Fenamiphos (Ref: BAY 68138)

Fenamiphos (Ref: BAY 68138)	Last updated: 22/05/2025
(Also known as: phenamiphos; methaphenamiphos; SRA 3886)

SUMMARY

Fenamiphos is an organophosphorous insecticide and nematicide. It is moderately soluble in water, has a low volatility and would not normally, based on its chemical properties, be expected to leach to groundwater. It is not normally persistent in soil or water systems. It is highly toxic to mammals, a cholinesterase inhibitor and a neurotoxicant. It shows moderate to high toxicity to most fauna and flora.

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: Drainflow: Moderately mobile	Ecotoxicity High alert: Birds acute ecotoxicity: High; Fish acute ecotoxicity: High; Fish chronic ecotoxicity: High; Daphnia acute ecotoxicity: High; Bees acute contact ecotoxicity: High; Bees acute oral ecotoxicity: High	Human health High alert: Mammals acute toxicity: High; Reproduction/development effects; Acetyl cholinesterase inhibitor; Neurotoxicant

GENERAL INFORMATION

Description

An insecticide and nematicide used to control ecoparasitic, endoparasitic, free-living and cyst-forming nematodes

Example pests controlled

Nematodes; Thrips

Example applications

Fruit including citrus, grapes and pineapples; Glasshouse crops including tomatoes, peppers;, aubergine, cucumber, zucchini; Vegetables; Peanuts; Tobacco; Turf; Ornamentals including herbaceous plants and nursery stock

Efficacy & activity

Efficacy demonstrated by long term use across the EU and in other countries.

Availability status

Current

Introduction & key dates

1967, first reported; 1968, first introduced; first registered in the United States in 1972; 2021, withdrawn UK

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

Greece/Cyprus

Date EC 1107/2009 inclusion expires

Expired

EU Candidate for substitution (CfS)

Yes - low ADI / ARfD / AOEL

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

Australia; USA

Chemical structure

Isomerism

A chiral molecule, fenamiphos is an isomeric mixture of the R- and S-enantiomers

Chemical formula

C₁₃H₂₂NO₃PS

Canonical SMILES

CCOP(=O)(NC(C)C)OC1=CC(=C(C=C1)SC)C

Isomeric SMILES

No data

International Chemical Identifier key (InChIKey)

ZCJPOPBZHLUFHF-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C13H22NO3PS/c1-6-16-18(15,14-10(2)3)17-12-7-8-13(19-5)11(4)9-12/h7-10H,6H2,1-5H3,(H,14,15)

2D structure diagram/image available?

Yes

General status

Pesticide type

Nematicide

Substance groups

Organophosphate insecticide; Organophosphate nematicide; Phosphoramidate insecticide; Phosphoramidate nematicide

Minimum active substance purity

940 g kg⁻¹

Known relevant impurities

EU dossier - None declared

Substance origin

Synthetic

Mode of action

Systemic, contact action, absorbed through roots. Acetylcholinesterase (AchE) inhibitor.

CAS RN

22224-92-6

EC number

244-848-1

CIPAC number

692

US EPA chemical code

100601

PubChem CID

31070

CLP index number

015-123-00-5

Molecular mass

303.36

PIN (Preferred Identification Name)

(E)-[ethyl 3-methyl-4-(methylsulfanyl)phenyl propan-2-ylphosphoramidate]

IUPAC name

(RS)-(ethyl 4-methylthio-m-tolyl isopropylphosphoramidate)

CAS name

ethyl 3-methyl-4-(methylthio)phenyl (1-methylethyl)phosphoramidate

Other status information

Potential groundwater contaminant; Marine Pollutant

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)

Fungicide Resistance Class (FRAC MOA class)

Not applicable

Examples of recorded resistance

Physical state

Colourless crystals to tan waxy solid depending on purity

Formulations

Property

Value

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

Bayer CropScience
King Tech Corp
AgroCare
Mobay

Example products using this active

Nemacur CS 240

Formulation and application details

Often supplied as a capsule suspension that is diluted with water and applied by drip irrigation or via a spray followed by incorporation into the soil

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

345

Moderate

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

27000

n-Hexane

250000

Acetone

250000

Ethyl acetate

250000

Dichloromethane

Melting point (°C)

Boiling point (°C)

Decomposes before boiling

Degradation point (°C)

200

Flashpoint (°C)

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

2.00 X 10⁰³

Calculated

Log P

3.3

High

Fat solubility of residues

Solubility

Soluble

Data type

Regulatory data

Density (g ml⁻¹)

1.19

Dissociation constant pKa) at 25 °C

Not applicable

No dissociation

Vapour pressure at 20 °C (mPa)

0.067

Low volatility

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

2.80 X 10^-05

Non-volatile

Volatilisation as max % of applied dose lost

From plant surface

0.1

7 day

Volatilisation is not considered critical for air pollution

From soil surface

0.1

7 day

Volatilisation is not considered critical for air pollution

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

In acetoniltrile: 251nm=11738, 290nm=1531

Surface tension (mN m⁻¹)

47.2

at 20 °C

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

0.90

Non-persistent

DT₅₀ (lab at 20 °C)

0.9

Non-persistent

DT₅₀ (field)

1.8

Non-persistent

DT₉₀ (lab at 20 °C)

3.51

Non-persistent

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

EU 2017 dossier lab studies DT₅₀ range 0.366-2.01 days, DT₉₀ range 1.28-7.06 days, Soils=4; EU 2006 dossier field studies DT₅₀ range 1.5-2.2 days; Other sources: 50 days (DW3)

Dissipation rate RL₅₀ (days) on plant matrix

Value

Note

Dissipation rate RL₅₀ (days) on and in plant matrix

Value

6.5

Note

Published literature RL₅₀ range 6.3-6.7 days, 2 field crops, various matrices, n=2

Aqueous photolysis DT₅₀ (days) at pH 7

Value

0.2

Fast

Note

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

Value

304

Persistent

Note

pH sensitive: 252 days at pH 5, 236 days at pH 9 all at 20 °C

Water-sediment DT₅₀ (days)

60.2

Moderately fast

Water phase only DT₅₀ (days)

5.8

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)

10.1

Moderately mobile

K_oc (mL g⁻¹)

446.2

Notes and range

EU 2017 dossier K_d range 4.2-23.0 mL g⁻¹, K_oc range 124-878 mL g⁻¹, Soils=5

Freundlich

K_f (mL g⁻¹)

1.86

Moderately mobile

K_foc (mL g⁻¹)

125.2

¹/_n

0.92

Notes and range

EU 2017 dossier K_f range 0.79-3.4 mL g⁻¹, K_foc range 43.8-240.9 mL g⁻¹, ¹/_n range 0.85-0.92, Soils=8

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

0.49

Calculated

Low leachability

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

Value

1.08 X 10^-03

Calculated

Note

Potential for particle bound transport index

Low

Calculated

Potential for loss via drain flow

Moderately mobile

Calculated

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

1.7

Calculated using the Atkinson method

Below the level of concern for long-range air transport

Bio-concentration factor

BCF (l kg⁻¹)

110

Threshold for concern

CT₅₀ (days)

0.22

Known soil metabolites

Metabolite

Major/Minor fraction

$Click here for further information on Major/Minor fraction$

Estimated maximum occurrence fraction

Notes

fenamiphos sulfoxide

Major fraction

0.772

fenamiphos sulfone

Major fraction

0.293

fenamiphos sulfoxide phenol

Minor fraction

0.065

fenamiphos sulfone phenol (Ref: FONP)

Major fraction

0.251

fenamiphos sulfone anisole

Minor fraction

0.082

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)

fenamiphos sulfoxide

Not relevant

fenamiphos sulfone

Not relevant

fenamiphos sulfone phenol (Ref: FONP)

Not relevant

fenamiphos sulfone anisole

Relevancy unknown

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

ethyl 3-methyl-4-(methylthio)phosphoramidic acid phenyl ester

des-isopropyl fenamiphos; fenamiphos metabolite M06

Ethyl 3-methyl-4-(methylsulfinyl)phosphoric acid phenyl ester

des-isopropylamino fenamiphos sulfoxide; fenamiphos metabolite M09

fenamiphos sulfonic acid

Water (Photolysis)

4-hydroxy-2-methylbenzenesulfonic acid

fenamiphos phenol sulfonic acid; fenamiphos metabolite M24

Water (Photolysis); Rat

3-methyl-4-(methylthio)phenol

fenamiphos phenol; fenamiphos metabolite M11

Rat

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

> 6.0

Rat

High

Mammals - Short term dietary NOEL

(mg kg⁻¹)

> 0.3

Rat

High

(ppm diet)

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

Birds - Acute LD₅₀ (mg kg⁻¹)

0.8

Colinus virginianus

High

Birds - Short term dietary (LC₅₀/LD₅₀)

> 43 mg kg feed⁻¹

Colinus virginianus

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

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

888

Eisenia foetida

Moderate

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

0.49

Eisenia foetida

Moderate

Soil micro-organisms

Nitrogen mineralisation: >25% effect
Carbon mineralisation: No significant adverse effect

Dose: 133 mg kg⁻¹ soil 28 Day

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)

0.28

Apis mellifera

High

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

0.45

Apis mellifera

High

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)

1.59

Bombus terrestris

Moderate

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) as Mortality LR₅₀ as g ha⁻¹

33.3

Chrysoperla carnea

Beneficial insects (Parasitic wasps) as Mortality LR₅₀ g ha⁻¹ 48 hr

0.175

Aphidius rhopalosiphi Adult

Beneficial insects (Predatory mites) as Mortality LR₅₀ g ha⁻¹ 7 day

1.7

Typhlodromus pyri Protonymph

Beneficial insects (Ground beetles) as Mortality LR₅₀ g ha⁻¹

219

Poecilus cupreus

Aquatic ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

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

0.0093

Oncorhynchus mykiss

High

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

0.0038

Oncorhynchus mykiss

High

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

24.3

Danio rerio EC₅₀ Embryo

Moderate

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

0.0011

Daphnia magna

High

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

0.01

Daphnia magna

Moderate

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

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

0.0057

Americamysis bahia

High

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

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

0.01

Chironomus riparius Emergence

Moderate

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)

3.8

Scenedesmus subspicatus

Moderate

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

Mesocosm study data

NOEAEC mg l⁻¹

0.0035

Fish and aquatic invertebrates

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)

> 6.0

Rat

High

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

72.0

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

0.065

Rat 4 hr (aerosl)

Other Mammal toxicity endpoints

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

0.0008

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

0.0025

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

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

0.0008

Dermal penetration studies (%)

1.0-5.0

concentration dependent

Dangerous Substances Directive 76/464

List I; List II

Exposure Routes

Public

Negligible risk to bystanders

Occupational

Negligible risk to operators

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

; ; ; ;

Reproduction / development effects

Acetyl cholinesterase inhibitor

Neurotoxicant

Respiratory tract irritant

Skin irritant

Skin sensitiser

No data found

Eye irritant

Phototoxicant

General human health issues

Toxic by inhalation and skin contact
Exposure may be fatal due to respiratory failure
May overstimulate the nervous system causing nausea, dizziness and confusion
Inhibition of erythrocyte ChE activity

Handling issues

Property

Value and interpretation

General

Not explosive or oxidising
IMDG Transport Hazard Class 6.1
Not explected to auto-ignite, Not highly flammable

CLP classification 2013

Health: H300, H310, H319, H330
Environment: H400, H410

WHO Classification

Ib (Highly hazardous)

UN Number

UN2783

Waste disposal & packaging

Packaging Group I (great danger)

Shelf-life, storage, stability and reactivity

TRANSLATIONS

Language

Name

English

fenamiphos

French

phenamiphos

German

Fenamiphos

Danish

fenamiphos

Italian

fenamifos

Spanish

fenamifos

Greek

fenamiphos

Polish

fenamifos

Swedish

Hungarian

Dutch

fenamifos

Norwegian

Record last updated:	22/05/2025
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