Cinmethylin (Ref: BAS 684 H)

Cinmethylin (Ref: BAS 684 H)	Last updated: 23/05/2025
(Also known as: WL 95481; cinch; SD 95481)

SUMMARY

Cinmethylin is a selective, pre-emergence herbicide used mainly for rice and cereal crops. It is moderately soluble in water, is quite volatile and, based on its chemical properties, it is non-mobile and would not be expected to leach to groundwater. It may be persistent in both soil and aquatic systems. It is not susceptible to hydrolysis. It is not acutely toxic to mammals but it is an eye and skin irritant. It shows a moderate level of toxicity to birds, fish and daphnia.

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: GUS: Transition state	Ecotoxicity Moderate alert: Birds chronic ecotoxicity: Moderate; Fish acute ecotoxicity: Moderate; Fish chronic ecotoxicity: Moderate; Daphnia acute ecotoxicity: Moderate; Daphnia chronic ecotoxicity: Moderate; Earthworms chronic ecotoxicity: Moderate	Human health Moderate alert: Neurotoxicant

GENERAL INFORMATION

Description

A pre-emergence herbicide used to control annual grasses and broad -eaved weeds

Example pests controlled

Barnyardgrass; Velvetleaf; Crabgrass; Pigweed; Annual ryegrass; Blackgrass; Annual meadow grass and annual dicots

Example applications

Rice; Soybeans; Cereals including winter wheat, winter barley; Winter oilseed rape

Efficacy & activity

Efficacy established via field trials

Availability status

Current

Introduction & key dates

1989, introduced

GB regulatory status

GB COPR regulatory status

Approved

Date COPR inclusion expires

06/06/2032

GB LERAP status

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Pending

Dossier rapporteur/co-rapporteur

Netherlands/France

Date EC 1107/2009 inclusion expires

Not applicable

EU Candidate for substitution (CfS)

Not applicable

Listed in EU database

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

Chemical structure

Isomerism

A chiral molecule with three stereocenters. The technical material is a racemic mixture.

Chemical formula

C₁₈H₂₆O₂

Canonical SMILES

CC1=CC=CC=C1COC2CC3(CCC2(O3)C)C(C)C

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

QMTNOLKHSWIQBE-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C18H26O2/c1-13(2)18-10-9-17(4,20-18)16(11-18)19-12-15-8-6-5-7-14(15)3/h5-8,13,16H,9-12H2,1-4H3/t16-,17+,18-/m1/s1

2D structure diagram/image available?

Yes

General status

Pesticide type

Herbicide; Other substance

Other bioactivity & uses

Biocide

Substance groups

Cineole compound; Unclassified herbicide

Minimum active substance purity

>950 g kg⁻¹

Known relevant impurities

UK HSE Dossier: BAS 4539586 (1SR,2RS,4RS)-1-methyl-4-(pro-pan-2-yl)-7--oxa-bicyclo2.2.1-heptan-2-ol: 4.0 g kg⁻¹; Toluene: 0.5 g kg⁻¹
EFSA 2022 dossier: Toluene < 0.5 g kg⁻¹

Substance origin

Synthetic

Mode of action

Selective, systemic, absorbed by roots and translocated. Disrupts the meristemic development in shoots and roots of susceptible weeds.

CAS RN

87818-31-3

EC number

402-410-9

CIPAC number

1022

US EPA chemical code

128837

PubChem CID

91745

CLP index number

603-093-00-1

Molecular mass

274.40

PIN (Preferred Identification Name)

rac-(1R,2S,4S)-1-methyl-2-[(2-methylphenyl)methoxy]-4-(propan-2-yl)-7-oxabicyclo[2.2.1]heptane

IUPAC name

rac-(1R,2S,4S)-1-methyl-4-(1-methylethyl)-2-((2-methylphenyl)methoxy)-7-oxabicyclo[2.2.1]heptane

CAS name

rel-(1R,2S,4S)-1-methyl-4-(1-methylethyl)-2-((2-methylphenyl)methoxy)-7-oxabicyclo[2.2.1]heptane

Other status information

Risk of spray drift; Registered Under REACH

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

Dark orange liquid, colourless in pure form and has a faint fruity odour

Formulations

Property

Value

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

BASF Agro B.V.
Dupont

Example products using this active

Argold
Cinch

Formulation and application details

Usually supplied as an emusifiable concentrate or as granules for use as a foliar spray

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

Moderate

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

Miscible

Acetone

Miscible

Ethyl acetate

Miscible

n-Heptane

Miscible

Methanol

Melting point (°C)

Not relevant

solidifies at -56 °C

Boiling point (°C)

330

Degradation point (°C)

None observed <400

Flashpoint (°C)

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

3.16 X 10⁰⁴

Calculated

Log P

4.5

High

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

1.014

Dissociation constant pKa) at 25 °C

n/a

No dissociation

Vapour pressure at 20 °C (mPa)

8.1

Moderately volatile. If applied directly to plants or soil, drift is a concern & mitigation is advisable

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

3.2 X 10^-02

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

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

pH 6.8: 209nm=8671.6, 262nm=269.0
pH 6.0: 196nm=22072.9, 208nm=8774.2, 263nm=327.9
pH 1.8: 9nm=12125.9, 208nm=8768;3, 263nm=327.9
pH 12.1: 215nm: 6017.6, 263nm=312.7

Surface tension (mN m⁻¹)

50.3

20 °C 99%

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Not readily biodegradable

Soil degradation (days) (aerobic)

DT₅₀ (typical)

93.6

Moderately persistent

DT₅₀ (lab at 20 °C)

93.6

Moderately persistent

DT₅₀ (field)

22.4

Non-persistent

DT₉₀ (lab at 20 °C)

231.9

Persistent

DT₉₀ (field)

111.5

DT₅₀ modelling endpoint

11.1

normalised

Note

UK HSE dossier 2020: Lab studies DT₅₀ (measured) range 18.5-93.6 days; DT₉₀ (measured)range 63.5-541.4 days, Soils= 4; Field studies DT₅₀ (measured) range 2.5-207.6 days, DT₉₀ (measured) range 18.2-207.6 days, Soils=11; Literature values DT₅₀ range 23-75 days; slower in paddy fields

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

41.8

Stable

Note

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

Value

Stable

Note

Stable pH 3 to pH 11 at 25 °C.

Water-sediment DT₅₀ (days)

39.2

Moderately fast

Water phase only DT₅₀ (days)

7.0

Moderately 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)

Non-mobile

K_oc (mL g⁻¹)

6850

Notes and range

Other data source: 300 mL g⁻¹ (US3)

Freundlich

K_f (mL g⁻¹)

4.6

Moderately mobile

K_foc (mL g⁻¹)

317.9

¹/_n

0.97

Notes and range

UK HSE Dossier 2020: kf range 1.9-13.5 mL g⁻¹, K_foc range 266.5-510.1 mL g⁻¹, ¹/_n range 0.94-1.00, Soils=5

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

2.02

Calculated

Transition state

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

Value

6.88 X 10^-02

Calculated

Note

Potential for particle bound transport index

Low

Calculated

Potential for loss via drain flow

Non-mobile

Calculated

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

2.0

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)

677

Threshold for concern

CT₅₀ (days)

1.12

Known metabolites

None

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 2000

Rat

Low

Mammals - Short term dietary NOEL

(mg kg⁻¹)

Rat

(ppm diet)

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

Birds - Acute LD₅₀ (mg kg⁻¹)

> 3776

Colinus virginianus

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

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

99.1

Colinus virginianus

Moderate

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

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

43.63

Eisenia andrei

Moderate

Soil micro-organisms

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

67.0

Folsomia foetida

Non-target plants

31.3

Ryegrass
Vegetative vigour, ER₅₀
as g ha⁻¹

Honeybees (Apis spp.)

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

> 200

Apis mellifera

Low

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

> 200

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

143.2

Apis mellifera

Notes

Bumblebees (Bombus spp.)

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

> 272

Bombus terrestris as BAS684 02 H

Low

Data based on preparation

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) as Mortality LR₅₀ g ha⁻¹

112

Aphidius rhopalosiphi

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

629.5

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)

> 5.75

Cyprinus carpio

Moderate

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

0.59

Pimephales promelas

Moderate

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

11.56

Danio rerio EC₅₀ Embryo

Moderate

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

> 10.68

Daphnia magna

Moderate

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

0.29

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)

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

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

0.089

Lemna gibba

Moderate

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

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

23.04

Pseudokirchneriella subcapitata

Low

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)

> 2000

Rat

Low

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

5000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 5.3

Rat 4 hr (nose only)

Other Mammal toxicity endpoints

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

0.08

Dog SF=100

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

0.3

Rat SF=100

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

0.21

Rat SF=100

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

0.06

Dog SF=100

Dermal penetration studies (%)

0.4-22.0

concentration dependent

Dangerous Substances Directive 76/464

Exposure Routes

Public

No unacceptable risks identified for proposed pattern of use

Occupational

No unacceptable risks identified for proposed pattern of use

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

Rapid excretion via both the urine and faeces

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

No data found

General human health issues

Gastrointestinal or liver toxicant
May damage nasal cavity

Handling issues

Property

Value and interpretation

General

Not explosive or oxidising
Not expected to auto-ignite; Not highly flammable

CLP classification 2013

Health: H332
Environment: H410

WHO Classification

III (Slightly hazardous)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

cinmethylin

French

cinméthyline

German

Danish

Italian

Spanish

Greek

Polish

cynmetylina

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	23/05/2025
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