Supplemental Information for Petition for Determination of Nonregulated Status for

Herbicide Tolerant DAS-68416-4 Soybean

Regulatory Overview of 2,4-D and Glufosinate Use on DAS-68416-4 Soybean

The undersigned submits this information under 7 CFR 340.6 to support the determination that 

the article should not be regulated under 7 CFR 340.

Submitting Company:

Dow AgroSciences LLC

Submitted by:

__________________________________

Mark S. Krieger

Regulatory Leader

Regulatory Sciences & Government Affairs

Dow AgroSciences LLC

9330 Zionsville Road

Indianapolis, IN 46268

Telephone: (317) 337-3458

FAX: (317) 337-4649

mkrieger2@dow.com

June 24, 2011
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Regulatory Overview of 2,4-D and Glufosinate Used on DAS-68416-4 Soybean

Summary

Dow AgroSciences (DAS) has submitted a petition to the United States Department of 

Agriculture (USDA)’s Animal and Plant Health Inspection Service (APHIS) for the 

determination of nonregulated status for DAS-68416-4 soybean, which provides tolerance to the 

herbicides 2,4-dichlorophenoxy acetic acid (2,4-D) and glufosinate.

This document provides information pertaining to the regulation of the use of 2,4-D and 

glufosinate on DAS-68416-4 soybean. This information includes: 

o Description of the responsibilities of various agencies of the U.S. government with 

respect to pesticide registration and use. 

o Comparison of the current and proposed new use patterns for 2,4-D and glufosinate on 

soybean.

o Evaluation of the current environmental risk assessments for 2,4-D and glufosinate

relative to the proposed new use patterns.
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Regulatory Overview of 2,4-D and Glufosinate Used on DAS-68416-4 Soybean

Table of Contents

1 Regulatory Oversight of Pesticides in the United States........................................................ 4

1.1 Coordinated Framework for the Regulation of Biotechnology........................................ 4

1.2 Environmental Protection Agency ................................................................................... 4

1.2.1 FIFRA ....................................................................................................................... 4

1.2.2 Registration Review.................................................................................................. 5

1.2.3 FIFRA Enforcement.................................................................................................. 5

1.2.4 FFDCA...................................................................................................................... 5

1.2.5 Pesticide Risk Assessment at EPA ........................................................................... 5

1.2.5.1 Human Health and Ecological Pesticide Risk Assessment at EPA................... 5

1.2.5.2 Cumulative and Aggregate Human Health Risk Assessments under FQPA..... 6

1.3 Endangered Species Act................................................................................................... 6

1.3.1 EPA Responsibilities ................................................................................................ 7

1.3.2 Effects Determinations.............................................................................................. 7

1.3.3 Consultation with the Service ................................................................................... 7

1.3.4 Implementing Measures to Protect Listed Species................................................... 8

1.4 Non-Federal Regulatory Oversight of Pesticides............................................................. 8

2 Regulatory Status of 2,4-D and Glufosinate at EPA............................................................... 9

2.1 2,4-D................................................................................................................................. 9

2.2 Glufosinate ....................................................................................................................... 9

2.3 Legal Challenges to EPA Decisions............................................................................... 10

3 Existing and Proposed Use Patterns ..................................................................................... 11

3.1 2,4-D............................................................................................................................... 11

3.2 Glufosinate ..................................................................................................................... 12

4 Environmental Risk Assessment........................................................................................... 12

4.1 2,4-D............................................................................................................................... 12

4.2 Glufosinate ..................................................................................................................... 13
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Regulatory Overview of 2,4-D and Glufosinate Used on DAS-68416-4 Soybean

1 Regulatory Oversight of Pesticides in the United States

1.1 Coordinated Framework for the Regulation of Biotechnology

The U.S. government established the Coordinated Framework for the Regulation of 

Biotechnology1in 1986. The Coordinated Framework specifies the division of responsibility and 

coordination of activities between the agencies of the federal government involved with 

regulation of genetically engineered crops. Each agency maintains separate decision-making 

power within its sphere of authority.

Under the Coordinated Framework, the U.S. Department of Agriculture's Animal and Plant 

Health Inspection Service (USDA-APHIS) will make a decision whether or not to deregulate 

DAS-68416-4 soybean. Separately, and independent of the Coordinated Framework, the US

Environmental Protection Agency (EPA) will make a decision whether or not to approve 

registration for specific use patterns of 2,4-D and/or glufosinate on DAS-68416-4 soybean 

pursuant to its authority under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) 

to register pesticides for use in the United States.2 These two decisions are independent, 

statutorily enumerated events.

1.2 Environmental Protection Agency

1.2.1 FIFRA

The EPA regulates the use of herbicides, including 2,4-D and glufosinate, under FIFRA. FIFRA 

requires that registration of a pesticide for a specific use be obtained from the EPA prior to 

distribution or sale of the pesticide for that use pattern. Before registering a new use for a new or 

previously registered pesticide, EPA must ensure that the pesticide, when used according to label 

directions, will not cause unreasonable adverse effects on the environment. In order to address 

this standard, EPA must evaluate potential risks to humans and the environment, and may require 

applicants to submit more than 100 different scientific studies and tests conducted according to 

EPA guidelines. EPA regulates both pesticidal active ingredients as well as end-use formulated 

products.

The data required by EPA are used to evaluate whether a pesticide has the potential to cause 

adverse effects on humans, wildlife, fish, and plants (including endangered species and “nontarget” organisms – organisms that the pesticide is not intended to act against). The registration 

applicant must also supply data addressing the pesticide’s potential impact on surface water and 

ground water. Potential human health and safety risks that are assessed range from short-term 

toxicity to long-term effects such as cancer and reproductive system disorders.

Based on its assessment of a pesticide’s potential health and environmental effects, EPA registers 

the pesticide and approves the language that appears on the pesticide product label regarding the 

new use. 

 

1

http://usbiotechreg.nbii.gov/

2

http://www.epa.gov/pesticides/about/aboutus.htm, 7 U.S.C. §§ 136-136y.
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1.2.2 Registration Review

The Food Quality Protection Act (FQPA)3of 1996 amended FIFRA to mandate a program called 

registration review.

4

The registration review program makes 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. Through the registration review program, 

the EPA periodically reevaluates pesticides to make sure that as change occurs, products in the 

marketplace can still be used safely.

1.2.3 FIFRA Enforcement

It is a violation of FIFRA for any person to use a pesticide in a manner inconsistent with its 

labeling.5

EPA may issue a civil administrative complaint to any person or company who violates FIFRA. 

The complaint may impose a civil penalty, including recovery of any economic benefit of noncompliance, and may also require correction of the violation. EPA may also issue a Stop Sale, 

Use or Removal Order (SSURO) prohibiting the person who owns, controls, or has custody of a 

violative pesticide or device from selling, using, or removing that product except in accordance 

with the provisions of the SSURO.6

1.2.4 FFDCA

Where pesticides may be used on food or feed crops, EPA also sets tolerances for the amount of 

pesticide chemical residue that can legally remain in or on foods. EPA undertakes this analysis 

under the authority of the Federal Food, Drug, and Cosmetic Act (FFDCA). Under FFDCA, EPA 

must find that such tolerances will be safe, meaning that there is a reasonable certainty that no 

harm will result from the aggregate exposure of the pesticide chemical residue. This finding must 

be made and the appropriate tolerance established before a pesticide can be registered for use on 

the particular food or feed crop in question, including DAS-68416-4 soybean. Taken together, 

the provisions of FIFRA and FFDCA vest EPA with comprehensive responsibility and authority 

for the regulation of 2,4-D and glufosinate and for addressing the cumulative health, safety and 

environmental effects of 2,4-D and glufosinate use in the United States. 

1.2.5 Pesticide Risk Assessment at EPA7

1.2.5.1 Human Health and Ecological Pesticide Risk Assessment at EPA

The process EPA uses for evaluating the potential health and environmental effects of 2,4-D, 

glufosinate, and every other registered pesticide, under either FIFRA or FFDCA, is called risk 

assessment. 

 

3

http://www.epa.gov/pesticides/regulating/laws/fqpa/

4

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

5

7 U.S.C. § 136j(a)(2)(G). 

6

http://www.epa.gov/compliance/civil/fifra/fifraenfstatreq.html; 7 U.S.C. §§ 136j, 136k, 136l.

7

http://www.epa.gov/pesticides/about/overview_risk_assess.htm
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For human health, the assessment includes a review of data that address potential exposure 

through consumption of food and drinking water, as well as occupational and bystander exposure 

that might result from pesticide use.8

For its environmental risk assessment, EPA evaluates the potential effects of pesticide use on: 

soil, surface water, groundwater, wildlife, and other non-target organisms such as birds, 

amphibians, mammals, soil microorganisms and beneficial insects, including bees. This review 

covers plants as well as animals, and includes consideration of threatened and endangered 

species. Detailed information on the EPA ecological risk assessment process is available on the 

EPA website.9

1.2.5.2 Cumulative and Aggregate Human Health Risk Assessments under FQPA

FQPA requires EPA to consider available information concerning the cumulative effects of a 

particular pesticide’s residue and other substances that have a common mechanism of toxicity 

when considering whether to establish, modify, or revoke a pesticide tolerance. Potential 

cumulative effects of chemicals with a common mechanism of toxicity are considered because 

low-level exposures to multiple chemicals causing a common toxic effect by a common 

mechanism could lead to the same adverse effect as would a higher level of exposure to any one 

of the individual chemicals. This assessment is termed a “Cumulative Assessment” by EPA; 

more detailed information is available on the EPA website.10

FQPA also requires EPA to consider aggregate exposure in its decision making. Aggregate 

exposure and risk assessment involve the analysis of exposure to a single chemical by multiple 

pathways and routes of exposure. The pathways of exposure considered are generally pesticide 

residues in food and drinking water, but also include non-occupational (e.g., residential) routes 

of exposure. 

EPA uses the aggregate and cumulative risk assessment processes to ensure that all registered 

(approved) uses of a specific pesticide fit within the “risk cup” for that pesticide. When EPA 

receives an application to amend an existing registration for a pesticidal active ingredient to 

include a new use pattern, EPA evaluates the impact of that proposed new use pattern on the 

aggregate and cumulative risk of that active ingredient, i.e., on the risk cup. A new use pattern 

cannot be approved if it would cause the risk cup to be exceeded.

1.3 Endangered Species Act 

The Endangered Species Act (ESA) is intended to protect and promote the recovery of animals 

and plants that are in danger of becoming extinct. All federal agencies are required under the 

ESA to ensure that their regulatory actions, including EPA’s registration of pesticides in the 

United States, are not likely to jeopardize the continued existence of threatened or endangered 

species (listed species) or destroy or adversely modify their critical habitat. The ESA also 

prohibits both federal and non-federal entities from injuring or killing individual listed animals 

 

8

http://www.epa.gov/pesticides/factsheets/riskassess.htm

9

http://www.epa.gov/pesticides/ecosystem/ecorisk.htm

10 http://www.epa.gov/pesticides/cumulative/
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without authorization. The ESA is administered by the U.S. Fish and Wildlife Service and 

National Marine Fisheries Service (NMFS) (together referred to as the Services). Detailed 

information on the processes followed by EPA to comply with the ESA is provided on the EPA 

website11 and summarized below.

1.3.1 EPA Responsibilities

When registering a pesticide or reassessing the potential ecological risks from use of a currently 

registered pesticide, EPA evaluates extensive toxicity and ecological effects data to determine 

how a pesticide will move through and break down in the environment. Risks to birds, fish, 

invertebrates, mammals and plants are routinely assessed and used in EPA’s determinations of 

whether a pesticide may be registered for use in the United States.

EPA’s core pesticide risk assessment and regulatory processes ensure that protections are in 

place for all populations of non-target species. Because endangered species may need specific 

protection, EPA has developed risk assessment procedures to determine whether individuals of a 

listed species have the potential to be harmed by a pesticide, and if so, what specific protections 

may be appropriate. EPA’s conclusion regarding the potential risks a pesticide may pose to a 

listed species and any designated critical habitat for the species, after conducting a thorough 

ecological risk assessment, results in an "effects determination." The Services have recognized 

the appropriateness of these procedures in their regulations implementing the ESA.12 

1.3.2 Effects Determinations

The result of an assessment to determine potential effects of a pesticide’s registration to a listed 

species will result in one of two determinations: 

 the pesticide’s registered use will have "no effect" on the species; or 

 the pesticide’s registered use "may affect" the species. 

If EPA determines the pesticide "may affect" the species, it refines its assessment to determine 

whether the pesticide’s use:

 "may affect, but is not likely to adversely affect" the species; or 

 "may affect and is likely to adversely affect" the species. 

A determination that the pesticide "may affect, but is not likely to adversely affect," is made 

where the effects on the listed species are expected to be discountable, or insignificant, or 

completely beneficial; terms which the Services have discussed in guidance as including effects 

extremely unlikely to occur, which cannot be evaluated, would never reach a scale where they 

would occur or are wholly beneficial. 

1.3.3 Consultation with the Service

Informal Consultation - If EPA determines that a pesticide will have "no effect" on a listed 

species, no further action is required relative to the pesticide’s registration, label or use 

 

11 http://www.epa.gov/oppfead1/endanger/

12 50 CFR Part 402, Subpart D.
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Regulatory Overview of 2,4-D and Glufosinate Used on DAS-68416-4 Soybean

instructions. If EPA determines that a pesticide’s use "may affect, but is not likely to adversely 

affect" a listed species, the Agency may engage the Services in a process called informal 

consultation. The result of this process is typically a letter of concurrence or non-concurrence 

from the Services, with EPA’s determination. 

Formal Consultation - If the Services non-concur with EPA’s determination that a pesticide’s 

registered use is "not likely to adversely affect" a species or if EPA determines that the pesticide 

"may affect and is likely to adversely affect" a listed species, it will engage the Services in a 

process called formal consultation. 

The Services’ regulations allow EPA to avail itself of either of two alternative procedures for 

formal consultation. Under the procedure available to all agencies (under 50 CFR Part 402, 

Subpart B), EPA provides the Services with its detailed assessment of potential risks and its 

effects determination. The Services review that information and consider it in light of the status 

and needs of the particular species potentially affected. The Services then generally provide EPA 

with a Biological Opinion, a document providing the Services' assessment and recommendations 

for steps that EPA should take, if any, to reduce or eliminate potential risk to the species. 

The Services’ Biological Opinion provides the Services’ view of whether the pesticide’s 

registered use is likely to jeopardize the continued existence of the species and, if so, describes 

alternatives to avoid jeopardy. The Services also authorize any "take" (unintended injury or 

killing of individual listed animals) that would otherwise be prohibited, as long as measures to 

minimize take are implemented. 

Alternatively, EPA may invoke all or part of the “optional formal consultation procedure for 

FIFRA actions” (set forth in 50 CFR § 402.46). Under this procedure, as under the standard 

procedure described above, EPA provides the Service with an effects determination. In this case, 

however, EPA also may include in that determination conclusions and other elements that 

typically would be included in the Services’ Biological Opinion, such as whether the action is 

likely to jeopardize the continued existence of a species and available alternatives. The Services 

then has a limited period to either adopt EPA’s conclusions or provide its alternative views in a 

separate Biological Opinion. 

1.3.4 Implementing Measures to Protect Listed Species

If, as a result of EPA’s risk assessment or formal consultation with the Services, EPA determines 

that a pesticide’s registration, label, or use instructions should be altered to ensure that use of a 

pesticide will not take or jeopardize the continued existence of a listed species, EPA may require 

changes to the use conditions specified on the label of the product. When such changes are 

necessary only in specific geographic areas rather than nationwide to ensure protection of the 

listed species, EPA implements these changes through geographically-specific Endangered 

Species Protection Bulletins.

1.4 Non-Federal Regulatory Oversight of Pesticides

After a pesticide is registered by EPA, it must be registered in individual states and territories 

under specific pesticide registration laws before it can be sold and used. A state or territory may 
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Regulatory Overview of 2,4-D and Glufosinate Used on DAS-68416-4 Soybean

have more stringent requirements for registering pesticides for use in that state, and the allowable 

use patterns of a pesticide can vary from state to state. 

Detailed information on state pesticide regulatory agencies is available from the National 

Pesticide Information Center.

13

2 Regulatory Status of 2,4-D and Glufosinate at EPA

2.1 2,4-D

2,4-D has been registered for use in the United States since 1948.

14 EPA concluded its 

reregistration evaluation of 2,4-D in 2005. At that time, the Agency produced a 304-page 

Reregistration Eligibility Document (“RED”) on 2,4-D, setting out the data on which it made a 

decision to reregister 2,4-D, and concluded that the pesticide met the no unreasonable adverse 

effects standard found in FIFRA. Detailed information on the reregistration of 2,4-D at the EPA 

is available on the EPA website.

15

As a currently registered pesticide, 2,4-D is included in the EPA Registration Review program.

16

The Registration Review for 2,4-D is scheduled to be opened in fiscal year 2013.

17

EPA can require registrants to modify proposed label language contained in registration 

applications, including use patterns, to ensure food safety and that the use of the pesticide will 

not cause unreasonable adverse effects on the environment. It is possible that EPA could 

approve, conditionally approve, or reject an application for the registered use of 2,4-D on 

DAS-68416-4 soybean. EPA could also register the use of 2,4-D on DAS-68416-4 soybean, but 

in the future amend or cancel that registration.

2.2 Glufosinate

Glufosinate was first registered as a pesticide in 2000,

18 and thus was not required to undergo 

reregistration. As a currently registered pesticide, however, glufosinate is included in the EPA 

Registration Review program.

19 The Registration Review for glufosinate was initiated in 2008

and a final decision is scheduled for 2013.

20,21

Glufosinate is currently registered by EPA for use on soybeans. It is possible that in the future 

EPA could amend or cancel that registration.

 

13 http://npic.orst.edu/state1.htm

14 http://www.epa.gov/oppsrrd1/REDs/factsheets/24d_fs.htm

15 http://www.epa.gov/opp00001/reregistration/24d/

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

17 http://www.epa.gov/oppsrrd1/registration_review/2010-13-schedule-summary.pdf

18 Glufosinate Summary Document Registration Review: Initial Docket March 2008, US EPA, EPA-HQ-OPP-2008-

0190-0003.

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

20 http://www.epa.gov/oppsrrd1/registration_review/glufosinate_ammonium/index.htm

21 Glufosinate Final Work Plan, Registration Review, August 2008, US EPA, EPA-HQ-OPP-2008-0190-0015.
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Regulatory Overview of 2,4-D and Glufosinate Used on DAS-68416-4 Soybean

2.3 Legal Challenges to EPA Decisions

The U.S. government provides mechanisms for individuals or groups to challenge decisions 

made by EPA. 

Individuals or groups can petition the EPA for specific actions related to pesticide registration 

decisions made by EPA, and this has occurred for 2,4-D. On November 6, 2008, the Natural 

Resources Defense Council (NRDC) submitted a petition to EPA to revoke all pesticide 

tolerances and cancel all registrations for 2,4-D based on allegations of human health risks, 

including estrogenic, neurodevelopmental and mutagenic effects. EPA opened a public docket 

that contains this petition from NRDC and over 500 public comments that were received.22 DAS 

and other 2,4-D registrants, through the Industry Task Force II on 2,4-D Research Data (2,4-D 

Taskforce), provided comments to EPA regarding this petition.23 The 2,4-D Taskforce 

comments stated that the studies on which the NRDC based its petition were either not relevant 

to human or environmental routes of exposure, or were run at excessively high doses that bear no 

relationship to possible levels of human or environmental exposure, and refuted the claims made 

in the petition. The 2,4-D Taskforce based its reasoning on over 500 studies, all conducted 

according to Good Laboratory Practices and many published in peer reviewed scientific journals, 

that were used to support EPA’s RED. On May 19, 2009, NRDC wrote to EPA, asking the 

agency to first address the residential uses of 2,4-D, “as these are the ones that we believe cause 

the greatest health risks.”24 EPA has not yet responded to NRDC’s petition, and the outcome of 

EPA’s review of the petition to cancel all tolerances and registrations of 2,4-D cannot be 

reasonably foreseen.

EPA’s registration of a pesticide for specific uses can also be challenged through litigation; see 

for example Washington Toxics Coalition v. EPA.

25

 In that case, a coalition of environmental 

groups filed a lawsuit against EPA for violating the ESA by failing to consult with NMFS 

regarding the impacts of certain pesticides, including 2,4-D, to endangered or threatened 

salmonid species in the Pacific Northwest. The court placed restrictions on the use of those 

pesticides in or near the habitat of the species at issue pending completion of the consultation 

process. EPA has determined that the use of 2,4-D in the formulation used for crops such as corn 

may affect, but is not likely to adversely affect, the endangered salmonid species26, but the 

consultation with NMFS has not yet taken place. EPA currently expects that consultation will be 

completed and that NMFS will issue a Biological Opinion for 2,4-D in June 2011.27

2,4-D is included, along with other pesticides, in a lawsuit brought in early 2011 by the Center 

for Biological Diversity against EPA alleging potential harm to threatened and endangered 

species arising from the use of these pesticides. It is possible this litigation could result in any 

number of actions to be taken by EPA, such as restrictions on the use of any of the pesticides 

named in the lawsuit, that could impact uses of 2,4-D on DAS-68416-4 soybean.

 

22 http://www.regulations.gov/search/Regs/home.html#docketDetail?R=EPA-HQ-OPP-2008-0877

23 http://24d.org/; comments available at http://24d.org/pdf/EPA-HQ-OPP-2008-0877-0350%201.pdf

24 http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2008-0877-0445.1

25 http://www.epa.gov/espp/litstatus/wtc/index.htm

26 http://www.epa.gov/espp/litstatus/effects/index.htm

27 http://www.epa.gov/espp/litstatus/effects/biopschedule01-20-11.pdf
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Regulatory Overview of 2,4-D and Glufosinate Used on DAS-68416-4 Soybean

The probability and potential outcome of any current or future legal challenge to the use of 2,4-D 

or glufosinate in general or on DAS-68416-4 soybean in particular cannot be reasonably 

foreseen.

3 Existing and Proposed Use Patterns

3.1 2,4-D

2,4-D is a herbicide registered by EPA for the control of broadleaf weeds, and is currently 

approved for preplant use on soybeans. For soybeans, EPA has approved a maximum seasonal 

application rate at 1.0 lb/acre, and a maximum single application rate at 1.0 lb/acre. EPA 

approved these application rates based on the safety standards established under both FIFRA and 

FFDCA.

Table 1. Summary of Current Use Pattern for 2,4-D on Soybeans.

Crop Stage

Maximum 

Application Rate 

(lb/acre)a Directions and Timing

Preplant 1.0 Apply not less than 15-30 days before planting soybeans, 

when weeds are small and actively growing.

a All values in acid equivalents.

DAS submitted an application to EPA to register the use of a new end-use formulation of 2,4-D 

on DAS-68416-4 soybean in April 2011. 

The proposed use pattern on DAS-68416-4 soybean allows a 1 lb ae/acre burn-down application 

followed by up to two 0.5-1.0 lb ae/acre post-emergent applications through the R2 growth stage. 

The proposed use pattern for 2,4-D on DAS-68416-4 soybean allows for flexibility in early 

season weed control when control of weeds is critical to minimize crop competition and 

maximize yield potential. 

Table 2. Proposed Use Pattern for 2,4-D on DAS-68416-4 Soybean.

Crop Stage

Maximum 

Application Rate 

(lb/acre)a Directions and Timing

Preplant or 

Preemergence

1.0 Apply before soybean emerges to control emerged 

broadleaf weed seedlings or existing cover crops.

Postemergence 1.0 Apply after crop and weed emergence but before 

soybean exceeds growth stage R2. 

Make 1 to 2 applications with a minimum of 12 days 

between applications.

a All values in acid equivalents.

DAS-68416-4 soybean will be combined through conventional breeding (i.e., “stacked”) with 

commercially available glyphosate-tolerance traits in soybean. The combination of 2,4-D, 

glufosinate, and glyphosate-tolerance will provide a superior weed control system that 
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Regulatory Overview of 2,4-D and Glufosinate Used on DAS-68416-4 Soybean

effectively controls many hard-to-control weeds and weeds that have developed resistance to 

glyphosate under glyphosate-only cultural practices. 

3.2 Glufosinate

Glufosinate is a non-selective foliar herbicide that is used for preplant and post-emergent control 

of broadleaf weeds. Glufosinate-ammonium acts by inhibiting glutamine synthetase, which leads 

to the overproduction of ammonia causing necrosis and death of the plant. It is registered for use 

on the following crops: apples, berries, canola, corn, cotton, currants, grapes, grass grown for 

seed, potatoes, rice, soybeans, sugar beets, and tree nuts. Registrations for non-crop areas include 

golf course turf, residential lawns, ornamentals, and a variety of industrial, residential, and public 

areas.

Application rates vary considerably by use pattern, with the highest rate (1.5 lb ai/A) for use 

patterns including orchard nuts and fruits, grapes, grasses grown for seed, and golf course turf. 

Multiple applications are allowed by most labels, with an annual maximum application rate of 

4.5 lbs ai/A for orchards and vineyards.18

DAS does not currently plan to make any regulatory submissions to US EPA relating to the use 

of glufosinate on DAS-68416-4 soybeans.

4 Environmental Risk Assessment

4.1 2,4-D

The proposed use pattern for 2,4-D on DAS-68416-4 is similar to that currently registered by 

EPA for use on corn. The evaluation of this use pattern of 2,4-D on corn provides an 

understanding of the process that EPA may use to evaluate the proposed use pattern for 2,4-D on 

DAS-68416-4 soybean.

In the environmental risk assessment conducted for the 2005 RED for 2,4-D, EPA considered 16 

environmental exposure scenarios to represent the greater than 600 different use patterns for 

2,4-D. The agency chose scenarios with one or more of the following properties in order to 

adequately represent all of the use patterns:

 Crops with higher than average application rates.

 Crops which have a large percentage of their total acreage treated with 2,4-D.

 Crops with a large total acreage treated with 2,4-D. 

By encompassing crops with large percentages of acreage treated with 2,4-D and a large 

geographic area, some crops with lower maximum application rates were, therefore, also covered 

by this set of scenarios.

The specific scenarios chosen included sugarcane in Florida, turf in Florida and Pennsylvania, 

spring wheat in North Dakota, winter wheat in Oregon, corn in Illinois and California, sorghum 

in Kansas and Texas, soybean in Mississippi, pasture in North Carolina, apples in North 

Carolina, Oregon, and Pennsylvania, filberts in Oregon, and citrus in California.
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Regulatory Overview of 2,4-D and Glufosinate Used on DAS-68416-4 Soybean

The use pattern considered by EPA for corn was 3 individual applications of 1.0 lb ae/A. The use 

pattern proposed by DAS for use on DAS-40278-9 corn has equivalent individual and seasonal 

maximum use. As DAS-40278-9 corn is expected to replace, not add to, current corn acreage 

where corn is currently cultivated, and is not expected to be grown in any areas where corn is not 

currently cultivated, EPA’s exposure and risk assessment would also encompass the use of 2,4-D 

on DAS-40278-9 corn.

Individual applications of 2.0 lb ae/A were modeled for sugarcane in Florida, turf in Florida and 

Pennsylvania, pasture in North Carolina, and apples in North Carolina, Oregon, and 

Pennsylvania. Seasonal applications of 4.0 lb ae/A were modeled for sugarcane in Florida, turf in 

Florida and Pennsylvania, pasture in North Carolina, apples in North Carolina, Oregon, and 

Pennsylvania, and filberts in Oregon. These RED scenarios developed by EPA for purposes of 

2,4-D’s environmental risk assessment exceed the maximum individual and seasonal application 

rates proposed for 2,4-D on DAS-40278-9 corn.

Detailed information on these assessments from EPA is available in 

 Revised Environmental Fate and Effects Division Revised Preliminary Risk Assessment 

for the 2,4-Dichlorophenoxyacetic acid (2,4-D) Reregistration Eligibility Document

o Summary (EPA-HQ-OPP-2004-0167-0091)28

o Complete Risk Assessment (EPA-HQ-OPP-2004-0167-0092)29

4.2 Glufosinate

Glufosinate is currently registered by EPA for use on soybeans.

DAS does not currently plan to make any regulatory submissions to US EPA relating to the use 

of glufosinate on DAS-68416-4 soybeans.

 

28 http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2004-0167-0091

29 http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2004-0167-0092