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OFFICE OF CHEMICAL SAFETY

AND POLLUTION PREVENTION

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

April 12, 2013

PC Codes: 030001, 030004, 030016, 

030019, 030025, 030035, 

030053, 030063, 030066, 

051505

MEMORANDUM DP Barcode: 402410

Subject: EFED Registration Review Problem Formulation for 2,4-D - REVISED

To: Garland Waleko, Chemical Review Manager

Cathryn Britton, Team Leader

Pesticide Re-evaluation Division (7508P)

From: Meghan Radtke, Ph.D., Biologist

Faruque Khan, Ph.D., Senior Scientist

Environmental Risk Branch 1

Environmental Fate and Effects Division (7507P)

Through: Edward Odenkirchen, Ph.D., Acting Branch Chief

Sujatha Sankula, Ph.D., Lead Biologist

Environmental Risk Branch 1

Environmental Fate and Effects Division (7507P)

Attached is the Environmental Fate and Effects Division’s (EFED) scoping document for 2,4-D 

acid, salts, and esters to support registration review. The updated document reflects revisions 

that were a result of public comments received on the draft Problem Formulation and an 

additional data requirement (honeybee larval toxicity) as recommended by the recent Pollinator 

White Paper.
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Table of Contents

1. Introduction................................................................................................................................ 3

 1.1 Purpose..................................................................................................3

1.2. Ecological Risk Assessments.............................................................................................. 3

1.3. Drinking Water Exposure Assessments.............................................................................. 3

1.4. Safe Drinking Water Act and Clean Water Act Programs ................................................. 4

2. Stressor Source and Distribution ............................................................................................... 4

2.1. Mechanism of Action.......................................................................................................... 9

2.2. Overview of Pesticide Usage ............................................................................................ 10

 2.3 Environmental Fate Bridging Strategy...........................................................10

2.4. Environmental Fate and Transport.................................................................................... 10

3. Receptors.................................................................................................................................. 16

3.1. Effects to Aquatic Organisms........................................................................................... 17

3.2. Effects to Terrestrial Organisms....................................................................................... 20

3.3. Ecological Incidents.......................................................................................................... 21

4. Conceptual Model..................................................................................................................... 22

5. Analysis Plan ........................................................................................................................... 24

5.1. Stressors of Concern ......................................................................................................... 24

5.2. Measures of Exposure....................................................................................................... 25

5.3. Measures of Effect ............................................................................................................ 25

5.4. Drinking Water Assessment ............................................................................................. 25

6. Endocrine Disruptor Screening Program................................................................................. 25

7. Preliminary Identification of Data Gaps.................................................................................. 25

7.1. Environmental Fate............................................................................................................ 25

7.2. Effects............................................................................................................................. 277

 7.3. Environmental Fate and Effects Data for Degradate, 2,4-DCP...............................30

8. References................................................................................................................................ 31

Appendix A. Physical Parameters of 2,4-D and Its Forms.............................................36

Appendix B. Screening Level Models to Evaluate Potential Importance of Drinking Water

and Inhalation Exposure Pathways.......................................................40

Appendix C. Incident Information from the EIIS Database...........................................42
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1. Introduction

1.1. Purpose

2,4-D is an herbicide in the phenoxy or phenoxyacetic acid family that is used postemergence for 

selective control of broadleaf weeds. The purpose of the Problem Formulation is to broadly 

review the registered uses of 2,4-D acid, salts, amines, and esters, and identify potentially 

complete environmental exposure pathways that will be assessed during the comprehensive 

Registration Review process. This document specifically addresses the following ten forms of 

2,4-D: 2,4-dichlorophenoxyacetic acid, dimethylamine salt of 2,4-D, 2-ethylhexyl ester of 2,4-

D, butoxyethyl ester of 2,4-D, triisopropanolamine salt of 2,4-D, isopropylamine salt of 2,4-D, 

diethanolamine salt of 2,4-D, sodium salt of 2,4-D, isopropyl ester of 2,4-D, and choline salt of 

2,4-D.

1.2. Ecological Risk Assessments

The Agency has conducted several ecological risk assessments on 2,4-dichlorophenoxyacetic 

acid (2,4-D) that serve as a basis for this scoping document. The two most recent are the 2005 

Reregistration Eligibility Decision (RED), and the 2009 California red-legged frog and Alameda 

whipsnake endangered species assessment. 

The RED document for 2,4-D (USEPA 2005a) found the following major ecological conclusions

(Table 1):

Table 1. Summary of Risk Concerns Identified for 2,4-D1 in the RED

Birds Mammals Terrestrial

Plants

Terrestrial

Inverts Fish Aquatic Inverts

Aquatic 

Plants

Yes Yes Yes No Yes Yes Yes

1 Risk conclusions are based on acid equivalent (ae) of various forms of 2,4-D. See 

Section 2.3 for a description of the bridging strategy between 2,4-D acid and it salts, 

amines, and esters.

Risks to terrestrial birds, mammals, and plants were primarily caused by spray drift and runoff 

while risks to aquatic fish, invertebrates, and plants (terrestrial and aquatic) were the result of 

direct applications of 2,4-D to aquatic systems for weed control.

The California red-legged frog and Alameda whipsnake assessment (USEPA 2009) concluded a 

“may affect and likely to adversely affect” determination for all uses of 2,4-D except for citrus 

and potatoes. For citrus and potatoes, the determination was “may affect, but not likely to 

adversely affect.

1.3. Drinking Water Exposure Assessments

In the 2005 RED, EFED conducted an evaluation of concentrations of 2,4-D to which humans 

may be exposed through the ingestion of drinking water. The assessment also included modeling 

and an evaluation of surface water and groundwater monitoring data. A number of modeling 
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approaches were used to provide estimated drinking water concentrations (EDWCs) for drinking 

water. The highest exposure scenario was the direct application of 2,4-D to surface water bodies 

for the control of aquatic weeds with an EDWC of 4000 μg ae/L for peak (acute) exposure and 

627 μg ae/L for the annual mean (chronic) exposure. As a refinement, a screening level model 

incorporating an advection dispersion equation, the predicted peak concentration at a drinking 

water intake in the EFED index reservoir with a setback of 1500 feet predicted an acute EDWC 

of 811μg ae/l and a chronic EDWC of 102 μg ae/l. 

1.4. Safe Drinking Water Act and Clean Water Act Programs

2,4-D is regulated under the Safe Drinking Water Act (SDWA) and has a Maximum 

Contaminant Level (MCL) of 70 μg ae/L, a One-Day Health Advisory (HA) for children of 1000 

μg ae/L, and a 10-day HA for children of 300 μg ae/L. EFED reviewed non-targeted 2,4-D use 

monitoring data, which provided context to modeled results and indicated that there is little 

evidence that concentrations are likely to be found exceeding the drinking water standards.

An Aquatic Life Ambient Water Quality Criteria (Clean Water Act, section 304(a)) document 

has not been published for 2,4-D. Aquatic life benchmarks have been published and are listed in 

Table 2 below (http://www.epa.gov/oppefed1/ecorisk_ders/aquatic_life_benchmark.htm). 

Table 2. OPP Aquatic Life Benchmarks (μg ae/L freshwater)

Fish Invertebrates Nonvascular 

Plants

Vascular 

Plants

Acute Chronic Acute Chronic Acute Acute

2,4-D salts and acid 12075 14200 12500 16050 3880 13.1

2,4-D esters 130 79.2 1100 200 66 330

2. Stressor Source and Distribution

There are multiple forms of 2,4-D (Table 3) that are designed to control a wide range of 

broadleaf weeds and aquatic weeds. Chemical forms covered by this risk assessment are: 2,4-D 

acid, 2,4-D DMA, 2,4-D IPA, 2,4-D TIPA, 2,4-D EHE, 2,4-D BEE, 2,4-D DEA, 2,4-D IPE, 2,4-

D sodium salt (Na), and 2,4-D choline. Registered formulation types include: emulsifiable 

concentrate, granular, soluble concentrate/solid, water dispersible granules (dry flowable), and 

wettable powder. 2,4-D may be applied with a wide range of application equipment including 

aircraft (fixed/rotary wing), ground boom sprayer, backpack/hand held sprayers, and tree 

injection equipment. Methods of application may include broadcast application, band treatment, 

basal spray treatment, frill treatment, girdle treatment, spot treatment, stump treatment, tree 

injection treatment, and surface water treatment. The timing of 2,4-D applications to crops can 

occur at emergence, before bud break, dormant, dough stage, established plantings, foliar, postemergence, pre-emergence, pre-harvest, pre-plant. Table 4 presents a summary of the registered 

2,4-D uses and maximum application rates, as derived from the 2,4-D Industry and IR-4 

supported Master Label (2012).
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Table 3. 2,4-D Acid, Salts, Amines, and Esters

PC Code Name1 Abbreviation

Acid

030001 2,4-dichlorophenoxyacetic acid Acid

Salts

030004 Sodium salt of 2,4-D Na 

051505 Choline salt of 2,4-D Choline

Amine Salts

030016 Diethanolamine salt of 2,4-D DEA

030019 Dimethylamine salt of 2,4-D DMA

030025 Isopropylamine salt of 2,4-D IPA

030035 Triisopropanolamine salt of 2,4-D TIPA

Esters

030053 Butoxyethyl ester of 2,4-D BEE

030063 2-ethylhexyl ester of 2,4-D 2-EHE

030066 Isopropyl ester of 2,4-D IPE

1

Structures of various chemical forms can be obtained from Appendix A
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Table 4. Labeled 2,4-D Use Patterns of Maximum Exposure 

Use

Max. Single App. 

Rate

(lbs ae/A)

Max. No. of 

App. per Year

Min. 

Reapp. 

Interval (d)

Max. Annual 

App. Rate

(lbs ae/A)

App. Method

Chemical Form

Cereal grains 1.25 1 post-emergence

1 preharvest NS A 1.75 Ground or aerial spray

Broadcast

Acid, DMA, 2-

EHE, BEE, TIPA, 

IPA, DEA, Na, 

Choline

Field corn and 

pop corn

1 (preplant or 

preemergence)

0.5 (postemergence)

1.5 (preharvest)

1 application per 

crop stage NS 3

Ground or aerial spray

Broadcast

Directed band

Acid, DMA, 2-

EHE, BEE, TIPA, 

IPA, DEA, Na, 

Choline

Sweet corn

1 (preplant or 

preemergence)

0.5 (post emergence)

1 application per 

crop stage 21 1.5

Ground or aerial spray

Broadcast

Directed band

Acid, DMA, 2-

EHE, BEE, TIPA, 

IPA, DEA, Na, 

Choline

Grain or 

forage 

sorghum

1 (amines, acid, 

salts) or

0.5 (esters) 1 NRB

1 (amines, 

acid, salts) or

0.5 (esters)

Ground or aerial spray

Broadcast

Directed band

Acid, DMA, 2-

EHE, BEE, TIPA, 

IPA, DEA, Na, 

Choline

Soybeans 1 1 NR 1 Ground or aerial spray

Broadcast

Acid, DMA, 2-

EHE, BEE, TIPA, 

IPA, DEA, Na, 

Choline

Sugarcane

2 (preemergence)

2 (postemergence) 1 application per 

crop stage NS 4 Ground or aerial spray

Broadcast or band

Acid, DMA, 

TIPA, IPA, DEA, 

Na, Choline

Rice

1 (preplant)

1.5 (postemergence) 1 application per 

crop stage NS 1.5

Ground or aerial spray

Broadcast or spot 

treatment

Acid, DMA, 

TIPA, IPA, DEA, 

Na, Choline

Wild riceE 0.25 1 NR 0.25

Ground or aerial spray

Broadcast or spot 

treatment

Acid, DMA, 

TIPA, IPA, DEA, 

Na

Pome fruits 2 2 75 4 Broadcast ground or 

spot treatment

Acid, DMA, 

TIPA, IPA, DEA, 

Na, Choline

Stone fruits 2 2 75 4 Broadcast ground or 

spot treatment

Acid, DMA, 

TIPA, IPA, DEA, 

Na, Choline

Nut orchards, 

pistachios 2 2 30 4 Broadcast ground or 

spot treatment

Acid, DMA, 

TIPA, IPA, DEA, 

Na, Choline

Filberts 1 lb ae/100 gal 4 30 NS Ground spot treatment

Acid, DMA, 

TIPA, IPA, DEA, 

Na
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Table 4. Labeled 2,4-D Use Patterns of Maximum Exposure 

Use

Max. Single App. 

Rate

(lbs ae/A)

Max. No. of 

App. per Year

Min. 

Reapp. 

Interval (d)

Max. Annual 

App. Rate

(lbs ae/A)

App. Method

Chemical Form

Established 

grass pastures, 

rangeland, 

and perennial 

grasslands not 

in agricultural 

production

2 2 30 4 Ground or aerial spray

Broadcast or spot

Acid, DMA, 2-

EHE, BEE, TIPA, 

IPA, DEA, Na, 

Choline

Ornamental 

turf 1.5 2 NS 3 Broadcast ground or 

spot treatment

Acid, DMA, 2-

EHE, BEE, TIPA, 

IPA, DEA, Na, 

Choline

Grass (turf) 

grown for 

seed and sod

2 2 21 4 Broadcast ground or 

spot treatment

Acid, DMA, 2-

EHE, BEE, TIPA, 

IPA, DEA, Na, 

Choline

Fallow land 

and crop 

stubble

2 2 30 4 Ground or aerial spray

Broadcast

Acid, DMA,2-

EHE, BEE, TIPA, 

IPA, DEA, Na, 

Choline

Forest site 

preparation, 

forest 

roadsides, 

brush control,

established 

conifer release

4 1 NR 4 Ground or aerial spray

Broadcast

Acid, DMA, 2-

EHE, BEE, TIPA, 

IPA, DEA, Na, 

Choline

Tree and 

brush control

8 lb ai/100 gal (basal 

spray, cut surface –

stumps, frill)

2 ml of 4 lb 

ae/injection site 

(injection)

1 NR 4 (broadcast 

only)

Ground or aerial spray

Broadcast, spot, basal, 

frill, cut stump or 

injection

Acid, DMA, 2-

EHE, BEE, TIPA, 

IPA, DEA, Na, 

Choline

Non-cropland 4 2 30 4 Ground or aerial spray

Broadcast or spot

Acid, DMA, 2-

EHE, BEE, TIPA, 

IPA, DEA, Na, 

Choline

Aquatic weed 

control 

(irrigation 

ditch bank 

application)

2 2

30 

(broadcast 

only)

4 Boat or aerial spray

Broadcast or spot

Acid, DMA, BEE, 

TIPA, IPA, DEA, 

Na, Choline
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Table 4. Labeled 2,4-D Use Patterns of Maximum Exposure 

Use

Max. Single App. 

Rate

(lbs ae/A)

Max. No. of 

App. per Year

Min. 

Reapp. 

Interval (d)

Max. Annual 

App. Rate

(lbs ae/A)

App. Method

Chemical Form

Aquatic weed 

control 

(surface 

application for 

floating and 

emergent 

weeds)

4 2

21 

(broadcast 

only)

8 Boat or aerial spray

Broadcast or spot

Acid, DMA, BEE, 

TIPA, IPA, DEA, 

Na, Choline

Aquatic weed 

control 

(surface 

application or 

subsurface 

injection for 

submersed 

weeds)

4 ppm ae/A (10.8 lb 

ae/Acre foot) 2 21 10.8 lb 

ae/Acre foot

Boat or aerial spray

Broadcast or spot

Acid, DMA, BEE, 

TIPA, IPA, DEA, 

Na, Choline

Potatoes 0.07 2 10 0.14 Ground or aerial spray

Broadcast

Acid, DMA, 2-

EHE, BEE, TIPA, 

IPA, DEA, Na

Asparagus 2 2 30 4 Ground or aerial spray

Broadcast

Acid, DMA, 

TIPA, IPA, DEA, 

Na

Hops 0.5 3 30 1.5 Ground or aerial spray

Broadcast

Acid, DMA, 

TIPA, IPA, DEA, 

Na

StrawberriesC 1.5 1 NR 1.5 Ground or aerial spray

Broadcast

Acid, DMA, 

TIPA, IPA, DEA, 

Na

Low bush 

blueberries

Wiper solution 

(0.0375 lb/gal) 

(postemergence)

1 lb ae/10 gal)

1 application per 

crop stage NS NS Directed, ground wipe 

or spot application

Acid, DMA, 

TIPA, IPA, DEA, 

Na

High bush 

blueberries

1.4 (postemergence 

and postharvest

1 application per 

crop stage NS 2.8 Directed, ground wipe 

or spot application

Acid, DMA, 

TIPA, IPA, DEA, 

Na

GrapesD 1.36 1 NR 1.36 Ground directed

Acid, DMA, 

TIPA, IPA, DEA, 

Na

Cranberries

4 (dormant –

granular ester only)

1.2 (postemergence 

– amines, salts, and 

acid only)

1 (dormant)

2 

(postemergence)

NS

4 (dormant)

2.4 

(postemergen

ce)

Ground wipe or spot 

(acid, amines, and salt)

Ground granule 

spreader (esters)

Acid, DMA, 2-

EHE, BEE, TIPA, 

IPA, DEA, Na
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Table 4. Labeled 2,4-D Use Patterns of Maximum Exposure 

Use

Max. Single App. 

Rate

(lbs ae/A)

Max. No. of 

App. per Year

Min. 

Reapp. 

Interval (d)

Max. Annual 

App. Rate

(lbs ae/A)

App. Method

Chemical Form

Citrus

0.1 (navel oranges, 

valencia oranges and 

grapefruit)

1 application per 

crop stage NR

0.1 Ground or aerial spray

Broadcast or directed

IPE

200 ppm (navel 

oranges and valencia 

oranges)

200 ppm

Ground or aerial spray

Broadcast or directed

(September – January)

24 ppm (lemons, 

navel oranges, 

valencia oranges, 

tangelos)

24 ppm

Ground or aerial spray

Broadcast or directed

Fall oil, water, 

whitewash sprays

500 ppm (lemons)

500 ppm 

(~0.7 lb 

ae/million lbs 

of lemons or 

0.7 ppm)

Dip or spray 

equipment

A NS means “not stated.” B

 NR means “not relevant.” C

 Do not apply in California or Florida D For use in California only E

 For use in Minnesota only

2.1. Mechanism of Action

2,4-D is a plant growth regulator (synthetic auxin herbicide) in the phenoxy or phenoxyacetic 

acid family. It is most commonly used as a post-emergence herbicide for the selective control 

of broadleaf weeds. 2,4-D causes disruption of multiple growth processes in susceptible plants 

by affecting proteins in the plasma membrane, interfering with RNA production, and changing 

the properties and integrity of the plasma membrane. Excessive cell division and the resulting 

growth destroy the plant’s vascular transport system. The most susceptible tissues are those that 

are undergoing active cell division and growth (Gibson and Liebman, 2002). Plant injuries 

include growth and reproduction abnormalities, especially on new growth. Broadleaf plants 

experience stem and petiole twisting (epinasty), leaf malformations (parallel venation, leaf 

strapping, and cupping), undifferentiated cell masses and adventitious root formation on stems, 

and stunted root growth. Grass plants exhibit rolled leaves (onion leafing), fused brace roots, 

leaning stems, and stalk brittleness. Disruption of reproductive processes may occur resulting 
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in sterile or multiple florets and nonviable seed production. Symptoms may appear on young 

growth almost immediately after application, but death may not occur for several weeks.

2.2. Overview of Pesticide Usage

National pesticide usage data from the USDA-NASS (United States Department of Agriculture's 

National Agricultural Statistics Service) and Private Pesticide Market Research indicate that an 

annual average of nearly 29 million pounds of all forms of 2,4-D were applied to agricultural 

crops in the United States annually between 2006 and 2010 (USEPA 2012a). The available 

usage data presents information in terms of 2,4-D acid and does not break down the usage into 

the various salts and esters of 2,4-D. The crops with the highest uses (based on average treated 

fraction of acreage) were: almond (15%), apples (20%), barley (25%), cherries (15%), fallow 

(25%), hazelnuts (25%), nectarines (15%), oats (15%), oranges (20%), peaches (20%), pears 

(15%), plums (15%), prunes (15%), sorghum (20%), sugarcane (40%), tangelos (30%), wheat 

(30%). All other treated crops averaged 10% or less of the total acreage grown. Average annual 

use on lawns, turf, nurseries, etc. in commercial settings has decreased from 5 million to 4 

million pounds per year (2002, 2004, 2006). Homeowner and aquatic weed control uses have 

remained fairly constant with average annual uses of 9 to 9.5 million pounds per year (2003, 

2005).

2.3. Environmental Fate Bridging Strategy 

Selected physicochemical properties, chemical structures, and the ratios of molecular weight of 

various forms of 2, 4-D are provided in Appendix A. The environmental fate strategy for 2,4-D 

is based on bridging the degradation of 2,4-D esters and 2,4-D amine salts to 2,4-D acid 

[Registration Standard for 2,4 Dichlorophenoxyacetic acid (2,4-D), 1988, 540/RS-88-115]. The 

bridging data provide information on the time of dissociation of 2,4-D amine salts and the rate of 

hydrolysis of 2,4-D esters. There are acceptable bridging data for 2,4-D DMA; 2,4-D IPA; 2,4-D 

TIPA; 2,4-D EHE; 2,4-D BEE; 2,4-D DEA; and 2,4-D IPE. The sodium and choline salts of 2,4-

D are also considered to be equivalent to 2,4-D acid. The 2,4-D amine salts as well as 2,4-D 

choline salt have been shown to dissociate rapidly in water. The bridging data indicate esters of 

2,4-D are rapidly hydrolyzed to 2,4-D acid in alkaline aquatic environments, soil/water slurries, 

and moist soils. Under extremely dry soil conditions, these degradation mechanisms may be 

inhibited, which could result in an increased persistence of 2,4-D esters. The laboratory bridging 

data indicate that under most environmental conditions, 2,4-D esters and 2,4-D amine salts will 

degrade rapidly to form 2,4-D acid. 

2.3. Environmental Fate and Transport

The physicochemical properties in Table 5 suggest that 2,4-D acid is soluble in water (569

mg/L). The vapor pressure (1.4 × 10-7 mm Hg) and Henry's Law Constant (8.56 x 10-6 atmm3

/mol) indicate that 2,4-D acid has a low volatility. However, based on the physical-chemical 

properties of the ester forms (Appendix A) of 2,4-D and on evidence from the open literature, 

there may be a concern for effects to non-target organisms from volatilization and off-site 

deposition of 2,4-D esters. 2,4-D acid is unlikely to bioaccumulate in fish given the low value of 

the log n-octanol/water partition coefficient (log Kow 0.18 at neutral pH). However, the log Kow
Page 11 of 85

of ester forms of 2,4-D ranges from 2.4 to 5.78, which is higher than 2,4-D acid (Appendix A). 

The higher values for the ester suggest that these compounds can potentially bioaccumulate in

aquatic organisms, but these values were based on a regression-based estimation method (i.e. 

EPIsuite) that assumes the compounds are not altered physically or chemically once released into 

the environment. A field study shows no accumulation in fish of applied 2,4-D DMA or 2,4-D 

BEE at the higher rate in a lake in Georgia (Hoeppel and Westerdahl 1983). Both formulations 

were converted to free 2,4-D acid rapidly – 2,4-D amines within 3 minutes and esters within 24 

hours after application.

Table 5 also provides environmental fate properties of 2,4-D acid, along with the major and 

minor degradates detected in the submitted environmental fate and transport studies. 2,4-D acid 

is stable to abiotic hydrolysis in buffered aqueous solutions at pH 4, 5, 7, and 9. The degradation 

of 2,4-D acid appears to be dependent on oxidative microbially-mediated mineralization in the 

terrestrial environment and photodegradation in water. Results from laboratory studies indicate 

rapid to moderately rapid degradation under aerobic soil conditions with half-lives ranging from 

1.4 days to 12.4 days and a median half-life of 2.9 days. Only minor degradates, 2,4-

dichlorophenol (2,4-DCP; a maximum of 3.5% of applied ) and 2,4-dichloroanisol (2,4-DCA; a 

maximum of 2.8% of applied ), were identified in soils. The photodegradation half-life of 2,4-D 

acid was 12.9 days in a pH 5.0 buffer solution and a major degradate, 1,2,4-benezenetriol (37% 

of applied) was identified. 2,4-D acid was stable to photodegradation in soil. 

2,4-D acid was not stable in aerobic aquatic environments (t1/2=15.0 days) but was moderately 

persistent to persistent (t1/2=28.5 to 333 days) in anaerobic aquatic laboratory studies. The major 

degradates were chlorohydroquinone (CHQ) (maximum of 16.0 % of applied) in aerobic aquatic 

conditions and 2,4-DCP (maximum of 32.0 % of applied) under anaerobic aquatic environment. 

There were three major degradates identified in the submitted environmental fate studies for 2,4-

D; a maximum of 37% of 1,2,4-benezenetriol, a maximum of 32.6% of 2,4-D-dichlorophenol 

(2,4-DCP), and a maximum of 16% of chlorohydroquinone (CHQ). The minor degradates (<3% 

of applied) detected were 4-chlorophenoxyacetic acid (4-CPA), 4-chlorophenol, and 2,4-DCA

(Table 5). The major degradate, 1,2,4-benzenetriol, is a photodegradate that was observed under 

abiotic conditions and is less likely to occur under natural conditions where microbe-mediated 

degradation occurs. However, there are insufficient data on the major degradates of 2,4-D to 

adequately assess their persistence and mobility.
Page 12 of 85

Table 5. Physical Chemical and Environmental Fate Properties of 2,4-D Acid

Parameter Value Source

Selected Physical/Chemical Parameters

Chemical Structure1

TOXNET

IUAPC Name (2,4-dichlorophenoxy)acetic acid U.S. EPA, 2005a

CAS Name (2,4-dichlorophenoxy)acetic acid U.S. EPA, 2005a

CAS No. 94-75-7 U.S. EPA, 2005a

Molecular Weight (molecular formula) 221.04 g/mol (C8H6Cl2O3) U.S. EPA, 2005a

Smiles Code O=C(O)COc(c(cc(c1)Cl)Cl)c1 EPISUITE4.1

Vapor pressure (25°C) 1.4 x 10-7 mm Hg U.S. EPA, 2005a

Aqueous solubility (20°C) 569 mg/L U.S. EPA, 2005a

Dissociation constants (pKa ) in water

(25°C)

2.60 MRID 471122-02

Henry’s Law Constant (25°C) 8.56 x10-6 atm-m3/mol Rice et al, 1997

Log octanol-to-water partition coefficient

(log KOW)

2.14 @ pH 5.0

0.18 @ pH 7.0

0.10 @ pH 9.0

U.S. EPA, 2005a

Persistence

Hydrolysis half-life Stable MRID 41007301

Aqueous photolysis half-life 12.98 days

Degradates 

1,2,4-benzenetriol (37% of applied) 

CO2 (25% of applied)

MRID 41125306

Soil photolysis half-life Stable 

CO2 (5% of applied)

MRID 41125305
Page 13 of 85

Table 5. Physical Chemical and Environmental Fate Properties of 2,4-D Acid

Parameter Value Source

Aerobic soil metabolism half-life (days) Catlin Silty clay loam – 1.7 day

Commerce Loam – 4.62 days

Catlin Silty clay loam – 1.4 days

Fargo Clay – 12.4 days

Keith Clay loam – 4.4 days

Walla Walla silt loam – 2.0 days

Cecil Sandy loam -2.9 days

Degradates 

2,4-DCP (3.5%) 

2,4-DCA (2.8%)

MRID 43167501, 

MRID 00116625

Anaerobic aquatic metabolism half-life 

(total system)

333 days

28.5 days

41.0 days 

Degradates

2,4 DCP (Maximum 32.6% of applied)

4-chlorophenoxy acetic acid(4 - CPA) 

<2.0% of applied), 

4-chlorophenol (4 - CPP) <2.0% of 

applied), 

2,4- DCA (<2% of applied)

MRID 43356001

MRID 42979201

MRID 41557901

Aerobic aquatic metabolism half-life (total 

system)

15 days

Inconclusive2

Degradates

Chlorohydroquinone (CHQ) (maximum 

16% of Applied)

2,4-DCP (4.9 of applied) 

MRIDs 42045301 

44188601
Page 14 of 85

Table 5. Physical Chemical and Environmental Fate Properties of 2,4-D Acid

Parameter Value Source

Mobility

Adsorption/desorption

Kd-ads / Kd-des (mL/g)

Kfoc-ads / (mL/g)

Adsorption

Freundlich adsorption Kf-ads values Sand 

0.36

Sandy loam 0.17

Loam 0.28

Silty clay loam 0.52

Clay 1.27

Desorption

Freundlich adsorption Kf-des values 

Sand 1.16

Sandy loam 0.87

Loam 1.58

Silty clay loam 1.99

Clay 1.64

Adsorption

Freundlich adsorption Kfoc values 

Sand 76

Sandy loam 70

Loam 117

Silty clay loam 59

Clay 58.1

MRID 44117901

MRID 42045302

Leaching Thin Layer Chromatography (TLC) 

Retention Value (Rf, unitless)

(Un-aged sample)

Sand 1.0

Sandy loam 0.77 .

Silt loam 0.60

Loam 0.41

Column Study

(Aged sample)

Immobile

MRID 00112937

MRID 00057313

MRID 42045302

MRID 44105201

MRID 00080124

MRID 44158501
Page 15 of 85

Table 5. Physical Chemical and Environmental Fate Properties of 2,4-D Acid

Parameter Value Source

Field Dissipation

Terrestrial field dissipation half-life The first order half-lives ranged from 1.1 

to 42.5 days with a median half-life of 

6.1 days

MRID 43914701

MRID 43762401 

MRID 43762402

MRID 43514601

MRID 43533401

MRID 43864001

MRID 43592801

MRID 43762403

MRID 43762404

MRID 43640601

MRID 43831702

MRID 43872703

MRID 43849102

MRID 43831701

MRID 43705202

Aquatic field dissipation half-life Estimated dissipation half-lives of 20.7 

and 2.7 days from the North Carolina 

pond after the first and second 

applications, 14 days and 6.1 days in 

water from a North Dakota pond after the 

first and second applications, and 1.0 day 

in water from the Louisiana rice paddy 

after a single application

MRID 43908302

MRID 43491601

MRID 43954701

Forest Field Dissipation half-life The estimated half lives for 2,4-D were 59 

days in exposed soil, 68 days in protected 

soil, 42 days on foliage, and 72 days on 

leaf litter at the OR site with DMA.

In GA Site, the estimated half-lives on 

foliage for 2,4-D of 32.5 days and for 

2,4-D EHE of 32.7 days. The 

estimated half-lives in leaf litter for 

2,4-D of 51.7 days and for 2,4-D EHE 

of 50.5 days.

MRID 43954702

MRID 43927101

1 Structures and other physicochemical properties of various chemical forms can be obtained from 

Appendix A

2 Half-life cannot be calculated because study duration was insufficient.

Given that 2,4-D acid is anionic (X-COO- H+) under most environmental conditions, it is 

expected to be mobile to moderately mobile with a range of Kfoc of 58.1 to 117 mL/g (using the 

classification scheme of FAO, 2006) in soil. The mobility of 2,4-D acid in supplemental soil 

thin layer chromatography (TLC) studies was classified as intermediately mobile (Rf=0.41) to 

very mobile (Rf=1.00) in mineral soils.
Page 16 of 85

A series of fate studies were also submitted for the various chemical forms of 2,4-D. These 

forms included DMA, IPA, TIPA, DEA, 2-EHE, BEE, and IPE. These data suggest that fate 

properties of 2,4-D salts and esters are comparable to 2,4-D acid. A detailed assessment of 2,4-

D’s environmental fate can be obtained from EFED’s Risk Assessment for the Reregistration 

Eligibility Document for 2,4-D (USEPA, 2005a).

The registrant conducted a total of 30 terrestrial field dissipation studies in CA, CO, NC, ND, 

NE, OH, and TX on bare ground plots as well as plots cropped with corn, pasture, turf, and 

wheat. The 2,4-D acid half-lives ranged from 1.1 days to 42.5 days with a median half-life of 

6.1 days. These half-lives reflect dissipation from the surface soil layer (0 to 6 inches). The data 

indicate a rapid to moderately rapid dissipation rate for 2,4-D acid. The half-lives of 2,4-D 

degradation products (2,4-DCP and 2,4-DCA) were not estimated because of their sporadic 

occurrence patterns in surface soils. 

To address the behavior of 2,4-D in aquatic systems, a series of aquatic field dissipation studies 

were conducted in ND, NC, and LA. The estimated dissipation half lives were 20.7 and 2.7 days 

in water from the NC pond after the first and second applications, 14 days and 6.1 days in water 

from a ND pond after the first and second applications, and 1.0 day in water from the LA rice 

paddy after the single application. The high application rates result in peak concentrations of 

4,800 μg ae/L at day 1 in the ND pond (application rate of 41.8 lb ae/A), of 2,800 μg ae/L on day 

0 in the NC pond (application rate of 41.8 lb ae/A), and of 2,300 μg ae/L on day 0 in the LA

pond (application rate of 1.8 lbs ae/A). These concentrations are higher than the 2,4-D Maximum 

Contaminant Level (MCL) of 70 μg ae/L. 2,4-D concentrations in water did not decrease to 

below the MCL until after day 30 (1,500 μg ae/L) at the ND pond, until after day 29 (860 μg

ae/L) at the NC pond, and until after day 3 (390 μg ae/L) at the LA pond. Three additional 

aquatic dispersion and dissipation studies were also conducted in FL and MN for the application 

of DMA to control aquatic weeds. At the maximum application rate, the target DMA 

concentration in aquatic environments does not exceed the solubility concentration for DMA.

In addition, two field dissipation studies using DMA were also submitted to address forest field 

dissipation. DMA was applied as a spray at a nominal rate of 4.0 lb ae/A onto a forest plot of 

loam soil planted with fir trees. Registrant-calculated dissipation half lives for 2,4-D acid were

38.7 days in exposed soil, 50.8 days in protected soil, 37.4 days on foliage, and 65.7 days on leaf 

litter. However, the apparent first half-lives occurred between 0 and 1 day post-treatment in the 

exposed soil, 1 and 3 days in the protected soil, 3 and 7 days on the foliage, and 7 and 14 days on 

the leaf litter; dissipation was observed to be biphasic in each case. EFED estimated half lives 

for 2,4-D acid of 59 days in exposed soil, 68 days in protected soil, 42 days on foliage, and 72 

days on leaf litter, at the OR site with DMA, and 51.7 days on foliage, and 32.5 days on leaf 

litter at the GA site with 2,4-D 2-EHE.

3. Receptors

In general, the ester forms of 2,4-D are more toxic to aquatic organisms than the acid, amine, and 

salt forms. Table 6 provides a summary of the most sensitive aquatic endpoints for salts, amines,

and the acid of 2,4-D. Table 7 provides a summary of the most sensitive aquatic endpoints for 
Page 17 of 85

2,4-D esters. These will be considered separately in the aquatic analyses. Table 8 provides a list 

of the most sensitive endpoints for mammals, birds, and terrestrial invertebrates, regardless of 

their chemical form; in contrast to the aquatics, data do not indicate that terrestrial organisms are 

more sensitive to one particular form of 2,4-D. Terrestrial plants are also considered separately 

for esters and acid, amine, and salt forms because esters are significantly more soluble in water. 

The terrestrial plant runoff scenario is based upon the solubility of the compound; thus, making it 

appropriate to consider esters separately.

3.1. Effects to Aquatic Organisms

Table 6. Summary of the Most Sensitive Endpoints from Aquatic Toxicity Studies for 2,4-D Acid,

Amines, and Salts

Taxonomic 

Group

Study 

Type

Surrogate Species

and Form

Toxicity Value MRID and 

Classification

Acute 

Toxicity 

Classification

Freshwater fish1

Acute

Rainbow trout 

(Oncorhynchus 

mykiss) – DEA

96-h LC50 > 81.6 mg 

ae/L

Acceptable

41975105 Slightly toxic

Chronic 

(Early 

LifeStage)

Fathead minnow 

(Pimphales 

promelas) - DMA

NOAEC = 23.6 mg 

ae/L (based on length)

Acceptable

41767701 ---

Freshwater 

invertebrates

Acute Waterflea (Daphnia 

magna) – 2,4-D acid

48-h LC50 =25 mg 

ae/L

Acceptable

41158301 Slightly toxic

Chronic Waterflea (Daphnia 

magna) - DEA

NOAEC = 16.05 mg 

ae/L (based on 

survival and 

reproduction)

Acceptable

42018303 ---

Freshwater 

amphibian Acute

Leopard frog 

tadpoles (Rana 

pipiens) - DMA

96-h LC50 = 278 mg 

ae/L

Supplemental

44517306

Practically 

non-toxic

Estuarine/marine 

fish Acute

Tidewater silverside 

(Menidia beryllina)

- DEA

96-h LC50 > 80.24 mg 

ae/L

Acceptable

42018301 Slightly toxic

Estuarine/marine 

invertebrates Acute

Eastern oyster 

(Crassostrea 

virginica) - IPA

96-h EC50 = 49.6 mg 

ae/L

Acceptable

41429003 Slightly toxic

Aquatic plants 

and algae

Vascular Duckweed, (Lemna 

gibba) - DEA

EC50 = 0.2992 mg 

ae/L

Acceptable

42712204 ---

Nonvascular

Freshwater diatom 

(Navicula 

pelliculosa) - DMA

EC50 = 3.88 mg ae/L Acceptable

41505903 ---

Terrestrial plants Seedling 

emergence

Sorghum (Sorghum 

bicolor ) – DMA

EC25 = 0.026

NOAEC = 0.015 

(based on fresh 

weight) TEP3

Acceptable

42389501 ---
Page 18 of 85

Table 6. Summary of the Most Sensitive Endpoints from Aquatic Toxicity Studies for 2,4-D Acid,

Amines, and Salts

Taxonomic 

Group

Study 

Type

Surrogate Species

and Form

Toxicity Value MRID and 

Classification

Acute 

Toxicity 

Classification

Lettuce (Lactuca 

sativa) – DMA

EC25 = 0.026

NOAEC = 0.025 

(based on dry weight) 

TEP3

Acceptable

47106001 ---

Vegetative 

vigor

Onion (Allium cepa)

– 2,4-D acid

EC25 ≥ 0.0075 lb ae/A 

NOAEC < 0.0075 lb 

ae/A (based on fresh 

weight)

TGAI2

Acceptable

42416801 ---

Lettuce (Lactuca 

sativa) – DMA

EC25 = 0.0038

NOAEC = 0.0017 

(based on dry weight) 

TEP3

Acceptable

47106002 ---

1 Freshwater fish may be surrogates for aquatic-phase amphibians. 2

Technical Gradient Active Ingredient (TEP studies are also available, but yielded less sensitive toxicity endpoints)

3

Typical End-use Product

Table 7. Summary of the Most Sensitive Endpoints from Aquatic Toxicity Studies for 2,4-D Esters

Taxonomic 

Group

Study 

Type

Surrogate Species

and Form

Toxicity Value MRID and 

Classification

Acute

Toxicity 

Classification

Freshwater fish1

Acute4

Bluegill sunfish 

(Lepomis 

macrochirus) -

IPE

96-h LC50 = 0.26 mg 

ae/L

Acceptable

43930701 Highly toxic

Acute

Bluegill sunfish 

(Lepomis 

macrochirus) –

BEE

96-hr LC50 = 0.428 mg 

ae/L

Acceptable

41353801 Highly toxic

Chronic 

(Full Life 

Cycle)

Fathead minnow 

(Pimephales 

promelas) - EHE

NOAEC = 0.0792 mg 

ae/L (based on larval 

fish survival)

Supplemental 

41737305 ---

Freshwater 

invertebrates

Acute4

Waterflea 

(Daphnia magna)

- IPE

96-h LC50 = 2.2 mg 

ae/L

Acceptable

43930601

Moderately 

toxic

Acute

Waterflea

(Daphnia magna) 

– EHE

96-hr LC50 = 3.4 mg 

ae/L

Acceptable

41158306

Moderately 

toxic

Chronic

Waterflea 

(Daphnia magna)

- BEE

NOAEC = 0.20 mg 

ae/L

Acceptable

41353802 ---

Estuarine/marine 

fish Acute

Tidewater 

silverside 

(Menidia 

beryllina) - EHE

96-h LC50 > 0.1564 

mg ae/L

Supplemental

41835205 Highly toxic
Page 19 of 85

Table 7. Summary of the Most Sensitive Endpoints from Aquatic Toxicity Studies for 2,4-D Esters

Taxonomic 

Group

Study 

Type

Surrogate Species

and Form

Toxicity Value MRID and 

Classification

Acute

Toxicity 

Classification

Chronic

Sheepshead 

minnow 

(Cyprinodon 

variegatus) - BEE

NOAEC = 0.05554 mg 

ae/L (based on 

survival)

Acceptable

41345701 ---

Estuarine/marine 

invertebrates Acute

Grass shrimp2

(Palaemonetes 

pugio) - EHE

96-h LC50 >0.092 mg 

ae/L

Supplemental

41835206

Very highly 

toxic

Aquatic plants 

and algae

Vascular Duckweed (Lemna 

gibba) - EHE EC50 = 0.33 mg ae/L Acceptable

41735203 ---

Nonvascular

Marine diatom 

(Skeletonema 

costatum) – EHE

EC50 = 0.152 mg ae/L Acceptable

41735204 ---

Terrestrial plants

Seedling 

emergence4

Onion (Allium

cepa) – IPE

EC25 = 0.010 lb ae/A

NOAEC = 0.005628 lb 

ae/A (based on shoot 

length) 

TGAI2

Acceptable

43982101 ---

Lettuce (Lactuca 

sativa) – IPE

EC25 = 0.00081 lb 

ae/A

NOAEC = 0.00047 

(based on shoot length)

TGAI2 

Supplemental

43982101 ---

Onion (Allium 

cepa) – EHE

EC25 = 0.17 lb ae/A

NOAEC = 0.0019 lb 

ae/A (based on shoot 

height) TEP3

Acceptable

47106003

Tomato 

(Lycopersicon 

esculentum) –

EHE

EC25 = 0.0012 lb ae/A

NOAEC = 0.0058 lb 

ae/A (based on dry 

weight) TEP3

Acceptable

47106003

Vegetative 

vigor

Onion (Allium 

cepa) – EHE

EC25 = 0.088

NOAEC = 0.0245 

(based on dry weight) 

TEP3

Acceptable

47106004 ---

Lettuce (Lactuca 

sativa) – EHE

EC25 = 0.0021 lb ae/A 

NOAEC = 0.00167 lb 

ae/A (based on dry 

weight)

TEP3

Acceptable

47106004 ---

1 Freshwater fish may be surrogates for aquatic-phase amphibians. 2

Technical Gradient Active Ingredient (TEP studies are also available, but yielded less sensitive toxicity endpoints) 3

Typical End-use Product 4

IPE use is currently limited to citrus and will only be used as an endpoint for this use. For other uses, the next most sensitive 

ester will be chosen.
Page 20 of 85

3.2. Effects to Terrestrial Organisms

Table 8. Summary of the Most Sensitive Endpoints from Terrestrial Toxicity Studies for 2,4-D (All 

Forms)

Taxonomic 

Group

Study Type Surrogate 

Species and 

Form

Toxicity Value MRID and 

Classification

Acute 

Toxicity 

Classification

Birds1

Acute

Northern bobwhite 

quail (Colinus 

virginianus) -

TIPA

LD50 = 218.7 mg ae/kg-bw Acceptable

41644401

Moderately 

toxic

Sub-acute 

dietary

Northern bobwhite 

quail (Colinus 

virginianus) –

TIPA

LC50 >3035 mg ae/kg-diet Acceptable

41644402

Mallard duck Slightly toxic

(Anas 

platyrhynchos) -

TIPA

LC50 >3035 mg ae/kg-diet Acceptable

41644403

Chronic

Northern bobwhite 

quail (Colinus 

virginianus) – 2.4-

D acid

NOAEC = 962 mg ae/kgdiet (no effects)Acceptable

45336401 ---

Mammals

Acute oral

Laboratory rat 

(Rattus 

norvegicus) -

TIPA

LD50 = 405 mg ae/kg-bw Acceptable

41413501

Moderately

toxic

Acute 

Inhalation

Laboratory rat 

(Rattus 

norvegicus) – 2,4-

D acid

LC50 > 1.79 mg ae/L Acceptable

00161660 Category III

Chronic

(reproduction)

Laboratory rat

(Rattus 

norvegicus) – 2,4-

D acid

Parental

NOAEL = 16.6 mg ae/kgbw (based on increased 

kidney weights, and 

degenerative lesions in the 

proximal convoluted tubules 

in P1 rats)

Reproductive

NOAEL = 45.3 mg/kg 

bw/day in males, 40.2 

mg/kg bw/day in females 

(based on no effects)

Offspring

NOAEL = 20.9/ mg/kg 

bw/day in males and 23.3 

mg/kg/day in females (based 

on decreased body weights, 

increased kidney weights 

and increased incidence of 

degeneration of the proximal 

convoluted tubules)

Acceptable

47972101 ---
Page 21 of 85

Table 8. Summary of the Most Sensitive Endpoints from Terrestrial Toxicity Studies for 2,4-D (All 

Forms)

Taxonomic 

Group

Study Type Surrogate 

Species and 

Form

Toxicity Value MRID and 

Classification

Acute 

Toxicity 

Classification

Insects Acute contact Honey bee (Apis 

mellifera) - EHE 96-h LD50 > 66 μg ae/bee Acceptable44517301

Practically 

non-toxic

Insects Acute oral Honey bee (Apis 

mellifera) - EHE 72-h LD50 > 66μg ae/bee Supplemental44517302

Practically 

non-toxic

1 Birds represent surrogates for terrestrial-phase amphibians and reptiles.

3.3. Ecological Incidents

The Avian Incident Monitoring System (AIMS) was searched on June 5, 2012 and three 

ecological incidents were identified that involved 2,4-D. One incident was classified as certain 

to have been caused by 2,4-D and involved a misuse of the pesticide to corn. The incident 

occurred in Iowa on May 19, 1996 and resulted in one dead bird (species unknown) at the site. 

The other two incidents were listed as unlikely to have been caused by 2,4-D. 

A search of the Ecological Incident Information System database (EIIS) on August 6, 2012 

returned more than 400 incidents for 2,4-D, ranging from 1949 to the present (Table 9). The 

majority of these incidents were reported for 2,4-D acid and involved plants. Entries included 

both residential and agricultural use of 2,4-D products. Many of the plant incidents appeared to 

result from over-application of 2,4-D products to lawns or application of 2,4-D products to types 

of grass that are sensitive to 2,4-D. Other plant incidents were the result of spray drift in 

agricultural settings. A limited number of incidents with other organisms (fish, aquatic plants, 

birds, mammals, reptiles, and terrestrial insects) were also reported. Incidents will need to be 

carefully reviewed to determine the role that 2,4-D products may have played; many incidents 

involved the application of other pesticides as well. In addition, incidents that are the result of a 

clear misuse of 2,4-D will be removed from the analysis. No incidents were reported for Na or 

IPE; the choline salt was not listed in the database (Appendix C). 

Table 9. EIIS Reports for all Forms of 2,4-D

Plants Fish Aquatic 

invertebrates

Aquatic 

plants

Birds Mammals Reptiles Terrestrial 

insects

N/S

2,4-D acid 304 22 N/R 1 4 4 1 1 4

DMA 90 3 N/R N/R 1 N/R N/R N/R N/R

2-EHE 6 N/R N/R N/R N/R N/R N/R N/R N/R

BEE 1 N/R N/R N/R N/R N/R N/R N/R N/R

TIPA 19 N/R N/R N/R N/R N/R N/R N/R N/R

IPA 1 N/R N/R N/R N/R N/R N/R N/R N/R

DEA 1 N/R N/R N/R N/R N/R N/R N/R N/R

Na N/R N/R N/R N/R N/R N/R N/R N/R N/R

IPE N/R N/R N/R N/R N/R N/R N/R N/R N/R
Page 22 of 85

Table 9. EIIS Reports for all Forms of 2,4-D

Plants Fish Aquatic 

invertebrates

Aquatic 

plants

Birds Mammals Reptiles Terrestrial 

insects

N/S

Choline N/R NR N/R N/R N/R N/R N/R N/R N/R

N/R = none reported

N/S = species not specified

The Aggregate Incident Reports database was searched on June 5, 2012 and contained numerous 

incidents for 2,4-D acid and its forms (Table 10). Incidents were reported from 1996 to the 

present. Specific information was not available for these incidents (e.g., species involved, other 

chemicals, etc.).

Table 10. Aggregate Incident Reports for All Forms of 2,4-D

Minor fish and 

wildlife incidents

Minor plant incidents Minor “other nontarget” incidents

2,4-D acid 40 7915 0

DMA 19 5787 0

2-EHE 0 84 2

BEE 5 1 0

TIPA 3 10 0

IPA N/R N/R N/R

DEA 0 1 0

Na N/R N/R N/R

IPE N/R N/R N/R

Choline N/R N/R N/R

N/R = none reported

4. Conceptual Model

There is potential for exposure to terrestrial and aquatic organisms from the labeled uses of 2,4-D

(Figure 1). The environmental fate properties indicate that exposures may result through spray 

drift, runoff, volatilization, wet/dry deposition, and leaching to ground water. The Screening 

Imbibition Program (SIP) model indicates that exposure to 2,4-D through drinking water may be 

a potential concern for birds and mammals. The Screening Tool for Inhalation Risk (STIR) 

model indicates that exposure via inhalation is not likely significant for mammals or birds.

The hypothesis for testing by risk assessment methods for each existing and proposed 2,4-D use 

is “2,4-D, used in accordance with the label, produces adverse effects on individual survival, 

growth, or reproduction in terrestrial vertebrates, terrestrial invertebrates, terrestrial plants, 

aquatic vertebrates, aquatic invertebrates, or aquatic plants.”
Page 23 of 85

Stressors

2,4-D products applied to use site 

Transport

Pathways

Spray 

Drift

Exposure

Media

Exposure 

Route

Ingestion/

Inhalation

Direct contact/

Root Uptake

Direct contact/

Root Uptake

Gill/ Integument 

Uptake

Receptors

Attribute

Changes

Birds/ Mammals/ Insects Terrestrial

Plants

Acute Effects

•Mortality

Aquatic Invertebrates

Aquatic Vertebrates

Amphibians 

Wetland/ Riparian

Plants/Aquatic plant

Individual Plants

• Seedling emergence

• Vegetative vigor

Terrestrial

Aquatic

Volatilization and 

Atmospheric transport

and deposition

Leaching to 

groundwater

Terrestrial Environment Aquatic Environment

Chronic Effects

•Reproduction

•Growth

•Survival

Acute Effects

•Mortality

Chronic Effects

•Reproduction

•Growth

•Survival

Chronic Effects

•Reproduction

•Growth

•Survival

Source/

In-situ deposition

(Soil and Foliage)

Runoff

Airplant 

transfer

Exposure Routes for 2,4-D

Figure 1. Aquatic and terrestrial exposure conceptual model
Page 24 of 85

5. Analysis Plan 

This analysis plan will be revisited and may be revised depending upon a full review of the data 

available in the open literature and the information submitted by the public in response to the 

opening of the registration review docket.

5.1. Stressors of Concern

The stressors of ecological concern for terrestrial and aquatic organisms are the 10 forms of 2,4-

D. Submitted ecological studies indicate that the ester forms for 2,4-D are generally more toxic 

to aquatic organisms than the salt, amine, and acid forms. Consequently, the esters will be 

considered separately for aquatic organisms, as has been done in recent risk assessments 

(USEPA 2005a and 2009). For terrestrial scenarios, the most sensitive endpoint, regardless of 

the 2,4-D form (ester, salt, amine, acid) will be used in the risk assessment. 

Several major degradates (1,2,4-benzenetriol, 2,4-DCP and CHQ) of 2,4-D (Table 5) were 

detected in submitted environmental fate studies. With the exception of 2,4-DCP (a maximum of 

3.5% of applied), the degradates were not detected in the terrestrial environment. The 1,2,4-

benzenetriol degradate was eliminated from concern because it is formed only via aqueous 

photolysis. It may be less likely to occur in many environments as degradation of 2,4-D, which

appears to be dependent primarily on oxidative microbial-mediated mineralization. The exposure 

of CHQ in the environment is likely to be low since it formed in aerobic aquatic environments to 

a significant extent only on day 27, and, from that point, dissipation was rapid (half-life of 5 

days). Although 2,4-DCP is a minor degradate in terrestrial environment, it is a major degradate 

(<32%) under anaerobic aquatic conditions. 2,4-DCP is also a product impurity of 2,4-D. There 

are some toxicity data of 2,4-DCP available in the ECOTOX (http://cfpub.epa.gov/ecotox/), 

which suggest it is more toxic than 2,4-D for selected aquatic organisms. Therefore, 2,4-D (acid, 

salts, and esters) as well as its degradate, 2,4-DCP will be considered as stressors of concern in 

ecological risk assessment.

Polychloro dibenzo-p-dioxin (PCDD) and polychloro dibenzo-p-furans (PCDF) may be formed 

during the manufacture of 2,4-D and can remain in the products as impurities. According to 2,4-

D registrants, since the 1990’s, the manufacturing processes for 2,4-D and its chemical 

intermediate, dichlorophenol, have been modified to reduce concentrations of PCDD and PCDF 

in the technical 2,4-D products. However, EFED will explore current data on impurities in 2,4-D 

and perform a similar ecological risk assessment to the one that was conducted in 2005 (US 

EPA, 2005b) for PCDD and PCDF, if warranted. 
Page 25 of 85

5.2. Measures of Exposure 

EFED will use standard available models to evaluate potential exposures to aquatic and 

terrestrial organisms. Screening level calculations for birds and mammals have suggested that 

the drinking water exposure pathway may be significant, but that the inhalation exposure 

pathway is unlikely to be significant (see Appendix B for a more detailed rationale). These 

exposure pathways may be further considered at the time of the risk assessment. The Agency is 

also aware of 2,4-D monitoring conducted in various environmental media by federal and state 

agencies. Routes of exposure will be considered in the assessment to the extent that data on 2,4-

D are available, based on the conceptual model (Figure 1).

5.3. Measures of Effect

Toxicity data presented in Section 3 of this problem formulation will be used to calculate risk 

quotients, which are calculated by dividing Estimated Environmental Concentrations (EECs) by 

the most sensitive toxicity value for a given taxon. Any additional information submitted by the 

registrant or found in the open literature prior to conduct of the risk assessment will also be 

considered. 

5.4. Drinking Water Assessment

If a revised drinking water assessment is warranted, EFED will conduct a drinking water 

assessment to support future human health dietary risk assessments of 2,4-D. The drinking water 

assessment will be performed based on EFED’s current guidance using appropriate surface and 

groundwater models. Descriptions of all executable versions of current models for drinking 

water exposure can be obtained from URL link below. 

http://www.epa.gov/oppefed1/models/water/

6. Endocrine Disruptor Screening Program

2,4-D was included in the first group of 67 chemicals issued an order to conduct Tier 1 EDSP 

testing (http://www.epa.gov/endo/pubs/prioritysetting/final_listfacts.htm). 

7. Preliminary Identification of Data Gaps 

7.1. Environmental Fate

Table 11 identifies environmental fate studies by MRID that offer data for each guideline 

requirement, as well as study classifications and whether or not further data are needed to 

support the risk assessment.
Page 26 of 85

Table 11. Submitted Environmental Fate Data for 2,4-D

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Sufficient 

for 

EFED?

Rationale for Additional Data Need

835.2120 Hydrolysis 41007301 Acceptable Yes Not Applicable

835.2240 Aqueous 

photolysis 41125306 Acceptable Yes Not Applicable

835.2410 Soil photolysis 41125305 Acceptable Yes Not Applicable

835.4100 Aerobic soil 

metabolism

43167501 Acceptable Yes Not Applicable 00116625

835.4200 Anaerobic soil 

metabolism --- --- ---

Submitted anaerobic aquatic study data 

showed that 2, 4-D is moderately 

persistent to persistent under anaerobic 

aquatic environment. Given the persistent 

nature of 2,4-D under anaerobic 

environment, an additional study may not 

provide new information on the 

persistence of this chemical.

835.4300 Aerobic aquatic 

metabolism

42045301 Acceptable Yes Not Applicable 44188601

835.4400

Anaerobic 

aquatic 

metabolism

43356001 Acceptable

42979201 Yes Not Applicable Supplemental

41557901

835.1230

835.1240

Adsorption/ 

desorption 

42045302

44117901 Acceptable Yes Not Applicable

00112937

Leaching 

00057313 Supplemental Yes Not Applicable

00080124 - Not Applicable

835.1410 Volatilitylaboratory 42059601 Acceptable Yes Not Applicable

835.8100 Volatility Field 48862902 --- In review

835.6100 Terrestrial field 

dissipation

43914701

Acceptable Yes Not Applicable

43762401

43762402

43514601

43533401

43864001

43592801

43762403

43763404

43640601
Page 27 of 85

Table 11. Submitted Environmental Fate Data for 2,4-D

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Sufficient 

for 

EFED?

Rationale for Additional Data Need

43831702

43872703

43849102

43831701

43705202

850.6100 Analytical 

method in soil No

An environmental chemistry method 

(ECM) in soil was not submitted in 

support of submitted terrestrial field 

dissipation studies. An independently 

validated environmental chemistry method 

as well as ECM in soil is necessary to 

evaluate the results of the most recently 

submitted terrestrial field dissipation 

study.

835.6200

850.6100

Aquatic field 

dissipation

43908302

43954701 Acceptable Yes Not Applicable

43491601

Analytical 

method in water

and sediment

42045301 Unacceptable No

The submitted study involves an aerobic 

aquatic metabolism evaluation of 14C-2,4-

D. Environmental chemistry method 

(ECM) and independent laboratory 

validation method (ILV) were not 

submitted. Therefore, ECM and ILV for 

2,4-D residues in water and sediment are 

required to support monitoring for 2,4-D 

residues and to evaluate submitted 

environmental fate and ecological effects 

data.

165-4 

(850.1730)

Fish 

bioconcentration --- ---- --- Waived for low Log Kow

Environmental Chemistry Methods and Associated Independent Laboratory Validation:

Guideline 850.6100

An independently validated environmental chemistry method for 2,4-D residues in soil, water 

and sediment has not been submitted by the registrant. Therefore, an environmental chemistry 

method for 2,4-D residues of concern in soil, water, and sediment as well as independent 

laboratory validation of the methods are required to support monitoring for 2,4-D residues and to 

evaluate newly submitted environmental fate and ecological effects data. Independently 

validated analytical methods for residues in soil, water, and sediment, and plant material 

(environmental chemistry methods) submitted by the registrant are used to evaluate analyses 

described in submitted environmental fate and ecological effects studies. Submitted analytical 

methods are also used by various federal, state, tribal, and local agencies to detect and monitor 

residues that are or are suspected to be in environmental compartments from outdoor uses and 

accidental releases. Independent laboratory validations for submitted analytical methods are 

necessary to confirm that the methods are functional and to confirm the levels of detection and 

quantitation reported in registrant-prepared validations.
Page 28 of 85

7.2. Effects

Tables 12 and 13 identify the ecological effects studies (most sensitive endpoints) by MRID that 

offer data for each guideline requirement, as well as study classifications and whether or not 

further data are needed to support risk assessment. Rationale for the additional data requested is 

presented below the tables.

Table 12. Aquatic Ecological Effects Data for 2,4-D

OCSPP

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Sufficient 

for 

EFED?

Rationale for Additional Data Need

850.1010 Freshwater 

invertebrate 

acute toxicity

41158301 

(non-ester)

Acceptable Yes

Not Applicable

43930601 

(ester)

850.1025

850.1035

850.1045

850.1055

Estuarine/marine 

invertebrate 

acute toxicity 

41429003 

(non-ester) Acceptable

Yes

Not Applicable

41835206

(ester) Supplemental

850.1075 Freshwater fish 

acute toxicity 

41975105

(non-ester)

Acceptable Yes

Not Applicable

43930701 

(ester)

850.1075 Estuarine/marine 

fish acute 

toxicity 

42018301 

(non-ester) Acceptable

Yes

Not Applicable

41835205 

(ester) Supplemental

850.1300 Freshwater 

invertebrate 

life cycle 

42018303 

(non-ester)

Acceptable Yes

Not Applicable

41353802 

(ester)

850.1350 Estuarine/marine 

invertebrates 

life cycle

N/A

N/A Yes

Although this is a data gap, EFED is not 

requesting data because 2,4-D is not 

expected to remain in the aquatic 

environment long enough to result in 

chronic exposures. 

850.1400 Freshwater fish 

early-life stage

41767701 

(non-ester) Acceptable Yes Not Applicable
Page 29 of 85

Table 12. Aquatic Ecological Effects Data for 2,4-D

OCSPP

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Sufficient 

for 

EFED?

Rationale for Additional Data Need

850.1400 Estuarine/marine 

fish 

early-life stage 

41345701 

(ester) Acceptable Yes

Not Applicable

850.1500 Freshwater fish 

life cycle 

41737305 

(ester) Supplemental Yes Not Applicable

850.4400 Aquatic plant 

growth:

Tier II vascular 

plants

42712204 

(non-ester)

Acceptable Yes Not Applicable 41735203 

(ester)

850.5400 Aquatic Plant 

Growth:

Tier II algae

41505903 

(non-ester)

Acceptable Yes Not Applicable 41735204 

(ester)

Table 13. Terrestrial Ecological Effects Data for 2,4-D

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Sufficient 

for 

EFED?

Rationale for Additional Data Need

850.2100 Avian oral 

toxicity

41644401 Acceptable No Acute oral toxicity data are necessary 

for a passerine species. 

850.2200 Avian dietary 

toxicity 

41644402 Acceptable Yes Not Applicable

41644403

850.2300 Avian 

reproduction

45336401 Acceptable Yes Although reproductive data are 

usually required for one upland game 

species and one waterfowl species, it 

is unlikely that the addition of a 

mallard duck reproductive study 

would change the risk picture. The 

oral and dietary studies have 

demonstrated that the bobwhite quail 

is more sensitive to 2,4-D than the 

mallard duck; thus the current 

reproductive study using bobwhite 

quail will be sufficient for ecological 

risk analysis.

850.3020 Honey bee 

acute contact 

toxicity

44517301 Acceptable Yes Not Applicable

NonguidelineHoney bee 

acute oral 

toxicity

44517302 Supplemental Yes Not Applicable
Page 30 of 85

Table 13. Terrestrial Ecological Effects Data for 2,4-D

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Sufficient 

for 

EFED?

Rationale for Additional Data Need

NonguidelineHoney bee 

larval toxicity

(None) (N/A) No A honeybee larval toxicity test is 

necessary for screening level 

assessments.

850.3030 Honey bee 

residue on 

foliage

(None) (N/A) Yes Not Applicable

850.3040 Field testing 

for pollinators

(None) (N/A) Yes Not Applicable

850.4100 Terrestrial 

plant toxicity:

Tier II 

seedling 

emergence

439821011 Acceptable Yes Not Applicable

850.4150 Terrestrial 

plant toxicity:

Tier II 

vegetative 

vigor

424168011 Acceptable Yes Not Applicable

47106004

1

TEP studies are also available, but yielded less sensitive toxicity endpoints.

The following terrestrial toxicity data are needed for the 2,4-D ecological effects assessment:

Avian Acute Oral Toxicity Test (Passerine Species): Guideline 850.2100

Acute avian oral toxicity data are required for either one waterfowl or one upland game species 

and one passerine species under the 40 CFR Part 158 (2010) data requirements for conventional 

pesticides with outdoor uses (can be performed with any 2,4-D salt or ester). The lowest 

endpoint from submitted acute oral avian effects data shows an LD50 of > 218.7 mg ae/kg-bw for 

the bobwhite quail (MRID 41644401). Given that passerine species have higher metabolic rates 

because of their smaller sizes than either waterfowl or upland game bird species and because 

they may utilize different metabolic pathways, they may be more or less sensitive to 2,4-D. 

EPA’s California Red Legged Frog and RED assessments showed the level of concern was 

exceeded for birds. A passerine study protocol should be submitted for review by the Agency 

prior to initiation of the study. 

Honeybee Larval Toxicity Test: Non-Guideline

Honeybee larval toxicity data are needed to complete a screening level risk assessment for risks 

to honeybees. In combination with acute contact toxicity and acute oral toxicity data, the larval 

toxicity component ensures that exposure routes to representative life stages of honeybees have 

been considered. The assessment process is further described in the Pollinator White Paper 

(USEPA 2012b).
Page 31 of 85

7.3 Environmental Fate and Effects Data for Degradate, 

2,4-DCP

There are some toxicity data for 2,4-DCP available in the ECOTOX 

(http://cfpub.epa.gov/ecotox/), which suggest it is more toxic than 2,4-D for selected aquatic 

organisms. There have been no registrant submitted environmental effects studies for this 

degradate. Given that this degradate is relevant to aquatic environments, the Agency notes that 

there are multiple freshwater invertebrate and fish studies for 2,4-DCP in the ECOTOX database. 

The Agency plans to review these studies for the registration review risk assessment and 

incorporate toxicity information from this degradate, as appropriate. Some registrant-submitted 

information is available for the environmental fate of 2,4-DCP. The 2,4-DCP degradate was 

measured and reported in all 30 plus field and aquatic dissipation studies. The registrant and/or 

public is welcome to submit additional information that would validate 2,4-DCP's environmental 

fate and effects properties. In the case that the ECOTOX studies are not found to meet the 

Agency's criteria, conservative assumptions will be made about the fate properties and 

toxicological effects of 2,4-DCP, including the use of predictive models to generate appropriate 

data. The Agency would be interested in any public perspective regarding the availability of data 

and its consistency with the Agency’s data evaluation criteria outlined in

http://www.epa.gov/pesticides/science/efed/policy_guidance/team_authors/endangered_species_

reregistration_workgroup/esa_evaluation_open_literature.htm

8. References 

MRID Citation

Environmental Fate and Product Chemistry Studies

00116625 McCall, P, S. Vrona, and S. Kelley. 1981. Fate of uniformly carbon-14 ring - labeled 2,4,5-

trichlorophenoxyacetic acid and 2,4-dichl orophenoxyacetic acid. Source unknown. Also In 

unpublished submission received Oct. 21, 1982 under 11683-EX-2; submitted U.S. Dept. of the 

Interior, Washington, DC; CDL: 248614-U.

41007301 Tamma, Rama V. and Samuel P. Cohen. 1989. Hydrolysis of 2,4,-D In Aqueous Solutions 

Buffered at pH 5, 7, and 9. Submitted by Industry Task Force on 2,4-D Research Data. Performed 

by Center for s - Hazardous Materials Research, Pittsburgh, PA.

41125305 Tamma, Rama V. and Samuel P. Cohen. 1989. Photodegradation of 2,4- Dichlorophenoxyacetic 

Acid on Soil. Submitted by Industry Task Force on 2,4-D Research Data. Performed by Center for 

Hazardous Materials Research, Pittsburgh, PA

41125306 Cohen, Samuel P. and Rama V. Tamma. 1989. Aqueous Photodegradation of 2,4 

Dichlorophenoxyacetic Acid in pH 7 Buffer Solution. Submitted by Industry Task Force on 2,4-D 

Research Data. Performed by Center for Hazardous Materials Research, Pittsburgh, PA.

41557901 Levine, A. (1990) Anaerobic Aquatic Metabolism of 2,4-Dichlorophenoxyacetic Acid: Lab 

Project Number: 002/001/007/88. Unpublished study prepared by Center for Hazardous Materials 

Research. Transmittal of 1 study.

42045301 Cohen, Samuel P. 19151. Aerobic Aquatic Metabolism of 2,4-Dichlorophenoxyacetic Acid. 

Submitted by Industry Task Force on 2,4-D Research Data. Performed by Center for

Hazardous Materials Research, Pittsburgh, PA

42045302 Cohen Samuel. 1989. Mobility of Unaged 2,4-Dichlorophenoxyacetic Acid Using Batch 

Equilibrium Technique. Submitted by Industry Task Force on 2,4-D Research Data. Performed by 

Center for Hazardous Materials Research, Pittsburgh, PA.
Page 32 of 85

MRID Citation

42059601 Doyle, R. (1991) Laboratory Volatility of the 2-Ethylhexyl Ester of 2,4-Dichloro-phenoxyacetic 

Acid: Lab Project Number: T08037T601. Unpublished study prepared by IIT Research Institute. 

257 p.

42979201 Concha, Marian and Kathryn Shepler, 1993. Aerobic Aquatic Metabolism of [14c] 2,4-D. 

Performed by PTRL-West, Inc. Richmond, CA. Submitted by Industry Task Force I1 on 2,4-D

Research Data c/o DowElanco, Indianapolis, IN.

43167501 Concha, Marian, and Kathryn Shepler. 1994. Aerobic Soil Metabolism of [14c] -2 , 4-

Dichlorophenoxyacetic Acid. Performed by PTRL-West, Inc. Richmond, CA. Submitted by 

Industry Task Force I1 on 2,4-D Research Data c/o DowElanco, Indianapolis, IN.

43356001 Concha, Marian and Kathryn Shepler. 1993. Anaerobic Aquatic Metabolism of [14C] 2 , 4-D. 

Performed by PTRL-West, Inc . Richmond, CA. Submitted by Industry Task Force I1 on 2,4-D 

Research Data c/o DowElanco, Indianapolis, IN.

43491601 Barney, W. (1994) Aquatic Field Dissipation Study of 2,4-D DMAS in Louisiana: Lab Project 

Number: 2001RI: F93154-032: F93309-517. Unpublished study prepared by Environmental 

Technologies Institute, Inc. 580p

43514601 Silvoy, J. (1995) Terrestrial Field Dissipation Study of 2,4-D 2-EHE on Bare Soil in Colorado: 

Lab Project Number: 2000WH03-COLORADO: SC930169: RAM 8862-93-001. Unpublished 

study prepared by ETI; Agvise; and A&L Labs, Inc. 780 p.

43533401 Silvoy, J. J. 1995. Terrestrial field dissipation study of 2,4-D 2-EHE on wheat in Colorado.

Study No. 2000WH07-Colorado. Unpublished study performed by Environmental Technologies

Institute, Inc., Research Triangle Park, NC (field phase); AGVISE Laboratories, Inc., Northwood,

ND (processing phase); Battelle Memorial Institute, Columbus, OH; and A&L Laboratories, Inc.,

Fort Wayne, IN (analytical phases); and submitted by Industry Task Force I1 on 2,4-D Research

Data.

43592801 Barney, W. P. 1995. Terrestrial field dissipation study of 2,4-D 2-EHE on bare soil in North

Carolina. Study No: 2000WH04. Unpublished study performed by ETI, Inc., Research Triangle

Park, NC (in-life phase); DowElanco, Indianapolis, IN; and AGVISE Laboratories, Inc.,

Northwood, ND (processing phase); Battelle Memorial Institute, Columbus, OH; and A & L

Great Lakes Laboratories, Inc., Fort Wayne, IN (analytical phase); and submitted by Industry

Task Force I1 on 2,4-D Research Data.

43640601 Barney, W.P. 1995. Terrestrial field dissipation study of 2,4-D 2-EHE on wheat in North

Carolina. ETI Study No. 2000WH08. Unpublished study performed by Environmental

Technologies Institute, Inc., Research Triangle Park, NC (field phase); AGVISE Laboratories,

Inc., Northwood, ND (processing phase); Battelle Memorial Institute, Columbus, OH; and A&L

Great Lakes Laboratories, Inc., Fort Wayne, lN (analytical phases); and submitted by Industry

Task Force I1 on 2,4-D Research Data.

43705202 Barney, W.P. 1995. Terrestrial field dissipation study of 2,4-D 2-EHE on pasture in Texas. ETI

Study Number: 2000PA04. Minnesota Valley Testing Laboratory Number: 10-9305-04.

Unpublished study performed by Environmental Technology Institute, Inc. (ETI), Research

Triangle Park, NC (field phase); AGVISE Laboratories, Northwood, ND (processing phase);

A&L Great Lakes Laboratories, Fort Wayne, IN; and Minnesota Valley Testing Labs, New Ulm,

MN (analytical phases); and submitted by Industry Task Force I1 on 2,4-D Research Data.

43762401 Hatfield, M.W. 1995. Field soil dissipation of the 2-ethylhexyl ester of 2,4-D in pasture in

California. AASI Study No. AA940017, Agvise Project No. RES94002, HWI Study No. 6397-

140. Unpublished study performed by American Agricultural Services, Cary, NC (in-life phase);

AGVISE Laboratories, Northwood, ND (processing phase), and Hazleton Wisconsin, Inc.,

Madison, WI (analytical phase); and submitted by The Industry Task Force I1 on 2,4-D Research

Data, c/o DowElanco, Indianapolis, IN.

43762402 Hatfield, M. W. 1995. Field soil dissipation of the 2-ethylhexyl ester of 2,4-D in turf in

California. AASI Study No. AA940019, Agvise Project No. RES94004, HWI Study No. 6397-

142. Unpublished study performed by American Agricultural Services, Cary, NC (in-life phase);

AGVISE Laboratories, Northwood ND (processing phase), and Hazleton Wisconsin, Inc.,

Madison Wisconsin (analytical phase); and submitted by the Industry Task Force I1 on 2,4-D

Research Data, c/o DowElanco, Indianapolis, IN.
Page 33 of 85

MRID Citation

43762403 Barney, W.P. 1995. Terrestrial field dissipation study of 2,4-D 2-EHE on bare soil in North

Carolina: conducted according to a turf use pattern. Laboratory Project ID: 2000BS04.

Unpublished study performed by ETI, Inc. Research Triangle Park, NC (in-life phase); AGVISE

Laboratories, Northwood, ND and DowElanco, Indianapolis IN (processing phase), and

McKenzie Laboratories Phoenix, AZ and A & L Great Lakes Laboratories, Inc., Fort Wayne, IN

(analytical phase); and submitted by The Industry Task Force I1 on 2,4-D Research Data, c/o

DowElanco, Indianapolis, IN.

43762404 Barney, W.P. 1995. Terrestrial field dissipation study of 2,4-D 2-EHE on turf in North Carolina.

Laboratory Project ID: 2000TF04. Unpublished study performed by ETI, Inc. Research Triangle

Park, NC (in-life phase); AGVISE Laboratories, Northwood, ND and DowElanco, Indianapolis

IN (processing phase), and McKenzie Laboratories Phoenix, AZ and A & L Great Laltes

Laboratories, Inc., Fort Wayne, IN (analytical phase); and submitted by The Industry Task Force

I1 on 2,4-D Research Data, c/o DowElanco, Indianapolis, IN.

43831701 Hatfield, M. (1995) Field Soil Dissipation of the 2-Ethylhexyl Ester of 2,4-D Granules on Turf in 

Ohio: Final Report: Lab Project Number: AA940024: 6397- 147: RES94011. Unpublished study 

prepared by American Agricultural Services, Inc.; Agvise, Inc.; and Hazleton Wisconsin, Inc. 513 

p.

43831702 Hatfield, M. (1995) Field Soil Dissipation of the 2-Ethylhexyl Ester of 2,4-D on Bare Soil in a 

Wheat Use Pattern in North Dakota: Final Report: Lab Project Number: AA940015: 6397-138: 

RES94022. Unpublished study prepared by American Agricultural Services, Inc.; Agvise, Inc.; 

and Hazleton Wisconsin, Inc. 445 p.

43849102 Hatfield, M. W. 1995. Field soil dissipation of the 2-ethylhexyl ester of 2,4-D on bare soil

in a corn use pattern in Ohio. AASI Study No. AA940013, Agvise Project No. RES94010,

HWI Study No. 6397- 136. Unpublished study performed by American Agricultural Services,

Inc., Cary, NC (in-life phase); AGVISE Laboratories, Northwood, ND (processing phase), and

Hazleton Wisconsin, Inc., Madison, WI (analytical phase); and submitted by the Industry Task

Force I1 on 2,4-D Research Data, c/o DowElanco, Indianapolis, IN.

43864001 Hatfield, M. W. 1995. Field soil dissipation of the 2-ethylhexyl ester of 2,4-D on bare soil in a

corn use pattern in Nebraska. Study No. AA40011, 6397-134, RES94008. Unpublished study 

performed by American

Agricultural Services, Inc., Cary, NC (in-life phase); AGVISE Laboratories, Northwood, ND

(processing phase); and Hazleton Wisconsin, Inc., Madison, WI (analytical phase); and submitted

by Industry Task Force I1 on 2,4-D Research Data.

43872703 Hatfield, M. W. 1995. Field soil dissipation of the 2-ethylhexyl ester of 2,4-D granules on bare

ground in Ohio. Study No. AA940025, 6397-148, RES94012. Unpublished study performed by 

American Agricultural

Services, Inc., Cary, NC (in-life phase); Agvise Laboratories, Northwood, ND (processing

phase); and Hazleton Wisconsin, Inc., Madison, WI (analytical phase); and submitted by the

Industry Task Force I1 on 2,4-D Research Data, c/o DowElanco, Indianapolis, IN.

43908302 Hatfield, M.W. 1995. Aquatic dissipation of the dimethylamine salt of 2,4-D in a small pond in 

North Dakota. American Ag; AGVISE; Hazleton, Wisconsin. Study number AA940027; 6397-

150; RES94027.

43914701 Hatfield, M. W. 1995. Field soil dissipation of the 2-ethylhexyl ester of 2,4-D in bare ground in

California. Study No. AA94002, 6397-144, RES94006. Unpublished study performed by 

American Agricultural

Services, Inc., Cary, NC (in-life phase); AGVISE Laboratories, Northwood, ND (processing

phase); and Hazleton Wisconsin, Inc., Madison, WI (analytical phase); and submitted by Industry

Task Force I1 on 2,4-D Research Data.

43927101 Barney, W. (1996) Forest Field Dissipation Study of 2,4-Dichlorophenoxyacetic Acid, Isooctyl (2-

Ethylhexyl) Ester in Georgia: Lab Project Number: 2002FO02: F93356-533: F93312-510. 

Unpublished study prepared by Environmental Technologies Institute, Inc. 1355 p.
Page 34 of 85

MRID Citation

43954701 Hatfield, M. (1995) Aquatic Dissipation of the Dimethylamine Salt of 2,4-D in a Small Pond in 

North Carolina: Final Report: Lab Project Number: RES94026: RES944226: HWI6397-149. 

Unpublished study prepared by Agvise Labs; Hazleton Wisconsin, Inc.; and American 

Agricultural Services, Inc. 713 p.

44105201 Fathulla, R. (1996) The Adsorption and Desorption of (carbon 14)-2,4-DCP on Representative 

Agricultural Soils: Lab Project Number: CHW 6397-168. Unpublished study prepared by Corning 

Hazleton Inc. 82 p.

44117901 Fathulla, R. (1996) The Adsorption and Desorption of (carbon 14)-2,4-D on Representative 

Agricultural Soils: Final Report: Lab Project Number: CHW 6397-166. Unpublished study 

prepared by Corning Hazleton Inc. 84 p.

44158501 Fathulla, R. (1996) The Adsorption and Desorption of (carbon 14)-2,4-DCA on Representative 

Agricultural Soils: Final Report: Lab Project Number: CHW 6397-170. Unpublished study 

prepared by Corning Hazleton, Inc. 84 p.

44188601 Fathulla, R. (1996) Aerobic Aquatic Metabolism of (carbon 14)-2,4-D: Final Report: Lab Project 

Number: CHW 6397-172. Unpublished study prepared by Corning Hazleton, Inc. 83 p.

47112202 Stoehr, C.M. (2007) Determination of physical and chemical characteristics and preliminary 

analyses of technical 2,4-D dichlorophenoxyacetic acid (2,4-D). Unpublished study prepared by 

EPL Bio Analytical Services. 176 p.

Ecological Effects Studies

00161660 Terrell, J.B. 1986. An acute inhalation toxicity study of 2,4-dichlorophenoxyacetic acid in the rat. 

Project number: 86-7893. Unpublished study prepared by Biodynamics, Inc.

41158301 Alexander, H.; Mayes, M.; Gersich, F. (1983) The Acute Toxicity of (2,4 -Dichlorophenoxy)acetic 

Acid to Representative Aquatic Organisms: Project Study ID: ES-DR-0002-2297-4. Unpublished 

study prepared by Dow Chemical U.S.A. 26 p.

41158306 Alexander, H., F. Gersich, M. Mayes, and S.L. Appelgath. 1983. The acute toxicity of (2,4-

dichlorophenoxy) acetic acid isooctyl ester to representative aquatic organisms. Performed by 

DOW Chemical USA for the Industry Task Force II on 2,4-D. Study ID: #ES-DR-0019-1208-3. 

41345701 Mayes, M.A., S.J. Gorzinski, D.W. Harms, C.H. Richardson,- and K.M. Lehr. 1989. 2,4-

Dichlorophenoxyacetic Acid, 2-Butoxyethyl Ester: Evaluation of the Toxicity to Early Life Stages 

of the Fathead Minnow, Pimephales promelas Rafinesque. Study ID No. ES-DR-0131-3037-1. 

Performed by Environmental Toxicology and Chemistry Research Laboratory, The Dow Chemical 

Company, Midland, MI. Submitted by Agricultural Products Dept., Dow Chemical USA.

41353801 Alexander, H.C., M.A. Mayes, F.M. Gersich, E.A. Bartlett, and S.L. Appelgath. 1983. 

Freshwater fish static acute toxicity test, coldwater species tested: rainbow trout (Salmo 

gairdneri), warmwater species tested: bluegill sunfish (Lepomis macrochirus) and fathead 

minnow (Pimphales promelus). Study no. ES-586. Performed by Environmental Toxicology and 

Chemistry Research Laboratory, The Dow chemical Company, Midland, MI. Submitted by The 

Dow Chemical Company.

41353802 Gersich, F.M., Gorzinski, S.J., Harms, D., Milazzo, D.P., and K.M. Lehr. 1989. Freshwater 

Invertebrate 21-Day Flow-through Life-cycle Toxicity Test, Species Tested: Daphnia magna. 

Study ID No. ES-DR-0131-3037-2. Performed by Environmental Toxicology and Chemistry 

Research Laboratory, The Dow Chemical Company, Midland, MI. Submitted by The Dow 

Chemical Company.

41413501 Berdasco, N.; Schuetz, D.; Jersey, G. et al. (1989) 2,4-Dichloro- phenoxyacetic Acid 

Triisopropanolamine Salt: Acute Oral Toxicity Study in Fischer 344 Rats: Lab Project Number: 

K-008866-002A. Unpublished study prepared by The Dow Chemical Co.

41429003 Dionne, E. 1990. (2,4-D IPA) - Acute Toxicity to Eastern Oyster (Crassostrea virginica) Under 

Flow-Through Conditions. SLI Report No. 89-11-3134. Dow Laboratory Project ID No. ES-2229. 

Performed by Springborn Laboratories, Inc., Wareham, Massachusetts. Submitted by The Dow 

Chemical Company, Midland, Michigan. 

41505903 Dimethylamine Salt to Navicula pelliculosa. Laboratory Project ID 0460-05-1100-5. Conducted 

by Malcolm Pirnie, Inc., Elmsford, NY. submitted by Industry Task Force II on 2,4-D Research 

Data, c/o DowElanco, Midland, MI.
Page 35 of 85

MRID Citation

41644401 Hoxter, K.A. 1990. 2,4-Dichlorophenoxyactic Acid, Triisorpropanolamine Salt: An Acute Oral 

Toxicity Study With The Northern Bobwhite. Performing Laboratory; Wildlife International Ltd. 

Easton, MD. Study Sponsor; Dow chemical Company, Midland, MI.

41644402 Hoxter, K.A. 1990. 2,4-Dichlorophenoxyacetic Acid, Triisopropanolamine Salt: A Dietary LC50 

Study With The Northern Bobwhite. Performing Laboratory; Wildlife International Ltd. Easton, 

MD. Study Sponsor; Dow Chemical Company, Midland, MI.

41644403 Hoxter, K.A. 1990. 2,4-Dichlorophenoxyacetic Acid, Triisopropanolamine Salt: A Dietary LC50 

Study With The Mallard. Performing Laboratory; Wildlife International Ltd. Easton, MD. Study 

Sponsor; Dow Chemical Company, Midland, MI.

41735203 Ester to Lemna gibba G3. Laboratory Project ID B460-07-4. Conducted by Malcolm Pirnie, Inc., 

Elmsford, NY. Submitted by Industry Task Force I1 on 2,4-D Research Data, c/o DowElanco, 

Indianapolis, IN.

41735204 Hughes, J.S. 1990. The Toxicity of 2,4-D 2-Ethylhexyl Ester to Skeletonema costatum. Laboratory 

Project ID B460-07-3. Conducted by Malcolm Pirnie, Inc., Elmsford, NY. Submitted by Industry 

Task Force I1 on 2,4-D Research Data, c/o DowElanco, Indianapolis IN.

41737305 Mayes, M.A., S.J. Gorzinski, R.B. Potter, and C.H. Richardson. 1990. 2,4-Dichlorophenoxyacetic 

Acid (2-Ethylhexyl Ester): Evaluation of the Toxicity to Early Life Stages of the Fathead Minnow, 

Pimephales promelas Rafinesque. Laboratory Project Study ID. ES-DR-0019-1208-7. Prepared 

by The Dow Chemical Company, Environmental Toxicology and Chemistry Research Laboratory, 

Midland, MI. Submitted by Industry Task Force I1 on 2,4-D Research Data.

41767701 Dill, D.C., S.J. Gorzinski, R.B. Potter, C.H. Richardson, and D.C. Stahl. 1990. 2,4-

dichlorophenoxyacetic Acid Dimethylamine Salt: Evaluation of the Toxicity to Early Life Stages 

of the Fathead Minnow, Pimphales promelas Rafinesque. Laboratory Project Study ID No. ESDR-0008-3556-4. Performed by the Dow Chemical Company, Midland, Michigan. submitted by 

the Industry Task Force I1 on 2,4-D Research Data, DowElanco, Indianapolis, Indiana.

41835205 Ward, T.J. and R.L. Boeri. 1991. Acute Flow- Through Toxicity of 2,4-D, 2-Ethylhexyl Ester to 

the Tidewater Silverside, Menidia beryllina. EnviroSystems Study No. 9035-D. Prepared by 

EnviroSystems Division, Resource Analysts, Inc., Hampton, NH. Submitted by Industry Task 

Force I1 on 2,4-D Research Data.

41835206 Ward, T.J. and R.L. Boeri. 1991. Acute Flow- Through Toxicity of 2,4-D, 2-Ethylhexyl Ester to 

the Grass Shrimp, Palaemonetes pugio. EnviroSystems Study No. 9036-D. Prepared by 

EnviroSystems Division, Resource Analysts, Inc., Hampton, NH. Submitted by Industry Task 

Force I1 on 2,4-D Research Data.

41975101 Campbell, Susan, Grimes, Jennie and Smith, Gregory. Diethanolamine salt of 2,4-D: An acute 

oral toxicity study with the Northern bobwhite. Wildlife International, 305 Commerce Drive, 

Easton, MD for PBI Gordon, 1217 West 12 St., P.O. Box 4090, Kansas City, MO 64101. Study 

ID#281-109.

41975105 Graves, William C., and Peters, Gregory T. 2,4-D diethanolamine salt: A 96-hour flow-through 

acute toxicity test with the rainbow trout, Oncorhvnchus mvkiss. Performed by Wildlife 

International, 305 Commerce Drive, Easton, MD 21601 for the PBI Gordon, 1217 West 12 St., PO 

Box 4090, Kansas City, MO. WI study ID #281A-101A.

42018301 Graves, W.C. and G.T. Peters. 1991. Diethanolamine Salt of 2,4-D: A 96-Hour Flow-Through 

Acute Toxicity Test with the Atlantic Silverside (Menidia menidia). Project No. 281A-102A. 

Prepared by Wildlife International Ltd., Easton, MD. Submitted by PBI/Gordon Corporation, 

Kansas City, MO.

42018303 Holmes, C.M. and G.T. Peters. 1991. Diethanolamine Salt of 2,4-D: A Flow-Through Life-Cycle

Toxicity Test with the Cladoceran (Daphnia magna). Project No. 281A-106. Prepared by Wildlife 

International Ltd., Easton, MD. Submitted by PBI/Gordon Corporation, Kansas City, MO.

42389501 Backus, P. and K. Crosby. 1992. Effect of 2,4-D DMAS on seed germination/seedling emergence 

(tier II). Laboratory project ID No. 90-0407. Conducted by Ricerca Inc., Painesville, OH. 

Submitted by Industry Task Force II on 2,4-D Research Data.

42416801 Backus, P. (1992) Effect of 2,4-D Acid on Vegetative Vigor of Plants: Tier II: Lab Project 

Number: 91-0390: 5097-91-0390-BE-001. Unpublished study prepared by Ricerca, Inc. 124 p.
Page 36 of 85

MRID Citation

42712204 Thompson, Susan G. and James P. Swigert. 1993. Diethanolamine Salt of 2,4-D: A 14-Day 

Toxicity Test With Duckweed (Lemna gibba G3). Wildlife International, Ltd. Project No. 281A116.

43930601 Drotter, K. R., and J. P. Swigert. 1996. 2,4-D isopropyl ester: a 48-hour flow-through acute 

toxicity test with the cladoceran (Daphnia magna). Performed by Wildlife International, Ltd., 

Easton, MD. Sponsored by California Citrus Quality Council, Diamond Bar, CA. Laboratory 

Report ID 435A-104A. 

43930701 Drotter, K. R., and J. P. Swigert. 1996. 2,4-D isopropyl ester: a 96-hour flow-through acute 

toxicity test with the bluegill (Lepomis macrochirus). Performed by Wildlife International, Ltd., 

Easton, MD. Sponsored by California Citrus Quality Council, Diamond Bar, CA. Laboratory 

Report ID 435A-105. 

43954702 Barney, W. 1995. Forest field dissipation study of 2,4-dichlorophenoxyacetic acid dimethylamine 

salt in Oregon. Environmental Technologies Institute, Inc.; Collins Ag Consultants; AGVISE. 

Study number 2002FO01: F9331-523: F9331-527.

43982101 Hoberg, J.R. 1996. 2,4-D Isopropyl Ester - Determination of Effects on Seed Germination, 

Seedling Emergence and Vegetative Vigor of Ten Plant Species. Performed by Springborn 

Laboratories, Inc., Wareham, MA. Sponsored by California Citrus Quality Council, Diamond 

Bar, CA. Laboratory Report ID 96-2-6356.

44517301 Palmer, S. J., and H, Krueger. 1997. An acute contact toxicity study with the honey bee. 

Performed by Wildlife International. Easton, MD. Sponsored by Industry Task Force II on 2,4-D 

Research Data, DowElanco, Indianapolis, IN. Laboratory Report ID 467-104.

44517306 Palmer, S. J., and H, Krueger. 1997. 2,4-D diethylamine salt: a 96-hour static acute test with the 

leopard frog tadpoles (Rana pipiens). Performed by Wildlife International. Easton, MD. 

Sponsored by Industry Task Force II on 2,4-D Research Data, DowElanco, Indianapolis, IN. 

Laboratory Report ID 467A-103.

45336401 Mitchell et al. 2000. 2,4-D Acid: a reproduction study with the northern bobwhite. Performed 

by Wildlife International, Easton, Md. Sponsored by the 2,4-D Working Group via Nufarm 

GmbH and Company KG, Linz, Austria. Laboratory report ID 467-106.

47106001 Porch, J.R., H.O. Krueger, and K.H. Martin. 2006. 2,4-D dimethylamine salt: a toxicity test to 

determine the effects of the test substance on the seedling emergence test of ten species of plants. 

Unpublished study performed by Wildlife International, Ltd., Easton, MD. Laboratory report 

number 467-111. Study submitted to Industry Task Force II on 2,4-D Research Data, c/o 

McKenna Long & Aldridge, LLP, Washington, DC. Study completed April 10, 2006.

47106002 Porch, J.R., H.O. Krueger, and K.H. Martin. 2006. 2,4-D dimethylamine salt: a toxicity test to 

determine the effects of the test substance on the vegetative vigor of ten species of plants grown 

under greenhouse conditions. Unpublished study performed by Wildlife International, Ltd., 

Easton, MD. Laboratory report number 467-112. Study submitted to Industry Task force II on 

2,4-D Research Data, c/o McKenna Long & Aldridge, LLP, Washington, DC. Study completed 

April 11, 2006.

47106003 Porch, John R., H.O. Krueger, and K.H. Martin. 2006. 2,4-D 2-ethylhexyl ester (2,4-D 2-EHE): 

a toxicity test to determine the effects of the test substance on seedling emergence of ten species of 

plants. Unpublished study performed by Wildlife International, Ltd., Easton, MD. Laboratory 

report number 467-107. Study submitted to Industry Task Force II on 2,4-D Research Data, c/o 

McKenna Long & Aldridge, LLP, Washington, DC. Study completed April 10, 2006.

47106004 Porch, John R., H.O. Krueger and K.H. Martin. 2006. 2,4-D 2-Ethylhexyl Ester (2,4-D 2-EHE): A

Toxicity Test to Determine the Effects of the Test Substance on Vegetative Vigor of Ten Species 

of Plants Grown Under Greenhouse Conditions. Unpublished study performed by Wildlife 

International, Ltd., Easton, MD. Laboratory report number 467-108. Study submitted to Industry 

Task Force II on 2,4-D Research Data, c/o McKenna Long & Aldridge, LLP, Washington, DC. 

Study completed April 10, 2006.

47972101 Marty, MS; Zablotny, CL; Andrus, AK; et al. (2010) 2, 4-D: An Extended One Generation Dietary 

Toxicity Study in Crl:CD(SD) Rats. Toxicology & Environmental Research and Consulting. The 

Dow Chemical Company. Laboratory Project Study ID 081104, January 30, 2010. MRID 

47972101. Unpublished.
Page 37 of 85

Gibson, L. R. and M. Liebman. 2002. Course Material for Principles of Weed Science, 

Agronomy 317, Iowa State University. Website accessed 15 July 2003, 

http://www.agron.iastate.edu/courses/Agron317/Herbicide_mode_of_action.htm. 

Hoeppel RE; Westerdahl HE. 1983. Dissipation of 2,4-D DMA and BEE from water, mud, and 

fish at Lake Seminole, Georgia. Jour. Am. Water Res. Asso.: 19: 197-204.

Industry Task Force II on 2,4-D Research Data and IR-4. 2012. Master label for registration 

review 2,4-dichlorophenoxyacetic acid uses. 2,4-D Industry and IR-4, May 2012.

Rice, C. P.; Chernyak, S. M.; McConnell, L. L. 1997. Henry’s Law Constants for Pesticides 

Measured as a Function of Temperature and Salinity. J. Agric. Chem. 45, 2291-2298.

USEPA. 2004. Revised Environmental Fate and Effects Division Revised Preliminary Risk

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

Decision Document.

USEPA. 2005a. Reregistration Eligibility Decision for 2,4-D. Office of Prevention, Pesticides 

and Toxic Substances, (7508C) EPA 738-R-05-002 June 2005.

U.S. EPA 2005b. Revised Screening level ecological risk assessment of polychlorinated 

dibenzodioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) contaminants from 

technical products of 2,4-dichlorophenoxyacetic acid (2,4-D). Confidential memo.

USEPA. 2009. Risk of 2,4-D Use to the Federally Threatened California Red-legged Frog 

(Rana aurora draytonii) and Alameda Whipsnake (Masticophis lateralis euryxanthus). 

Office of Pesticide Programs, Washington, DC.

USEPA. 2012a. BEAD chemical profile for registration review: 2,4-D chemical case. 

Biological and Economic Analysis Division, Office of Pesticide Programs, United State 

Environmental Protection Agency, Washington, DC.

USEPA. 2012b. White paper in support of the proposed risk assessment process for bees. 

Environmental Protection Agency, Health Canada, and California Department of 

Pesticide Regulation
Page 38 of 85

APPENDIX A

Physical Parameters of 2,4-D and Its Forms

Table A.1. Molecular weight ratio and chemical structure of registered 2,4-D forms

Active Ingredient and 

PC Code

Molecular Weight 

Ratio

Structure

2,4-D 

dichlorophenoxyacetic 

acid

030001 (2,4-D)

1.0

 

Sodium Salt of 2,4-D

030004 (2,4-D Na)

1.10

Choline Salt of 2,4-D 

051505 (Choline) 1.47

Amine Salts

Diethanolamine Salt of 

2,4-D

030016 (DEA)

1.48

O

Cl Cl

O

O-[NH2(CH2

CH2OH)

2]

+
Page 39 of 85

Table A.1. Molecular weight ratio and chemical structure of registered 2,4-D forms

Active Ingredient and 

PC Code

Molecular Weight 

Ratio

Structure

Dimethylamine Salt of 

2,4-D

030019 (DMA) 1.20

Isopropylamine Salt of 

2,4-D

030025 (IPA) 1.27

Triisopropanolamine 

Salt of 2,4-D

030035 (TIPA)

1.87

Esters

Butoxyethyl Ester of 

2,4-D

030053 (BEE)

1.45

Cl Cl

O O

O

-

[NH3

CH(CH3)

2]

+

O

Cl Cl

O

O

NH+(CH2CHOHCH3)3
Page 40 of 85

Table A.1. Molecular weight ratio and chemical structure of registered 2,4-D forms

Active Ingredient and 

PC Code

Molecular Weight 

Ratio

Structure

2-Ethylhexyl Ester of 

2,4-D

030063 (2-EHE)

1.51

Isopropyl Ester of 

2,4-D

030066 (IPE)

1.19

Table A.2. Selected physical chemical properties of various forms of 2,4-D1

PC Code 

Active 

Ingredient 

Molecular 

Formula and 

weight (g/mol)

Solubility 

(mg/L)

Density

(g/cm3) Log Kow

Vapor Pressure 

(mm Hg@ ≈25°C)

030001

2,4-D

C8H6Cl2O3

221.04 569 1.42 0.18 @pH 7.0 1.4 x 10-7

030004

2,4-D Na 

Salt

C8H5Cl2NaO3

243.02 4500 0.68 Na salt dissociate to acid

030016

2,4-D DEA 

salt

C12H17Cl2NO5

326.17 

806 0.76 2.24 x 10-2 <9.98 x 10-8

030019

2,4-D DMA 

salt

C10H13Cl2NO3

266.12 72900 1.23

DMA salt 

dissociate to 

acid and 

water

<1 x 10-7

030025

2,4-D IPA 

C11H15Cl2NO3

280.15 17400 1.15 IPA salt dissociate to acid
Page 41 of 85

Table A.2. Selected physical chemical properties of various forms of 2,4-D1

PC Code 

Active 

Ingredient 

Molecular 

Formula and 

weight (g/mol)

Solubility 

(mg/L)

Density

(g/cm3) Log Kow

Vapor Pressure 

(mm Hg@ ≈25°C)

salt

030035

2,4-D TIPA 

salt

C17H27Cl2NO6

412.31 46100 1.21 TIPA salt dissociate to acid

030053

2,4-D BEE

C14H18Cl2O4 

321.20 8.03 1.03 4.49 <1.0 x 10-7

030063

2,4-D EHE

C16H22Cl2O3

333.25 0.087 1.16 5.78 3.59X10-6

030066

2,4-D IPE C11H12Cl2O3 230 1.27 2.40 3.98 x 10-6

0515052

2,4-D 

Choline

C13H19Cl2NO4

324.7 NA 1.21 Choline salt dissociate to acid

1 Data assembled for 2005 RED (USEPA, 2005a) 2 MRID 482346-01

NA Not available 
Page 42 of 85

Appendix B

Screening Level Models to Evaluate Potential Importance of Drinking Water and 

Inhalation Exposure Pathways

SIP (Screening Imbibition Program, v1.0) was used to calculate an upper bound estimate of 2,4-

D exposure via drinking water using solubility of 2,4-D forms, the most sensitive acute and 

chronic avian toxicity endpoints (bobwhite quail, LD50 > 218.7 mg/kg-bw and NOAEC = 962 

mg ae/kg-diet) and the most sensitive acute and chronic mammalian toxicity endpoints (rat, LD50

= 405 mg/kg-bw and NOAEL = 5 mg/kg-bw). The model indicated that EHE (0.087 mg/L) and 

BEE (8.03 mg/L) do not present acute or chronic concerns for birds and mammals. All other 

2,4-D salts, amines, and esters present potential acute and chronic concerns for birds and 

mammals through drinking water exposure. Results for IPE (solubility = 230 mg/L) are 

presented in Tables B.1 and B.2; all other 2,4-D forms had higher solubility limits (2,4-D = 569 

mg/L; DEA = 806 mg/L; Na = 4500 mg/L; IPA = 17400 mg/L; TIPA 46100 mg/L; and DMA = 

72900 mg/L. 

Table B.1. SIP Avian Results for IPE

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 186.3000 186.3000

Adjusted toxicity value (mg/kg-bw) 157.5579 102.2590

Ratio of exposure to acute toxicity 1.1824 1.8218

Conclusion*

Exposure through drinking

water alone is a potential 

concern for birds

Exposure through drinking 

water alone is a potential 

concern for birds

Table B.2. SIP Mammalian Results for IPE

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 39.5600 39.5600

Adjusted toxicity value (mg/kg-bw) 311.5100 3.8458

Ratio of exposure to toxicity 0.1270 10.2865

Conclusion*

Exposure through drinking 

water alone is a potential 

concern for mammals

Exposure through drinking 

water alone is a potential 

concern for mammals

*Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. Therefore, when 

aggregated with other routes (i.e., diet, inhalation, dermal), pesticide exposure through drinking water may 

contribute to a total exposure that has the potential for additional effects to non-target animals.

STIR (Screening Tool for Inhalation Risk, v1.0) was used to calculate an upper bound estimate 

of 2,4-D exposure via inhalation using 2,4-D’s molecular weight (221.04 g/mole), vapor pressure 

(1.4 x 10-7 mmHg), highest non-granular application rate (4 lb ae/A), most sensitive acute avian 

toxicity endpoint (bobwhite quail, LD50 = 218.7 mg/kg-bw), and most sensitive acute oral and 

inhalation mammalian toxicity endpoints (rat, LD50 = 405 mg/kg-bw and 4 hr LC50 > 1.79 mg/L, 

respectively). Inhalation alone is not a potential pathway of concern for birds (droplet 

inhalation) for any of the 2,4-D forms (Table B.3 shows an example); exposure is not likely 
Page 43 of 85

significant for birds. The results for mammals also indicated no adverse effects from the 

inhalation exposure route (Table B.4). Exposure is not likely significant for mammals. 

Table B.3. STIR Avian (0.020 kg) Results for EHE

Maximum Vapor Concentration in Air at Saturation (mg/m3) 6.43E-02

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 8.09E-03

Adjusted Inhalation LD50 5.39E+00

Ratio of Vapor Dose to Adjusted Inhalation LD50 1.50E-03 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 3.84E-01

Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD50 7.13E-02 Exposure not Likely Significant

Table B.4. STIR Mammalian (0.15 kg) Results for EHE

Maximum Vapor Concentration in Air at Saturation (mg/m3) 6.43E-02

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 1.02E-02

Adjusted Inhalation LD50 1.07E+02

Ratio of Vapor Dose to Adjusted Inhalation LD50 9.54E-05 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 4.83E-01

Ratio of Droplet Inhalation Dose to Adjusted Inhalation 

LD50 4.53E-03 Exposure not Likely Significant
Page 44 of 85

Appendix C

Incident Information from the EIIS Database

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I000636-

017 Catfish Several 1987 MO Home/ lawn Registered High 

probability N/R No

Mortality caused 

by runoff into a 

pond

2,4-D I010581-

056 Grass Unknown 2000 NJ Turf, residential Registered Probable N/R Mecoprop

Plant damage 

caused by direct 

treatment

2,4-D I010581-

057 Grass 75% of lawn 2000 VA Turf, residential Registered Possible N/R DicambaMecoprop-P

Plant damage 

caused by direct 

treatment

2,4-D I010581-

060 Grass 95% of lawn 2000 NY Turf, residential Registered Possible N/R Mecoprop

Plant damage 

caused by direct 

treatment

2,4-D I010581-

062 Grass 50% of lawn 2000 CA Turf, residential Registered Possible N/R Mecoprop

Plant damage 

caused by direct 

treatment

2,4-D I009786-

013 Grass N/R 1999 FL Home/lawn Misuse Probable N/R Mecoprop

Plant damage 

caused by 

accidental 

treatment

2,4-D I009916-

014 Grass N/R 2000 PA Home/lawn Misuse Probable N/R No

Plant damage 

caused by 

accidental overapplication

2,4-D I010546-

001 Bluegrass 85% of 

lawn 2000 OH Home/lawn Misuse Probable N/R Dicamba

Mecoprop

Plant damage 

caused by 

accidental overapplication
Page 45 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I010546-

002 Bluegrass 60-70% of 

lawn 2000 NY Home/lawn Misuse Probable N/R Dicamba

Mecoprop

Mortality caused 

by overapplication

2,4-D I010581-

052 Grass 60-70% of 

lawn 2000 MD Turf, residential Registered Probable N/R Mecoprop 

Plant damage 

caused by direct 

treatment

2,4-D I010581-

054 Grass 60% of 

lawn 2000 CT Turf, residential Registered Probable N/R Dicamba

Mecoprop-P

Plant damage 

caused by direct 

treatment

2,4-D I009445-

052 Grass 50% of 

lawn 1999 IL Home/lawn Not 

determined Probable N/R No

Mortality caused 

by direct 

treatment

2,4-D I009445-

053 Grass 20-25% of lawn 1999 PA Home/lawn Not determined Probable N/R No

Mortality caused 

by direct 

treatment

2,4-D I009445-

054 Grass 50% of 

lawn 1999 NY Home/lawn Not 

determined Probable N/R No

Mortality caused 

by direct 

treatment

2,4-D I009445-

057 Grass N/R 1999 IL Home/lawn Registered Probable N/R No

Mortality caused 

by direct 

treatment

2,4-D I009786-

011 Grass 50% of 

lawn 1999 FL Home/lawn Misuse Probable N/R Mecoprop

Plant damage 

caused by direct 

treatment 

2,4-D I009786-

012 Grass All portions 

treated 2000 FL Home/lawn Misuse Probable N/R Mecoprop

Plant damage 

caused by 

accidental direct 

treatment

2,4-D I009445-

044 Grass 50% of 

lawn 1999 NY Home/lawn Misuse Probable N/R No

Mortality caused 

by accidental 

over-application

2,4-D I009445-

045 Grass N/R 1999 MI Home/lawn Not 

determined Probable N/R No

Mortality caused 

by direct 

treatment
Page 46 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I009445-

047 Grass 90% of 

lawn 1999 OR Home/lawn Not 

determined Probable N/R No

Mortality caused 

by direct 

treatment

2,4-D I009445-

049 Grass 90% of 

lawn 1999 CT Home/lawn Misuse Probable N/R No

Mortality caused 

by accidental 

over-application

2,4-D I009445-

050 Grass 90% of 

front lawn 1999 GA Home/lawn Not 

determined Probable N/R No

Mortality caused 

by direct 

treatment

2,4-D I009445-

051 Grass Unknown 1999 CT Home/lawn Not determined Probable N/R No

Mortality caused 

by direct 

treatment

2,4-D I009262-

064 Grass 60% of 

lawn 1999 NY Home/lawn Misuse Probable N/R No

Browning caused 

by direct 

treatment

2,4-D I009445-

039 Grass 85% of lawn 1999 MD Home/lawn Registered Probable N/R No

Mortality caused 

by direct 

treatment

2,4-D I009445-

040 Grass N/R 1999 FL Home/lawn Misuse Probable N/R No

Mortality caused 

by accidental 

over-application

2,4-D I009445-

041 Grass Unknown 1999 GA Home/lawn Not 

determined Probable N/R No

Mortality caused 

by direct 

treatment

2,4-D I009445-

042 Grass N/R 1999 Cana

da Home/lawn Registered Probable N/R No

Mortality caused 

by direct 

treatment

2,4-D I009445-

043 Grass 50% of 

lawn 1999 CT Home/lawn Registered Probable N/R No

Mortality caused 

by direct 

treatment

2,4-D I009262-

053 Grass 100% of 

lawn 1999 MA Home/lawn Misuse Probable N/R No

Browning caused 

by accidental 

over-application
Page 47 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I009262-

054 Grass N/R 1999 NJ Home/lawn Registered Probable N/R Pendimethalin

Browning caused 

b y direct 

application

2,4-D I009262-

057 Grass 50% of 

lawn 1999 MI Home/lawn Registered Probable N/R No

Browning caused 

by direct 

treatment

2,4-D I009262-

061 Grass 50% of 

lawn 1999 OH Home/lawn Misuse Probable N/R No

Plant damage 

caused by 

accidental overapplication

2,4-D I009262-

062 Grass 75% of 

lawn 1999 VA Home/lawn Registered Probable N/R No

Browning caused 

by direct 

treatment

2,4-D I009262-

063 Grass 95% of 

lawn 1999 IL Home/lawn Misuse Probable N/R No

Browning caused 

by direct 

treatment

2,4-D I009262-

047 Grass Unknown 1999 England Home/lawn Not determined Probable N/R No

Browning caused 

by direct 

treatment

2,4-D I009262-

048 Grass 50% of 

lawn 1999 MI Home/lawn Not 

determined Probable N/R No

Browning caused 

by direct 

treatment

2,4-D I009262-

049 Grass 90% of 

lawn 1999 NJ Home/lawn Not 

determined Probable N/R No

Browning caused 

by direct 

treatment

2,4-D I009262-

050 Grass 100% of 

lawn 1999 OH Home/lawn Not 

determined Probable N/R No

Browning caused 

by direct 

treatment

2,4-D I009262-

051 Grass 100% of 

lawn 1999 FL Home/lawn Misuse Probable N/R No

Browning caused 

by accidental 

direct treatment

2,4-D I009262-

052 Grass 50% of 

lawn 1999 TN Home/lawn Misuse Probable N/R No

Browning caused 

by accidental 

over-application
Page 48 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I009262-

040 Grass 50% of 

lawn 1999 NY Home/lawn Registered Probable N/R No

Browning caused 

by direct 

treatment

2,4-D I009262-

041 Grass 65% of 

lawn 1999 OH Home/lawn Registered Probable N/R No

Browning caused 

by direct 

treatment

2,4-D I009262-

042 Grass 50% of 

lawn 1999 FL Home/lawn Not 

determined Probable N/R No

Browning caused 

by direct 

treatment

2,4-D I009262-

043 Grass 85% of 

lawn 1999 SC Home/lawn Registered Probable N/R No

Browning caused 

by direct

treatment

2,4-D I009262-

045 Grass 100% of 

lawn 1999 PA Home/lawn Not 

determined Probable N/R No

Browning caused 

by direct 

treatment

2,4-D I009262-

046 Grass 50% of 

lawn 1999 FL Home/lawn Not 

determined Probable N/R No

Browning caused 

by direct 

treatment

2,4-D I009262-

034 Grass 90% of 

lawn 1999 OH Home/lawn Not 

determined Probable N/R No

Browning caused 

by direct 

treatment

2,4-D I009262-

035 Grass 60% of 

lawn 1999 NJ Home/lawn Not 

determined Probable N/R No

Browning caused 

by direct 

treatment

2,4-D I009262-

036 Grass 100% of 

front lawn 1999 NJ Home/lawn Registered Probable N/R No

Browning caused 

by direct 

treatment

2,4-D I009262-

037 Grass 750 ft2 1999 NY Home/lawn Misuse Probable N/R No

Browning caused 

by accidental 

over-application

2,4-D I009262-

039 Grass N/R 1999 MA Home/lawn Registered Probable N/R No

Browning caused 

by direct 

treatment
Page 49 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I007371-

030 Grass Unknown 1997 PA Turf, residential Registered Probable N/R No Plant damage caused by drift

2,4-D I007714-

001 Corn 20-30% of 

crop

1998 IL Agricultural 

area Registered Probable N/R Clopyralid

Flumetsulam

Plant damage 

caused by direct 

treatment

2,4-D I007750-

001 Corn 60 acres 1998 ND Corn Registered Probable N/R Clopyralid

Plant damage 

caused by direct 

treatment

2,4-D I007754-

001 Corn 56 acres 1998 IL Agricultural 

area Registered Probable N/R Flumetsulam

Clopyralid

Plant damage 

caused by direct 

treatment

2,4-D I007875-

001 Ornamental N/R 1991 WI Pasture Registered Probable N/R Triclopyr Plant damage 

caused by drift

2,4-D I008571-

031 Grass Unknown 1998 FL Home/lawn Not 

determined Probable N/R Mecoprop

Plant damage 

caused by direct 

treatment

2,4-D I006214-

012 Soybean Unknown 1997 IL Soybean Registered Probable N/R ClopyralidFlumetsulam

Plant damage 

caused by direct 

treatment

2,4-D I006442-

001 Corn N/R 1998 WI Field Registered Probable N/R Clopyralid

Flumetsulam

Incapacitation 

caused by direct 

treatment

2,4-D I006442-

002 Corn N/R 1998 NE Field Registered Probable N/R Clopyralid

Flumetsulam

Incapacitation 

caused by direct 

treatment

2,4-D I006442-

003 Corn N/R 1998 IL Field Registered Probable N/R Clopyralid

Flumetsulam

Incapacitation 

caused by direct 

treatment

2,4-D I007259-

001 Corn Unknown 1998 WI N/R Not 

determined Possible N/R Clopyralid

Flumetsulam Plant damage

2,4-D I006214-

005 Corn Unknown 1997 IA Corn Registered Probable N/R Clopyralid

Flumetsulam

Plant damage 

caused by direct 

treatment
Page 50 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I006214-

006 Corn Unknown 1997 IA Corn Registered Probable N/R Clopyralid

Flumetsulam

Plant damage 

caused by direct 

treatment

2,4-D I006214-

007 Corn Unknown 1997 IL Corn Registered Probable N/R ClopyralidFlumetsulam

Mortality caused 

by direct 

treatment

2,4-D I006214-

008 Corn Unknown 1997 IA Corn Registered Probable N/R Clopyralid

Flumetsulam

Plant damage 

caused by direct 

treatment

2,4-D I006214-

009 Corn Unknown 1997 MN Corn Registered Probable N/R Clopyralid

Flumetsulam

Plant damage 

caused by direct 

treatment

2,4-D I006130-

001 Willow oak N/R 1997 MS Agricultural 

area Registered Probable N/R No Plant damage 

caused by drift

2,4-D I006214-

001 Corn Unknown 1997 MN Corn Registered Probable N/R Clopyralid

Flumetsulam

Plant damage 

caused by direct 

treatment

2,4-D I006214-

002 Corn Unknown 1997 IA Corn Registered Probable N/R Clopyralid

Flumetsulam

Plant damage 

caused by direct 

treatment

2,4-D I006214-

003 Corn Unknown 1997 IA Corn Registered Probable N/R Clopyralid

Flumetsulam

Plant damage 

caused by direct 

treatment

2,4-D I006214-

004 Soybean Unknown 1997 IL Soybean Registered Probable N/R ClopyralidFlumetsulam

Plant damage 

caused by direct 

treatment

2,4-D I006214-

011 Corn Unknown 1997 MN Corn Registered Probable N/R Clopyralid

Flumetsulam

Plant damage 

caused by direct 

treatment

2,4-D I003826-

024 Unknown fish Unknown 1994 NC Agricultural 

area Registered Unlikely N/A

Pyrethrin I

Glyphosate 

isopropylamine salt

Mortality
Page 51 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I004374-

002

Bluegill

Largemouth bass

Bluegill –

150

Bass – N/R

1995 MO N/R Spill Unlikely

2,4-D was not 

found in the 

residue 

testing

Linuron

Pentachlorophenol

Mortality caused 

by runoff into 

pond

2,4-D I004668-

001 Unknown fish 600 fish 1996 LA N/R Misuse Probable N/R Bromacil Mortality caused 

by spill into river

2,4-D I004848-

001 Corn N/A 1996 IL Agricultural area Registered Probable N/R ClopyralidFlumetsulam

Stunted growth 

caused by direct 

treatment

2,4-D I005880-

046 Raspberry Unknown N/R WI Agricultural 

area Misuse Probable N/R Clomazone

Discoloration 

caused by drift 

(300 ft)

2,4-D I003578-

001 Cotton 1248 acres N/A CA Rice Misuse Probable N/R No

Plant damage 

caused by 

accidental drift

2,4-D I003601-

001

White sucker

Notropis minnow

American eel

Blacknose dace

Hundreds 1993 DE Stream Registered Probable N/R Bromacil Mortality

2,4-D I003654-

004 Unknown fish Hundreds 1993 NC Lake Registered Unlikely Foliage – 90 

ppb No Mortality

2,4-D I003826-

002 N/R Unknown 1995 NC Tobacco Not 

determined Unlikely N/R

Disulfoton

Dimethoate

Aldicarb

Mortality caused 

by runoff into 

pond

2,4-D I003826-

003 N/R Unknown 1995 NC Pond Not 

determined Unlikely Foliage –

38000 ppb No Mortality caused 

by drift into pond

2,4-D I006214-

010 Corn Unknown 1997 MN Corn Registered Probable N/R Clopyralid

Flumetsulam

Plant damage 

caused by direct 

treatment

2,4-D I001358-

001 Home lawn Unspecified 

area 1994 CO Home/lawn Not 

determined Unlikely N/R No Plant damage

2,4-D I001849-

010 Unknown fish 20 1994 LA Sugarcane Misuse Probable N/R Azinphos-methyl Mortality caused 

by accidental drift
Page 52 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I002168-

001 Tobacco N/R 1995 FL Agricultural area Misuse Probable N/R Picloram Plant damage (accidental)

2,4-D I003138-

001 Switch grass Thousands N/R MN Switch grass Registered Probable N/R Clopyralid

Plant damage 

caused by direct 

treatment

2,4-D I003151-

001 Corn N/R 1996 MN Corn Registered Probable N/R Clopyralid

Flumetsulam

Mortality caused 

by direct 

treatment

2,4-D B000150-

002

Bluegill

Greengill

Silver minnow

Catfish

Smallmouth bass

Largemouth bass

Crappie

Sunfish

Watersnake

Fox squirrel

Catfish – 1

Watersnake 

– 1

Fox squirrel 

– 2

All others –

N/R

1970 IL Agricultural 

area Registered Probable 2,4-D not 

tested

Propachlor

Phorate

Mortality caused 

by runoff into 

pond

2,4-D I000008-

001 Bluebird 3 nests 1992 NC N/R Misuse Unlikely N/R No Mortality 

(accidental)

2,4-D I000026-

001 Poplar N/R 1991 IA Fencerow/ soybean Misuse Probable N/R No Mortality caused by accidental drift

2,4-D I000546-

001 Unknown tree N/R 1993 AR Home/tree Not 

determined Probable N/R 2,4,5-T

Plant damage 

caused by drift 

(1.5 miles)

2,4-D I000799-

003

Turkey

Cardinal

Blackbird

Duck

Bream

Bass

Duck, 

Bream, 

Bass –

hundreds

All others –

Unknown

1991 NC Home/lawn Not 

determined Probable

2,4-D tested 

for in duck 

and blackbird 

tissue; 2,4-D 

detected in 

water – 1 ppb

Dicamba

Mecoprop

Carbaryl

Diazinon

Pentachlorophenol

Oxamyl

Mortality caused 

by ingestion 

(birds) and runoff 

into stream (fish)

2,4-D B0000-

300-69 Ornamental Unknown 1976 OR Tree farm Misuse Probable N/R 2,4,5-T Plant damage 

caused by drift

2,4-D B0000-

300-70 Unknown tree 1 tree 1976 AR Ornamental, 

woody Misuse Probable N/R 2,4,5-T

Plant damage 

caused by direct 

treatment
Page 53 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D B0000-

300-77 N/R One-mile 

stretch 1970 NC Right-of-way Spill Probable N/R 2,4,5-T

Mortality caused 

by direct 

treatment (spill) 

into river

2,4-D B0000-

300-78 Salmon 5400 1974 ME Spill Misuse Probable Water – 7900 

ppb 2,4,5-T

Juvenile mortality 

caused by spill 

into adjacent 

stream

2,4-D B000150-

001

Bluegill

Bass

Bluegill –

30

Bass - 20

1970 IL Corn Not 

determined Unrelated N/R

Propachlor

EPTC

Phorate

Atrazine

Mortality caused 

by runoff into 

pond

2,4-D B0000-

300-58 Ornamental Unknown 1969 AZ Hillside Misuse Probable N/R 2,4,5-T

Plant damage 

caused by 

accidental drift

2,4-D B0000-

300-59 Unknown fish Unknown 1970 NC N/R Spill Probable N/R 2,4,5-T

Mortality caused 

by spill into 

adjacent river

2,4-D B0000-

300-61 Cotton N/R N/R TX N/R Misuse Probable N/R 2,4,5-T Plant damage

2,4-D B0000-

300-62 Unknown plant N/R N/R OR Municipal site Not 

determined Probable N/R 2,4,5-T Plant damage 

caused by drift

2,4-D B0000-

300-65

Unknown plant

Ornamental Unknown 1973 MO Pasture Misuse Probable N/R 2,4,5-T

Plant damage 

caused by 

accidental spill

2,4-D B0000-

300-35 N/R (aquatic) N/R 1984 SC N/R Not 

determined Probable N/R No Mortality caused 

by ingestion

2,4-D B0000-

300-36 Mullet 18 fish 1984 SC N/R Not determined Probable N/R No Mortality caused by ingestion

2,4-D B0000-

300-37

Drum

Bream

Croaker

100 fish 

each 1984 SC N/R Not 

determined Probable N/R No Mortality caused 

by ingestion
Page 54 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D B0000-

300-48

Pumpkin

Cantaloupe

Watermelon

Pepper

N/R 1973 OK Right-of-way Misuse Probable N/R MSMA

Diuron

Plant damage 

caused by 

accidental drift 

(125 yards)

2,4-D B0000-

300-56

Alfalfa

Wheat

Thousands 

of acres 1966 UT Rangeland Misuse Probable N/R 2,4,5-T

Plant damage 

caused by 

accidental spray 

drift

2,4-D I000925-

001 Unknown fish 23000 1993 WV Right-of-way, 

rail Registered High 

probability

Confirmed in 

water, 

concentration 

not reported

Triclopyr

Mortality caused 

by drift into 

stream

2,4-D I003116-

001 Cherry N/R 1994 OR Ag area Misuse High probability N/R No Accidental aerial spill near orchard

2,4-D I003386-

001 Sweet Cherry 665 1994 OR Wheat Misuse High 

Probability

Foliage – 1.2-

7.5 ppb

Cherries –

0.00-0.20 ppb

Metsulfuron-methyl

Intentional 

misuse resulted in 

drift (aerial) to 

nearby orchard

2,4-D I003104-

001 Canola, potato N/R 1996 ID Green-house, ag area Registered High probability

Canola tissue 

– 0.1-1 ppm Clopyralid

Mortality caused 

by drift from use 

in greenhouse and 

ag area

2,4-D I003249-

006 Carrot Thousands 1996 CA Ag area Registered High 

probability N/R No Mortality caused 

by drift

2,4-D I004875-

001 N/R (aquatic) Hundreds 1996 LA N/R Misuse High probability N/R Bromacil Mortality caused by ingestion

2,4-D I004495-

001 Unknown bird Unknown 1996 IA Corn Misuse High 

probability

Foliage

EHE- 4.5 ppb

2,4-D –

0.041-4.5 ppb

Glyphosate, 

isopropylamine salt

Mortality caused 

by drift from 

accidental misuse
Page 55 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I013883-

026 Cypress trees N/R 1997 WA N/R Not 

determined

High 

probability

Residue 

found in 

plants, 

concentration 

not reported

Triclopyr Plant damage 

caused by drift

2,4-D I009262-

033 Grass 50% of 

lawn 1999 FL 00598-009 Not 

determined

High 

probability N/R No

Browning of lawn 

caused by treating 

with 2,4-D

2,4-D I014290-

001 Ornamental 900 ft2 2003 ID Right-of-way, road Misuse High 

probability N/R Metsulfuronmethyl

Plant damaged 

caused by drift 

from garden in 

accidental misuse 

2,4-D I020627-

026 Grape N/R N/R WA Ag area Not 

determined Possible N/R No Plant damage 

caused by drift

2,4-D I015748-

001 Hay 10.2 acres N/R VA Hay Registered Possible N/R Picloram

Plant damage 

caused by treating 

directly

2,4-D I003780-

002

Unknown grass 

and tree Unknown N/R IA Ag area Not 

determined Possible N/R Atrazine

Cyanazine

Plant damage 

from runoff

2,4-D I020627-

005

Unknown tree 

and shrub Unknown N/R WA Right-of-way, 

road Misuse Possible N/R Diuron

Bromacil

Plant damage 

from spray drift

2,4-D I020627-

037 Grape N/R N/R WA N/R Not 

determined Possible Tissues –

positive test

Glyphosate

Dicamba

Plant damage 

caused by spray 

drift

2,4-D B0000-

300-45

Tomato, squash, 

pepper

Tomato -98

Squash – 6

Pepper - 70

1972 OK Right-of-way, 

rail

Not 

determined Possible N/R Diuron

MSMA

Plant damage 

caused by drift

2,4-D B0000-

300-63

Unknown plant 

and tree Unknown 1973 OR Municipal 

operation

Not 

determined Possible N/R 2,4,5-T Plant damage 

caused by drift

2,4-D B0000-

300-64 Unknown plant N/R 1973 TN Right-of-way

Not 

determined Possible N/R 2,4,5-T Plant damage caused by drift
Page 56 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D B0000-

300-87

Bass, bream, 

mullet, eel

Bass -200

Bream -500

Mullet -50

Eel -10

1979 SC N/R Not 

determined Possible N/R 2,4,5-T

Mortality caused 

by ingestion in 

contaminated 

pond

2,4-D B0000-

502-13

Spot tail bass, 

bream, croaker 100 of each 1984 SC Turf, golf course Not determined Possible Water – 6.02 ppb Malathion Mortality

2,4-D I000598-

009

Carp

Bluegill

Gizzard shad

Catfish

Unknown fish

Unknown 

fish –

numerous

All others -

N/R 

1988 NE Right-of-way, 

rail

Not 

determined Possible

Tested water, 

but nothing 

found

Atrazine Mortality caused 

by drift

2,4-D I014404-

023 Onion N/R 1990 WA N/R Not determined Possible N/R Glyphosate isopropylamine salt

Plant damage 

caused by 

carryover

2,4-D I014404-

003 Pea N/R 1990 WA Wheat Not 

determined Possible N/R No

Plant damage 

caused by spray 

drift

2,4-D I014404-

017 Unknown plant N/R 1990 WA N/R Misuse Possible N/R Dicamba Plant damage 

caused by drift

2,4-D I014404-

026 Ornamental N/R 1991 WA Corn Misuse Possible N/R Dicamba

Plant damage 

caused by spray 

drift

2,4-D I000804-

014 Unknown fish Unknown 1991 SD Lake Misuse Possible

Water and 

soil, but no 

detects

Dimethoate Mortality caused 

by ingestion

2,4-D I003602-

003 Bluegill 1000 1991 NY Pond Registered Possible N/R Copper sulfate pentahydrate Mortality

2,4-D I014409-

002 Alfalfa Half of crop 1992 WA N/R Not 

determined Possible N/R Glyphosate Plant damage 

caused by drift

2,4-D I014409-

003 Concord grape N/R 1992 WA N/R Misuse Possible N/R No Plant damage caused by drift
Page 57 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I000309-

001

Forage/ hay, 

horse, dog, 

squirrel, 

chipmunk

Forage/hay 

– N/R

Horse – 7

Dog – 6

Chipmunk 

and squirrel 

- numerous

1992 UT Ag area Not 

determined Possible

Tissue 

samples from 

dog, but no 

results 

reported

Dicamba

Mortality in 

hay/forage caused 

by drift. 

Mortality in other 

animals caused 

by ingestion. 

One horse was 

incapacitated

2,4-D I014409-

009 Unknown plant N/R 1992 WA Driveway Registered Possible N/R Triclopyr

Glyphosate

Plant damage 

caused by spray 

drift

2,4-D I014409-

042 Grape N/R 1992 WA N/R Misuse Possible N/R No

Plant damage 

from direct 

treatment

2,4-D I014409-

044 Apricot 30-40 trees 1992 WA N/R Not 

determined Possible N/R No Mortality caused 

by drift

2,4-D I014409-

048 Wheat 18 acres 1992 WA Winter wheat Misuse Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I014409-

019 Baby’s breath N/R 1992 WA N/R Not determined Possible N/R No Plant damage caused by drift

2,4-D I000360-

016 Corn 399 acres 1993 MN Corn Registered 

use Possible N/R

Dicamba 

diethylamine salt

Alachlor

Plant damage 

from direct 

treatment

2,4-D I000358-

003 Ornamental N/R 1993 CO N/R Not determined Possible N/R Glyphosate isopropylamine salt Plant damage

2,4-D I000358-

002 Cotton 30 acres 1993 MS Cotton Not 

determined Possible N/A Glyphosate 

isopropylamine salt Plant damage

2,4-D I000360-

004 Pinto bean 540 acres 1993 CO Pinto beans Registered Possible N/A Trifluralin

Alachlor Plant damage

2,4-D I001473-

001 Tobacco N/R 1994 KY Right-of-way, 

road Registered Possible

Tissue 

samples, but 

no reported 

value

Chlorsulfuron

Plant damage 

caused by 300 ft 

drift
Page 58 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I014407-

045

Unknown tree 

and lilac N/R 1994 WA N/R Not 

determined Possible N/R No

Plant damage 

caused by spray 

drift

2,4-D I014407-

047 Potato N/R 1994 WA N/R Not 

determined Possible

Laboratory 

analysis was 

negative

No

Plant damage 

caused by spray 

drift

2,4-D I014405-

014 Ornamental N/R 1996 WA N/R Not 

determined Possible N/R No Plant damage

2,4-D I013883-

012 Apple N/R 1997 WA Right-of-way Registered 

use Possible Residues at 

right-of-way

No Plant damage 

from spray drift

2,4-D I013883-

022 Grape N/R 1997 WA N/R Not 

determined Possible N/R No

Plant damage 

caused by spray 

drift

2,4-D I013883-

037 Grape N/R 1997 WA Wheat Registered Possible N/R No Plant damage 

caused by drift

2,4-D I013883-

034 Grape N/R 1997 WA N/R Not 

determined Possible N/R No Plant damage 

caused by drift

2,4-D I013883-

020 Canola N/R 1997 WA N/R Not 

determined Possible No residues 

detected Glyphosate

Plant damage 

caused by spray 

drift

2,4-D I013884-

007 Unknown tree N/R 1997 WA Orchard Misuse Possible N/R No Plant damage

2,4-D I013883-

038 Grape N/R 1997 WA N/R Not 

determined Possible N/R No Plant damage 

caused by drift

2,4-D I005879-

014 Hickory Unknown 1997 IA N/R Not 

determined Possible Clomazaone 

detected Clomazone Whitening caused 

by drift

2,4-D I013883-

028 Unknown plant N/R 1997 WA Road Registered Possible N/R Clopyralid Plant damage 

caused by drift

2,4-D I013883-

027

Blackberry and 

cottonwood N/R 1997 WA N/R Not 

determined Possible N/R No Plant damage 

caused by drift
Page 59 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I006139-

001

Bass, catfish, 

crappie, perch, 

grass seed

N/R 1997 OK N/R Not 

determined Possible N/R Picloram

Mortality caused 

by runoff into 

pond and pond 

edge

2,4-D I007259-

001 Corn N/R 1998 WI N/R Not 

determined Possible N/R Clopyralid

Flumetsulam Plant damage

2,4-D I008336-

001 Tomato N/R 1998 TX Hay Registered Possible N/R Picloram 

triethylamine salt

Plant damage 

caused by direct 

treatment

2,4-D I007340-

654 Grass Lawn 1998 CO Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007340-

710 Grass Lawn 1998 CA Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I013884-

025 Ornamental N/R 1998 WA Right-of-way Misuse Possible N/R No

Plant damage 

caused by spray

drift

2,4-D I007980-

047 Grass 65% of 

lawn 1998 SD Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

029 Grass Lawn 1998 NY Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

042 Grass Lawn 1998 OH Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

039 Grass Lawn 1998 CA Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

028 Grass 80% 

mortality 1998 GA Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment
Page 60 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I007980-

038 Grass Lawn 1998 NJ Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I008333-

001 Wheat 40 acres 1998 KS Wheat Registered Possible N/R

Glyphosate 

isopropylamine salt

Picloram

Plant damage 

caused by direct 

treatment

2,4-D I013884-

022 Tomato 4 plants 1998 WA Lawn Registered Possible N/R No Plant damage 

caused by drift

2,4-D I007980-

046 Grass 75% of 

lawn 1998 CA Home/ lawn Not 

determined Possible N/R No

Plant damaged 

caused by direct 

treatment

2,4-D I007980-

037 Grass 50% of 

lawn 1998 OH Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

036 Grass Lawn 1998 NY Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

045 Grass Lawn 1998 OH Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I013884-

034 Grape N/R 1998 WA N/R Not determined Possible

Samples did 

not detect 

residues

No Plant damage

2,4-D I007980-

010 Grass Home lawn 1998 PA Home/ lawn Not 

determined Possible N/R No

Browning caused 

by direct 

treatment

2,4-D I007980-

011 Grass 144 ft2 lawn 1998 NY Home/ lawn Misuse Possible N/R No

Browning caused 

by accidental 

direct treatment

2,4-D I007980-

012 Grass Lawn 1998 IA Home/ lawn Not 

determined Possible N/R No

Browning caused 

by direct 

treatment
Page 61 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I013884-

030 Unknown tree Several 

willows 1998 WA Right-of-way Registered Possible N/R No Plant damage

2,4-D I007980-

013 Grass Lawn 1998 NJ Home/ lawn Not 

determined Possible N/R No

Browning caused 

by direct 

treatment

2,4-D I007980-

015 Grass Lawn 1998 LA Home/ lawn Misuse Possible N/R No

Plant damage 

caused by 

accidental direct 

treatment

2,4-D I007980-

014 Grass Lawn 1998 NV Home/ lawn Not determined Possible N/R No

Browning caused 

by direct 

treatment

2,4-D I007980-

017 Grass Lawn 1998 NY Home/ lawn Not determined Possible N/R No

Browning caused 

by direct 

treatment

2,4-D I007980-

016 Grass Lawn 1998 PA Home/ lawn Not determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

052 Grass N/R 1998 NY Home/ lawn Not determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I013884-

032 Unknown tree N/R 1998 WA Wheat Registered Possible N/R Dicamba Plant damage 

caused by drift

2,4-D I007980-

026 Grass 60% lawn 1998 CO Home/ lawn Not determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

021 Grass Lawn 1998 WV Home/ lawn Not determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

035 Grass Lawn 1998 NY Home/ lawn Not determined Possible N/R No

Mortality caused

by direct 

treatment
Page 62 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I007980-

022 Grass 80% lawn 1998 MO Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

034 Grass Lawn 1998 CT Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

033 Grass Lawn 1998 CA Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

030 Grass Unknown 1998 NY Home/ lawn Not 

determined Possible N/R No

Plant damaged 

caused by direct 

treatment

2,4-D I007980-

031 Grass Lawn 1998 CA Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

032 Grass Lawn 1998 MA Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

053 Grass 60% of 

lawn 1998 CA Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

027 Grass Whole lawn 1998 OH Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

040 Grass Lawn 1998 CO Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

043 Grass Lawn 1998 PA Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

001 Grass Unknown 1998 PA Home/ lawn Registered Possible N/R No

Plant damage 

caused by direct 

treatment
Page 63 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I008033-

007 Grass Lawn 1998 OH Home/ lawn Not 

determined Possible N/R Diazinon

Mortality caused 

by direct 

treatment

2,4-D I007980-

044 Grass 3 lawns 1998 KY Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

023 Grass Lawn 1998 MO Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

050 Grass Lawn 1998 VA Home/ lawn Not 

determined Possible N/R No

Browning caused 

by direct 

treatment

2,4-D I007980-

051 Grass N/R 1998 CT Home/ lawn Not 

determined Possible N/R No

Browning caused 

by direct 

treatment

2,4-D I007980-

008 Grass 50% of 

lawn 1998 IL Home/ lawn Registered Possible N/R No

Plant damage 

caused by direct 

treatment

2,4-D I007980-

025 Grass 75% 

affected 1998 CT Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

002 Grass N/R 1998 NJ Home/ lawn Registered Possible N/R No

Plant damage 

caused by direct 

treatment

2,4-D I007980-

024 Grass 50% 

damaged 1998 NY Home/ lawn Not 

determined Possible N/R No

Plant damage 

caused by direct 

treatment

2,4-D I007980-

048 Grass Lawn 1998 IL Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

009 Grass Unknown 1998 FL Home/ lawn Registered Possible N/R No

Browning caused 

by direct 

treatment
Page 64 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I007980-

054 Grass 75% of 

lawn 1998 IN Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

041 Grass Lawn 1998 NJ Home/ lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

006 Grass Unknown 1998 FL Home/ lawn Misuse Possible N/R No

Plant damage

caused by 

accidental direct 

treatment

2,4-D I007980-

007 Grass N/R 1998 FL Home/ lawn Misuse Possible N/R No

Plant damage 

caused by 

accidental direct 

treatment

2,4-D I007980-

018 Grass Lawn 1998 VA Home/ lawn Not 

determined Possible N/R No

Browning caused 

by direct 

treatment

2,4-D I007980-

005 Grass Unknown 1998 FL Home/ lawn Misuse Possible N/R No

Plant damage 

caused by 

accidental direct 

treatment

2,4-D I007980-

004 Grass Unknown 1998 RI Home/ lawn Registered Possible N/R No

Plant damage 

caused by direct 

treatment

2,4-D I007980-

049 Grass 80-90% of lawn 1998 CA Home/ lawn Not determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I007980-

003 Grass N/R 1998 FL Home/ lawn Registered Possible N/R No

Plant damage 

caused by direct 

treatment

2,4-D I008027-

001 Grass N/R 1998 TX Home/ lawn Misuse Possible N/R No

Mortality caused 

by accidental 

direct treatment
Page 65 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I007980-

020 Grass Lawn 1998 TX Home/ lawn Misuse Possible N/R No

Browning caused 

by accidental 

direct treatment

2,4-D I007980-

019 Grass 80% of 

lawn 1998 NJ Home/ lawn Not 

determined Possible N/R No

Browning caused 

by direct 

treatment

2,4-D I008027-

004 Evergreen 40 1998 IA Home/ tree Not 

determined Possible N/R No

Browning caused 

by direct 

treatment

2,4-D I008027-

003 Grass 80% affected 1998 NJ Home/ lawn Not determined Possible N/R No

Mortality caused 

by direct 

treatment

2,4-D I008027-

002 Grass N/R 1998 FL Home/ lawn Misuse Possible N/R No

Mortality caused 

by accidental 

direct treatment

2,4-D I013587-

074 Unknown plant Unknown 1999 WA Pasture Registered Possible N/R No

Plant damage 

caused by spray 

drift

2,4-D I013587-

008 Pine Unknown 1999 WA Right-of-way, 

road Misuse Possible N/R Dicamba

Plant damage 

caused by direct 

treatment

2,4-D I009262-

038 Grass Lawn 1999 OH Home/ lawn Registered Possible N/R No

Browning caused 

by direct 

treatment

2,4-D I013587-

013 Potato Unknown 1999 WA Potato Misuse Possible

Residues in 

potato foliage 

and tubers

Methamidophos

Glyphosate

Plant damage 

caused by 

accidental direct 

treatment

2,4-D I020459-

018 Beet N/R 2000 WA N/R Not 

determined Possible N/R Glyphosate Plant damage 

caused by drift

2,4-D I020459-

015 Unknown tree N/R 2000 WA N/R Not 

determined Possible N/R Triclopyr

Plant damage 

caused by spray 

drift
Page 66 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I020459-

003 Potato N/R 2000 WA Right-of-way, 

road

Not 

determined Possible N/R Diuron

Imazapyr

Plant damage 

caused by drift

2,4-D I020459-

027 Grape N/R 2000 WA Grape Not 

determined Possible N/R No Plant damage 

caused by drift

2,4-D I020459-

026 Grape 40 acres 2000 WA N/R Not 

determined Possible N/R No Plant damage

2,4-D I020459-

028 Arborvitae 100 2000 WA Right-of-way, 

railroad

Not 

determined Possible N/A Dicamba

Plant damage 

caused by spray 

drift

2,4-D I010581-

059 Grass 2/3 

damaged 2000 MN Turf, residential Registered Possible N/R

Dicamba

Mecoprop

Mecoprop-P

Plant damage 

caused by direct 

treatment

2,4-D I020459-

031 Grape $290,000 losses 2000 WA N/R Not determined Possible N/R No Plant damage caused by drift

2,4-D I010527-

001 Pensacola bahia 45% of 65 

acres 2000 TX Rangeland Registered Possible N/R

Picloram 

triisopropanolamine 

salt

Plant damage 

from direct 

treatment

2,4-D I010581-

063 Grass Unknown 2000 NH Turf, residential Registered Possible N/R Dicamba

Mecoprop-P

Plant damage 

caused by direct 

treatment

2,4-D I010581-

065 Grass 3/4 Damaged 2000 IL Turf, residential Registered Possible NR Mecoprop

Plant damage 

caused by direct 

treatment

2,4-D I010581-

066 Grass 95% Damage 2000 NV Turf, residential Misuse Probable NR Mecoprop

Plant damage 

caused by 

accidental direct 

treatment

2,4-D I010581-

069 Grass All 2000 TN Turf, residential Registered Probable N/R Mecoprop

Plant damage 

caused by direct 

treatment

2,4-D I010581-

070 Grass All 2000 NY Turf, residential Misuse Probable N/R Mecoprop

Plant damage 

caused by 

accidental overapplication
Page 67 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I010581-

071 Grass 5000 ft2 2000 AL Turf, residential Registered Possible N/R Mecoprop

Plant damage 

caused by direct 

treatment

2,4-D I010581-

072 Grass 95% of 

lawn 2000 CO Turf, residential Registered Probable N/R Mecoprop

Plant damage 

caused by direct 

treatment

2,4-D I010581-

073 Grass Unknown 2000 NJ Turf, residential Registered Possible N/R Mecoprop

Plant damage 

caused by direct 

treatment

2,4-D I010581-

074 Grass Unknown 2000 FL Turf, residential Misuse Probable N/R Mecoprop

Plant damage 

caused by 

accidental overapplication

2,4-D I010581-

075 Grass 15,000 ft2 2000 MN Turf, residential Registered Probable N/R Mecoprop

Plant damage 

caused by direct 

treatment

2,4-D I010581-

076 Grass 2675 ft2 2000 WA Turf, residential Misuse Probable N/R Mecoprop

Plant damage 

caused by 

accidental overapplication

2,4-D I010581-

077 Grass 50% of 

lawn 2000 CA Turf, residential Misuse Probable N/R Mecoprop

Plant damage 

caused by 

accidental overapplication

2,4-D I010581-

078 Grass Unknown 2000 OR Turf, residential Misuse Probable N/R Mecoprop

Plant damage 

caused by 

accidental overapplication

2,4-D I010581-

081 Grass All 2000 TX Turf, residential Registered Probable N/R Mecoprop

Plant damage 

caused by direct 

treatment

2,4-D I010581-

086 Grass 75% of 

lawn 2000 WV Turf, residential Misuse Probable N/R Mecoprop

Plant damage 

caused by 

accidental over 

application

2,4-D I010581-

087 Grass 70% of 

lawn 2000 MI Turf, residential Registered Probable N/R Mecoprop-P

Dicamba

Plant damage 

caused by direct 

treatment
Page 68 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I010581-

089 Grass 7,000 ft2 2000 PA Home/lawn Registered Probable N/R Mecoprop

Plant damage 

caused by direct 

treatment

2,4-D I010581-

090 Grass All 2000 CA Turf, residential Misuse Probable N/R Mecoprop

Plant damage 

caused by 

accidental overapplication

2,4-D I010581-

094 Grass 9000 ft2 2000 NY Turf, residential Registered Possible N/R Mecoprop

Plant damage 

caused by direct 

treatment

2,4-D I010581-

095 Grass 21,780 ft2 2000 NJ Turf, residential Registered Possible N/R Mecoprop

Plant damage 

caused by direct 

treatment

2,4-D I010581-

096 Grass All 2000 MA Turf, residential Misuse Probable N/R Mecoprop

Plant damage 

caused by 

accidental over 

application

2,4-D I010581-

097 Grass All 2000 NY Turf, residential Registered Probable N/R Mecoprop

Plant damage 

caused by direct 

treatment

2,4-D I010581-

099 Grass All 2000 NM Turf, residential Misuse Probable Mecoprop

Plant damage 

caused by 

accidental overapplication

2,4-D I010927-

015 Corn 132 acres 1999 IA Corn Registered Probable N/R Clopyralid

Flumetsulam

Plant damage 

caused by direct 

treatment

2,4-D I011249-

001 Soybean Unknown 2000 NE Pasture Registered 

use Possible N/R Picloram

Plant damage 

caused by half 

mile spray drift

2,4-D I012243-

001 Cotton 40,000 acres 2001 MO Cotton Registered Possible N/R No Plant damage caused by drift

2,4-D I012366-

008 Field corn 30 acres 2001 IA Corn, field Registered Possible N/R Clopyralid

Flumetsulam

Plant damage 

caused by direct 

treatment

2,4-D I012366-

009 Field corn 105 acres 2001 IA Corn, field Registered Possible N/R

Acetochlor

Flumetsulam

Clopyralid

Plant damaged 

caused by direct 

treatment
Page 69 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I012366-

010 Field corn 134 acres 2001 IA Corn, field Registered Possible N/R

Acetochlor

Flumetsulam

Clopyralid

Plant damage 

caused by direct 

treatment

2,4-D I012366-

062 Field corn 105 acres 2001 IA Corn, field Not 

determined Possible N/R

Acetochlor

Flumetsulam

Clopyralid

Plant damage 

caused by direct 

treatment

2,4-D I012366-

063 Field corn 134 acres 2001 IA Corn, field Not determined Possible N/R

Acetochlor

Flumetsulam

Clopyralid

Plant damage 

caused by direct 

treatment

2,4-D I012786-

005 Ornamental trees 10 trees 2001 France

Ornamental, 

woody

Not 

determined Possible N/R Triclopyr

Phytotoxicity 

caused by direct 

treatment

2,4-D I013550-

004 Grass 18 acres 2001 FL Grass Registered Probable N/R Triclopyr 

butoxyethyl ester

Stunting caused 

by direct 

application

2,4-D I013587-

023 Alfalfa Unknown 1999 WA Wheat Misuse Probable N/R No

Plant damage 

caused by spray 

drift

2,4-D I013587-

043 Ornamental Unknown 1999 WA Barley Misuse Probable N/R No

Plant damage 

caused by spray 

drift

2,4-D I013587-

053 Grape Unknown 1999 WA Yard Misuse Probable N/R No

Plant damage 

caused by spray 

drift

2,4-D I013636-

002 Field corn 68 acres 2003 OH Field corn Registered Probable N/R Atrazine

Acetochlor

Plant damage 

from direct 

application

2,4-D I013636-

006 Field corn 27 acres 2002 IN Field corn Registered Possible N/R

Ammonium 

sulfamate

Atrazine

Glyphosate 

isopropylamine salt

s-Metalochlor

Plant damage 

from direct 

treatment

2,4-D I013883-

003

Apple

Cherry Unknown 1997 WA Wheat Registered Probable N/R Chlorsulfuron

Plant damage 

caused by spray 

drift

2,4-D I013883-

005 Ornamental Unknown 1997 WA N/R Registered Probable N/R No Plant damage 

caused by spray 
Page 70 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

drift

2,4-D I013883-

006

Cherry

Grape Unknown 1997 WA Rangeland Registered Probable N/R Dicamba

Plant damage 

caused by spray 

drift

2,4-D I013883-

007 Ornamental N/R 1997 WA Rangeland Registered Probable N/R Dicamba

Plant damage 

caused by spray 

drift

2,4-D I013883-

019 Bean N/R 1997 WA Bean Misuse Probable N/R Dicamba

Plant damage 

caused by 

accidental direct 

treatment

2,4-D I013884-

006 Grass N/R 1998 WA Pasture Registered Probable N/R Clopyralid Plant damage

2,4-D I013884-

009 Unknown plant N/R 1998 WA Wheat Registered Probable N/R No Plant damage 

caused by drift

2,4-D I013884-

021 Potato N/R 1998 WA Right-of-way, road Misuse Probable N/R Dicamba Plant damage caused by drift

2,4-D I013884-

035 Unknown tree 36 trees 1998 WA Right-of-way Registered Probable N/R Dicamba

MCPA

Plant damage 

caused by drift

2,4-D I014266-

002 Strawberry Unknown 2003 Cana

da N/R Misuse Possible N/R

Fluorxypyr 1-

methylheptyl ester

Clodinafoppropargyl

Plant damage 

caused by spray 

drift

2,4-D I014404-

019 Ornamental N/R 1990 WA Fencerow Misuse Probable N/R Triclopyr

Plant damage 

caused by spray 

drift

2,4-D I014407-

016 Ornamental N/R 1994 WA Ornamental Not 

determined Probable N/R Dicamba Plant damage 

caused by drift

2,4-D I014407-

034 Blueberry N/R 1994 WA Lawn Misuse Probable N/R No

Mortality caused 

by accidental 

drift

2,4-D I014407-

041 Unknown tree N/R 1994 WA Trees Not determined Probable N/R No Plant damage
Page 71 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I014407-

043 Grape N/R 1949 WA N/R Not 

determined Probable N/R No Plant damage

2,4-D I014409-

028 Cherry N/R 1992 WA Cherry Registered Probable N/R No Plant damage

2,4-D I014409-

075

Poplar

Ornamental

Poplar – 1 

row 

Ornamental 

– N/R 

1992 WA Pasture Misuse Possible N/R No Plant damage

2,4-D I014702-

002 Potato N/R 2003 ID Potato Registered Possible N/R Clopyralid

Plant damage 

caused by 

carryover

2,4-D I014806-

001 Potato 3020 acres 2003 ID Agricultural 

area Registered Unlikely N/R Clopyralid

Plant damage 

caused by 

carryover

2,4-D I016297-

001

Tomato

Melon 5 acres 2005 MD N/R Not 

determined Possible N/R

Glyphosate 

isopropylamine salt

Thifensulfuron 

methyl

Tribenuron-methyl

Flumioxazin

Plant damage 

caused by spray 

drift (400ft)

2,4-D I016680-

001 Grape 13 acres 2005 OR Right-of-way

Not 

determined Possible N/R

Triclopyr 

triethylamine salt

Sulfometuron

Hexazinone

Plant damage 

caused by spray 

drift

2,4-D I017483-

001 Wheat 23 acres 2006 KY Wheat Registered Possible N/R

Nicosulfuron

Thifensulfuron 

methyl

Tribenuron-methyl

Plant damage 

caused by direct 

treatment

2,4-D I017576-

001

Horned lark

Mourning dove

Kangaroo rat

American robin

Western 

meadowlark

Red-winged 

blackbird

Lark bunting

2200 2006 CO Sunflower Registered Unlikely N/R Carbofuran

Glyphosate

Mortality caused 

by ingestion
Page 72 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

Sparrow

Common grackle

American kestrel

Unknown bird

2,4-D I017841-

001 Soybean 1500 acres 2006 LA Soybean Misuse Probable N/R Dicamba

Glyphosate

Plant damage 

caused by direct 

treatment

2,4-D I017958-

011 Tobacco 6 acres 2006 KY Pasture Registered 

Use Possible N/R Aminopyralid

Plant damage 

200 yards from 

treated site

2,4-D I019025-

039 Rabbit 4 rabbits 2007 PA Turf, residential Not determined Possible N/R MecopropDicamba

Mortality caused 

by ingestion

2,4-D I019442-

001

Clover

Timothy grass

Grass

N/R 2007 OH Right-of-way, 

road Misuse Possible

Residues 

found, but not 

of 2,4-D

Atrazine

Acetochlor

Metribuzin

Clomazone

Permethrin

Glyphosate

Plant damage 

caused by drift

2,4-D I020459-

021

Unknown plant

Unknown aquatic 

plant

N/R 2000 WA Ornamental Misuse Possible N/R Glyphosate

Plant damage 

caused by spray 

drift into a canal

2,4-D I020459-

032 Grape N/R 2000 WA N/R Not 

determined Probable N/R No Plant damage 

caused by drift

2,4-D I020627-

003 Grape 350 acres 2001 WA Grape Misuse Possible N/R Fluoxypyr

Plant damage 

caused by spray 

drift

2,4-D I020627-

007 Ornamental N/R 2001 WA Wheat Not determined Possible N/R

Metsulfuronmethyl

Sulfometuron

Plant damage 

caused by spray 

drift

2,4-D I020627-

008

Tomato

Strawberry N/R 2001 WA Turf, residential Registered Possible N/R

MCPP diethanoline 

salt

MCPP isoocytl ester

Plant damage 

caused by drift

2,4-D I020627-

010 Hay N/R 2001 WA Hay Not 

determined Possible N/R Glyphosate Plant damage

caused by drift

2,4-D I020627-

011 Ornamental N/R 2001 WA Turf, residential Not 

determined Possible N/R Dicamba Plant damage 

caused by drift
Page 73 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I020627-

014 Willow N/R 2001 WA Right-of-way

Not 

determined Possible N/R Glyphosate Plant damage

caused by drift

2,4-D I020627-

015 Ornamental N/R 2001 WA Right-of-way

Not 

determined Possible N/R MSMA Plant damage 

caused by drift

2,4-D I020627-

017 Unknown plant Unknown 2001 WA Berry, 

blackberry

Not 

determined Possible N/R Triclopyr

Plant damage 

caused by spray 

drift

2,4-D I020627-

018

Unknown tree

Unknown shrub Unknown 2001 WA Berry, 

blackberry

Not 

determined Possible N/R Triclopyr

Plant damage 

caused by drift, 

vapor

2,4-D I020627-

021 Unknown plant Unknown 2001 WA Berry, 

blackberry

Not 

determined Possible N/R Triclopyr Plant caused by

drift

2,4-D I020627-

025 Grape N/R 2001 WA Right-of-way

Not 

determined Possible N/R No Plant damage caused by drift

2,4-D I020627-

028 Grape N/R 2001 WA Right-of-way

Not 

determined Unlikely N/R No Plant damage 

caused by drift

2,4-D I020627-

031 Grape Unknown 2001 WA Right-of-way, 

road Misuse Probable N/R Glyphosate

Clopyralid

Plant damage 

caused by drift

2,4-D I020998-

030 Alfalfa N/R 2002 WA Agricultural area

Not 

determined Possible N/R Glyphosate

Plant damage 

caused by spray 

drift

2,4-D I021002-

005

Tomato

Pepper

Squash

Unknown 2009 NC Hay Not 

determined Unlikely N/R Aminopyralid

Plant damage 

caused by

compost

2,4-D I021457-

005 Cherry Orchard 

and Feed 2006 WA Orchard

(unspecified) Misuse Possible N/R Tribenuron- methyl Mortality caused 

by spray drift.

2,4-D I021457-

011 Grape Vineyard 2006 WA Home, exterior Misuse Possible N/R Dicamba

Mecoprop

Plant damage 

caused by 

volatilization

2,4-D I021457-

013 N/R Some 2006 WA Grass field Not 

determined Possible N/R Triclopyr Plant damage 

caused by drift
Page 74 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2,4-D I021457-

018 American 

Mountain Ash

1 aspen tree 2006 WA N/R Not 

determined Possible N/R Diuron

Plant damage 

caused by direct 

application

2,4-D I021457-

019 Bean bean plants 2006 WA N/R Misuse Possible N/R Dicamba Plant damage 

caused by drift

2,4-D I021587-

001 Honey Bee 320 hives 2009 UT Agricultural 

area

Not 

determined Unlikely N/R

Carbaryl

Fenoxaprop-ethyl

Coumaphos

Fluvalinate

Fenhexamid

Boscalid

Chlorothalonil

Chlorpyrifos

Cyprodinil

Diflubenzuron

Pendimethalin

Pyraclostrobin

Tebuconazole

Mortality 

DMA I000058-

001

Pecan

Sago Palm

Mountain Laurel

Rose

Avocado

Poinsettia

Grapefruit

18 plants 1992 TX Yard Not 

determined Possible N/R No Mortality caused by drift.

DMA I000500-

002 Rhododendron Unknown 1993 MO Rhododendrons Not 

determined Possible N/R No Plant damage

DMA I000910-

001

Bream

Garfish

Catfish

Minnow

Perch

Sunfish

Unknown 1992 LA Turf, golf course Registered Possible N/R

Carbaryl

Chlorpyrifos 

Atrazine

Iprodione 

MSMA 

Dicamba with 2,4-D 

Mortality caused 

by runoff. 

DMA I000941-

075 Grass N/R 1994 FL Home/lawn Registered Probable N/R No Plant damage
Page 75 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

DMA I000941-

076 Grass N/R 1994 FL Home/lawn Registered Probable N/R No Plant damage

DMA I000941-

083 Ornamental N/R 1994 FL Home/lawn Registered Probable N/R No Plant damage

DMA I001863-

002 Bass 32 fish 1994 LA Sugarcane Registered Unlikely N/R Azinphos-methyl Morality caused 

by drift.

DMA I001965-

002 Grass Seed All 1995 FL Home/lawn Registered Possible N/R Azinphos-methyl Morality caused 

by drift

DMA I001965-

003 Grass Seed All 1995 FL Home/lawn Registered Possible N/R No

Plant damage 

caused by direct

treatment.

DMA I001965-

004 Grass Seed All 1995 PA Home/lawn Registered Possible N/R No

Plant damage 

caused by direct

treatment.

DMA I003258-

001 Grass N/R 1996 CA Home Misuse Probable N/R No

Plant damage 

caused by

accidental 

application

DMA I003619-

001 Ornamental Unknown 1995 N/R Home/lawn Misuse Probable N/R No

Incapacitation 

caused by drift or 

use error

DMA I003826-

017 Unknown Fish N/R 1994 NC Athletic fields Not 

determined Possible N/R

Dicamba 

dimethylamine salt 

MCPP-p,DMA salt

Diazinon

Atrazine

Alachlor

Diclofop-methyl

Mortality caused 

by runoff

DMA I007340-

613 Grass Unknown 1998 FL Home/lawn Not 

determined Possible N/R No

Plant damage 

caused by direct 

application

DMA I007340-

621 Grass Unknown 1998 TX Home/lawn Not 

determined Possible N/R

Dicamba 

dimethylamine salt

Mecoprop 

dimethylamine

Plant damage 

caused by direct 

application
Page 76 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

DMA I007340-

627 Grass Lawn 1998 PA Home/lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

633 Grass Lawn 1998 VA Home/lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

637 Grass Unknown 1998 NY Home/lawn Not determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

639 Grass Lawn 1998 NJ Home/lawn Not determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

641 Grass Lawn 1998 IL Home/lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

642 Grass Lawn 1998 MN Home/lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

645 Grass Lawn 1998 IL Home/lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

646 Grass Lawn 1998 MO Home/lawn Not 

determined Possible N/R

Mecoprop 

dimethylamine 

Mortality caused 

by direct 

application

DMA I007340-

649 Grass Lawn 1998 CO Home/lawn Not 

determined Possible N/R Mecoprop 

dimethylamine 

Mortality caused 

by direct 

application

DMA I007340-

652 Grass Lawn 1998 FL Home/lawn Not 

determined Possible N/R

Dicamba

dimethylamine salt 

Mecoprop 

dimethylamine

Mortality caused 

by direct 

application

DMA I007340-

653 Grass Lawn 1998 NY Home/lawn Not 

determined Possible N/R Mecoprop

dimethylamine 

Mortality caused 

by direct 

application

DMA I007340-

655 Grass Lawn 1998 PA Home/lawn Not 

determined Possible N/R Mecoprop 

dimethylamine 

Mortality caused 

by direct 

application
Page 77 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

DMA I007340-

659 Grass Lawn 1998 SD Home/lawn Not 

determined Possible N/R Mecoprop 

dimethylamine 

Mortality caused 

by direct 

application

DMA I007340-

660 Grass Lawn 1998 MO Home/lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

664 Grass Lawn 1998 NC Home/lawn Not determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

668 Grass Lawn 1998 IL Home/lawn Not determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

673 Grass Lawn 1998 WI Home/lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

674 Grass Lawn 1998 MO Home/lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

676 Grass Lawn 1998 CT Home/lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

678 Grass Lawn 1998 KY Home/lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

679 Grass Lawn 1998 FL Home/lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

683 Grass Lawn 1998 UT Home/lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

688 Grass Lawn 1998 NE Home/lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

691 Grass Lawn 1998 KY Home/lawn Not determined Possible N/R No

Mortality caused 

by direct 

application
Page 78 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

DMA I007340-

694 Grass Lawn 1998 CO Home/lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

695 N/R Unknown 1998 NJ N/R Not 

determined Possible N/R No

Plant damage 

caused by direct 

application

DMA I007340-

696 Grass Lawn 1998 MO Home/lawn Not determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

697 Grass Lawn 1998 PA Home/lawn Not determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

705 Grass Lawn 1998 TN Home/lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

709 Grass Lawn 1998 MO Home/lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

711 Grass Lawn 1998 OH Home/lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007340-

713 Grass Lawn 1998 MN Home/lawn Not 

determined Possible N/R No

Mortality caused 

by direct 

application

DMA I007908-

001 Grass 10 acres 1998 AL Rangeland Registered Possible N/R No

Mortality caused 

by direct 

application

DMA I008693-

031 Grass N/R 1999 PA Home/lawn Misuse Probable N/R No

Mortality caused 

by overapplication

DMA I008693-

032 Grass Lawn 1997 TX Home/lawn Registered Possible N/R No

Browning caused 

by direct 

application

DMA I008693-

033 Grass Lawn 1999 N/R Home/lawn Misuse Probable N/R No

Mortality caused 

by overapplication
Page 79 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

DMA I008693-

034 Grass 5000 ft2 1999 FL Home/lawn Misuse Probable N/R No

Mortality caused 

by accidental

direct application

DMA I008693-

036 Grass Lawn 1999 TX Home/lawn Misuse Probable N/R No

Mortality caused 

by direct 

application

DMA I008693-

037 Grass Lawn 1999 NJ Home/lawn Misuse Probable N/R No

Mortality caused 

by accidental

direct application

DMA I008693-

038 Ross’ Goose 14 

rosebushes 1999 N/R Home/lawn Not 

determined Possible N/R No Mortality caused 

by drift.

DMA I008693-

039 Rose 11 plants 1999 OH Ornamental Misuse Probable N/R No

Mortality caused 

by accidental

direct application

DMA I008693-

040 Grass 70% of 

lawn 1999 IL Home/lawn Registered Possible N/R No

Mortality caused 

by direct 

application

DMA I008969-

015 Grass 3000 ft2 1999 OR Home/lawn Registered Possible N/R Mecopropdimethylamine 

Plant damage 

caused by direct 

application

DMA I009262-

072 Grass All 1999 MA Home/lawn Not 

determined Probable N/R No

Browning caused 

by direct 

application

DMA I009262-

103 Grass All 1999 FL Home/lawn Misuse Probable N/R Dicamba

dimethylamine salt 

Plant damage 

caused by direct 

application

DMA I009262-

118 Grass Unknown 1999 WA Home/lawn Registered Probable N/R No

Mortality caused 

by direct 

application

DMA I009786-

014 Grass 60% of lawn 2000 FL Home/lawn Registered Probable N/R

Dicamba

dimethylamine salt 

Mecoprop

dimethylamine 

Plant damage 

caused by direct 

application

DMA I009786-

015 Grass 50 to 60% 

of lawn 2000 FL Home/lawn Registered Probable N/R

Dicamba

dimethylamine salt 

Mecoprop

dimethylamine 

Plant damage 

caused by direct 

application
Page 80 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

DMA I009786-

016 Grass 80% of 

lawn 2000 FL Home/lawn Registered Probable N/R

 Dicamba

dimethylamine salt 

Mecoprop

dimethylamine 

Plant damage 

caused by direct 

application

DMA I009786-

017 Grass Unknown 2000 FL Home/lawn Registered Possible N/R

Dicamba

dimethylamine salt 

Mecoprop

dimethylamine 

Plant damage 

caused by direct 

application

DMA I009786-

018 Grass Unknown 2000 FL Home/lawn Registered Possible N/R

 Dicamba

dimethylamine salt 

Mecoprop 

dimethylamine 

Plant damage 

caused by direct 

application

DMA I009786-

019 Grass Lawn 2000 FL Home/lawn Registered Probable N/R

Mecoprop 

dimethylamine

Plant damage 

caused by direct 

application

DMA I009916-

017 Grass 95% of 

lawn 2000 FL Home/lawn Registered Probable N/R

 Dicamba

dimethylamine salt 

Mecoprop

dimethylamine 

Plant damage 

caused by direct 

application

DMA I009916-

018 Grass Unknown 2000 FL Home/lawn Registered Probable N/R

 Dicamba

dimethylamine salt 

Mecoprop 

dimethylamine 

Plant damage 

caused by direct 

application

DMA I009916-

019 Grass Unknown 2000 FL Home/lawn Not determined Possible N/R

 Dicamba

dimethylamine salt 

Mecoprop

dimethylamine 

Plant damage 

caused by direct 

application

DMA I009916-

020 Grass 90% of lawn 2000 FL Home/lawn Not determined Probable N/R

 Dicamba

dimethylamine salt 

Mecoprop 

dimethylamine 

Plant damage 

caused by direct 

application

DMA I009916-

021 Grass Lawn 2000 FL Home/lawn Registered Probable N/R Mecopropdimethylamine

Mortality caused 

by direct 

application

DMA I009916-

022 Grass 7000 ft2 2000 FL Home/lawn Misuse Probable N/R Mecoprop dimethylamine

Mortality caused 

by accidental

direct application
Page 81 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

DMA I010017-

013 Grass Lawn 2000 FL Home/lawn Registered Probable N/R

Dicamba

dimethylamine salt 

Mecoprop 

dimethylamine 

Plant damage 

caused by direct 

application

DMA I010017-

014 Grass 50% of 

lawn 2000 FL Home/lawn Registered Probable N/R

Dicamba

dimethylamine salt 

Mecoprop

dimethylamine 

Plant damage 

caused by direct 

application

DMA I010017-

015 Grass Lawn 2000 FL Home/lawn Registered Probable N/R Mecoprop

dimethylamine

Plant damage 

caused by direct 

application

DMA I010062-

002 Grass Unknown 2000 N/R Home/lawn Misuse Probable N/R

Dicamba

dimethylamine salt 

Mecoprop 

dimethylamine 

Plant damage 

caused by 

accidental direct 

application

DMA I010764-

001 Grass 210 ft2 2000 NY Home/lawn Registered Probable N/R Mecopropdimethylamine

Plant damage 

caused by direct 

application

DMA I012452-

004 White pine tree 6 trees 2001 PA Fence row Registered Possible N/R

Dicamba

dimethylamine salt 

Mecoprop 

dimethylamine 

Mortality caused 

by drift.

DMA I013850-

001 Grass 1/3 of 

backyard 2002 MI Right-of-way, 

rail Registered Unlikely N/R

Bromacil 

Diuron 

Glyphosate

isopropylamine salt

Mortality caused 

by runoff

DMA I014415-

001 Cotton 75% of 120 

acres 2003 TX Conservation 

Reserve

Not 

determined Possible N/R

 Dicamba

dimethylamine salt 

Metsulfuron-methyl

Plant damage 

caused by drift.

DMA I016656-

001 Millet 35 of 140 

acres 2004 ND Agricultural 

area

Not 

determined Possible N/R No

Plant damage 

caused by direct 

application

DMA I017837-

003 Unknown Tree $118,000 2004 MN Right-of-way, 

utility Registered Possible N/R Triclopyr

triethylamine salt

Mortality caused 

by spray drift.

DMA I017893-

021 Alfalfa $ 49,999 

damage 2006 CA Agricultural 

area Misuse Possible N/R

Malathion 

Dicamba

dimethylamine salt

Plant damage 

caused by 

accidental spray 

drift.
Page 82 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

DMA I020366-

001 Cotton 65,378.5 

acres 2008 AR Agricultural 

area

Not 

determined Probable N/R No

Plant damage 

caused by spray 

drift.

DMA I020366-

001 Cotton 65,378.5 

acres 2008 AR Agricultural 

area

Not 

determined Probable N/R No

Plant damage 

caused by spray 

drift.

DMA I020366-

001 Cotton 65,378.5 acres 2008 AR Agricultural area

Not 

determined Probable N/R No

Plant damage 

caused by spray 

drift.

DMA I020388-

001 Cotton 65,378.5 acres 2006 AR Rice Registered Probable N/R No

Plant damage 

caused by spray 

drift.

DMA I020388-

001 Cotton 65,378.5 

acres 2006 AR Rice Registered Probable N/R No

Plant damage 

caused by spray 

drift.

DMA I020388-

001 Cotton 65,378.5 

acres 2006 AR Rice Registered Probable N/R No

Plant damage 

caused by spray 

drift.

DMA I020388-

001 Cotton 65,378.5 

acres 2006 AR Rice Registered Probable N/R No

Plant damage 

caused by spray 

drift.

DMA I020388-

001 Cotton 65,378.5 

acres 2006 AR Rice Registered Probable N/R No

Plant damage 

caused by spray 

drift.

DMA I020388-

001 Cotton 65,378.5 

acres 2006 AR Rice Registered Probable N/R No

Plant damage 

caused by spray 

drift.

DMA I020388-

001 Cotton 65,378.5 

acres 2006 AR Rice Registered Probable N/R No

Plant damage 

caused by spray 

drift.

2-EHE I007898-

001 Vegetable ALL 1998 CO Agricultural area Registered Possible N/R Dicamba Plant damage caused by drift.

2-EHE I020340-

001 Vegetable 80% of 235 

acres 2008 WA Barley Registered Unlikely N/R Metsulfuronmethyl

Plant damage 

caused by 

carryover

2-EHE I020388-

001 Cotton 65,378.5 

acres 2006 AR Rice Registered Probable N/R DMA Plant damage 

caused by drift.
Page 83 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

2-EHE I020388-

001 Cotton 65,378.5 

acres 2006 AR Rice Registered Probable N/R DMA

Plant damage 

caused by due to 

drift.

2-EHE I020388-

001 Cotton 65,378.5 acres 2006 AR Rice Registered Probable N/R DMA Plant damage caused by drift.

2-EHE I020627-

006 Wheat 1400 acres 2001 WA Agricultural 

area Misuse Possible N/R Glyphosate 

Metsulfuron-methyl 

Plant damage 

caused by 

accidental drift 

and glyphosate 

and late 

application of 

2,4-D. 

BEE I021421-

001 Grape N/R N/R NC Pasture Misuse Highly 

probable N/R Triclopyr, 

butoxyethyl ester 

Plant damage 

caused by spray 

drift.

TIPA I009507-

001 Soybean 10 acres 1999 SD Soybean Registered Possible N/R Clopyralid

Plant damage 

from direct 

treatment. Heavy 

amounts of straw 

manure present.

TIPA I010624-

001

Potato

Tomato N/R 2000 WA Hay Registered Unlikely N/R

Picloram

triisopropanolamine 

salt

Plant damage 

possibly from 

Tordon-treated 

grass hay in 

compost stream.

TIPA I012366-

045 Brome 500 acres 2000 KS Brome Registered Probable N/R

Picloram

triisopropanolamine 

salt

Plant damage 

from direct 

treatment.

TIPA I012366-

046 Bahia grass 30 acres 2000 TX Pasture Registered Probable N/R

Picloram

triisopropanolamine 

salt

 Plant damage 

from direct 

treatment.

TIPA I012366-

047 Hay 42 acres 2000 AR Hay Registered Possible N/R

Picloram 

triisopropanolamine 

salt

Metsulfuron-methyl 

Plant damage 

caused by 

carryover.

TIPA I013550-

001 Peanut 360 acres 2002 TX Peanut Misuse Probable N/R

 Picloram 

triisopropanolamine 

salt

Plant damage 

from direct 

treatment.
Page 84 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

Picloram potassium 

salt

Ethalfluralin 

TIPA I014034-

009 Pasture Grass 60 acres 2003 GA Pasture Registered Possible N/R

Picloram 

triisopropanolamine 

salt

Paraquat dichloride 

Plant damage 

from direct 

treatment.

TIPA I014561-

012 Oak Various 2003 TX N/R Not 

determined Possible N/R

Picloram 

triisopropanolamine 

salt

Plant damage 

caused by drift.

TIPA I014702-

018 Pasture Grass 60 acres N/R MO Pasture Registered Possible N/R

 Picloram 

triisopropanolamine 

salt

Plant damage 

from direct 

treatment.

TIPA I014702-

019 Hay 40 acres 2003 MS Hay Registered Possible N/R

 Picloram

triisopropanolamine 

salt

Plant damage 

from direct 

treatment.

TIPA I015748-

016 Field corn 132 acres 2004 OH Corn, field Registered Possible N/R

Atrazine

Clopyralid

monoethanolamine 

salt 

Acetochlor

Plant damage 

from direct 

treatment.

TIPA I015921-

002 Unknown tree trees 

(hundreds) 2003 OK Agricultural 

area

Not 

determined Possible N/R

Picloram

Tebuthiuron

Triclopyr 

Plant damage 

and mortality 

caused by drift.

TIPA I018930-

031

Watermelon

Tomato

Onion

Pepper

2 acres 2007 TX Hay Misuse Possible N/R

 Picloram

triisopropanolamine 

salt 

Plant damage 

caused by misuse.

TIPA I020761-

001

Tomato

Cucumber

Squash

Zinnia

N/R 2008 NC Hay Registered Possible N/R Aminopyralid 

triisopropanolamine 

Plant damage 

possibly from 

compost.

IPA I000360-

015 Milo 340 acres 1993 KS Milo Registered Possible N/R Glyphosate 

isopropylamine salt Plant damage

DEA I018984-

004 Alfalfa N/R 2007 CA Agricultural 

area Registered Possible N/R Dicamba

diglycoamine salt 

Mortality and 

damage caused 
Page 85 of 85

Table C.1 Ecological Incidents Associated with 2,4-D Acid, Salts, Amines, and Esters from the EIIS Database

Incident 

Number 

(Source)

Taxa Magnitude Year State Use Legality of 

Use

Certainty 

Category Residues Other Chemicals 

Involved Comments

by direct 

application.