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Chlorthiophos (Ref: ENT 27635)
(Also known as: chlorthiofos; CM S-2957; celathion; OMS 1342; S 2597)
SUMMARY
Chlorthiophos is an obsolete organophosphate insecticide used mainly for the control of ants and mites. The substance has not been extensively studied and so very little data is available. Chlorthiophos is non-volatile and considered to be non-mobile. It is highly toxic to mammals, is a cholinesterase inhibitor and a neurotoxin.
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
Low alert:
Drainflow: Non-mobile
Warning:
Significant data are missing
Ecotoxicity
Moderate alert:
Fish acute ecotoxicity: Moderate
Warning:
Significant data are missing
Human health
High alert:
Mammals acute toxicity: High; Acetyl cholinesterase inhibitor; Neurotoxicant
Warning:
Significant data are missing
GENERAL INFORMATION
Description
An obsolete organophosphate insecticide used mainly for the control of ants and mites
Example pests controlled
Ants; Termites; Mites including varroa mite, phytophagous mites, spidermites; Thrips
Example applications
Cotton; Citrus
Efficacy & activity
-
Availability status
Considered obsolete but may be available in some countries
Introduction & key dates
1971, first reported
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
Not applicable
Date EC 1107/2009 inclusion expires
Expired
EU Candidate for substitution (CfS)
Not applicable
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
-
Chemical structure
Isomerism
Reaction mix of three isomers
Chemical formula
C₁₁H₁₅Cl₂O₃PS₂
Canonical SMILES
CCOP(=S)(OCC)OC1=CC(=C(C=C1Cl)Cl)SC
Isomeric SMILES
-
International Chemical Identifier key (InChIKey)
WIQNXNHXIZXZFM-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C11H15Cl2O3PS2/c1-4-14-17(18,15-5-2)16-8-6-9(12)11(13)10(7-8)19-3/h6-7H,4-5H2,1-3H3
2D structure diagram/image available?
Yes
General status
Pesticide type
Insecticide, Acaricide, Miticide
Substance groups
Organophosphate insecticide; Organophosphate acaricide; Organothiophosphate insecticide; Organothiophosphate acaricide
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Acetylcholinesterase (AChE) inhibitor.
CAS RN
21923-23-9
Alternative/old CAS RN
60238-56-4
EC number
244-663-6
CIPAC number
None allocated
US EPA chemical code
111814
PubChem CID
30859
CLP index number
015-115-00-1
Molecular mass
361.25
PIN (Preferred Identification Name)
reaction mixture of the three isomers: (i) O-[2,4-dichloro-5-(methylsulfanyl)phenyl] O,O-diethyl phosphorothioate; (ii) O-[2,5-dichloro-4-(methylsulfanyl)phenyl] O,O-diethyl phosphorothioate (major component); and (iii) O-[4,5-dichloro-2-(methylsulfanyl)phenyl] O,O-diethyl phosphorothioate
IUPAC name
mix of (i) O-2,4-dichlorophenyl-5-methylthiophenyl O,O-diethyl phosphorothioate; (ii) O-2,5-dichlorophenyl-4-methylthiophenyl O,O-diethyl phosphorothioate (major component); and (iii) O-4,5-dichlorophenyl-2-methylthiophenyl O,O-diethyl phosphorothioate
CAS name
O-[dichloro(methylthio)phenyl] O,O-diethyl phosphorothioate
Other status information
Marine Pollutant; PAN Bad Actor Chemical
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
Culex pipiens pipiens
Physical state
Yellow-brown liquid
Formulations
Property
Value
Example manufacturers & suppliers of products using this active now or historically
  • Shell Agrar
  • Celamerck
Example products using this active
  • Celathion
Formulation and application details
Was available in a wide variety of formulations including emulsifiable concentrates, dry powders, granules and wettable powders
ENVIRONMENTAL FATE
Property
Value
Source; quality score; and other information
Interpretation
Solubility - In water at 20 °C (mg l⁻¹)
- - -
Solubility - In organic solvents at 20 °C (mg l⁻¹)
- - -
Melting point (°C)
- - -
Boiling point (°C)
- - -
Degradation point (°C)
- - -
Flashpoint (°C)
- - -
Octanol-water partition coefficient at pH 7, 20 °C
P
2.19 X 1004 Calculated -
Log P
4.34
Q2 Q = Miscellaneous data from online sources
2 = Unverified data of unknown source
 High
Fat solubility of residues
Solubility
- - -
Data type
- - -
Density (g ml⁻¹)
1.46
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)
0.122
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
 Low volatility
Henry's law constant at 25 °C (Pa m³ mol⁻¹)
- - -
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)
- - -
DT₅₀ (lab at 20 °C)
- - -
DT₅₀ (field)
- - -
DT₉₀ (lab at 20 °C)
- - -
DT₉₀ (field)
- - -
DT₅₀ modelling endpoint
- - -
Note
-
Dissipation rate RL₅₀ on plant matrix
Value
- - -
Note
-
Dissipation rate RL₅₀ on and in plant matrix
Value
- - -
Note
-
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)
- - -
Soil adsorption and mobility
Property
Value
Source; quality score; and other information
Interpretation
Linear
Kd
-
Q1 Q = Miscellaneous data from online sources
1 = Estimated data with little or no verification
 Non-mobile
Koc
5461
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
- - -
SCI-GROW groundwater index (μg l⁻¹) for a 1 kg ha⁻¹ or 1 l ha⁻¹ application rate
Value
Cannot be calculated - -
Note
-
Potential for particle bound transport index
- - -
Potential for loss via drain flow
- - -
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)
7.8
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
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)
- - -
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
Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
1.3
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
Lepomis macrochirus		 Moderate
Fish - Chronic 21 day NOEC (mg l⁻¹)
- - -
Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
- - -
Aquatic invertebrates - Chronic 21 day NOEC (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)
7.8
L3 L = Pesticide manuals and hard copy reference books / other sources
3 = Unverified data of known source
Rat		 High
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
153
L3 L = Pesticide manuals and hard copy reference books / other sources
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
- - -
Exposure Routes
Public
-
Occupational
Absorbed by the skin, as well as by the respiratory and gastrointestinal tracts
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
No data found
A0 A = Chromosome aberration (EFSA database)
0 = No data
;
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
 No data found
Reproduction / development effects Acetyl cholinesterase inhibitor Neurotoxicant
No data found
✓Yes, known to cause a problem
✓Yes, known to cause a problem
Respiratory tract irritant Skin irritant Skin sensitiser
✓Yes, known to cause a problem
 No data found No data found
Eye irritant Phototoxicant  
No data found No data found  
General human health issues
Extremely hazardous
May cause conjunctival congestion and diminished vision
May cause gastrointestinal symptoms
Handling issues
Property
Value and interpretation
General
May generate highly toxic and flammable phosphine gas under certain conditions
Corrosive
CLP classification 2013
Health: H300, H311
Environment: H400, H410
WHO Classification
Ia (Extremely hazardous)
UN Number
-
Waste disposal & packaging
-
Shelf-life, storage, stability and reactivity
-
TRANSLATIONS
Language
Name
English
chlorthiophos
French
-
German
-
Danish
-
Italian
clortiofos
Spanish
-
Greek
-
Polish
chlortiofos
Swedish
-
Hungarian
-
Dutch
-
Norwegian
-
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