Substance profile
Methylhydrazine
Methylhydrazine is a clear liquid with an odor characteristic of short chain, organic amines.
01 · Identification
What Methylhydrazine is
Methylhydrazine is a clear liquid with an odor characteristic of short chain, organic amines. Its molecular formula is CH6N2 and its molecular weight is 46.072 g/mol. It boils at 87.5 °C, melts at -52.4 °C.
Under the GHS it carries the signal word Danger. It is classed as hazardous Air Pollutants (HAPs).
02 · Identifiers
Methylhydrazine identifiers and molecular data
Methylhydrazine CAS number and EC number
Methylhydrazine molecular formula and molecular weight
03 · GHS classification
Methylhydrazine hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Methylhydrazine pictograms and signal word
Methylhydrazine hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Carcinogenicity GHS chapter 3.6 | Category 1A or 1B | H350 | GHS08 |
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.
Methylhydrazine hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H350 | May cause cancer <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>. |
This page lists only the codes assigned to Methylhydrazine. 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 Methylhydrazine
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 Methylhydrazine 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
Methylhydrazine precautionary statements
CLP Annex VI assigns 4 precautionary statements to Methylhydrazine. 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.
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
Methylhydrazine 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 | метилхидразин |
| Spanish español | Metilhidrazina |
| Czech čeština | methylhydrazin |
| Danish dansk | methylhydrazin |
| German Deutsch | Methylhydrazin |
| Estonian eesti | metüülhüdrasiin |
| Greek ελληνικά | μεθυλυδραζίνη |
| English English | methylhydrazine |
| French français | méthylhydrazine |
| Croatian hrvatski | metilhidrazin |
| Italian italiano | metilidrazina |
| Latvian latviešu | metilhidrazīns |
| Lithuanian lietuvių | metilhidrazinas |
| Hungarian magyar | metilhidrazin |
| Maltese Malti | metilidrażina |
| Dutch Nederlands | methylhydrazine |
| Polish polski | metylohydrazyna |
| Portuguese português | Metil-hidrazina |
| Romanian română | metilhidrazină |
| Slovak slovenčina | metylhydrazín |
| Slovenian slovenščina | metilhidrazin |
| Finnish suomi | metyylihydratsiini |
| Swedish svenska | metylhydrazin |
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
Methylhydrazine GHS label elements
Everything CLP Annex VI fixes for Methylhydrazine, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Methylhydrazine
- May cause cancer <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>.
- Obtain special instructions before use.
- Wear protective gloves/protective clothing/eye protection/face protection/hearing protection/…
- IF exposed or concerned:
- Get medical advice/attention.
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Methylhydrazine in the GHS label constructor →
07 · Health hazards
Methylhydrazine health hazards and exposure limits
Methylhydrazine hazard summary
Methylhydrazine is used as a high-energy fuel in military applications. Acute (short-term) inhalation exposure to high levels of methylhydrazine may cause lacrimation, eye redness, nasal and respiratory irritation, headache, malaise, vomiting, diarrhea, ataxia, anoxia, cyanosis, tremors, and convulsions in humans. Acute exposure to methylhydrazine in humans has also been observed to affect the blood, kidneys, and liver. Methylhydrazine is highly corrosive and irritating to the skin, eyes, and mucous membranes of the respiratory system in humans and animals. Chronic (long-term) inhalation exposure to methylhydrazine has been observed to impair function of the kidneys and liver, affect the blood and spleen, and cause convulsions in animals. EPA has not classified methylhydrazine for carcinogenicity.
Source: EPA Hazardous Air Pollutants
Methylhydrazine occupational exposure limits
| Limit | Value | Source |
|---|---|---|
| PEL | 0.2 ppm (0.35 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| PEL | C 0.2 ppm (0.35 mg/m3) [skin] | The National Institute for Occupational Safety and Health (NIOSH) |
| REL | 0.04 ppm (0.08 mg/m³), [120 minutes] | Occupational Safety and Health Administration (OSHA) |
| REL | Ca C 0.04 ppm (0.08 mg/m3) [2-hr] See Appendix A | The National Institute for Occupational Safety and Health (NIOSH) |
| IDLH | 20 ppm ; A potential occupational carcinogen. (NIOSH, 2024) | CAMEO Chemicals |
| IDLH | 20.0 [ppm] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| IDLH | 20 ppm; NIOSH considers methyl hydrazine to be a potential occupational carcinogen. | Hazardous Substances Data Bank (HSDB) |
These are United States values. The European Union sets its own indicative and binding limits, and the figure that applies at a given workplace is the one in the local regulation — not the one shown here.
08 · Physical and chemical properties
Methylhydrazine 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.
Methylhydrazine boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 87.5 °C (189.5 °F) | HSDB | |
| 87.78 °C (190 °F) | NIOSH | ||
| 87.78 °C (190 °F) | at 760 mmHg | CAMEO |
Methylhydrazine melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | -52.4 °C (-62.3 °F) | HSDB | |
| -52.22 °C (-62 °F) | NIOSH | ||
| -52.39 °C (-62.3 °F) | CAMEO |
Methylhydrazine density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 0.87 g/cm³ | ICSC | |
| 0.874 g/cm³ | at 25 °C | HSDB |
Methylhydrazine solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | >10% in ethyl ether | HSDB | |
| >10% in ethanol | HSDB | ||
| >10% in water | HSDB |
Methylhydrazine vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 38 mmHg | NIOSH | |
| 50 mmHg | at 25 °C | HSDB | |
| 49.6 mmHg | at 25 °C | CAMEO |
Methylhydrazine flash point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Flash point | -8 °C (17.6 °F) | closed cup | HSDB |
| -8.33 °C (17 °F) | NIOSH | ||
| 70 °C (158 °F) | CAMEO |
Methylhydrazine autoignition temperature
| Property | Value | Conditions | Source |
|---|---|---|---|
| Autoignition temperature | 194 °C (381.2 °F) | HSDB | |
| 194.44 °C (382 °F) | CAMEO | ||
| 196 °C (384.8 °F) | ICSC |
Methylhydrazine lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | 2.5 % by volume | HSDB |
Methylhydrazine upper explosive limit (UEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Upper explosive limit (UEL) | 92 % by volume | HSDB | |
| 97 % by volume | HSDB |
Methylhydrazine vapor density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor density | 1.6 (air = 1) | HSDB |
Methylhydrazine odor threshold
| Property | Value | Conditions | Source |
|---|---|---|---|
| Odor threshold | 1.75 mg/cu m (low); 5.25 mg/cu m (high) | HSDB | |
| Odor Threshold Low: 1.7 [ppm] | Haz-Map |
Methylhydrazine critical temperature and pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Critical temperature and pressure | 312 °C (593.6 °F) | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
Methylhydrazine fire and explosion behaviour
These are descriptions rather than measured values, so they are kept out of the table above and quoted here with the source that reported them.
Methylhydrazine fire potential
Very dangerous fire hazard when exposed to heat or flame.
Source: Hazardous Substances Data Bank (HSDB)
Odor
The warning properties (irritation & odor) of the hydrazines are probably sufficient to prevent acute poisoning from short exposures. However, in view of the chronic toxicity properties, the warning properties should not be considered adequate for prolonged exposures. /Hydrazines/
Source: HSDB
10 · Handling and storage
Methylhydrazine storage and handling
Methylhydrazine safe storage
Fireproof. Separated from strong oxidants, strong acids, metal oxides, porous materials and food and feedstuffs. Dry. Well closed. Keep under inert gas.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Methylhydrazine storage conditions
Store in a cool, dry, well-ventilated location. Separate from acids, oxidizing materials, halogens, & air. Outside or detached storage is preferred.
Source: Hazardous Substances Data Bank (HSDB)
Methylhydrazine incompatible materials
Reacts violently with oxidizing materials, oxygen, & peroxides; sometimes resulting in autoignition.
Source: Hazardous Substances Data Bank (HSDB)
Methylhydrazine reactivity
METHYLHYDRAZINE is a powerful reducing agent. Ignites upon contact with oxidizing agents i.e. dinitrogen tetraoxide, hydrogen peroxide [Hawley]. Water used to extinguish a fire may cause pollution and should be diked for later disposal. Gives basic solutions with water that generate heat when water is added.
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Methylhydrazine in the storage compatibility matrix →
11 · Transport
Methylhydrazine UN number and transport classification
Transport classification is a separate system from the GHS classification above. It decides how a package is marked and how a load may be carried; it does not follow from the workplace label, and the workplace label does not follow from it. The entries below are linked by CAS number, never by name.
Methylhydrazine under UN 1244 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| METHYLHYDRAZINE | 6.1 | TFC | I | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 6.1 is “Toxic substances” (ADR 2.1.1.1).
United States · 49 CFR 172.101 Hazardous Materials Table
| Proper shipping name (column 2) | Class or division | PG | Labels (column 6) |
|---|---|---|---|
| Methylhydrazine | 6.1 | I | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 6.1 is “Poisonous materials” (49 CFR 173.2).
12 · Questions
Methylhydrazine — frequently asked questions
What is the CAS number of Methylhydrazine?
The CAS number of Methylhydrazine is 60-34-4. Its EC number is 200-471-4.
What is the chemical formula of Methylhydrazine?
The molecular formula of Methylhydrazine is CH6N2 and its molecular weight is 46.072 g/mol.
What does a Methylhydrazine label have to show?
Under CLP Annex VI the label for Methylhydrazine carries the pictogram Health hazard and the signal word is Danger.
Is Methylhydrazine flammable?
CLP Annex VI assigns Methylhydrazine 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. The flash point reported for it is -8 °C (17.6 °F), closed cup (HSDB).
Is Methylhydrazine a carcinogen?
Yes. CLP Annex VI classifies Methylhydrazine as a category 1A or 1B carcinogen and assigns it H350: may cause cancer.
What is the exposure limit for Methylhydrazine?
The US occupational exposure limit reported for Methylhydrazine is 0.2 ppm (0.35 mg/m³) (Occupational Safety and Health Administration (OSHA)). Limits differ by country: the EU sets its own indicative and binding values, and the figure that applies at a given workplace is the one in the local regulation.
What is the boiling point of Methylhydrazine?
The boiling point reported for Methylhydrazine is 87.5 °C (189.5 °F) (HSDB).
What is the melting point of Methylhydrazine?
The melting point reported for Methylhydrazine is -52.4 °C (-62.3 °F) (HSDB).
How should Methylhydrazine be stored?
Store in a cool, dry, well-ventilated location. Separate from acids, oxidizing materials, halogens, & air. Outside or detached storage is preferred. (Hazardous Substances Data Bank (HSDB))
Nearby
Substances next to Methylhydrazine
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