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Fenthion (Ref: OMS 2)
Last updated: 23/08/2024
(Also known as: MPP; ENT 25540; Bayer 29493; S-1752; BAY 29493; DMTP)

SUMMARY
Fenthion is an insecticide for sucking and chewing pests. It has a low water solubility but is generally highly soluble in organic solvents. It is volatile and is not expected to leach to groundwater. Its persistence in soil and water systems depends on local conditions. It is moderately toxic to mammals and a cholinesterase inhibitor. Fenthion is highly toxic to birds and honeybees and has a high to moderate toxicity to most aquatic species and earthworms.
GENERAL INFORMATION
Description
A organophosphate insecticide used in veterinary medicine for external parasite control
Availability status
Current
Introduction & key dates
1960, first reported & introduced
Examples of veterinary uses
Used to to control lice, fleas, ticks, flies and other external parasites
Examples of species treated
Cattle; Pigs; Dogs
Approval status
VMR 2013/2033 approval status (GB/UK)
Not approved
EU Regulatory approval status
Not approved
Chemical structure
Isomerism
None
Chemical formula
C₁₀H₁₅O₃PS₂
Canonical SMILES
CC1=C(C=CC(=C1)OP(=S)(OC)OC)SC
Isomeric SMILES
-
International Chemical Identifier key (InChIKey)
PNVJTZOFSHSLTO-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C10H15O3PS2/c1-8-7-9(5-6-10(8)16-4)13-14(15,11-2)12-3/h5-7H,1-4H3
2D structure diagram/image available?
Yes
General status
Veterinary substance type
Insecticide, Antiparasitic
Substance groups
Organophosphate insecticide
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Contact, stomach and respiratory action. Acetylcholinesterase (AchE) inhibitor.
Molecular targets
[Cholinesterase, Inhibitor]
CAS RN
55-38-9
EC number
200-231-9
CIPAC number
79
US EPA chemical code
053301
PubChem CID
3346
CLP index number
015-048-00-8
Therapeutic Class
Antiparasitic products, insecticides & repellents: Ectoparasiticides
ATCvet Code
QP53BB02
Controlled Drug?
No
Regulation 37/2010 MRL Classification
-
Molecular mass
278.33
PIN (Preferred Identification Name)
O,O-dimethyl O-[3-methyl-4-(methylsulfanyl)phenyl] phosphorothioate
IUPAC name
O,O-dimethyl O-4-methylthio-m-tolyl phosphorothioate
CAS name
O,O-dimethyl O-(3-methyl-4-(methylthio)phenyl) phosphorothioate
Other status information
Severe Marine Pollutant; Evidence of use in third world countries; Chemical subject to PIC regulations; Highly toxic to birds
Relevant Environmental Water Quality Standards
-
Physical state
Colourless oily liquid
Related substances & organisms
Formulations
Property
Product
Manufacturer
Authorisation Route
Legal Class (GB/UK)
Example products (past and present) using this active
- - - -
Formulation and application details
-
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
4.2
H4 H = The US ARS pesticide properties database. Dataset is no longer available.
4 = Verified data
Low
Solubility - In organic solvents at 20 °C (mg l⁻¹)
100000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Hexane
-
250000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Toluene
-
250000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Dichloromethane
-
250000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Isopropanol
-
Melting point (°C)
7.5
AC4 AC = EC Joint Research Centre ESIS European Chemical Substance Information Systems including EINECS, now integrated with the database provided by the European Chemicals Agency (ECHA) (click here )
4 = Verified data
-
Boiling point (°C)
90
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
-
Degradation point (°C)
- - -
Flashpoint (°C)
170
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
-
Octanol-water partition coefficient at pH 7, 20 °C
P
6.92 X 1004 Calculated -
Log P
4.84
H4 H = The US ARS pesticide properties database. Dataset is no longer available.
4 = Verified data
High
Fat solubility of residues
Solubility
Soluble
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
-
Data type
Regulatory data - observed in metabolism and farm animal feeding studies
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
-
Density (g ml⁻¹)
1.25
AC4 AC = EC Joint Research Centre ESIS European Chemical Substance Information Systems including EINECS, now integrated with the database provided by the European Chemicals Agency (ECHA) (click here )
4 = Verified data
-
Dissociation constant pKa) at 25 °C
- - -
-
Vapour pressure at 20 °C (mPa)
0.37
H4 H = The US ARS pesticide properties database. Dataset is no longer available.
4 = Verified data
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)
2.40 X 10-02
H4 H = The US ARS pesticide properties database. Dataset is no longer available.
4 = Verified data
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
- - -
Environmental release
-
Degradation
Property
Value
Source; quality score; and other information
Interpretation
Soil degradation (days) (aerobic)
DT₅₀ (typical)
22
W4 W = French database provided by ARVALIS-Institut du Végétal. Dataset no longer available.
4 = Verified data
Non-persistent
DT₅₀ (lab at 20 °C)
34
DW4 DW = Don Wauchope personal database for Pka data: Wauchope, R. D. and Edwards, J. Dissociation constants for pesticide active ingredients: a database and comparison with predicted values. Dataset is no longer available.
4 = Verified data
Moderately persistent
DT₅₀ (field)
- - -
DT₉₀ (lab at 20 °C)
- - -
DT₉₀ (field)
- - -
Note
Data variable DT₅₀ ranges 1(aerobic) - 34 days
Manure DT₅₀ (days)
- - -
Aqueous photolysis DT₅₀ (days) at pH 7
Value
0.4
AC4 AC = EC Joint Research Centre ESIS European Chemical Substance Information Systems including EINECS, now integrated with the database provided by the European Chemicals Agency (ECHA) (click here )
4 = Verified data
Fast
Note
-
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7
Value
Stable
W4 W = French database provided by ARVALIS-Institut du Végétal. Dataset no longer available.
4 = Verified data
Stable
Note
-
Water-sediment DT₅₀ (days)
92
Q3 Q = Miscellaneous data from online sources
3 = Unverified data of known source
Moderately fast
Water 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
Kd (mL g⁻¹)
-
G3 G = Extension Toxicology network database EXTOXNET. Available online but no longer updated. (click here )
3 = Unverified data of known source
Slightly mobile
Koc (mL g⁻¹)
1500
Notes and range
-
Freundlich
Kf (mL g⁻¹)
- - -
Kfoc (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
1.26 Calculated Low leachability
Bio-concentration factor
BCF (l kg⁻¹)
154
R3 R = Peer reviewed scientific publications
3 = Unverified data of known source
Whole body (Other literature Log BCF range 1.0-2.3 (
R3 R = Peer reviewed scientific publications
3 = Unverified data of known source
))
Threshold for concern
CT₅₀ (days)
5 -
Known soil metabolites
Metabolite
Major/Minor fraction
Estimated maximum occurrence fraction
Notes
fenthion sulfone
- - -
fenthion sulfoxide (Ref: BAY S 2281)
- - -
Known groundwater metabolites

None

Other known metabolites

None

ECOTOXICOLOGY
Terrestrial ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
586
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Rat
Moderate
Mammals - Short term dietary NOEL
(mg kg⁻¹)
-
L2 L = Pesticide manuals and hard copy reference books / other sources
2 = Unverified data of unknown source
Rat 2 yr
-
(ppm diet)
5 -
Mammals - Chronic 21d NOAEL (mg kg⁻¹ bw d⁻¹)
- - -
Birds - Acute LD₅₀ (mg kg⁻¹)
7.2
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
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)
375
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
Eisenia foetida
Moderate
Earthworms - Chronic NOEC, reproduction (mg kg⁻¹)
- - -
Soil micro-organisms
Nitrogen mineralisation: >25% effect
Carbon mineralisation: No significant adverse effect
AC4 AC = EC Joint Research Centre ESIS European Chemical Substance Information Systems including EINECS, now integrated with the database provided by the European Chemicals Agency (ECHA) (click here )
4 = Verified data

Dose: 10 uL/kg soil 20 °C
-
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)
> 0.308
F3 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
3 = Unverified data of known source
Apis mellifera
High
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
- - -
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)
0.8
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
Oncorhynchus mykiss
Moderate
Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)
0.12
P3 P = Other non-EU, UK or US Governments and Regulators
3 = Unverified data of known source
Pimephales promelas 30 day
Moderate
Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
4.25
F3 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
3 = Unverified data of known source
Danio rerio EC₅₀ Embryo
Moderate
Temperate Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
0.0057
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
Daphnia magna
High
Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)
0.000013
P4 P = Other non-EU, UK or US Governments and Regulators
4 = Verified data
Daphnia magna
High
Tropical Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
0.0015
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Ceriodaphnia dubia
High
Aquatic crustaceans - Acute 96 hour LC₅₀ (mg l⁻¹)
0.00018
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Americamysis bahia
High
Sediment dwelling organisms - Acute 96 hour LC₅₀ (mg l⁻¹)
0.0078
R4 R = Peer reviewed scientific publications
4 = Verified data
Chironomus salinarius 24 hr
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 - Acute 7 day EC₅₀, biomass (mg l⁻¹)
- - -
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)
1.79
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Scenedesmus subspicatus
Moderate
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)
> 0.3
P3 P = Other non-EU, UK or US Governments and Regulators
3 = Unverified data of known source
Pseudokirchneriella subcapitata 48 hr
Moderate
Mesocosm study data
NOEAEC mg l⁻¹
- - -
NOEAEC mg l⁻¹
- - -
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)
586
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
Rat
Moderate
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
1680
AC4 AC = EC Joint Research Centre ESIS European Chemical Substance Information Systems including EINECS, now integrated with the database provided by the European Chemicals Agency (ECHA) (click here )
4 = Verified data
Rat
-
Mammals - Inhalation LC₅₀ (mg l⁻¹)
1.2
AC4 AC = EC Joint Research Centre ESIS European Chemical Substance Information Systems including EINECS, now integrated with the database provided by the European Chemicals Agency (ECHA) (click here )
4 = Verified data
Rat
-
Other Mammal toxicity endpoints
Intraperitoneal LD₅₀ = 260 mg kg⁻¹
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Rat
-
Intravenous LD₅₀ = 320 mg kg⁻¹
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Mouse
-
ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)
None allocated
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
-
ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)
0.01
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
-
AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)
- - -
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)
None allocated
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
-
Dermal penetration studies (%)
- - -
Dangerous Substances Directive 76/464
List I; List II - -
Exposure Routes
Public
-
Occupational
Ingestion main poisoning route
Mammalian dose elimination route and rate
Excreted in the faeces and urine almost completely after 3days
Q3 Q = Miscellaneous data from online sources
3 = Unverified data of known source
-
Health issues
Specific human health issues
Carcinogen
Genotoxic
Endocrine disruptor
XNo, known not to cause a problem
A3 A = Chromosome aberration (EFSA database)
3 = Negative
;
B0 B = DNA damage/repair (EFSA database)
0 = No data
;
C0 C = Gene mutation (EFSA database)
0 = No data
;
D0 D = Genome mutation (EFSA database)
0 = No data
;
E2 E = Unspecified genotoxicity type (miscellaneous data source)
2 = Mixed/ambiguous results
No data found
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
?Possibly, status not identified
Yes, known to cause a problem
?Possibly, status not identified
Respiratory tract irritant Skin irritant Skin sensitiser
Yes, known to cause a problem
Yes, known to cause a problem
No data found
Eye irritant Phototoxicant  
Yes, known to cause a problem
No data found  
General human health issues
Harmful in contact with skin or if inhaled or swallowed
May harm central nervous, cardiovascular, and respiratory systems
Suspected of causing genetic defects
Handling issues
Property
Value and interpretation
General
IMDG Transport Hazard Class 6.1
CLP classification 2013
Health: H302, H312, H331, H341
Environment: H400, H410
WHO Classification
II (Moderately hazardous)
UN Number
UN3018
Waste disposal & packaging
-
Shelf-life, storage, stability and reactivity
-
TRANSLATIONS
Language
Name
English
fenthion
French
fenthion
German
Fenthion
Danish
fenthion
Italian
fention
Spanish
fention
Greek
fenthion
Polish
fention
Swedish
-
Hungarian
fention
Dutch
fenthion
Norwegian
-

Record last updated: 23/08/2024
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