proposed registrations for Enlist com and soybeans. BEAD also fails to 

provide any agronomic explanation for past changes in 2,4-D use that it does record. For 

instance, BEAD data (Table 2, p. 5) show substantial increases in 2,4-D use (both pounds 

applied and total acres treated) on soybeans, cotton and to a lesser extent com from the 2001-

2005 period to the 2006-2010 period. Since 2,4-D is frequently recommended to control 

glyphosate-resistant (GR)weeds, and GR weeds have expanded dramatically over this time 

period in precisely those three crops, these increases are very likely attributable to farmers 

making increasing use of2,4-D to control GR weeds. Agronomically informed assessments 

of2,4-D use patterns are critical for estimating future use, for instance if the requested new 

use applications are granted. 

4 We note that Dow AgroSciences anticipates introduction of 2,4-D-resistant corn in 2014, suggesting that it 

expects EPA to register 2,4-D choline salt for use on it before that time (Gillam 2013). 

CFS provides such informed analyses of2,4-D use patterns in Appendix B (pages 5-10) for 

soybeans and Appendix A (pages 6-13) for com and soybeans. Four critical aspects of these 

analyses deserve emphasis. First, Enlist com and soybeans eliminate, for all practical 

purposes, the biological constraint of crop injury that has hitherto been a major factor limiting 

the extent, the frequency, and the intensity (lbs./acre) of2,4-D use in American agriculture 

since its introduction in the 1940s. Second, Enlist crops would facilitate a strong shift in 2,4-

D use patterns, from predominantly early season use (pre-emergence) at present to midseason, post- emergence use, particularly on soybeans. The shift to post-emergence herbicide 

use patterns is associated with increased drift-related crop injury episodes and more rapid 

evolution of herbicide-resistant (HR) weeds. HR weeds in turn trigger greater herbicide use 

as well as more tillage operations and associated soil erosion. Third, use of Enlist com and 

soybean systems will foster rapid evolution of 2,4-D resistance in weeds already resistant to 

glyphosate and often other herbicides. Multiple HR weeds are already a huge and growing 

problem in U.S. agriculture, and will be greatly exacerbated by Enlist crops. Finally, only a 

renewed commitment to much greater use of non-chemical weed control tactics in the context 

of truly Integrated Weed Management can slow the epidemic emergence of herbicide 

resistance in weeds. 

Based on reasonable adoption scenarios and usage rates, CFS estimates that Enlist com and 

soybeans would each lead to roughly a 60-70 million lb./year increase in overall2,4-D use in 

American agriculture, compared to a total of 7 million lbs. used on both com and soybeans at 

present. BEAD estimates that an average of 28 million lbs. of 2,4-D was applied each year in 

all of U.S. agriculture from 2006-2010 (BEAD, p. 5-6), though this might be a slight 

underestimate since a few lower-use states are excluded. 21 million lbs. are applied to crops 

other than com or soybeans, and usage on these crops may be expected to continue at roughly 

similar levels. Once they are widely adopted, Enlist com and soybeans would lead to an 

estimated 120-140 million lbs. ofadditional2,4-D use, for 140 to 160 million lbs. total 

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agricultural use of this herbicide. This would represent a five-fold increase in overall 

agricultural use of2,4-D. Dow's expected introduction of2,4-D-resistant cotton would move 

increase usage still more. 

It should not be thought that this is an unrealistic scenario for herbicide use driven by an HR 

crop system and the resistant weeds it fosters. EPA estimated glyphosate usage, driven by 

Roundup Ready crops and glyphosate-resistantweeds, at 180-185 million lbs. in 2007, and 

current usage easily exceeds 200 million lbs. While glyphosate use with Roundup Ready crops 

significantly displaced use of other herbicides, a similar phenomenon is not expected with 2,4-D 

used with Enlist crop systems. This is because 2,4-D is a broadleafherbicide that will be used 

primarily to kill glyphosate-resistant weeds, while broader-spectrum glyphosate will continue to 

be used in conjunction with it to kill grass-family weeds and others it controls more effectively. 

Additional analysis is presented in the usage analysis and resistant weed sections of Appendices 

A and B. 

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