Cyanofenphos (Ref: OMS-870)

Cyanofenphos (Ref: OMS-870)	Last updated: 06/09/2025
(Also known as: CYP; cyanophenphos; S-4087; cyanofenfos; ENT 25832)

GENERAL INFORMATION

Description

Cyanofenphos is an obsolete organophosphate insecticide

Examples of veterinary uses

Use mainly for the control of insects affecting livestock such as blow flies, lice and ticks.

Examples of species treated

Farmed livestock

Approval status

VMR 2013/2033 approval status (GB/UK)

Not approved

EU Regulatory approval status

Not approved

Chemical structure

Isomerism

Cyanofenphos exhibits structural isomerism rather than stereoisomerism. Its structure includes a phosphonothioate group, a cyano-substituted aromatic ring, and an ethoxy side chain, which allows for potential positional isomerism, where the location of substituents like the cyano group or the ethoxy group on the aromatic rings could vary, forming distinct isomers. However, in practice, the commercial compound is typically sold as a single isomer, with a fixed arrangement of these groups. Due to the absence of chiral centres or double bonds that would allow for optical or geometrical isomerism, cyanofenphos does not exhibit stereoisomerism. Its isomerism is mainly theoretical.

Chemical formula

C₁₅H₁₄NO₂PS

Canonical SMILES

CCOP(=S)(C1=CC=CC=C1)OC2=CC=C(C=C2)C#N

Isomeric SMILES

International Chemical Identifier key (InChIKey)

LRNJHZNPJSPMGK-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C15H14NO2PS/c1-2-17-19(20,15-6-4-3-5-7-15)18-14-10-8-13(12-16)9-11-14/h3-11H,2H2,1H3

2D structure diagram/image available?

Yes

General status

Veterinary substance type

Insecticide

Substance groups

Organophosphate insecticide

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Acetylcholine esterase inhibitor

Molecular targets

[Cholinesterase, Inhibitor]

CAS RN

13067-93-1

EC number

620-377-0

CIPAC number

US EPA chemical code

268400

PubChem CID

25669

Therapeutic Class

ATCvet Code

None allocated

Controlled Drug?

Regulation 37/2010 MRL Classification

Molecular mass

303.32

PIN (Preferred Identification Name)

IUPAC name

4-[ethoxy(phenyl)phosphinothioyl]oxybenzonitrile

CAS name

O-(4-cyanophenyl) O-ethyl phenylphosphonothioate

Forever chemical

Other status information

PAN Bad Actor Chemical

Relevant Environmental Water Quality Standards

Physical state

White crystalline solid

Commercial

Property

Value

Availability status

Considered obsolete but may be available in some countries

Introduction & key dates

1960, first reported

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

Sumitomo Chemical Company

Example products using this active

Surazon
Surecide

Formulation and application details

Usually sold as a liquid concentrate formulation

Commercial production

The production of cyanofenphos typically involves a multi-step synthesis starting with the preparation of phenylphosphonothioic acid derivatives. These intermediates are then reacted with 4-cyanophenol and ethanol under controlled conditions to form the ester linkages characteristic of cyanofenphos. The process includes thionation, where a sulphur atom is introduced to the phosphorus centre, followed by esterification to attach the ethyl and cyanophenyl groups. The final product is purified through crystallisation or distillation.

Impact on climate of production and use

Data for the amount of life cycle GHGs produced by cyanofenphos are not available in the public domain. However, whilst estimates vary, more general data suggests that between 14 and 19 kilograms of CO₂e is emitted per kilogram of insecticide produced.

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

6.0

Low

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

89000

Methanol

515000

Xylene

Melting point (°C)

Boiling point (°C)

Degradation point (°C)

Flashpoint (°C)

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

1.95 X 10⁰⁴

Calculated

Log P

4.29

High

Fat solubility of residues

Solubility

Data type

Density (g ml⁻¹)

Dissociation constant pKa) at 25 °C

Vapour pressure at 20 °C (mPa)

0.161

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)

7.10 X 10^-03

Non-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

1.5839

Environmental release

Degradation

Property

Value

Source; quality score; and other information

Interpretation

Soil degradation (days) (aerobic)

DT₅₀ (typical)

DT₅₀ (lab at 20 °C)

DT₅₀ (field)

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

Note

Manure DT₅₀ (days)

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Note

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

Value

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)

K_oc (mL g⁻¹)

Notes and range

Freundlich

K_f (mL g⁻¹)

K_foc (mL g⁻¹)

¹/_n

Notes and range

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

Bio-concentration factor

BCF (l kg⁻¹)

CT₅₀ (days)

Known soil and groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

cyanofenphos-oxon

Animal; Water (Photolysis)

4-cyanophenol

Plant; Water (Photolysis)

desethyl cyanofenphos-oxon

Plant

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

28.5

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)

20.3

Gallus domesticus

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)

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

Soil micro-organisms

Collembola

Acute LC₅₀ (mg kg⁻¹)

Chronic NOEC (mg kg⁻¹)

Non-target plants

Vegetative vigour ER₅₀ (g ha⁻¹)

Seedling emergence ER₅₀ (g ha⁻¹)

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)

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)

> 1.107

Gambusia affinis

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)

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, fonds growth, fresh) - 7 day (mg l⁻¹)

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

Algae - Acute (growth rate, fresh; mg l⁻¹)

Algae - Chronic (growth rate, fresh; 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)

28.5

Rat

High

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

600

Mouse

Mammals - Inhalation LC₅₀ (mg l⁻¹)

Other Mammal toxicity endpoints

Intraperitoneal LD₅₀ = 45 mg kg⁻¹

Mouse

Subcutaneous LD₅₀ = 122 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

Excreted predominantly via urine (95%) and faeces (5%) within 72 hours.

Health issues

Specific human health issues

Carcinogen

Genotoxic

Endocrine disruptor

No data found

; ; ; ;

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

No further information available

Handling issues

Property

Value and interpretation

General

Flammable

CLP classification 2013

WHO Classification

Not classified: Obsolete (Not classified: Obsolete)

UN Number

Waste disposal & packaging

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

cyanofenphos

French

German

Danish

Italian

Spanish

Greek

Polish

Swedish

Hungarian

Dutch

Norwegian

Record last updated:	06/09/2025
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