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malathion (Ref: OMS 1)
** carbophos ** maldison ** mercaptothion ** carbofos ** ENT 17034 ** Translations

Environmental Fate - Ecotoxicology - Human Health - A to Z Index - Home
Further data may be found in the VSDB

for malathion

Description: An insecticide and acaricide used to control a wide range of pests including Coleoptera, Diptera, Hemiptera and Lepidoptera

Introduction: 1952, first reported

EC Regulation 1107/2009 (repealing 91/414):
Status Approved
Dossier rapporteur/co-rapporteur Finland
Date inclusion expires 30/04/2020

Approved for use () or known to be used () in the following European countries:




























Also registered in: USA

General status:
Pesticide type Insecticide, Acaricide, Veterinary substance
Substance group Organophosphate
Substance origin Synthetic
Mode of action Broad-spectrum, non-systemic with contact, stomach and respiratory action. Acetylcholinesterase (AChE) inhibitor.
CAS RN 121-75-5
EC number 204-497-7
CIPAC number 12
US EPA chemical code -
Chiral molecule Chiral, a specific isomer or a derivative of a chiral molecule
Chemical formula C10H19O6PS2
International Chemical Identifier key (InChIKey) JXSJBGJIGXNWCI-UHFFFAOYSA-N
International Chemical Identifier (InChI) InChI=1S/C10H19O6PS2/c1-5-15-9(11)7-8(10(12)16-6-2)19-17(18,13-3)14-4/h8H,5-7H2,1-4H3
Structure diagram/image available? Yes
Molecular mass (g mol-1) 330.36
PIN (Preferred Identification Name) -
IUPAC name diethyl (dimethoxyphosphinothioylthio)succinate
CAS name diethyl [(dimethoxyphosphinothioyl)thio]butanedioate
Other status information Marine Pollutant; Evidence of use in third world countries; Chemical subject to PIC regulations
Herbicide Resistance Classification (HRAC) Not applicable
Herbicide Resistance Classification (WSSA) Not applicable
Insecticide Resistance Classification (IRAC) 1B
Fungicide Resistance Classification (FRAC) Not applicable
Physical state Clear to amber liquid
Related substances & organisms

Property Value
Example manufacturers & suppliers of products using this active
  • Cheminova A/S
  • FMC Chemicals
  • Headland
  • Nickerson
Example products using this active
  • Fyfanon 440
  • Karbofos
  • Cythion
  • Maltox
UK LERAP status None
Formulation and application details Often supplied as oil suspension that is mixed with water and used as a spray, dip or pour-on.


for malathion

Property Value Source/Quality Score/Other Information Interpretation
Solubility - In water at 20oC (mg l-1) 148 A5 Moderate
Solubility - In organic solvents at 20oC (mg l-1) 250000 A5 - Xylene -
62000 A5 - Heptane -
250000 A5 - Acetone -
250000 A5 - Methanol -
Melting point (oC) -20 A5 -
Boiling point (oC) Decomposes before boiling A5 -
Degradation point (oC) 174 A5 -
Flashpoint (oC) 173 A5 -
Octanol-water partition coefficient at pH 7, 20oC P 5.62 X 1002 Calculated -
Log P 2.75 A5 Moderate
Bulk density (g ml-1)/Specific gravity 1.23 B5 -
Dissociation constant (pKa) at 25oC Not applicable B5 -
Note: No dissociation
Vapour pressure at 25oC (mPa) 3.1 A5 Intermediate state
Henry's law constant at 25oC (Pa m3 mol-1) 1.00 X 10-03 A5 Non-volatile
Henry's law constant at 20oC (dimensionless) 4.80 X 10-05 K3 Volatile
GUS leaching potential index -1.28 Calculated Low leachability
SCI-GROW groundwater index (μg l-1) for a 1 kg ha-1 or 1 l ha-1 application rate Value 3.12 X 10-05 Calculated -
Note -
Potential for particle bound transport index - Calculated Low
Maximum UV-vis absorption L mol-1 cm-1 No absorbance above 290nm A5 -
Surface tension (mN m-1) 58.0 A5 at 20oC -

Property Value Source/Quality Score/Other Information Interpretation
Soil degradation (days) (aerobic) DT50 (typical) 0.17 A5 Non-persistent
DT50 (lab at 20oC) 0.17 A5 Non-persistent
DT50 (field) 1 A5 Non-persistent
DT90 (lab at 20oC) 0.63 A5 -
DT90 (field) - - -
Note EU dossier lab studies range DT50 0.1-0.25 days, DT90 range 0.3-0.84 days; Other sources: DT50 1.0 days (DW4)
Aqueous photolysis DT50 (days) at pH 7 Value 98 B5 Stable
Note DT50 156 days under test conditions - not natural light (A5)
Aqueous hydrolysis DT50 (days) at 20oC and pH 7 Value 6.2 A5 Non-persistent
Note pH sensitive: DT50 107 days at pH 5, 0.49 days at pH 9, all at 25 degC
Water-sediment DT50 (days) 0.4 A4 Fast
Water phase only DT50 (days) 0.4 A4 Fast

Soil adsorption and mobility:
Property Value Source/Quality Score/Other Information Interpretation
Linear Kd - DW2 Slightly mobile
Koc 1800
Notes and range -
Freundlich Kf 1.58 A5 Moderately mobile
Kfoc 217
1/n 0.94
Notes and range EU dossier kf range 0.83-2.47 mL/g, Kfoc range 151-308 mL/g, 1/n range 0.904-0.978, Soils=5
pH sensitivity No

Key metabolites:
Metabolite Formation medium Estimated maximum occurrence fraction 91/414 relevancy
malathion monocarboxylic acid (Ref: MMCA) Soil   0.25   Major fraction, Relevant
malathion dicarboxylic acid Soil   0.62   Major fraction, Relevant
isomalathion On heating     Relevant

Other known metabolites:
Metabolite name and reference Aliases Formation medium / Rate Estimated maximum occurrence fraction Metabolising enzymes
diethyl (2RS)-2-[(dimethoxyphosphoryl)sulfanyl]butanedioate
Note: Considerably more toxic than malathion
Malaoxon Plant; Animal - -
desmethyl malathion DMM Plant - -
malathion dicarboxylic acid DCA Human (Liver) - -
malathion monocarboxylic acid DMA Human (Liver) - -


for malathion

Property Value Source/Quality Score/Other Information Interpretation
Bio-concentration factor BCF 103 A5 (Other literature Log BCF range 0-3.7 (R3)) Threshold for concern
CT50 (days) 0.69 -
Bioaccumulation potential - Calculated Low
Mammals - Acute oral LD50 (mg kg-1) 1778 A5 Rat Moderate
Mammals - Short term dietary NOEL (mg kg-1) 34.4 A5 Rat High
(ppm diet) - -
Birds - Acute LD50 (mg kg-1) 359 A5 Colinus virginianus Moderate
Birds - Short term dietary (LC50/LD50) 554 mg kg bw-1 day-1 A5 Colinus virginianus -
Fish - Acute 96 hour LC50 (mg l-1) 0.018 A5 Oncorhynchus mykiss High
Fish - Chronic 21 day NOEC (mg l-1) 0.091 A5 Oncorhynchus mykiss -
Aquatic invertebrates - Acute 48 hour EC50 (mg l-1) 0.0007 A5 Daphnia magna High
Aquatic invertebrates - Chronic 21 day NOEC (mg l-1) 0.00006 A5 Daphnia magna -
Aquatic crustaceans - Acute 96 hour LC50 (mg l-1) 0.0015 F3 Americamysis bahia High
Sediment dwelling organisms - Acute 96 hour LC50 (mg l-1) 0.0004 F2 Chironomus riparius, 1 day 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) 13 B5 Raphidocelis subcapitata, EU dossier EC50 = 4.1 Unknown species Low
Algae - Chronic 96 hour NOEC, growth (mg l-1) - - -
Honeybees Contact acute 48 hour LD50 (μg bee-1) 0.16 A5 High
Oral acute 48 hour LD50 (μg bee-1) - - -
Unknown mode acute 48 hour LD50 (μg bee-1) - - -
Earthworms - Acute 14 day LC50 (mg kg-1) 306 A5 Eisenia foetida, corr Moderate
Earthworms - Chronic 14 day NOEC, reproduction (mg kg-1) - - -
Other soil macro-organisms - e.g. Collembola LR50 / EC50 / NOEC / % Effect - - -
Other arthropod (1) LR50 g ha-1 0.061 48 hour
A5 Aphidius rhopalosiphi
Harmful at 1 kg ha-1
Harmful at 0.1 kg ha-1
Harmful at 0.01 kg ha-1
% Effect - - -
Other arthropod (2) LR50 g ha-1 85.4 A5 Typhlodromus pyri Moderately harmful at 1 kg ha-1
Harmless at 0.1 kg ha-1
Harmless at 0.01 kg ha-1
% Effect - - -
Soil micro-organisms Nitrogen mineralisation: No significant adverse effect
Carbon mineralisation: No significant adverse effect
Dose: 6.3 kg ha-1
Mesocosm study data NOEAEC mg l-1 0.030 A5 Aquatic invertebrates -
NOEAEC mg l-1 - - -


for malathion

Property Value Source/Quality Score/Other Information Interpretation
Mammals - Acute oral LD50 (mg kg-1) 1778 A5 Rat Moderate
Mammals - Dermal LD50 (mg kg-1 body weight) > 2000 A5 Rat -
Mammals - Inhalation LC50 (mg l-1) > 5.0 A5 Rat, 4 hr -
Other Mammal toxicity endpoints Intraperitoneal LD50 = 250 mg kg-1 V3 Rat -
Intravenous LD50 = 50 mg kg-1 V3 Rat -
ADI - Acceptable Daily Intake (mg kg-1bw day-1) 0.03 A5 Rat, SF=1000 -
ARfD - Acute Reference Dose (mg kg-1bw day-1) 0.3 A5 Rat, SF=100 -
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg-1bw day-1) 0.03 A2 Rat, SF=1000 -
Dermal penetration studies (%) 5.0-15.0 A5 concentration dependant -
Dangerous Substances Directive 76/464 List I; List II - -
Exposure Limits [LT TWA 8hr: 10 mg/m3] MEL UK HSE -
Exposure Routes Public Possible concerns for bystanders especially children should they enter a sprayed area
Occupational Operators should use PPC/PPE at all times
Examples of European MRLs (mg kg-1) Value Strawberry: 0.3
Note A5 EU dossier proposals
For the EU pesticides database click here
Drinking Water MAC (μg l-1) - - -

Health issues:
Carcinogen Mutagen Endocrine disrupter Reproduction / development effects Cholinesterase inhibitor Neurotoxicant Respiratory tract irritant Skin irritant Eye irritant

General human health issues Possible adrenal gland, thyroid and liver toxicant
Possible skin sensitiser
Acetylcholinesterase inhibition

: Yes, known to cause a problem
: No, known not to cause a problem
: Possibly, status not identified
- : No data

Handling issues:
Property Value Source/Quality Score/Other Information Interpretation
General Prevent generation of mists
Store at low temperatures, do not heat
Not explosive or oxidising
IMDG Transport Code is usually 6.1
CLP classification 2013 -
EC Risk Classification Xn - Harmful: R22, R43
N - Dangerous for the environment: R50, R53
EC Safety Classification S2, S24, S37, S46, S60, S61
WHO Classification III - Slightly hazardous
US EPA Classification (formulation) III - Caution - Slightly toxic
UN Number Usually 2783
Waste disposal & packaging Packaging Group III (minor danger)


for malathion

Language Name
English malathion
French malathion
German Malathion
Danish malathion
Italian malation
Spanish malation
Greek malathion
Slovenian malation
Polish malation
Swedish -
Hungarian malathion
Dutch malathion

Record last updated: Wednesday 14 January 2015