Isoxaflutole (Ref: RPA 201772)

Isoxaflutole (Ref: RPA 201772)	Last updated: 26/05/2025
(Not known by any other names)

SUMMARY

Data alerts

The following alerts are based on the data in the tables below. An absence of an alert does not imply the substance has no implications for human health, biodiversity or the environment but just that we do not have the data to form a judgement.

Environmental fate	Ecotoxicity	Human health
Environmental fate Moderate alert: Drainflow: Moderately mobile	Ecotoxicity Moderate alert: Birds chronic ecotoxicity: Moderate; Fish acute ecotoxicity: Moderate; Fish chronic ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate; Daphnia chronic ecotoxicity: Moderate; Earthworms acute ecotoxicity: Moderate; Earthworms chronic ecotoxicity: Moderate	Human health Moderate alert: Possible Carcinogen; Reproduction/development effects; Neurotoxicant

GENERAL INFORMATION

Description

A broad-spectrum pre-emergence soil herbicide for the control of weeds in maize and sugarcane

Example pests controlled

Broadleaved weeds; Annual grasses

Example applications

Maize; Sugar cane

Efficacy & activity

Availability status

Current

Introduction & key dates

1998, registered USA

GB regulatory status

GB COPR regulatory status

Approved

Date COPR inclusion expires

31/07/2034

GB LERAP status

Check label - may vary with formulation

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Approved

Dossier rapporteur/co-rapporteur

Italy/Slovenia

Date EC 1107/2009 inclusion expires

31/07/2034

EU Candidate for substitution (CfS)

Listed in EU database

Yes

Approved for use (✓) under EC 1107/2009 in the following EU Member States

ATAustria	BEBelgium	BGBulgaria	CYCyprus	CZCzech Republic	DEGermany	DKDenmark	EEEstonia	ELGreece
✓	✓	✓		✓	✓			✓
ESSpain	FIFinland	FRFrance	HRCroatia	HUHungary	IEIreland	ITItaly	LTLithuania	LULuxembourg
✓		✓	✓	✓	✓			✓
LVLatvia	MTMalta	NLNetherlands	PLPoland	PTPortugal	RORomania	SESweden	SISlovenia	SKSlovakia
		✓	✓	✓	✓		✓	✓

Approved for use (✓) under EC 1107/2009 by Mutual Recognition of Authorisation and/or national regulations in the following EEA countries

ISIceland	NONorway

Additional information

Also used in

Australia; USA

Chemical structure

Isomerism

None

Chemical formula

C₁₅H₁₂F₃NO₄S

Canonical SMILES

CS(=O)(=O)C1=C(C=CC(=C1)C(F)(F)F)C(=O)C2=C(ON=C2)C3CC3

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

OYIKARCXOQLFHF-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C15H12F3NO4S/c1-24(21,22)12-6-9(15(16,17)18)4-5-10(12)13(20)11-7-19-23-14(11)8-2-3-8/h4-8H,2-3H2,1H3

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
isoxaflutole	-

General status

Pesticide type

Herbicide

Substance groups

Oxazole herbicide; Cyclopropylisoxazole herbicide

Minimum active substance purity

950 g kg⁻¹

Known relevant impurities

EU dossier - None declared

Substance origin

Synthetic

Mode of action

Systemic absorbed by roots and leaves. Bleaching: inhibition of 4-hydroxyphenyl-pyruvate-dioxygenase.

CAS RN

141112-29-0

EC number

604-222-4

CIPAC number

575

US EPA chemical code

123000

PubChem CID

84098

CLP index number

606-054-00-7

Molecular mass

359.32

PIN (Preferred Identification Name)

IUPAC name

(5-cyclopropyl-1,2-oxazol-4-yl)(α,α,α-trifluoro-2-mesyl-p-tolyl)methanone

CAS name

(5-cyclopropyl-4-isoxazolyl)[2-(methylsulfonyl)-4-(trifluoromethyl)phenyl]methanone

Other status information

Phytotoxic

Relevant Environmental Water Quality Standards

Herbicide Resistance Class (HRAC MoA class)

Herbicide Resistance Class (WSSA MoA class)

Insecticide Resistance Class (IRAC MoA class)

Not applicable

Fungicide Resistance Class (FRAC MOA class)

Not applicable

Examples of recorded resistance

Physical state

Off-white solid

Formulations

Property

Value

Example manufacturers & suppliers of products using this active now or historically

Bayer CropScience
Rhone-Poulenc Ag Company

Example products using this active

Cadu Star
Balance Herbicide
Balance Pro
Merlin
Flexx
Spade

Formulation and application details

Usually supplied as water dispersible granules

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

Solubility - In water at 20 °C (mg l⁻¹)

6.2

Low

Solubility - In organic solvents at 20 °C (mg l⁻¹)

293000

Acetone

142000

Ethyl acetate

31200

Toluene

13800

Methanol

Melting point (°C)

140

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

205

Flashpoint (°C)

Octanol-water partition coefficient at pH 7, 20 °C

2.19 X 10⁰²

Calculated

Log P

2.34

Low

Fat solubility of residues

Solubility

Insoluble

Data type

Regulatory data based on LogP

Density (g ml⁻¹)

1.59

Dissociation constant pKa) at 25 °C

Not applicable

No dissociation

Vapour pressure at 20 °C (mPa)

3.22 X 10^-04

Low volatility

Henry's law constant at 25 °C (Pa m³ mol⁻¹)

1.87 X 10^-05

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

1.0

24 hr

Volatilisation is not considered critical for air pollution

From soil surface

Negligible

24 hr

Maximum UV-vis absorption L mol⁻¹ cm⁻¹

Neutral solution: 204nm = 22668, 269.4nm = 11764, No absorption <290nm
Acid solution: 205.4nm = 22393, 269.2nm= 11788
Basic solution: 218.4nm = 18262, 292nm = 12861

Surface tension (mN m⁻¹)

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

0.9

Non-persistent

DT₅₀ (lab at 20 °C)

0.9

Non-persistent

DT₅₀ (field)

1.3

Non-persistent

DT₉₀ (lab at 20 °C)

30.1

Moderately persistent

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

EU dossier (2016) lab studies DT₅₀ range 0.2-5.9 days, DT₉₀ range 0.94-35.8 days, Soil =5; Field study DT₅₀ range 0.5-2.4 days

Dissipation rate RL₅₀ (days) on plant matrix

Value

Note

Dissipation rate RL₅₀ (days) on and in plant matrix

Value

Note

Aqueous photolysis DT₅₀ (days) at pH 7

Value

1.7

Moderately fast

Note

Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7

Value

0.8

Non-persistent

Note

pH sensitive: DT₅₀ 11 days pH 4 and pH 5, 3.2 hours at pH 9, all at 25 °C

Water-sediment DT₅₀ (days)

0.36

Fast

Water phase only DT₅₀ (days)

0.36

Fast

Sediment phase only DT₅₀ (days)

Air degradation

As this parameter is not normally measured directly, a surrogate measure is used: ‘Photochemical oxidative DT₅₀’. Where data is available, this can be found in the Fate Indices section below.

Decay in stored produce DT₅₀

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d (mL g⁻¹)

2.8

Moderately mobile

K_oc (mL g⁻¹)

145

Notes and range

Literature data K_d range 1.24-3.77 mL g⁻¹, K_oc range 124-160 mL g⁻¹, soils=4

Freundlich

K_f (mL g⁻¹)

2.73

Moderately mobile

K_foc (mL g⁻¹)

79.8

¹/_n

0.94

Notes and range

EU dossier (2016)K_d range 0.24-8.15 mL g⁻¹, K_foc range 48-109 mL g⁻¹, ¹/_n range 0.87-1.03, Soils=4; Other litertaure data K_f range 1.17-3.22 mL g⁻¹, K_foc range 117-136 mL g⁻¹, Soils=4 (R4)

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

0.24

Calculated

Low leachability

SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate

Value

8.47 X 10^-04

Calculated

Note

Potential for particle bound transport index

Low

Calculated

Potential for loss via drain flow

Moderately mobile

Calculated

Photochemical oxidative DT₅₀ (hrs) as indicator of long-range air transport risk

43.92

Calculated using the Atkinson method. Assumed 1.5E+06 OH/cm³, 12 hr

Below the level of concern for long-range air transport

Bio-concentration factor

BCF (l kg⁻¹)

Low potential

CT₅₀ (days)

Not available

Known soil metabolites

Metabolite

Major/Minor fraction

$Click here for further information on Major/Minor fraction$

Estimated maximum occurrence fraction

Notes

(2RS)-3-cyclopropyl-2-(2-(methylsulfonyl)-4-(trifluoromethyl)benzoyl)-3-oxopropanenitrile (Ref: RPA 202248)

Major fraction

0.964

Bayer verified

2-mesyl-4-trifloromethylbenzoic acid (Ref: RPA 203328)

Major fraction

0.900

Bayer verified

Known groundwater metabolites

Metabolite

EC SANCO/221/2000 relevancy

ADI (mg kg⁻¹ bodyweight day⁻¹)

WHO drinking water guidance value (μg L⁻¹ day⁻¹)

2-mesyl-4-trifloromethylbenzoic acid (Ref: RPA 203328)

Not relevant

0.8

4800

(2RS)-3-cyclopropyl-2-(2-(methylsulfonyl)-4-(trifluoromethyl)benzoyl)-3-oxopropanenitrile (Ref: RPA 202248)

Relevant

0.8

4800

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

Ref: RPA 205834
Note: LC50(fish) = 35 mg/l; LC50(Daphnia) = 100 mg/l

Water; Sediment

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 5000

Rat

Low

Mammals - Short term dietary NOEL

(mg kg⁻¹)

Rat 2 yr

High

(ppm diet)

Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)

500

Rat Reproductive NOAEL

Low

Birds - Acute LD₅₀ (mg kg⁻¹)

> 2150

Anas platyrhynchos

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

> 4150 mg kg feed⁻¹

Anas platyrhynchos

Birds - Chronic 21d NOEL (mg kg⁻¹ bw d⁻¹)

Colinus virginianus NOAEL

Moderate

Earthworms - Acute 14 day LC₅₀ (mg kg⁻¹)

> 500

Eisenia foetida corr

Moderate

Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)

8.9

Eisenia foetida corr

Moderate

Soil micro-organisms

Nitrogen mineralisation: No significant adverse effect
Carbon mineralisation: No significant adverse effect

Dose: 1.0 mg kg⁻¹ soil

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

> 500

Folsomia candida corr

Non-target plants

Honeybees (Apis spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

> 100

Apis mellifera

Low

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

> 168.7

Apis mellifera

Low

Unknown mode acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Chronic

Notes

Bumblebees (Bombus spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Mason bees (Osmia spp.)

Contact acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Oral acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg bee⁻¹)

Other bee species (1)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Other bee species (2)

Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)

Mode of exposure

Beneficial insects (Ladybirds)

Beneficial insects (Lacewings)

Beneficial insects (Parasitic wasps)

Beneficial insects (Predatory mites)

Beneficial insects (Ground beetles)

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Temperate Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

> 1.7

Oncorhynchus mykiss

Moderate

Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)

0.08

Oncorhynchus mykiss

Moderate

Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)

Temperate Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

> 1.5

Daphnia magna

Moderate

Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)

0.35

Daphnia magna

Moderate

Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)

Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)

0.014

Americamysis bahia

High

Sediment dwelling organisms - Acute 96 hour LC₅₀ (mg l⁻¹)

> 1.5

Chironomus riparius

Moderate

Sediment dwelling organisms - Chronic 28 day NOEC, static, water (mg l⁻¹)

0.1

Chironomus riparius

Moderate

Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)

Aquatic plants (free-floating, growth) - Acute 7 day EC₅₀, biomass (mg l⁻¹)

0.016

Lemna gibba

Moderate

Aquatic plants (rooted, growth) - Acute 14 day EC₅₀, biomass (mg l⁻¹)

Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)

0.12

Raphidocelis subcapitata 120 hr

Moderate

Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)

Mesocosm study data

NOEAEC mg l⁻¹

Marine bivalves

HUMAN HEALTH AND PROTECTION

General

Property

Value

Source; quality score; and other information

Interpretation

Threshold of Toxicological Concern (Cramer Class)

High (class III)

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 5000

Rat

Low

Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 5.23

Rat 4 hr (whole body)

Other Mammal toxicity endpoints

ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)

0.02

Rat SF=100

ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)

0.05

Rabbit SF=100

AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)

AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)

0.012

Rat SF=167

Dermal penetration studies (%)

0.7-3

concentration dependent

Dangerous Substances Directive 76/464

List II

Exposure Routes

Public

No unacceptable risks to bystanders identified

Occupational

No unacceptabe risk to operators or other workers identified

MRLs

European

EU MRL pesticide database

Great Britain

GB MRL Register

Notes

Drinking Water Standards

Drinking Water MAC (μg l⁻¹)

Mammalian dose elimination route and rate

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

; ; ; ;

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

Respiratory tract irritant

Skin irritant

Skin sensitiser

Eye irritant

Phototoxicant

General human health issues

Possible liver toxicant
May damage corneal opacity
US EPA - likely to be human carcinogen

Handling issues

Property

Value and interpretation

General

Not explosive or oxidising
IMDG Transport Hazard Class 9
Not expected to auto-ignite; Not highly flammable

CLP classification 2013

Health: H361d
Environment: H400, H410

WHO Classification

III (Slightly hazardous)

UN Number

UN3077

Waste disposal & packaging

Packaging Group III (minor danger)

Shelf-life, storage, stability and reactivity

Chemically stable under standard ambient conditions

TRANSLATIONS

Language

Name

English

isoxaflutole

French

isoxaflutole

German

Isoxaflutol

Danish

isoxaflutol

Italian

isoxaflutolo

Spanish

isoxaflutol

Greek

isoxaflutole

Polish

izoksaflutol

Swedish

Hungarian

izoxaflutol

Dutch

isoxaflutole

Norwegian

Record last updated:	26/05/2025
Contact:	aeru@herts.ac.uk
Please cite as:	Lewis, K.A., Tzilivakis, J., Warner, D. and Green, A. (2016) An international database for pesticide risk assessments and management. Human and Ecological Risk Assessment: An International Journal, 22(4), 1050-1064. DOI: 10.1080/10807039.2015.1133242