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Fenchlorphos (Ref: Dow ET-14)
Last updated: 23/02/2024
(Also known as: ronnel; fenclofos; dermaphos; dermafos; Dow ET-57)
GENERAL INFORMATION
Description
An organophosphate insecticide once used in veterinary medicine for parasite management but now mainly obsolete
Availability status
Considered obsolete but may be available in some countries
Introduction & key dates
-
Examples of veterinary uses
Used for scabies management
Examples of species treated
Cattle; Sheep
Approval status
VMR 2013/2033 approval status (GB/UK)
Not approved
EU Regulatory approval status
Not approved
Chemical structure
Isomerism
None
Chemical formula
C₈H₈Cl₃O₃PS
Canonical SMILES
COP(=S)(OC)OC1=CC(=C(C=C1Cl)Cl)Cl
Isomeric SMILES
-
International Chemical Identifier key (InChIKey)
JHJOOSLFWRRSGU-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C8H8Cl3O3PS/c1-12-15(16,13-2)14-8-4-6(10)5(9)3-7(8)11/h3-4H,1-2H3
2D structure diagram/image available?
Yes
Cambridge Crystallographic Data Centre diagrams
Common Name Relationship Link
fenchlorphos -
General status
Veterinary substance type
Insecticide
Substance groups
Organophosphate insecticide; Organothiophosphate insecticide; Phenyl organothiophosphate insecticide
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Systemic, Cholinesterase inhibitor.
Molecular targets
[Cholinesterase, Inhibitor]
CAS RN
299-84-3
EC number
206-082-6
CIPAC number
112
US EPA chemical code
-
PubChem CID
9298
CLP index number
015-052-00-X
Therapeutic Class
-
ATCvet Code
None allocated
Controlled Drug?
No
Regulation 37/2010 MRL Classification
-
Molecular mass
321.55
PIN (Preferred Identification Name)
O,O-dimethyl O-(2,4,5-trichlorophenyl) phosphorothioate
IUPAC name
O,O-dimethyl O-2,4,5-trichlorophenyl phosphorothioate
CAS name
O,O-dimethyl O-(2,4,5-trichlorophenyl) phosphorothioate
Other status information
-
Relevant Environmental Water Quality Standards
UK Environment Agency non-statutory standard for the protection of aquatic life in freshwater and saltwater: 0.03 µg l⁻¹ as annual average, 0.1 µg l⁻¹ as max acceptable conc.
Physical state
Colourless to light tan coloured crystalline powder
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)
40.0
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
 Low
Solubility - In organic solvents at 20 °C (mg l⁻¹)
9080000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Acetone		 -
3470000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Chloroform		 -
5950000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Toluene		 -
5030000
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Xylene		 -
Melting point (°C)
41
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
 -
Boiling point (°C)
97
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
 -
Degradation point (°C)
- - -
Flashpoint (°C)
- - -
Octanol-water partition coefficient at pH 7, 20 °C
P
7.59 X 1004 Calculated -
Log P
4.88
Q3 Q = Miscellaneous data from online sources
3 = Unverified data of known source
 High
Fat solubility of residues
Solubility
- - -
Data type
- - -
Density (g ml⁻¹)
1.58
Q2 Q = Miscellaneous data from online sources
2 = Unverified data of unknown source
 -
Dissociation constant pKa) at 25 °C
- - -
-
Vapour pressure at 20 °C (mPa)
110
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
 Highly volatile. If applied directly to plants or soil, drift is a concern & mitigation is advisable
Henry's law constant at 25 °C (Pa m³ mol⁻¹)
- - -
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)
- - -
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)
- - -
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.
Soil adsorption and mobility
Property
Value
Source; quality score; and other information
Interpretation
Linear
Kd
-
Q2 Q = Miscellaneous data from online sources
2 = Unverified data of unknown source
 Non-mobile
Koc
10232
Notes and range
Estimated
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
- - -
Bio-concentration factor
BCF (l kg⁻¹)
- - -
CT₅₀ (days)
- -
Known metabolites

None

ECOTOXICOLOGY
Terrestrial ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
500
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Rat		 Moderate
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)
> 3500
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Anas platyrhynchos		 Low
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
- - -
- - -
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
- - -
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)
0.74
R3 R = Peer reviewed scientific publications
3 = Unverified data of known source
Oncorhynchus mykiss juvenile 48 hr		 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 - Acute 7 day EC₅₀, biomass (mg l⁻¹)
- - -
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)
- - -
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)
- - -
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)
500
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Rat		 Moderate
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
2000
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Rat		 -
Mammals - Inhalation LC₅₀ (mg l⁻¹)
- - -
Other Mammal toxicity endpoints
- - -
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
List II - -
Exposure Routes
Public
-
Occupational
May be absorbed through the skin
Mammalian dose elimination route and rate
Mainly excreted in urine
Q3 Q = Miscellaneous data from online sources
3 = Unverified data of known source
 -
Health issues
Specific human health issues
Carcinogen
Genotoxic
Endocrine disruptor
No data found
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
;
E0 E = Unspecified genotoxicity type (miscellaneous data source)
0 = No data
XNo, known not to cause a problem
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
✓Yes, known to cause a problem
✓Yes, known to cause a problem
✓Yes, known to cause a problem
Respiratory tract irritant Skin irritant Skin sensitiser
No data found No data found No data found
Eye irritant Phototoxicant  
No data found No data found  
General human health issues
Harmful in contact skin or if swallowed
Handling issues
Property
Value and interpretation
General
Prevent generation of dust
Incompatible with alkaline pesticides
IMDG Transport Hazard Class 6.1
CLP classification 2013
Health: H302, H312
Environment: H400, H410
WHO Classification
II (Moderately hazardous)
UN Number
UN2811
Waste disposal & packaging
Packaging Group III (minor danger)
Shelf-life, storage, stability and reactivity
-
TRANSLATIONS
Language
Name
English
fenchlorphos
French
fenchlorphos
German
Fenchlorphos
Danish
-
Italian
-
Spanish
fenclorfos
Greek
-
Polish
fenchlorfos
Swedish
-
Hungarian
-
Dutch
fenchloorfos
Norwegian
-
Record last updated: 23/02/2024
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