Substance profile
2-Methylaziridine
2-Methylaziridine is colorless, oily liquid with odor like aliphatic amines.
01 · Identification
What 2-Methylaziridine is
2-Methylaziridine is colorless, oily liquid with odor like aliphatic amines. Its molecular formula is C3H7N and its molecular weight is 57.09 g/mol. It boils at 67 °C, melts at -65 °C.
Under the GHS it carries the signal word Danger. It is classed as hazardous Air Pollutants (HAPs).
02 · Identifiers
2-Methylaziridine identifiers and molecular data
2-Methylaziridine CAS number and EC number
2-Methylaziridine molecular formula and molecular weight
Other names for 2-Methylaziridine
- propyleneimine
03 · GHS classification
2-Methylaziridine hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
2-Methylaziridine pictograms and signal word
2-Methylaziridine hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Flammable liquids GHS chapter 2.6 | Category 2 | H225 | GHS02 |
| Acute toxicity - oral GHS chapter 3.1 | Category 1 or 2 | H300 | GHS06 |
| Acute toxicity - dermal GHS chapter 3.1 | Category 1 or 2 | H310 | GHS06 |
| Acute toxicity - inhalation GHS chapter 3.1 | Category 1 or 2 | H330 | GHS06 |
| Serious eye damage/eye irritation GHS chapter 3.3 | Category 1 | H318 | GHS05 |
| Carcinogenicity GHS chapter 3.6 | Category 1A or 1B | H350 | GHS08 |
| Hazardous to the aquatic environment - chronic GHS chapter 4.1 | Category 2 | H411 | 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.
2-Methylaziridine hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H225 | Highly flammable liquid and vapour. |
| H350 | May cause cancer <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>. |
| H310 | Fatal in contact with skin. |
| H330 | Fatal if inhaled. |
| H300 | Fatal if swallowed. |
| H318 | Causes serious eye damage. |
| H411 | Toxic to aquatic life with long lasting effects. |
This page lists only the codes assigned to 2-Methylaziridine. 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 2-Methylaziridine
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 2-Methylaziridine 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
2-Methylaziridine precautionary statements
CLP Annex VI assigns 23 precautionary statements to 2-Methylaziridine. 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
2-Methylaziridine 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 | 2-метилазиридин пропиленимин |
| Spanish español | 2-Metilaziridina propilenimina |
| Czech čeština | 2-methylaziridin propylenimin |
| Danish dansk | 2-methylaziridin propyleneimin |
| German Deutsch | 2-Methylaziridin Propylenimin |
| Estonian eesti | 2-metüülasiridiin propüleenimiin |
| Greek ελληνικά | 2-μεθυλαζιριδίνη προπυλενιμίνη |
| English English | 2-methylaziridine propyleneimine |
| French français | 2-méthylaziridine propylèneimine |
| Croatian hrvatski | 2-metilaziridin propilenimin |
| Italian italiano | metilaziridina propileneimina |
| Latvian latviešu | 2-metilpiridīns propilēnimīns |
| Lithuanian lietuvių | 2-metilaziridinas propileniminas |
| Hungarian magyar | 2-metilaziridin propilén-imin |
| Maltese Malti | 2-metilażiridina propileneimina |
| Dutch Nederlands | 2-methylaziridine propyleenimine |
| Polish polski | 2-metyloazirydyna propylenoimina |
| Portuguese português | 2-metilaziridina propilenoimina |
| Romanian română | 2-metilaziridină propilenimină |
| Slovak slovenčina | 2-metylaziridín propylénimín |
| Slovenian slovenščina | 2-metilaziridin propilenimin |
| Finnish suomi | 2-metyyliatsiridiini propyleeni-imiini |
| Swedish svenska | 2-metylaziridin propylenimin |
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
2-Methylaziridine GHS label elements
Everything CLP Annex VI fixes for 2-Methylaziridine, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
2-Methylaziridine
- Highly flammable liquid and vapour.
- May cause cancer <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>.
- Fatal in contact with skin.
- Fatal if inhaled.
- Fatal if swallowed.
- Causes serious eye damage.
- Toxic to aquatic life with long lasting effects.
- Obtain special instructions before use.
- Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
- Keep container tightly closed.
- Use explosion-proof [electrical/ventilating/lighting/…] equipment.
- Use only non-sparking tools.
- 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:
- IF IN EYES:
- IF exposed or concerned:
- Immediately call a POISON CENTER/doctor/…
- Get medical advice/attention.
- Rinse mouth.
- Remove contact lenses, if present and easy to do. Continue rinsing.
- Wash with plenty of water/…
- Collect spillage.
- Store in a well-ventilated place.
- Dispose of contents/container to …
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open 2-Methylaziridine in the GHS label constructor →
07 · Health hazards
2-Methylaziridine health hazards and exposure limits
2-Methylaziridine hazard summary
1,2-Propyleneimine is used as an intermediate in the paper, textile, rubber, and pharmaceutical industries. 1,2-Propyleneimine is severely irritating to the eyes and upper respiratory tract from acute (short-term) inhalation exposure in humans. Headaches, dizziness, nausea, bronchitis, shortness of breath, and edema of the lungs have also been reported in humans. No information is available on the chronic (long-term), reproductive, developmental, or carcinogenic effects of 1,2-propyleneimine in humans. Animal studies have reported effects on the kidneys, blood, and gastrointestinal system from chronic inhalation and oral exposure to 1,2-propyleneimine. Animal studies have reported tumors of the mammary glands and intestines, leukemia, and other tumor types from oral exposure to 1,2-propyleneimine. The International Agency for Research on Cancer (IARC) has classified 1,2-propyleneimine as a Group 2B, possible human carcinogen. EPA has not classified 1,2-propyleneimine for carcinogenicity.
Source: EPA Hazardous Air Pollutants
2-Methylaziridine carcinogenicity classification
Evaluation: No epidemiological data relevant to the carcinogenicity of 2-methylaziridine were available. There is sufficient evidence in experimental animals for the carcinogenicity of 2-methylaziridine. Overall evaluation: 2-Methylaziridine is possibly carcinogenic to humans (Group 2B).
Source: Hazardous Substances Data Bank (HSDB)
2-Methylaziridine (Propyleneimine): reasonably anticipated to be a human carcinogen.
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.
2-Methylaziridine occupational exposure limits
| Limit | Value | Source |
|---|---|---|
| PEL | 2.0 [ppm] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| PEL | 2 ppm (5 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| PEL | TWA 2 ppm (5 mg/m3) [skin] | The National Institute for Occupational Safety and Health (NIOSH) |
| REL | 2 ppm (5 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| REL | Ca TWA 2 ppm (5 mg/m3) [skin] See Appendix A | The National Institute for Occupational Safety and Health (NIOSH) |
| IDLH | 100 ppm ; A potential occupational carcinogen. (NIOSH, 2024) | CAMEO Chemicals |
| IDLH | 100.0 [ppm] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| IDLH | Excerpts from Documentation for IDLHs: It has been reported that rats survived a 2hour exposure to 500 ppm and guinea pigs survived a 30minute exposure to 500 ppm [Carpenter et al. 1948]. | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
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
2-Methylaziridine 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.
2-Methylaziridine boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 67 °C (152.6 °F) | HSDB | |
| 66.67 °C (152 °F) | NIOSH |
2-Methylaziridine melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | -65 °C (-85 °F) | HSDB |
2-Methylaziridine density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 0.8 g/cm³ | NIOSH | |
| 0.8054 g/cm³ | range, midpoint shown, at 25 °C | HSDB |
2-Methylaziridine solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | In water, miscible in all proportions | HSDB | |
| Soluble in ethanol | HSDB | ||
| Soluble in most organic solvents | HSDB |
2-Methylaziridine vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 112 mmHg | NIOSH | |
| 112 mmHg | at 20 °C | CAMEO | |
| 140 mmHg | at 25 °C | HSDB |
2-Methylaziridine flash point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Flash point | -3.9 °C (25 °F) | HSDB | |
| -3.89 °C (25 °F) | NIOSH |
2-Methylaziridine lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | Class IB Flammable Liquid: Fl.P. below 73 °F and BP at or above 100 °F. | NIOSH |
2-Methylaziridine vapor density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor density | 2 (air = 1) | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
2-Methylaziridine 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.
2-Methylaziridine fire potential
Flammable, dangerous fire risk.
Source: Hazardous Substances Data Bank (HSDB)
10 · Handling and storage
2-Methylaziridine storage and handling
2-Methylaziridine safe storage
Fireproof. Separated from acids, oxidants and food and feedstuffs. Cool. Ventilation along the floor. Store only in original container. Store only if stabilized.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
2-Methylaziridine storage conditions
PRECAUTIONS FOR "CARCINOGENS": Storage site should be as close as practicable to lab in which carcinogens are to be used, so that only small quantities required for ... expt need to be carried. Carcinogens should be kept in only one section of cupboard, an explosion-proof refrigerator or freezer (depending on chemicophysical properties ...) that bears appropriate label. An inventory ... should be kept, showing quantity of carcinogen & date it was acquired ... Facilities for dispensing ... should be contiguous to storage area. /Chemical Carcinogens/
Source: Hazardous Substances Data Bank (HSDB)
2-Methylaziridine incompatible materials
Can react vigorously with oxidizing materials. Polymerizes explosively on exposure to acids or acid fumes.
Source: Hazardous Substances Data Bank (HSDB)
2-Methylaziridine reactivity
PROPYLENEIMINE is subject to violent polymerization on contact with an acid. (The inhibitor is intended to prevent polymerization). Incompatible with isocyanates, halogenated organics, peroxides, phenols (acidic), epoxides, anhydrides, and acid halides. Flammable gaseous hydrogen is generated in combination with strong reducing agents, such as hydrides.
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check 2-Methylaziridine in the storage compatibility matrix →
11 · Transport
2-Methylaziridine 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.
2-Methylaziridine under UN 1921 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| PROPYLENEIMINE, STABILIZED | 3 | FT1 | I | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 3 is “Flammable liquids” (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) |
|---|---|---|---|
| Propyleneimine, stabilized | 3 | I | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 3 is “Flammable and combustible liquid” (49 CFR 173.2).
12 · Questions
2-Methylaziridine — frequently asked questions
What is the CAS number of 2-Methylaziridine?
The CAS number of 2-Methylaziridine is 75-55-8. Its EC number is 200-878-7.
What is the chemical formula of 2-Methylaziridine?
The molecular formula of 2-Methylaziridine is C3H7N and its molecular weight is 57.09 g/mol.
What does a 2-Methylaziridine label have to show?
Under CLP Annex VI the label for 2-Methylaziridine carries the pictograms Flame, Skull and crossbones, Health hazard, Corrosion and Environment and the signal word is Danger.
Is 2-Methylaziridine flammable?
Yes. CLP Annex VI assigns 2-Methylaziridine H225 — highly flammable liquid and vapour. The flash point reported for it is -3.9 °C (25 °F) (HSDB).
Is 2-Methylaziridine a carcinogen?
Yes. CLP Annex VI classifies 2-Methylaziridine as a category 1A or 1B carcinogen and assigns it H350: may cause cancer. IARC places it in Group 2B: possibly carcinogenic to humans.
What is the exposure limit for 2-Methylaziridine?
The US occupational exposure limit reported for 2-Methylaziridine is 2.0 [ppm] (Haz-Map, Information on Hazardous Chemicals and Occupational Diseases). 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 2-Methylaziridine?
The boiling point reported for 2-Methylaziridine is 67 °C (152.6 °F) (HSDB).
What is the melting point of 2-Methylaziridine?
The melting point reported for 2-Methylaziridine is -65 °C (-85 °F) (HSDB).
How should 2-Methylaziridine be stored?
CLP Annex VI assigns 2-Methylaziridine the storage statement P403. PRECAUTIONS FOR "CARCINOGENS": Storage site should be as close as practicable to lab in which carcinogens are to be used, so that only small quantities required for ... expt need to be carried. Carcinogens should be kept in only one section of cupboard, an explosion-proof refrigerator or freezer (depending on chemicophysical properties ...) that bears appropriate label. An inventory ... should be kept, showing quantity of carcinogen & date it was acquired ... Facilities for dispensing ... should be contiguous to storage area. /Chemical Carcinogens/ (Hazardous Substances Data Bank (HSDB))
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