Permethrin (Ref: OMS 1821)

Permethrin (Ref: OMS 1821)	Last updated: 26/05/2025
(Also known as: permethrine)

SUMMARY

Permethrin is a contact insecticide. It is not highly soluble in water, has a low volatility and is not normally expected to leach to groundwater. It would also not be expected to persist in soil or water systems. It is moderately toxic to humans, is an irritant and may be a CNS toxicant. It is highly toxic to most aquatic species and honeybees but is not highly toxic to birds or earthworms.

GENERAL INFORMATION

Description

A general purpose pyrethroid insecticide used to control animal ectoparasites

Availability status

Current

Introduction & key dates

circa 1973, introduced

Examples of veterinary uses

Used to eradicate various ecoparasites including ticks, lice, fleas

Examples of species treated

Cats; Dogs

Approval status

VMR 2013/2033 approval status (GB/UK)

Approved

EU Regulatory approval status

Approved

Chemical structure

Isomerism

Permethrin is a chiral molecule presenting two forms, the cis and the trans isomers.

Chemical formula

C₂₁H₂₀Cl₂O₃

Canonical SMILES

CC1(C(C1C(=O)OCC2=CC(=CC=C2)OC3=CC=CC=C3)C=C(Cl)Cl)C

Isomeric SMILES

International Chemical Identifier key (InChIKey)

RLLPVAHGXHCWKJ-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C21H20Cl2O3/c1-21(2)17(12-18(22)23)19(21)20(24)25-13-14-7-6-10-16(11-14)26-15-8-4-3-5-9-15/h3-12,17,19H,13H2,1-2H3/t17-,19-/m0/s1

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
cispermethrin	Cis-isomer
transpermethrin	Trans-isomer

General status

Veterinary substance type

Insecticide, Antiparasitic, Veterinary hygiene

Other bioactivity & uses

Biocide; Wood preservative; Disinfectant; Embalming fluid

Substance groups

Pyrethroid insecticide; Pyrethroid ester insecticide

Minimum active substance purity

>=90%

Known relevant impurities

Substance origin

Synthetic

Mode of action

Broad-spectrum with contact and stomach action. Slight repellant effect. Sodium channel modulator.

Molecular targets

[Sodium channel protein type 1 subunit alpha, Blocker]

CAS RN

52645-53-1

EC number

258-067-9

CIPAC number

331

US EPA chemical code

109701

PubChem CID

40326

CLP index number

613-058-00-2

Therapeutic Class

Antiparasitic products, insecticides & repellents: Ecoparasiticides, insecticides & repellents

ATCvet Code

QP53AC04

Controlled Drug?

Regulation 37/2010 MRL Classification

Allowed substance (Table 1: Bovine)

Molecular mass

391.29

PIN (Preferred Identification Name)

IUPAC name

3-phenoxybenzyl (1RS,3RS;1RS,3SR)-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylate

CAS name

(3-phenoxyphenyl)methyl 3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylate

Other status information

Chemical subject to PIC regulations; Some applications may be approved under GB Biocides Products Regulations

Relevant Environmental Water Quality Standards

UK statutory standard for the protection of aquatic life: freshwater and saltwater: 0.01 µg l⁻¹

Physical state

Colourless crystalline solid to brown viscous liquid depending upon purity

Formulations

Property

Product

Manufacturer

Authorisation Route

Legal Class (GB/UK)

Example products (past and present) using this active

Advantix Spot-on Solution

Elanco Europe Ltd

GB National authorisation

Prescription only medicine to be authorised by a veterinarian (POM-V)

Beaphar Soft Cat Flea Collar

Sinclair Animal and Household Care Ltd

UK National authorisation

Authorised veterinary medicine for general sale (AVM-GSL)

Dysect Cattle Pour-on Solution

Zoetis UK Ltd

UK National authorisation

Authorised veterinary medicine for general sale (AVM-GSL)

Z-Itch Pour-on Solution

Floris Holding B.V.

GB National authorisation

Authorised veterinary medicine for general sale (AVM-GSL)

Formulation and application details

Usually formulated for topical application e.g. spot-on products

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

0.011

Low

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

1000000

Hexane

258000

Methanol

1000000

Xylene

Melting point (°C)

34.5

Boiling point (°C)

465.9

Degradation point (°C)

Flashpoint (°C)

159.4

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

1.26 X 10⁰⁶

Calculated

Log P

6.1

High

Fat solubility of residues

Solubility

Soluble

Data type

Regulatory data - observed in metabolism and farm animal feeding studies

Density (g ml⁻¹)

1.19

Dissociation constant pKa) at 25 °C

Vapour pressure at 20 °C (mPa)

0.007

at 25°C

Low volatility

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

1.89 X 10^-01

Moderately volatile

Volatilisation as max % of applied dose lost

From plant surface

From soil surface

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

Surface tension (mN m⁻¹)

Refractive Index

Environmental release

Degradation

Property

Value

Source; quality score; and other information

Interpretation

Soil degradation (days) (aerobic)

DT₅₀ (typical)

Non-persistent

DT₅₀ (lab at 20 °C)

Non-persistent

DT₅₀ (field)

Moderately persistent

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

Note

Manure DT₅₀ (days)

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Moderately fast

Note

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

Value

Moderately persistent

Note

Water-sediment DT₅₀ (days)

Moderately 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

[Wheat grain: >50 wks @ 30 DegC, 50% RH; Modelled data], [Mushroom (Agaricus bisporus): 3.6 days @ 25 DegC; 3.1 days @ 4 DegC; 36.5 days @ -18 DegC; Lab study]

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)

100000

Notes and range

Freundlich

K_f (mL g⁻¹)

1.87

K_foc (mL g⁻¹)

¹/_n

0.99

Notes and range

Soil with 68% loam, 24% silt, 8% clay, pH 6.5, OC=2.1%

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

-1.62

Calculated

Low leachability

Bio-concentration factor

BCF (l kg⁻¹)

300

(Other literature Log BCF range 1.4-3.3 (R3))

Threshold for concern

CT₅₀ (days)

Not available

Known metabolites

None

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 430

Rat

Moderate

Mammals - Short term dietary NOEL

(mg kg⁻¹)

Rat 2 yr

(ppm diet)

100

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

Birds - Acute LD₅₀ (mg kg⁻¹)

> 9800

Anas platyrhynchos

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

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

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

1440

Low

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)

0.024

Apis mellifera

High

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

0.13

Apis mellifera

High

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

Chronic

Notes

[The residual time to 25% mortality (RT25) value for honeybees is 72 hrs - USEPA data]

Bumblebees (Bombus spp.)

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

> 0.22

Bombus terrestris

High

Literature DT₅₀ values range 0.22-0.82 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)

0.29

Osmia lignaria

High

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)

0.0157

Megachile rotundata

High

Mode of exposure

Contact

Other bee species (2)

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

0.07

Trigona spinipes

High

Mode of exposure

Contact

Beneficial insects (Ladybirds) as Mortality, LD₅₀ ppm

Coccinella septempunctata Adult

Beneficial insects (Lacewings) as Mortality, Contact LC₅₀ ppm

> 10.5

Chrysoperla carnea Larva

Beneficial insects (Parasitic wasps)

Harmful

Parasitic wasp

Beneficial insects (Predatory mites)

Harmful

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)

0.0125

Oncorhynchus mykiss

High

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

0.000093

Anabas testudineus

High

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

> 0.0017

Danio rerio

High

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

0.0006

Daphnia magna

High

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

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

> 0.000001

Ceriodaphnia dubia

High

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

0.00002

Americamysis bahia

High

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

0.0029

Chironomus riparius

High

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)

0.0125

Unknown species

Moderate

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

0.0009

Unknown species

High

Mesocosm study data

NOEAEC mg l⁻¹

Marine bivalves – Acute EC₅₀, immobility (mg l⁻¹)

> 1.05

Crassostrea gigas Embryo

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)

> 430

Rat

Moderate

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

2000

Rabbit

Mammals - Inhalation LC₅₀ (mg l⁻¹)

> 0.685

Rat

Other Mammal toxicity endpoints

Intraperitoneal LD₅₀ = 429 mg kg⁻¹

Mouse

Intravenous LD₅₀ = 31.0 mg kg⁻¹

Mouse

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

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

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

Mammalian dose elimination route and rate

Rapidly metabolised by ester hydrolysis to inactive metabolites which are excreted primarily in the urine

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

Harmful
Estrogenic
IARC Group 3 carcinogen - not classifiable; US EPA - weak evidence to suggest human carcinogen
Endocrine issues - Inhibition of estrogen-sensitive cells proliferation

Handling issues

Property

Value and interpretation

General

IMDG Transport Hazard Class 6.1

CLP classification 2013

Health: H302, H332, H335
Environment: H400, H410

WHO Classification

II (Moderately hazardous)

UN Number

UN3077

Waste disposal & packaging

Packaging Group III (minor danger)

Shelf-life, storage, stability and reactivity

Chemically stable under standard ambient conditions. Shelf-life of 2 yrs. Store -20 DegC in an inert atmosphere

TRANSLATIONS

Language

Name

English

permethrin

French

permethrine

German

Permethrin

Danish

permethrin

Italian

permetrina

Spanish

permetrin

Greek

permethrin

Polish

permetryna

Swedish

permetrin

Hungarian

permetrin

Dutch

permethrin

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