Substance profile
Methamidophos
Methamidophos is colorless crystals with a mercaptan-like odor.
01 · Identification
What Methamidophos is
Methamidophos is colorless crystals with a mercaptan-like odor. Its molecular formula is C2H8NO2PS and its molecular weight is 141.13 g/mol. It melts at 44.9 °C.
Under the GHS it carries the signal word Danger.
02 · Identifiers
Methamidophos identifiers and molecular data
Methamidophos CAS number and EC number
Methamidophos molecular formula and molecular weight
Other names for Methamidophos
- methamidophos (ISO)
- O,S-dimethyl phosphoramidothioate
03 · GHS classification
Methamidophos hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Methamidophos pictograms and signal word
Methamidophos hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Acute toxicity - oral GHS chapter 3.1 | Category 1 or 2 | H300 | GHS06 |
| Acute toxicity - dermal GHS chapter 3.1 | Category 3 | H311 | GHS06 |
| Acute toxicity - inhalation GHS chapter 3.1 | Category 1 or 2 | H330 | GHS06 |
| Hazardous to the aquatic environment - acute GHS chapter 4.1 | Category 1 | H400 | GHS09 |
Where two values are shown with “or”, the hazard statement is shared by more than one category or by more than one class, and the code alone does not say which. H272, for example, belongs to oxidising liquids and to oxidising solids — the physical state decides. The binding answer for a specific entry is in the CLP Annex VI table itself.
Methamidophos hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H330 | Fatal if inhaled. |
| H300 | Fatal if swallowed. |
| H311 | Toxic in contact with skin. |
| H400 | Very toxic to aquatic life. |
This page lists only the codes assigned to Methamidophos. The full reference lives on the hazard statements hub, the precautionary statements hub and the GHS pictograms hub.
Safety Data Sheet
Getting an SDS for Methamidophos
A Safety Data Sheet is written for a product, not for a substance: the supplier of the grade you actually buy issues it, so two suppliers of Methamidophos issue two different sheets. That is why there is no single authoritative SDS for a substance to download — what there is, is the job of collecting the sheets for the products you hold and keeping them current as suppliers revise them.
04 · Precautionary statements
Methamidophos precautionary statements
CLP Annex VI assigns 13 precautionary statements to Methamidophos. They are grouped the way a label groups them: what to do before handling, what to do when something has already happened, how to store it and how to dispose of it.
Prevention
What to do before and during handling so the hazard never happens.
Response
What to do once exposure, spillage or fire has already happened.
Disposal
What has to happen to the contents and the empty container.
Reading the notation. … is a blank the supplier fills in — not a truncated sentence.· [square brackets] mark a part printed only when it applies.
05 · Names in the regulation
Methamidophos name in 23 EU languages
CLP Annex VI Part 3 is published in every language edition of the regulation, and the identification column is written out in each of them. Nothing below is translated by us: each line is the name as that edition prints it. Under Art. 18(2) the substance name from Annex VI is a lawful product identifier, so this is the wording to put on a label going to that market — and where the cell lists several designations, any one of them qualifies.
| Language | Name in CLP Annex VI Part 3 |
|---|---|
| Bulgarian български | метамидофос (ISO) O , S -диметилов фосфорамидотиоат |
| Spanish español | Metamidofós (ISO) fosforamidotioato de O, S -dimetilo |
| Czech čeština | methamidofos (ISO) O, S -dimethyl-fosforamidothioát |
| Danish dansk | methamidophos (ISO) O, S- dimethylthiophosphoramidat |
| German Deutsch | Methamidophos (ISO) O, S -Dimethylphosphoramidothioat |
| Estonian eesti | metamidofoss (ISO) O , S -dimetüülatsetüülfosforamidotioaat |
| Greek ελληνικά | methamidophos (μεθαμιδοφός) (ISO) φωσφοραμιδοθειοϊκός O , S -διμεθυλεστέρας |
| English English | methamidophos (ISO) O , S -dimethyl phosphoramidothioate |
| French français | méthamidophos (ISO) phosphoramidothioate de O, S -diméthyle |
| Croatian hrvatski | metamidofos (ISO) O , S -dimetil-fosforamidotioat |
| Italian italiano | metamidofos (ISO) tiofosforammidato di O, S-dimetile |
| Latvian latviešu | metamidofoss (ISO) O , S -dimetilfosforamidotioāts |
| Lithuanian lietuvių | metamidofosas (ISO) O , S -dimetilamidotiofosfatas |
| Hungarian magyar | metamidofosz (ISO) O , S -dimetil-foszforamidotioát |
| Maltese Malti | metammidofos (ISO) fosforammidotijoat ta’ O , S -dimetil |
| Dutch Nederlands | methamidofos (ISO) O , S -dimethylthiofosforamidaat |
| Polish polski | metamidofos (ISO) amidotiofosforan O , S -dimetylu |
| Portuguese português | metamidofos (ISO) tiofosforamidato de O , S -dimetilo |
| Romanian română | metamidofos (ISO) tiofosforamidat de O, S - dimetil |
| Slovak slovenčina | metamidofos (ISO) O, S -dimetyl-fosforamidotioát |
| Slovenian slovenščina | metamidofos (ISO) O , S -dimetil fosforamidotioat |
| Finnish suomi | metamidofossi (ISO) O , S -dimetyylifosforamidotioaatti |
| Swedish svenska | metamidofos (ISO) O , S -dimetylfosforamidotioat |
All 23 language editions of Annex VI carry this entry. Irish is the twenty-fourth official EU language and has no line here for a different reason: no consolidated CLP text has ever been published in Irish, so there is no Irish edition of Annex VI to quote a name from. Source: consolidated CLP, CELEX 02008R1272, language editions. © European Union, https://eur-lex.europa.eu — only the electronic Official Journal of the European Union is authentic.
06 · Label elements
Methamidophos GHS label elements
Everything CLP Annex VI fixes for Methamidophos, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Methamidophos
- Fatal if inhaled.
- Fatal if swallowed.
- Toxic in contact with skin.
- Very toxic to aquatic life.
- Do not breathe dust/fume/gas/mist/vapours/spray.
- Do not eat, drink or smoke when using this product.
- Use only outdoors or in a well-ventilated area.
- Avoid release to the environment.
- Wear protective gloves/protective clothing/eye protection/face protection/hearing protection/…
- IF SWALLOWED:
- IF ON SKIN:
- IF INHALED:
- Immediately call a POISON CENTER/doctor/…
- Rinse mouth.
- Wash with plenty of water/…
- Collect spillage.
- Dispose of contents/container to …
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Methamidophos in the GHS label constructor →
07 · Health hazards
Methamidophos health hazards and exposure limits
Methamidophos hazard summary
Classified as highly toxic, it may be used only by certified applicators. [EXTOXNET] A small number of the organophosphates (OPs) can Induce Delayed Neuropathy (OPIDN). OPIDN usually occurs after ingestion and is usually nonoccupational. [Levy, p. 431] An eye irritant; Can be absorbed through skin; A cholinesterase inhibitor that may cause CNS effects (convulsions and respiratory failure) on short-term exposure; Extended or repeated exposure may cause delayed neuropathy; [ICSC] Reports of delayed neuropathy form occupational exposures; [HSDB] Also a metabolite of the OP pesticide acephate; A cholinesterase inhibitor that is one of the most acutely toxic of the OP pesticides; A moderate eye (corneal opacity persisting up to ten days in 2/6 rabbits) and mild skin irritant; Not sensitizing to guinea pig skin; Neuropathology observed in hens but not in rats; [Reference #2] Ranked second in the US for percentage of cases with life-threatening symptoms among occupational Poison Control Center cases; Reproductive studies have shown effects to several parameters at relatively low exposure levels; No evidence of mutagenicity or carcinogenicity; [UNEP DGDs] The average of two baseline respective cholinesterase activity determinations three days apart, with no exposures to enzyme inhibiting pesticides for at least 30 days, is recommended for each worker prior to exposure to cholinesterase inhibitors because of large inter-individual differences in published baseline values. To be established at least once a year. Removal from workplace exposures is recommended until the cholinesterase activity returns to within 20% of baseline. [TLVs and BEIs]
Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
Methamidophos carcinogenicity classification
Cancer Classification: Not Likely to be Carcinogenic to Humans
Source: Hazardous Substances Data Bank (HSDB)
An IARC group and a CLP classification answer different questions. IARC judges whether the evidence for cancer in humans is strong enough; CLP Annex VI is the legally binding EU classification. A substance can carry one and not the other.
08 · Physical and chemical properties
Methamidophos properties
Every value is shown with the conditions it was measured under and the source it came from. Where sources disagree, all values are listed rather than one being picked — the difference is usually a different form of the substance, not an error.
Methamidophos boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | Decomposes on heating without boiling | decomposes | HSDB |
| Decomposes (EPA, 1998) | decomposes | CAMEO |
Methamidophos melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | 44.9 °C (112.8 °F) | HSDB | |
| 44.44 °C (112 °F) | CAMEO | ||
| 44 °C (111.2 °F) | ICSC |
Methamidophos density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 1.3 g/cm³ | ICSC | |
| 1.27 g/cm³ | at 20 °C | HSDB | |
| 1.31 g/cm³ | at 44.5 °C | CAMEO |
Methamidophos solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Soluble in aliphatic chlorinated hydrocarbons, alcohols; slightly soluble in ether. | HSDB | |
| Readily sol in n-hexane, dichloromethane, 2-propanol, toluene | HSDB | ||
| Solubility (g/l) at 20 °C in: isopropanol: >200; dichloromethane: >200; hexane: 0.1-1; toluene: 2-5 | at 20 °C | HSDB |
Methamidophos vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 0.000015 mmHg | at 20 °C | ICSC |
| 35250 mmHg | at 25 °C | HSDB | |
| 0.0003 mmHg | at 25 °C | DOE PAC |
Methamidophos corrosivity
| Property | Value | Conditions | Source |
|---|---|---|---|
| Corrosivity | Slightly corrosive to mild steel and copper-containing alloys. | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Handling and storage
Methamidophos storage and handling
Methamidophos safe storage
Provision to contain effluent from fire extinguishing. Separated from food and feedstuffs. Dry. Keep in a well-ventilated room. Store in an area without drain or sewer access.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Methamidophos storage conditions
...Concentrates... should not be stored in mild steel containers.
Source: Hazardous Substances Data Bank (HSDB)
Methamidophos incompatible materials
Attacks mild steel and copper-containing alloys (technical grade).
Source: Hazardous Substances Data Bank (HSDB)
Methamidophos reactivity
Organophosphates, such as METHAMIDOPHOS, are susceptible to formation of highly toxic and flammable phosphine gas in the presence of strong reducing agents such as hydrides. Partial oxidation by oxidizing agents may result in the release of toxic phosphorus oxides. Avoid strong acids or alkalis. [EPA, 1998].
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Methamidophos in the storage compatibility matrix →
10 · Questions
Methamidophos — frequently asked questions
What is the CAS number of Methamidophos?
The CAS number of Methamidophos is 10265-92-6. Its EC number is 233-606-0.
What is the chemical formula of Methamidophos?
The molecular formula of Methamidophos is C2H8NO2PS and its molecular weight is 141.13 g/mol.
What does a Methamidophos label have to show?
Under CLP Annex VI the label for Methamidophos carries the pictograms Skull and crossbones and Environment and the signal word is Danger.
Is Methamidophos flammable?
CLP Annex VI assigns Methamidophos no flammability hazard class. That is not a statement that it cannot burn: the harmonised list only records the hazards that were assessed for it.
Is Methamidophos a carcinogen?
CLP Annex VI records no harmonised carcinogenicity classification for Methamidophos. Annex VI is a list of agreed classifications, not a list of substances found safe, so this is an absence of a classification rather than a clean bill of health.
What is the boiling point of Methamidophos?
The boiling point reported for Methamidophos is Decomposes on heating without boiling, decomposes (HSDB).
What is the melting point of Methamidophos?
The melting point reported for Methamidophos is 44.9 °C (112.8 °F) (HSDB).
How should Methamidophos be stored?
...Concentrates... should not be stored in mild steel containers. (Hazardous Substances Data Bank (HSDB))
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