Flazasulfuron (Ref: OK 1166)

Flazasulfuron (Ref: OK 1166)	Last updated: 26/05/2025
(Also known as: SL 160)

SUMMARY

Flazasulfuron is a sulfonylurea herbicide used to control a wide range of annual and perennial weeds. It has a high aqueous solubility and a low volatility. Evidence suggests it is not persistent in soil systems. Its persistence in water bodies may be very high depending on local conditions. Based on physico-chemical properties, flazasulfuron is not expected to leach to groundwater. It is moderately toxic to most species with the main exception being aquatic plants for which ecotoxicity is high. It has a low mammalian oral toxicity and there are some concerns that this substance may be a reproduction/developmental toxin.

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 High alert: Drainflow: 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 High alert: Reproduction/development effects

GENERAL INFORMATION

Description

A pre- and post-emergence selective herbicide used to control a wide range of annual and perennial weeds

Example pests controlled

Grasses; Broadleaved weeds; Sedges

Example applications

Turf; Citrus; Grapes; Olives; Sugarcane; Non-cropped areas

Efficacy & activity

Efficacy has been scientifically demonstrated. Many crops show very good tolerance as long as green parts are not exposed.

Availability status

Current

Introduction & key dates

1989, registered Japan

GB regulatory status

GB COPR regulatory status

Approved

Date COPR inclusion expires

31/07/2032

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

Spain/France

Date EC 1107/2009 inclusion expires

31/07/2032

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

South Africa; Brazil; Colombia; Mexico; Japan; Taiwan

Chemical structure

Isomerism

None

Chemical formula

C₁₃H₁₂F₃N₅O₅S

Canonical SMILES

COC1=CC(=NC(=N1)NC(=O)NS(=O)(=O)C2=C(C=CC=N2)C(F)(F)F)OC

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

HWATZEJQIXKWQS-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C13H12F3N5O5S/c1-25-8-6-9(26-2)19-11(18-8)20-12(22)21-27(23,24)10-7(13(14,15)16)4-3-5-17-10/h3-6H,1-2H3,(H2,18,19,20,21,22)

2D structure diagram/image available?

Yes

General status

Pesticide type

Herbicide

Substance groups

Sulfonylurea herbicide; Pyrimidinylsulfonlurea herbicide

Minimum active substance purity

960 g kg⁻¹

Known relevant impurities

EU dossier - None declared

Substance origin

Synthetic

Mode of action

Systemic, absorbed through leaves. Inhibits plant amino acid synthesis - acetohydroxyacid synthase AHAS

CAS RN

104040-78-0

EC number

600-514-0

CIPAC number

595

US EPA chemical code

119011

PubChem CID

93539

CLP index number

016-085-00-2

Molecular mass

407.37

PIN (Preferred Identification Name)

N-[(4,6-dimethoxypyrimidin-2-yl)carbamoyl]-3-(trifluoromethyl)pyridine-2-sulfonamide

IUPAC name

1-(4,6-dimethoxypyrimidin-2-yl)-3-(3-trifluoromethyl-2-pyridylsulfonyl)urea

CAS name

N-[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]-3-(trifluoromethyl)-2-pyridinesulfonamide

Other status information

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

White crystalline powder

Formulations

Property

Value

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

ISK Biosciences
Ishihara Sangyo Kaisha Ltd.
Belchim

Example products using this active

Mission
Aikido
Chikara
Epsilon
Katana
Paradise

Formulation and application details

Usually supplied as a wettable powder.

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

2100

High

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

0.5

n-Hexane

560

Toluene

22100

Dichloromethane

6900

Ethyl acetate

Melting point (°C)

180

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

181.5

Flashpoint (°C)

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

8.71 X 10^-01

Calculated

Log P

-0.06

Low

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

1.62

Dissociation constant pKa) at 25 °C

4.37

Weak acid

Vapour pressure at 20 °C (mPa)

0.0133

Low volatility

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

2.58 X 10^-06

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

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

241.0nm = 17300

Surface tension (mN m⁻¹)

70.5

at 20 °C 100%

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

41.2

Moderately persistent

DT₅₀ (lab at 20 °C)

41.2

Moderately persistent

DT₅₀ (field)

Non-persistent

DT₉₀ (lab at 20 °C)

162.3

Persistent

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

EU 2016 dossier lab studies DT₅₀ range 7.65-102.1 days, DT₉₀ range 55.5-339.3 days, field studies DT₅₀ range 2-18 days, DT₉₀ range 10-100 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

Stable

Note

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

Value

Non-persistent

Note

pH sensitive: DT₅₀ 0.5 days at pH 4, 2.6 days at pH 5, 8.8 days at pH 9, all at 25 °C

Water-sediment DT₅₀ (days)

Fast

Water phase only DT₅₀ (days)

Slow

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)

Mobile

K_oc (mL g⁻¹)

46.2

Notes and range

EU dossier K_oc range 32.4-80.9 mL g⁻¹, Soils=4

Freundlich

K_f (mL g⁻¹)

4.79

Moderately mobile

K_foc (mL g⁻¹)

283.3

¹/_n

0.844

Notes and range

EU 2016 dossier K_f range 1.87-8.45 mL g⁻¹, K_foc range 59-768 mL g⁻¹, ¹/_n range 0.80-0.87, Soils=4

pH sensitivity

Yes

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

1.55

Calculated

Low leachability

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

Value

2.32 X 10^-02

Calculated

Note

Potential for particle bound transport index

Low

Calculated

Potential for loss via drain flow

Mobile

Calculated

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

0.6

Calculated using the Atkinson method. Assumed 1.5E+05 OH/cm³, 12 hr

Below the level of concern for long-range air transport

Bio-concentration factor

BCF (l kg⁻¹)

Low risk

Based on LogP < 3

Low risk

CT₅₀ (days)

Known soil metabolites

Metabolite

Major/Minor fraction

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

Estimated maximum occurrence fraction

Notes

1-(4,6-dimethoxypyrimidin-2-yl)-1-(3-trifluoromethyl-2-pyridyl)urea

Major fraction

0.663

3-trifluoromethyl-2-pyridylsulfonamide

Major fraction

0.260

4,6-dimethoxy-N-(3-(trifluoromethyl)pyridin-2-yl)pyrimidin-2-amine

Major fraction

0.478

6-methoxy-2-{[3-(trifluoromethyl)pyridin-2-yl]amino}pyrimidin-4-ol

1-(4,6-dimethoxypyrimidin-2-yl)urea

N-[(4-methoxy-6-oxo-1,6-dihydropyrimidin-2-yl)carbamoyl]-3-(trifluoromethyl)pyridine-2-sulfonamide

1-(4-hydroxy-6-methoxypyrimidin-2-yl)-1-[3-(trifluoromethyl)pyridin-2-yl]urea

3-(trifluoromethyl)pyridin-2(1H)-one

4,6-dimethoxy-2-pyrimidinamine

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)

3-trifluoromethyl-2-pyridylsulfonamide

Not relevant

2-amino-4,6-dimethoxypyrimidine

Not relevant

1-(4-hydroxy-6-methoxypyrimidin-2-yl)-1-[3-(trifluoromethyl)pyridin-2-yl]urea (Ref: HMTU)

Not relevant

N-guanidinocarbonyl-3-trifluoromethylpyridine-2-sulfonamide (Ref: GTPS)

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

N-[(4-Methoxy-6-oxo-1,6-dihydropyrimidin-2-yl)carbamoyl]-3-(trifluoromethyl)pyridine-2-sulfonamide

HMTU

Mammal

1-(4-Hydroxy-6-methoxypyrimidin-2-yl)-1-[3-(trifluoromethyl)pyridin-2-yl]urea

HTPU

Mammal; Surface water

3-(Trifluoromethyl)pyridin-2(1H)-one

HTF

Surface water

4,6-dimethoxy-2-pyrimidinamine
Note: Oral LD50(rat) = 737mg/kg

ADMP

Mammal; Plant

6-Methoxy-2-{[3-(trifluoromethyl)pyridin-2-yl]amino}pyrimidin-4-ol

HTPP

Water; Sediment

1-(4,6-Dimethoxypyrimidin-2-yl)urea

DMPU

Mammal; Plant; Surface water

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)

11.7

Rat

High

(ppm diet)

200

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

11.7

Rat Reproduction

Moderate

Birds - Acute LD₅₀ (mg kg⁻¹)

> 2000

Colinus virginianus

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

> 5620 mg kg feed⁻¹

Colinus virginianus

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

> 100

Colinus virginianus

Moderate

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

> 15.75

Eisenia foetida

Moderate

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

8.0

Eisenia foetida

Moderate

Soil micro-organisms

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

Dose: 10 x field rate

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

125

Folsomia candida

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)

> 100

Apis mellifera

Low

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

Chronic as 10-day LDD₅₀ µg bee⁻¹ day⁻¹

> 59.2

Apis mellifera

Notes

Bumblebees (Bombus spp.)

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

> 100

Bombus terrestris

Low

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

97.5

Bombus terrestris

Moderate

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) as Mortality LR₅₀ g ha⁻¹

> 50

Aphidius rhopalosiphi

Beneficial insects (Predatory mites) as Mortality LR₅₀ g ha⁻¹

Typhlodromus pyri

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)

Oncorhynchus mykiss

Moderate

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

Oncorhynchus mykiss

Moderate

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

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

> 25

Daphnia magna

Moderate

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

6.25

Daphnia magna

Moderate

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

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

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

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)

0.00004

Lemna gibba 7 day

High

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

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

0.014

Pseudokirchneriella subcapitata

Moderate

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

0.005

Pseudokirchneriella subcapitata

Moderate

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)

> 5.99

Rat 4 hr (whole body)

Other Mammal toxicity endpoints

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

0.013

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

1.0

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

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

0.02

Dog 1 year SF=100

Dermal penetration studies (%)

10.0

Dangerous Substances Directive 76/464

List II

Exposure Routes

Public

No unacceptable risks to bystanders identified

Occupational

No unacceptable risks 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, kidney & blood toxicant

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

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

TRANSLATIONS

Language

Name

English

flazasulfuron

French

flazasulfuron

German

Flazasulfuron

Danish

flazasulfuron

Italian

flazasulfuron

Spanish

flazasulfuron

Greek

Polish

flazasulfuron

Swedish

Hungarian

flazaszulfuron

Dutch

flazasulfuron

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