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Methyl isothiocyanate (Ref: SN-32866)
Last updated: 15/03/2024
(Also known as: methyl mustard oil; MITC; isothiocyanic acid methyl ester; MIT; R014821)
GENERAL INFORMATION
Description
A highly toxic multipurpose soil fumigant. Also a pesticide transformation product and used in the production of many pesticides and other chemicals.
Availability status
-
Introduction & key dates
-
Examples of veterinary uses
-
Examples of species treated
-
Approval status
VMR 2013/2033 approval status (GB/UK)
-
EU Regulatory approval status
-
Chemical structure
Isomerism
None
Chemical formula
C₂H₃NS
Canonical SMILES
CN=C=S
Isomeric SMILES
-
International Chemical Identifier key (InChIKey)
LGDSHSYDSCRFAB-UHFFFAOYSA-N
International Chemical Identifier (InChI)
InChI=1S/C2H3NS/c1-3-2-4/h1H3
2D structure diagram/image available?
Yes
General status
Veterinary substance type
-
Metabolite Type
Soil, Groundwater
Substance groups
Fumigant pesticide
Minimum active substance purity
-
Known relevant impurities
-
Substance origin
Synthetic
Mode of action
Fumigant with contact action
Molecular targets
-
CAS RN
556-61-6
EC number
209-132-5
CIPAC number
None allocated
US EPA chemical code
068103
PubChem CID
11167
CLP index number
615-002-00-2
Therapeutic Class
-
ATCvet Code
-
Controlled Drug?
-
Regulation 37/2010 MRL Classification
-
Molecular mass
73.11
PIN (Preferred Identification Name)
-
IUPAC name
methyl isothiocyanate
CAS name
isothiocyanatomethane
Other status information
-
Relevant Environmental Water Quality Standards
-
Physical state
Colourless crystalline solid
Can be a metabolite of:
Parent
Formation medium
Estimated maximum occurrence fraction
1107/2009 relevancy
metam-sodium Soil 0.829 Major fraction
metam-sodium Groundwater - Relevant
imazalil sulfate Soil - Minor fraction
metam-potassium Groundwater - Relevant
metam-potassium Soil 0.829 Major fraction
metam-ammonium Soil 0.829 Major fraction
metam-ammonium Groundwater - Relevant
imazalil nitrate Soil - Minor fraction
dazomet Soil 0.740 Major fraction
dazomet Groundwater - Relevancy unknown
metam Soil 0.829 Major fraction
metam Groundwater - Relevant
imazalil Soil 0.096 Minor fraction
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)
8940
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
 High
Solubility - In organic solvents at 20 °C (mg l⁻¹)
- - -
Melting point (°C)
35
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
 -
Boiling point (°C)
119
V3 V = ChemID Online Databases; Chemspider; PubChem. (ChemID )
3 = Unverified data of known source
 -
Degradation point (°C)
- - -
Flashpoint (°C)
- - -
Octanol-water partition coefficient at pH 7, 20 °C
P
1.12 X 1001 Calculated -
Log P
1.05
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
 Low
Fat solubility of residues
Solubility
- - -
Data type
- - -
Density (g ml⁻¹)
1.07
E3 E = Manufacturers safety data sheets
3 = Unverified data of known source
 -
Dissociation constant pKa) at 25 °C
12.3
Q3 Q = Miscellaneous data from online sources
3 = Unverified data of known source
 -
Strong base
Vapour pressure at 20 °C (mPa)
1739000
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
 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)
14.2
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
 Moderately volatile
Volatilisation as max % of applied dose lost
From plant surface
- - -
From soil surface
- - -
Maximum UV-vis absorption L mol⁻¹ cm⁻¹
Neutral soln: 235nm=635, 283nm=65, 321nm=17
Alkaline soln: 276nm=46, 320nm=5, 290nm=>10
Acidic soln: 235nm=635, 283nm=23, 290nm=>10
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
 -
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)
2.1
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
 Non-persistent
DT₅₀ (lab at 20 °C)
2.1
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
 Non-persistent
DT₅₀ (field)
3.2
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
 Non-persistent
DT₉₀ (lab at 20 °C)
6.99
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
 Non-persistent
DT₉₀ (field)
13.1
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
 -
Note
EU dossier (2023 metam) lab studies DT₅₀ (normalised) range: 1.08-3.24 days, DT₉₀ (normalised) range 3.6-10.78 days Soils=4;Ffield studies DT₅₀ (normalised) range 1.2-5.0 days, DT₉₀ (measured) 4.1-16.5 days, Soils=4; EU dossier (dazomet) lab studies range 5-32.7 days; Other literature studies Lab range - 24 soils, nursery and forest, various app rates
Manure DT₅₀ (days)
- - -
Aqueous photolysis DT₅₀ (days) at pH 7
Value
6
K2 K = Research datasets (e.g. Pandora, Demetra; these datasets no longer available). Norman Ecotoxicology database. (click here )
2 = Unverified data of unknown source
 Moderately fast
Note
-
Aqueous hydrolysis DT₅₀ (days) at 20 °C and pH 7
Value
50
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
 Moderately persistent
Note
pH sensitive. DT40 50 days at pH4, 11 days at pH9
Water-sediment DT₅₀ (days)
0.37
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
 Fast
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
- - -
Koc
-
Notes and range
-
Freundlich
Kf
0.56
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
 Mobile
Kfoc
21.7
1/n
0.86
Notes and range
EU dossier (Metam, 2023) Kf range 0.21-1.38 mL g⁻¹, Kfoc range 9.0-71.7 mL g⁻¹, 1/n range 0.755-9.1, Soils=10
pH sensitivity
No
Fate indices
Property
Value
Source; quality score; and other information
Interpretation
GUS leaching potential index
1.35 Calculated Low leachability
Bio-concentration factor
BCF (l kg⁻¹)
2.6
K2 K = Research datasets (e.g. Pandora, Demetra; these datasets no longer available). Norman Ecotoxicology database. (click here )
2 = Unverified data of unknown source
Estimated		 Low potential
CT₅₀ (days)
Not available -
Known metabolites

None

ECOTOXICOLOGY
Terrestrial ecotoxicology
Property
Value
Source; quality score; and other information
Interpretation
Mammals - Acute oral LD₅₀ (mg kg⁻¹)
> 100
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
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)
127
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
Colinus virginianus		 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)
4.0
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
Eisenia foetida		 High
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)
0.0531
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
Oncorhynchus mykiss		 High
Temperate Freshwater Fish - Chronic 21 day NOEC (mg l⁻¹)
0.005
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
Oncorhynchus mykiss 28 day		 High
Tropical Freshwater Fish - Acute 96 hour LC₅₀ (mg l⁻¹)
0.137
F3 F = U.S. EPA ECOTOX database / U.S. EPA pesticide fate database / Miscellaneous WHO documents / FAO data, IPCS INCHEM data (US EPA Databases Related to Pesticide Risk Assessment )
3 = Unverified data of known source
Danio rerio Embryo		 Moderate
Temperate Freshwater Aquatic invertebrates - Acute 48 hour EC₅₀ (mg l⁻¹)
0.076
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
Daphnia magna		 High
Temperate Freshwater Aquatic invertebrates - Chronic 21 day NOEC (mg l⁻¹)
0.00625
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
Daphnia magna		 High
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)
0.59
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
Lemna gibba		 Moderate
Algae - Acute 72 hour EC₅₀, growth (mg l⁻¹)
0.58
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
Pseudokirchneriella subcapitata		 Moderate
Algae - Chronic 96 hour NOEC, growth (mg l⁻¹)
> 0.125
L2 L = Pesticide manuals and hard copy reference books / other sources
2 = Unverified data of unknown source
Unknown species		 Moderate
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)
> 100
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
Rat		 Moderate
Mammals - Dermal LD₅₀ (mg kg⁻¹ body weight)
1290
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
Rabbit		 -
Mammals - Inhalation LC₅₀ (mg l⁻¹)
0.54
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
Rat 4 hr (whole body)		 -
Other Mammal toxicity endpoints
- - -
ADI - Acceptable Daily Intake (mg kg⁻¹ bw day⁻¹)
0.004
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
Dog SF=100		 -
ARfD - Acute Reference Dose (mg kg⁻¹ bw day⁻¹)
0.03
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
Rat SF=100		 -
AAOEL - Acute Acceptable Operator Exposure Level (mg kg⁻¹ bw day⁻¹)
0.004
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
Rabbit SF=300		 -
AOEL - Acceptable Operator Exposure Level - Systemic (mg kg⁻¹ bw day⁻¹)
0.004
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
Dog. SF=100		 -
Dermal penetration studies (%)
- - -
Dangerous Substances Directive 76/464
- - -
Exposure Routes
Public
Some bystander risk identified via spray drift exposure
Occupational
May be fatal if absorbed through the skin
Respiratory equipment required to mitigate risk
Risks identified in glasshouse environments
Mammalian dose elimination route and rate
80-85% excreted with urine within approx. 80 hrs
A5 A = EU regulatory and evaluation data as published by EC, EFSA (RAR, DAR & Conclusion dossiers), EMA (e.g. EU Annex III PIC DGD) (EU - Pesticides database; EFSA Scientific Publications )
5 = Verified data used for regulatory purposes
 -
Health issues
Specific human health issues
Carcinogen
Genotoxic
Endocrine disruptor
?Possibly, status not identified
A2 A = Chromosome aberration (EFSA database)
2 = Mixed/ambiguous results
;
B1 B = DNA damage/repair (EFSA database)
1 = Positive
;
C3 C = Gene mutation (EFSA database)
3 = Negative
;
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
✓Yes, known to cause a problem
 No data found No data found
Respiratory tract irritant Skin irritant Skin sensitiser
✓Yes, known to cause a problem
✓Yes, known to cause a problem
✓Yes, known to cause a problem
Eye irritant Phototoxicant  
✓Yes, known to cause a problem
XNo, known not to cause a problem
  
General human health issues
Highly toxic by ingestion
Harmful via skin exposure and inhalation
Possible thyroid toxicant
US EPA - probable human carcinogen, CLP data - suspected carcinogen
Handling issues
Property
Value and interpretation
General
Corrosive
Not explosive or oxidising
CLP classification 2013
Health: H301, H312, H314; H317; H335, H351, H372
Environment: H400, H410
WHO Classification
II (Moderately hazardous)
UN Number
-
Waste disposal & packaging
-
Shelf-life, storage, stability and reactivity
-
TRANSLATIONS
Language
Name
English
methyl isothiocyanate
French
isothiocyanate de methyle
German
Methylisothiocyanat
Danish
methylisothiocyanat
Italian
Isotiocianato di metile
Spanish
isotiocianato de metilo
Greek
-
Polish
metyloizotiocyjanian
Swedish
-
Hungarian
-
Dutch
methylisothiocyanaat
Norwegian
-
Record last updated: 15/03/2024
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