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Fenthion (Ref: OMS 2)
Last updated: 05/10/2021
(Also known as: MPP; ENT 25540; Bayer 29493; S-1752; BAY 29493; DMTP)

SUMMARY
Fenthino 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.
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:
Moderately persistent; Drainflow: Slightly mobile; Potential for particle bound transport: Medium
Ecotoxicity
High alert:
Birds acute ecotoxicity: High; Daphnia acute ecotoxicity: High; Daphnia chronic ecotoxicity: High; Bees acute contact ecotoxicity: High
Human health
High alert:
Acetyl cholinesterase inhibitor
GENERAL INFORMATION
Description
A broad spectrum insecticide used to control various sucking and biting insect pests in a range of agricultural, commercial and domestic situations. It is also used in veterinary medicine and for bird control
Example pests controlled
Fruit flies, Leafhoppers, Leaf miners, Stem borers, Codling moth, Mosquitoes, Pigeons, Weaver birds
Example applications
Fruit including apples, pears, avocadoes, grapes, stone fruit; Peppers; Ornamental trees, flowers and shrubs
Efficacy & activity
-
Availability status
Current
Introduction & key dates
1960, first reported & introduced
UK regulatory status
UK COPR regulatory status
Not approved
Date COPR inclusion expires
Expired
UK LERAP status
No UK approval for use
EC Regulation 1107/2009 (repealing 91/414)
EC Regulation 1107/2009 status
Not approved
Dossier rapporteur/co-rapporteur
Greece
Date EC 1107/2009 inclusion expires
Expired
EU Candidate for substitution (CfS)
-
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
                 
Additional information
Also used in
-
Chemical structure
Isomerism
None
Chemical formula
C₁₀H₁₅O₃PS₂
Canonical SMILES
CC1=C(C=CC(=C1)OP(=S)(OC)OC)SC
Isomeric SMILES
No data
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
Pesticide type
Insecticide, Veterinary substance, Avicide
Substance group
Organophosphate
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Contact, stomach and respiratory action. Cholinesterase inhibitor.
CAS RN
55-38-9
EC number
200-231-9
CIPAC number
79
US EPA chemical code
053301
PubChem CID
3346
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
-
Herbicide Resistance Classification (HRAC)
Not applicable
Herbicide Resistance Classification (WSSA)
Not applicable
Insecticide Resistance Classification (IRAC)
1B
Fungicide Resistance Classification (FRAC)
Not applicable
Examples of recorded resistance
Many recorded cases, mosquitoes, Bactrocera dorsalis, Myzus persicae, Panonychus ulmi, Rhizoglyphus robini
Physical state
Colourless oily liquid
Formulations
Property
Value
Example manufacturers & suppliers of products using this active now or historically
  • Bayer CropScience
  • AgroCare
  • King Tech Corp
  • Mobay
Example products using this active
  • Baycid
  • Baytex
  • Lebaycid
  • Queletox
  • Pilartex
  • Spotton
Formulation and application details
Available in a wide range of formulations including dustable powders, emulsifiable concentrates, granules, concentrates, ULV liquids and wettable powders.
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 (click here )
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 (click here )
4 = Verified data
High
Bulk 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 (click here )
4 = Verified data
Low volatility
Henry's law constant at 25 °C (Pa m³ mol⁻¹)
2.40 X 10-02
H4 H = The US ARS pesticide properties database (click here )
4 = Verified data
Non-volatile
Maximum UV-vis absorption L mol⁻¹ cm⁻¹
- - -
Surface tension (mN m⁻¹)
- - -
Degradation
Property
Value
Source; quality score; and other information
Interpretation
General biodegradability
-
Soil degradation (days) (aerobic)
DT₅₀ (typical)
22
W4 W = French database provided by ARVALIS-Institut du Végétal
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. MS in preparation
4 = Verified data
Moderately persistent
DT₅₀ (field)
- - -
DT₉₀ (lab at 20 °C)
- - -
DT₉₀ (field)
- - -
DT₅₀ modelling endpoint
- - -
Note
Data variable DT₅₀ ranges 1(aerobic) - 34 days
Dissipation rate RL₅₀ on plant matrix
Value
6.6
R4 R = Peer reviewed scientific publications
4 = Verified data
-
Note
Published literature RL₅₀ range 5.6-7.6 days, grape berries, n=2; Grape berries in cold storage RL₅₀ range 42-45 days, n=2
Dissipation rate RL₅₀ on and in plant matrix
Value
4.4
R4 R = Peer reviewed scientific publications
4 = Verified data
-
Note
Published literature RL₅₀ range 1.0-8.0 days, 6 field crops, various matrices, n=12
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
4 = Verified data
Stable
Note
-
Water-sediment DT₅₀ (days)
92
Q3 Q = Miscellaneous internet resources
3 = Unverified data of known source
Moderately fast
Water phase only DT₅₀ (days)
- - -
Soil adsorption and mobility
Property
Value
Source; quality score; and other information
Interpretation
Linear
Kd
-
G3 G = Extension Toxicology network database EXTOXNET (click here )
3 = Unverified data of known source
Slightly mobile
Koc
1500
Notes and range
-
Freundlich
Kf
- - -
Kfoc
-
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
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
2.77 X 10-02 Calculated -
Note
-
Potential for particle bound transport index
Medium Calculated -
Potential for loss via drain flow
Slightly mobile Calculated -
Key metabolites
Metabolite
Formation medium
Estimated maximum occurrence fraction
1107/2009 relevancy
fenthion sulfoxide (Ref: BAY S 2281)
Soil - -
fenthion sulfone
Soil - -
ECOTOXICOLOGY
Property
Value
Source; quality score; and other information
Interpretation
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 -
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
~ 250
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
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 year
-
(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)
- - -
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
Fish - Chronic 21 day NOEC (mg l⁻¹)
0.12
P3 P = Other governments and regulators
3 = Unverified data of known source
Pimephales promelas 30 day
Moderate
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
Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)
0.000013
P4 P = Other governments and regulators
4 = Verified data
Daphnia magna
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 (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)
- - -
Non-target plants
- - -
- - -
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
Scenedemus subspicatus
Moderate
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)
> 0.3
P3 P = Other governments and regulators
3 = Unverified data of known source
Pseudokirchneriella subcapitata 48 hr
Moderate
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 (US EPA Databases Related to Pesticide Risk Assessment )
3 = Unverified data of known source
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)
- - -
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 pollinators (1)
Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)
- - -
Mode of exposure
-
Other pollinators (2)
Acute LD₅₀ (worst case from 24, 48 and 72 hour values - μg insect⁻¹)
- - -
Mode of exposure
-
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)
- - -
Other soil macro-organisms
Acute LC₅₀ (mg kg⁻¹)
- - -
Chronic NOEC (mg kg⁻¹)
- - -
Other arthropod (1)
LR₅₀ g ha⁻¹
- - -
% Effect
- - -
Other arthropod (2)
LR₅₀ g ha⁻¹
- - -
% Effect
- - -
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
-
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)
~ 250
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
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 / IPCS INCHEM (ChemID; IPCS INCHEM )
3 = Unverified data of known source
Rat
-
Intravenous LD₅₀ = 320 mg kg⁻¹
V3 V = ChemID online databases / IPCS INCHEM (ChemID; IPCS INCHEM )
3 = Unverified data of known source
Mouse
-
ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)
0.007
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
JMPR 1995
-
ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)
0.01
F4 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents (US EPA Databases Related to Pesticide Risk Assessment )
4 = Verified data
JMPR 1997
-
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
List I; List II - -
Exposure Routes
Public
-
Occupational
Ingestion main poisoning route
MRLs
European
EU MRL pesticide database 
Great Britain
GB MRL Register 
Notes
-
Drinking Water Standards
- - -
Drinking Water MAC (μg l⁻¹)
- - -
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
XNo, known not to cause a problem
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
Handling issues
Property
Value and interpretation
General
No information available
CLP classification 2013
Health: H302, H312, H331, H341
Environment: H400, H410
EC Risk Classification
T - Toxic: R23, R48/25, R68
Xn - Harmful: R21/22
N - Dangerous for the environment: R50, R53
EC Safety Classification
S1/2, S36/37, S45, S60, S61
WHO Classification
II (Moderately hazardous)
UN Number
3018
Waste disposal & packaging
-
TRANSLATIONS
Language
Name
English
fenthion
French
fenthion
German
Fenthion
Danish
fenthion
Italian
fention
Spanish
fention
Greek
fenthion
Polish
fention
Swedish
-
Hungarian
fention
Dutch
fenthion

Record last updated: 05/10/2021
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