Endosulfan (Ref: OMS 570)

Endosulfan (Ref: OMS 570)	Last updated: 22/05/2025
(Also known as: thiodan; benzoepin; FMC 5462; ENT 23979; thiosulfan)

SUMMARY

Endosulfan is an insecticide and acaricide. It has a low aqueous solubility and is volatile. Based on its chemical properties it may have a tendency to leach to groundwater. Endosulfan is moderately persistent in soil but does not tend to persist in water systems. It is highly toxic to mammals, a neurotoxin and possibly a mutagen. It is moderately toxic to birds, honeybees and earthworms but slightly more toxic to aquatic organisms.

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 High alert: GUS: High leachability	Ecotoxicity High alert: Fish acute ecotoxicity: High; Fish chronic ecotoxicity: High	Human health High alert: Mammals acute toxicity: High; Genotoxic; Endocrine disrupter; Reproduction/development effects; Neurotoxicant

GENERAL INFORMATION

Description

An isomer mixture of alpha- and beta-endosulfan which is an insecticide and acaricide used to control sucking, chewing and boring insects

Example pests controlled

Whiteflies; Aphids; Leafhoppers; Colorado beetle; Cabbage worms; Ticks; Mites; Tstetse flies

Example applications

Vegetable crops; Cotton; Potatoes; Tomatoes; Apples

Efficacy & activity

Availability status

Current

Introduction & key dates

circa 1956, introduced

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

Spain

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

Australia; USA

Chemical structure

Isomerism

A molecule with 4 chiral centres, endosulfan is is a mixture of the alpha- and beta-forms.The alpha isomer is considerably more toxic than the beta isomer.

Chemical formula

C₉H₆Cl₆O₃S

Canonical SMILES

C1C2C(COS(=O)O1)C3(C(=C(C2(C3(Cl)Cl)Cl)Cl)Cl)Cl

Isomeric SMILES

C1[C@@H]2[C@H](COS(=O)O1)[C@@]3(C(=C([C@]2(C3(Cl)Cl)Cl)Cl)Cl)Cl

International Chemical Identifier key (InChIKey)

RDYMFSUJUZBWLH-UHFFFAOYSA-N

International Chemical Identifier (InChI)

InChI=1S/C9H6Cl6O3S/c10-5-6(11)8(13)4-2-18-19(16)17-1-3(4)7(5,12)9(8,14)15/h3-4H,1-2H2

2D structure diagram/image available?

Yes

Cambridge Crystallographic Data Centre diagrams

Common Name	Relationship	Link
endosulfan	Beta-isomer
endosulfan sulphate	Variant

General status

Pesticide type

Insecticide; Acaricide

Substance groups

Organochloride insecticide; Organochloride acaricide; Cyclodiene insecticide; Cyclodiene acaricide

Minimum active substance purity

Known relevant impurities

Substance origin

Synthetic

Mode of action

Non-systemic with contact and stomach action. Non-competitive GABA-gated chloride channel antagonist.

CAS RN

115-29-7

EC number

204-079-4

CIPAC number

US EPA chemical code

079401

PubChem CID

3224

CLP index number

602-052-00-5

Molecular mass

406.93

PIN (Preferred Identification Name)

(5aE,6E,9E,9aE)-6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin-3-one

IUPAC name

1,4,5,6,7,7-hexachloro-8,9,10-trinorborn-5-en-2,3-ylenebismethylene sulfite

CAS name

6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin 3-oxide

Other status information

POP chemical; OSPAR pfa/soc; WFD priority substance; Marine Pollutant; Global ban (2011); Subject to PIC regulations; Subject to the provisions of the UK Poisons Act 1972

Relevant Environmental Water Quality Standards

EU Directive 2008/105/EC EQS surface waters: annual average 0.005 µg l⁻¹; max measured 0.01 µg l⁻¹
UK Statutory standard for the protection of aquatic life in inland waters, coastal and territorial waters: 0.003 µg l⁻¹ as annual average

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

Many recorded cases, Aphis gossypii, Bemisia tabaci, Dasineura tetensi, Leptinotarsa decemlineata, Myzus persicae, many others

Physical state

Colourless to brown coloured crystals

Formulations

Property

Value

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

Bayer CropScience
Hoechst
FMC
Velsicol
Makhteshim-Agan

Example products using this active

Thiodan
Benzoepin

Formulation and application details

Supplied in a variety of formulations including emulsifiable concentrates, wettable powders, granules and dusts

ENVIRONMENTAL FATE

Property

Value

Source; quality score; and other information

Interpretation

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

0.32

Low

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

200000

Ethyl acetate

65000

Ethanol

24000

Hexane

200000

Toluene

Melting point (°C)

Boiling point (°C)

Degradation point (°C)

Flashpoint (°C)

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

5.62 X 10⁰⁴

Calculated

Log P

4.75

High

Fat solubility of residues

Solubility

Soluble

Data type

Regulatory data - observed in metabolism and farm animal feeding studies

Density (g ml⁻¹)

1.8

Dissociation constant pKa) at 25 °C

Vapour pressure at 20 °C (mPa)

0.83

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)

1.48

Moderately 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)

Degradation

Property

Value

Source; quality score; and other information

Interpretation

General biodegradability

Soil degradation (days) (aerobic)

DT₅₀ (typical)

Moderately persistent

DT₅₀ (lab at 20 °C)

Moderately persistent

DT₅₀ (field)

Moderately persistent

DT₉₀ (lab at 20 °C)

DT₉₀ (field)

DT₅₀ modelling endpoint

Note

EU dossier lab studies DT₅₀ range 28-50 days, field studies DT₅₀ range 62-126 days for summer applications, 68-87 days for autumn applications (UK); FAO state DT₅₀ 60-800 days

Dissipation rate RL₅₀ (days) on plant matrix

Value

3.7

Note

Published literature RL₅₀ range 0.1-5.5 days, 19 field crops, various matrices, n=23

Dissipation rate RL₅₀ (days) on and in plant matrix

Value

4.2

Note

Published literature RL₅₀ range 0.4-14.5 days, 19 field & undercover grown crops, various matrices, n=43

Aqueous photolysis DT₅₀ (days) at pH 7

Value

Note

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

Value

Non-persistent

Note

Water-sediment DT₅₀ (days)

Water phase only DT₅₀ (days)

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

[Wheat grain (dried): ~85 days @ ~25 DegC, ~80% RH; Lab study]

Soil adsorption and mobility

Property

Value

Source; quality score; and other information

Interpretation

Linear

K_d (mL g⁻¹)

Non-mobile

K_oc (mL g⁻¹)

11500

Notes and range

Freundlich

K_f (mL g⁻¹)

0.28

Mobile

K_foc (mL g⁻¹)

18.6

¹/_n

0.558

Notes and range

Literature data K_f range 0.08-0.52 mL g⁻¹, K_foc range 5.7-38.5 mL g⁻¹, ¹/_n range 0.500-0.648, soils=4

pH sensitivity

Fate indices

Property

Value

Source; quality score; and other information

Interpretation

GUS leaching potential index

5.28

Calculated

High leachability

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

Value

5.86 X 10⁰⁰

Calculated

Note

Potential for particle bound transport index

Medium

Calculated

Potential for loss via drain flow

Non-mobile

Calculated

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

Bio-concentration factor

BCF (l kg⁻¹)

2755

Whole fish (Literature values log BCF range 1.0-3.7 (R3))

Threshold for concern

CT₅₀ (days)

Not available

Known soil metabolites

Metabolite

Major/Minor fraction

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

Estimated maximum occurrence fraction

Notes

endosulfan sulfate

endosulfan lactone

Minor fraction

CAS no: 3868-61-9

Known groundwater metabolites

None

Other known metabolites

Metabolite name and reference

Aliases

Formation medium / Rate

Estimated maximum occurrence fraction

endosulfan sulfate

Human kidney; Rat

endosulfan lactone

Human kidney; Rat

endosulfan-diol

Human kidney; Rat

alpha-hydroxyendosulfan ether

Animal

ECOTOXICOLOGY

Terrestrial ecotoxicology

Property

Value

Source; quality score; and other information

Interpretation

Mammals - Acute oral LD₅₀ (mg kg⁻¹)

Rat

High

Mammals - Short term dietary NOEL

(mg kg⁻¹)

Rat 2 yr

(ppm diet)

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

Birds - Acute LD₅₀ (mg kg⁻¹)

> 111

Anas platyrhynchos

Moderate

Birds - Short term dietary (LC₅₀/LD₅₀)

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

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

> 14

Eisenia foetida

Moderate

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)

> 7.81

Apis mellifera

Moderate

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

> 15.6

Apis mellifera 24 hr

Moderate

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

Chronic

Notes

[The residual time to 25% mortality (RT25) value for honeybees is 3 hrs - USEPA data]

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)

> 1.72

Bombus terrestris

Moderate

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)

0.210

Trigona spinipes

High

Mode of exposure

Contact

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)

Harmless

Chrysoperla carnea

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)

0.002

Oncorhynchus mykiss

High

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

0.0000005

Cyprinodon variegatus 28 day

High

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

> 0.0013

Danio rerio

High

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

0.44

Daphnia magna

Moderate

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

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

> 0.03

Ceriodaphnia dubia

High

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

0.24

Americamysis bahia

Moderate

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

0.1

Chironomus riparius 2 day

Moderate

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

Sediment dwelling organisms - Chronic 28 day NOEC, sediment (mg kg⁻¹)

5.22

Chironomus dilutus 10 day LC₅₀

Moderate

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)

2.15

Anabaena doliolum

Moderate

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

Mesocosm study data

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)

Rat

High

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

500

Rat

Mammals - Inhalation LC₅₀ (mg l⁻¹)

0.013

Rat

Other Mammal toxicity endpoints

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

0.006

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

0.02

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

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

Excretion rapid as metabolites

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

No data found

General human health issues

Mutagenic potential
Highly toxic
Research shows that endosulfan interferes with the spermatogenic & steroidogenic cycles in rats
Endocrine issues - Competitive binding to androgen receptors

Handling issues

Property

Value and interpretation

General

Corrosive
IMDG Transport Hazard Class 6.1

CLP classification 2013

Health: H300, H312, H330
Environment: H400, H410

WHO Classification

II (Moderately hazardous)

UN Number

UN2811

Waste disposal & packaging

Packaging Group II (moderate danger)

Shelf-life, storage, stability and reactivity

Chemically stable under standard ambient conditions

TRANSLATIONS

Language

Name

English

endosulfan

French

endosulfan

German

Endosulfan

Danish

endosulfan

Italian

endosulfan

Spanish

endosulfan

Greek

endosulphan

Polish

endosulfan

Swedish

Hungarian

endoszulfan

Dutch

endosulfan

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