Chlorophacinone (Ref: LM 91)

Chlorophacinone (Ref: LM 91)	Last updated: 26/05/2025
(Also known as: chlorphacinone; chlorofacinone; chlorfacinone)

SUMMARY

Chlorophacinone is a first generation anticoagulant rodenticide. It has a moderate aqueous solubility and vapour pressure. It is moderately persistent in soil and aquatic systems depending on conditions. It is moderately to highly toxic for most species including, birds, fish and honeybees. It has a high human toxicity and may also be a development and reproduction 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 Moderate alert: Moderately persistent; Potential for particle bound transport: Medium	Ecotoxicity High alert: Birds acute ecotoxicity: High	Human health High alert: Mammals acute toxicity: High; Reproduction/development effects

GENERAL INFORMATION

Description

A rodenticide used as a concentrate for dosing bait material

Example pests controlled

Small animal damage

Example applications

Rats; Mice; Gophers

Efficacy & activity

Availability status

Current

Introduction & key dates

mid-1960s, introduced

GB regulatory status

GB COPR regulatory status

Not approved

Date COPR inclusion expires

Expired

GB LERAP status

No UK approval for use as a plant protection agent

EC Regulation 1107/2009 (repealing 91/414)

EC Regulation 1107/2009 status

Not approved

Dossier rapporteur/co-rapporteur

Portugal

Date EC 1107/2009 inclusion expires

Expired

EU Candidate for substitution (CfS)

Not applicable

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

USA

Chemical structure

Isomerism

A chiral molecule - chlorophacinone is racemic

Chemical formula

C₂₃H₁₅ClO₃

Canonical SMILES

C1=CC=C(C=C1)C(C2=CC=C(C=C2)Cl)C(=O)C3C(=O)C4=CC=CC=C4C3=O

Isomeric SMILES

International Chemical Identifier key (InChIKey)

UDHXJZHVNHGCEC-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C23H15ClO3/c24-16-12-10-15(11-13-16)19(14-6-2-1-3-7-14)23(27)20-21(25)17-8-4-5-9-18(17)22(20)26/h1-13,19-20H

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
chlorophacinone	-

General status

Pesticide type

Rodenticide

Substance groups

Indandione rodenticide

Minimum active substance purity

>978 g kg⁻¹

Known relevant impurities

None declared

Substance origin

Synthetic

Mode of action

Metabolic inhibitor and 1st generation anticoagulant

CAS RN

3691-35-8

EC number

223-003-0

CIPAC number

208

US EPA chemical code

067707

PubChem CID

19402

CLP index number

606-014-00-9

Molecular mass

374.82

PIN (Preferred Identification Name)

rac-2-[(2R)-(4-chlorophenyl)phenylacetyl]-1H-indene-1,3(2H)-dione

IUPAC name

2-[(RS)-2-(4-chlorophenyl)-2-phenylacetyl]indan-1,3-dione

CAS name

2-[(4-chlorophenyl)phenylacetyl]-1H-indene-1,3(2H)-dione

Other status information

PAN Bad Actor Chemical

Relevant Environmental Water Quality Standards

Herbicide Resistance Class (HRAC MoA class)

Not applicable

Herbicide Resistance Class (WSSA MoA class)

Not applicable

Insecticide Resistance Class (IRAC MoA class)

Not applicable

Fungicide Resistance Class (FRAC MOA class)

Not applicable

Examples of recorded resistance

Physical state

Pale yellow or white crystals

Formulations

Property

Value

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

Irish Drugs
BH&B
Certox

Example products using this active

Topitox
Endorats
Liphadione
Drat Rat Bait
Raviac
Liphadione
Certox Rozol Rat And Mouse Bait
Rozol Rat And Mouse Bait

Formulation and application details

Usually supplied as ready-to-use baits and tracking powders

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

13.0

Moderate

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

854

Hexane

Melting point (°C)

143

Boiling point (°C)

Decomposes belfore boiling

Degradation point (°C)

250

Flashpoint (°C)

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

2.63 X 10⁰²

Calculated

Log P

2.42

Low

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

1.430

Dissociation constant pKa) at 25 °C

8.0

Vapour pressure at 20 °C (mPa)

0.476

Low volatility. If applied directly to plants, drift is a concern & mitigation is advisable

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

0.13725

Moderately volatile

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

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

Max @ 260nm & 315 nm

Surface tension (mN m⁻¹)

69.0

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

47.3

Moderately persistent

DT₅₀ (lab at 20 °C)

47.3

Moderately persistent

DT₅₀ (field)

Moderately persistent

DT₉₀ (lab at 20 °C)

200

Persistent

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

EU dossier lab studies at 24°C

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

Note

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

Value

Moderately persistent

Note

Water-sediment DT₅₀ (days)

Water phase only DT₅₀ (days)

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)

75766

Notes and range

Freundlich

K_f (mL g⁻¹)

540

Non-mobile

K_foc (mL g⁻¹)

75800

¹/_n

No data

Notes and range

EU dossier K_f range 80-1000 mL g⁻¹; kfoc range 15600-13600 mL g⁻¹

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

-1.37

Calculated

Low leachability

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

Value

5.35 X 10^-03

Calculated

Note

Estimated concentrations of chemicals with Koc values greater than 9995 ml g⁻¹ are beyond the scope of the regression data used in SCI-GROW development. If there are concerns for such chemicals, a higher tier groundwater exposure assessment should be considered, regardless of the concentration returned by SCI-GROW

Potential for particle bound transport index

Medium

Calculated

Potential for loss via drain flow

Non-mobile

Calculated

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

Bio-concentration factor

BCF (l kg⁻¹)

Low risk

Based on LogP < 3

Low risk

CT₅₀ (days)

Known metabolites

None

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

3.15

Rat

High

Mammals - Short term dietary NOEL

(mg kg⁻¹)

(ppm diet)

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

Birds - Acute LD₅₀ (mg kg⁻¹)

Colinus virginianus

High

Birds - Short term dietary (LC₅₀/LD₅₀)

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

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

> 300

Eisenia foetida

Moderate

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

Soil micro-organisms

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Non-target plants

Honeybees (Apis 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)

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

> 11

Moderate

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)

0.45

Oncorhynchus mykiss

Moderate

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

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

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

0.64

Daphnia magna

Moderate

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

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)

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

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

2.2

Desmodesmus subspicatus

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)

3.15

Rat

High

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

0.329

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

0.009

Rat

Other Mammal toxicity endpoints

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

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

None allocated

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

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

Dermal penetration studies (%)

Dangerous Substances Directive 76/464

Exposure Routes

Public

Occupational

Primarily absorbed from the gastrointestinal tract
May also be absorbed via skin absorption and inhalation

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

; ; ; ;

No data found

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

Respiratory tract irritant

Skin irritant

Skin sensitiser

No data found

Eye irritant

Phototoxicant

No data found

General human health issues

Highly toxic
Anticoagulant
Causes internal haemorrhages
Suspected cardiovascular toxicant

Handling issues

Property

Value and interpretation

General

No explosive
Not expected to auto-ignite; Not highly flammable
IMDG Transport Hazard Class 6.1

CLP classification 2013

Health: H300, H310, H331, H372
Environment: H400, H410

WHO Classification

Ia (Extremely hazardous)

UN Number

UN2588

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

chlorophacinone

French

chlorophacinone

German

Chlorphacinon

Danish

chlorophacinon

Italian

clorofacinone

Spanish

clorofacinon

Greek

chlorophacinone

Polish

chlorofacynon

Swedish

Hungarian

chlorophacinone

Dutch

chloorfacinon

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