Deltamethrin (Ref: OMS 1998)

Deltamethrin (Ref: OMS 1998)	Last updated: 04/09/2025
(Also known as: decamethrin; deltamethrine; AE F032640)

SUMMARY

Deltamethrin is a pyrethroid insecticide and veterinary treatment that is approved for use in the EU, Australia and the USA. It has a low aqueous solubility, is semi-volatile and has a low potential to leach to groundwater. It is not persistent in soil and is non-mobile. Deltamethrin is highly toxic to humans and other mammals and is a neurotoxin. It is relatively non-toxic to birds and earthworms although it presents a high risk to most aquatic organisms and honeybees.

GENERAL INFORMATION

Description

A pyrethroid insecticide with veterinary applications

Examples of veterinary uses

Used to eradicate external parasites on farm animal, domestic pets and fish.

Examples of species treated

Cattle; Fish; Dogs; Cats

Approval status

VMR 2013/2033 approval status (GB/UK)

Approved - legal class depends on product and application

EU Regulatory approval status

Approved

Chemical structure

Isomerism

A chiral molecule. Deltamethrin is the cis-isomer of 8 stereoisomeric esters of the dibromo analogue of chrysanthemic acid.

Chemical formula

C₂₂H₁₉Br₂NO₃

Canonical SMILES

CC1(C(C1C(=O)OC(C#N)C2=CC(=CC=C2)OC3=CC=CC=C3)C=C(Br)Br)C

Isomeric SMILES

CC1([C@H]([C@H]1C(=O)O[C@H](C#N)C2=CC(=CC=C2)OC3=CC=CC=C3)C=C(Br)Br)C

International Chemical Identifier key (InChIKey)

OWZREIFADZCYQD-NSHGMRRFSA-N

International Chemical Identifier (InChI)

InChI=1S/C22H19Br2NO3/c1-22(2)17(12-19(23)24)20(22)21(26)28-18(13-25)14-7-6-10-16(11-14)27-15-8-4-3-5-9-15/h3-12,17-18,20H,1-2H3/t17-,18+,20-/m0/s1

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
deltamethrin	Isomer

General status

Veterinary substance type

Insecticide

Metabolite Type

Soil

Other bioactivity & uses

Biocide; Wood preservative

Substance groups

Pyrethroid insecticide; Pyrethroid ester insecticide

Minimum active substance purity

985 g kg⁻¹

Known relevant impurities

EU dossier - None declared

Substance origin

Synthetic

Mode of action

Non-systemic with contact and stomach action. Sodium channel modulator.

Molecular targets

[Sodium channel, Modulator]

CAS RN

52918-63-5

EC number

258-256-6

CIPAC number

333

US EPA chemical code

978051

PubChem CID

40585

CLP index number

607-319-00-X

Therapeutic Class

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

ATCvet Code

QP53AC11

Controlled Drug?

Regulation 37/2010 MRL Classification

Allowed substance (Table 1: Ruminants, Fin fish)

Molecular mass

505.2

PIN (Preferred Identification Name)

(S)-cyano(3-phenoxyphenyl)methyl (1R,3R)-3-(2,2-dibromoethenyl)-2,2-dimethylcyclopropane-1-carboxylate

IUPAC name

(S)-α-cyano-3-phenoxybenzyl (1R,3R)-3-(2,2-dibromovinyl)-2,2-dimethylcyclopropanecarboxylate

CAS name

(S)-cyano(3-phenoxyphenyl)methyl (1R,3R)-3-(2,2-dibromoethenyl)-2,2-dimethylcyclopropanecarboxylate

Forever chemical

Other status information

Marine pollutant

Relevant Environmental Water Quality Standards

Physical state

Colourless crystals

Can be a metabolite of:

Parent

Formation medium

Estimated maximum occurrence fraction

1107/2009 relevancy

tralomethrin

Soil

0.400

Major fraction

Commercial

Property

Product

Manufacturer

Authorisation Route

Legal Class (GB/UK)

Availability status

Current

Introduction & key dates

1974, first described; 1994, first registered USA

Example products (past and present) using this active

AMX 10 mg/ml concentrate for fish treatment

Pharmaq A.S.

GB National authorisation

Prescription only medicine to be authorised by suitably qualified person (POM-VPS)

Butox Swish Pour On Suspension

MSD Animal Health UK Ltd

UK National authorisation

Prescription only medicine to be authorised by suitably qualified person (POM-VPS)

Canishield Medicated Collar

Beaphar B.V.

GB National authorisation

For non-food animal use and may be supplied without a prescription by a suitable qualified person (NFA-VPS)

Scalibor Protectorband Collar

MSD Animal Health UK Ltd

GB National authorisation

For non-food animal use and may be supplied without a prescription by a suitable qualified person (NFA-VPS)

Formulation and application details

Formulated for topical use as, for example, pour-ons, cutaneous sprays and impregnated collars

Commercial production

The production of deltamethrin involves a multi-step chemical synthesis process. It begins with the preparation of key intermediates such as cis/trans-cyano-3-phenoxybenzyl alcohol and dibromovinyl derivatives, which are then esterified to form the active deltamethrin compound. The reaction typically requires controlled temperature and pressure conditions, along with the use of organic solvents and catalysts to ensure high yield and purity. After synthesis, the crude product undergoes purification, crystallisation, and drying to remove impurities and achieve the desired technical grade.

Impact on climate of production and use

Data for the amount of life cycle GHGs produced by deltamethrin are not available in the public domain. However, given that its synthesis involves organic solvents, energy-intensive reactions, and specialised purification steps, it likely has a moderate to high carbon footprint compared to simpler chemical processes. Whilst estimates vary, general data for insecticides suggests that between 14 and 19 kilograms of CO₂e is emitted per kilogram of insecticide produced. So it is likely that deltamethrin emits GHGs towards the higher end of the range.

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

0.0002

Low

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

450000

Acetone

175000

Xylene

8150

Methanol

2470

n-Heptane

Melting point (°C)

101

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

Flashpoint (°C)

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

3.98 X 10⁰⁴

Calculated

Log P

4.6

High

Fat solubility of residues

Solubility

Soluble

Data type

Regulatory data - observed in metabolism and farm animal feeding studies

Density (g ml⁻¹)

0.55

Dissociation constant pKa) at 25 °C

Not applicable

No dissociation

Vapour pressure at 20 °C (mPa)

0.0011

Low volatility

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

3.10 X 10^-02

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

Negligible

From soil surface

Negligible

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

267, 271 and 278nm, Low to very low absorption at 290-300nm

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)

58.2

Moderately persistent

DT₅₀ (lab at 20 °C)

28.2

Non-persistent

DT₅₀ (field)

Non-persistent

DT₉₀ (lab at 20 °C)

Moderately persistent

DT₉₀ (field)

Note

EU dossier 2017 lab studies (normalised) DT₅₀ range 12.5-231 days, Soils=22; EU 2002 dossier Lab studies DT₅₀ range 18-35 days, DT₉₀ range 58-117 days, field studies DT₅₀ 1-4 wks with realistic estimate of 3 wks (Germany), DT₉₀ estimates range 1 month to 1 year; Other sources: 104 days (DW4)

Manure DT₅₀ (days)

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Note

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

Value

Stable

Note

pH sensitive: Stable pH 5 to pH 7, DT₅₀ 8 to 9 days at pH 9, 20 °C

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], [Wheat grain (dried): 88.5 days @ ~25 DegC, ~80% RH; Lab study], [Rice: 24.4 days @ -20 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)

10240000

Notes and range

EU dossier K_oc range 460000-16300000 mL g⁻¹

Freundlich

K_f (mL g⁻¹)

17500

Non-mobile

K_foc (mL g⁻¹)

10240000

¹/_n

0.93

Notes and range

EU 2017 dossier kfoc range 460000-16300000 mL g⁻¹, ¹/_n range 0.74-1.2, Soils=4

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

-3.98

Calculated

Low leachability

Bio-concentration factor

BCF (l kg⁻¹)

1400

Threshold for concern

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

decamethrinic acid (Ref: AE F108565)

Major fraction

0.520

3-phenoxybenzoic acid

Minor fraction

0.056

Bayer verified

3-(2,2-dibromoethenyl)-2,2-dimethylcyclopropanecarboxylic acid (Ref: Br2CA)

Major fraction

0.230

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)

3-(2,2-dibromoethenyl)-2,2-dimethylcyclopropanecarboxylic acid (Ref: Br2CA)

Not relevant

3-phenoxybenzoic acid

Not relevant

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

3-(4-hydroxyphenoxy)benzoic acid

4'HO3PBA

Plant; Animal

4-hydroxydeltamethrin

Plant

0.003

3-phenoxybenzoic acid

Animal

0.03

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

Rat

High

Mammals - Short term dietary NOEL

(mg kg⁻¹)

2.5

Rat

High

(ppm diet)

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

18.3

Rat Reproductive NOAEL

Moderate

Birds - Acute LD₅₀ (mg kg⁻¹)

> 2250

Colinus virginianus

Low

Birds - Short term dietary (LC₅₀/LD₅₀)

> 5620 ppm

Colinus virginianus

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

> 55

Colinus virginianus NOAEL

Moderate

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

> 645

Eisenia foetida corr

Moderate

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

0.165

Eisenia foetida corr

Moderate

Soil micro-organisms

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

Dose: 0.375 kg ha⁻¹

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

16.0

Folsomia candida corr

Non-target plants

Vegetative vigour ER₅₀ (g ha⁻¹)

> 48.5

11 plant species tested

Seedling emergence ER₅₀ (g ha⁻¹)

> 48.5

11 plant species tested

Honeybees (Apis spp.)

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

0.0015

Apis mellifera

High

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

0.07

Apis mellifera

High

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

> 0.0837

Apis mellifera

Notes

[The residual time to 25% mortality (RT25) value for honeybees is 16.5 hrs (range 10-34 hrs) - USEPA data]

Bumblebees (Bombus spp.)

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

> 0.2

Bombus terrestris

High

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

> 0.61

Bombus terrestris

High

Mason bees (Osmia spp.)

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

0.057

Osmia bicornis

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)

0.556

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)

0.0074

Nomia melanderi

High

Mode of exposure

Contact

Beneficial insects (Ladybirds) as Mortality LD₅₀ ug/g bw insect

0.8

Coccinella septempunctata Larva

Moderate

Beneficial insects (Lacewings) as Mortality LR₅₀ g ha⁻¹, Glass plate

> 13.5

Chrysoperla carnea

Moderate

Beneficial insects (Parasitic wasps) as Mortality LR₅₀ g ha⁻¹, Std lab test

1.726

Aphidius rhopalosiphi

Moderate

Beneficial insects (Predatory mites) as Mortality LR₅₀ g ha⁻¹, Std lab test

0.00439

Typhlodromus pyri

High

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)

0.00015

Oncorhynchus mykiss

High

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

< 0.000032

Oncorhynchus mykiss

High

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

0.00008

Danio rerio

High

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

0.00056

Daphnia magna

High

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

0.0000041

Daphnia magna

High

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

> 0.00004

Ceriodaphnia dubia

High

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

0.0000017

Americamysis bahia

High

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

0.039

Chironomus spp. 24 hr

High

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

0.01

Chironomus riparius

Moderate

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

0.004

Chironomus riparius

High

Aquatic Plants (free-floating, fonds growth, fresh) - 7 day (mg l⁻¹) (EC₅₀, Semi-static)

> 0.000405

Lemna gibba

High

Aquatic plants (rooted, growth rate, fresh) - 14 day (mg l⁻¹)

Algae - Acute (growth rate, fresh; mg l⁻¹) (96 hr ErC₅₀, Static)

> 0.00047

Navicula pelliculosa

High

Algae - Chronic (growth rate, fresh; mg l⁻¹) (96 hr NOEC, Static)

> 0.00047

Navicula pelliculosa

High

Mesocosm study data

NOEAEC mg l⁻¹

0.0032

Aquatic community

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)

Rat

High

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

2000

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

0.6

Rat 6 hr (aerosol whole body)

Other Mammal toxicity endpoints

Intraperitoneal LD₅₀ = 10.0 mg kg⁻¹

Mouse

Intravenous LD₅₀ = 2.53 mg kg⁻¹

Rat

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

0.01

Dog SF=100

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

0.025

Dog SF=100

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

0.019

Dog SF=133

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

0.0075

Dog 90 day SF=100

Dermal penetration studies (%)

2-10

concentration and formulation dependent

Dangerous Substances Directive 76/464

Exposure Routes

Public

Slight risk of dietary exposure for small children however ARfD would not normally be exceeded

Occupational

PPE/PPC recommended

Mammalian dose elimination route and rate

Rapidly metabolised in rats, excreted via urine and faeces, circa 75% eliminated within 24 hr of dose

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

Eye irritant

Phototoxicant

General human health issues

IARC Group 3 carcinogen - not classifiable
Endocrine issues - Weak estrogenic activity

Handling issues

Property

Value and interpretation

General

IMDG Transport Hazard Class 6.1
Not expected to auto-ignite; Not highly flammable

CLP classification 2013

Health: H301, H331
Environment: H400, H410

WHO Classification

II (Moderately hazardous)

UN Number

UN2811

Waste disposal & packaging

Packaging Group II (moderate danger)

Shelf-life, storage, stability and reactivity

Chemically stable under standard ambient conditions. Limited shelf-life.

TRANSLATIONS

Language

Name

English

deltamethrin

French

deltamethrine

German

Deltamethrin

Danish

deltamethrin

Italian

deltametrina

Spanish

deltametrin

Greek

deltamethrin

Polish

deltametryna

Swedish

deltametrin

Hungarian

deltamethrin

Dutch

deltamethrin

Norwegian

deltametrin

Record last updated:	04/09/2025
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