Substance profile
Chloromethane
Chloromethane is a colorless compressed gas or liquid with a faint sweet ethereal odor.
01 · Identification
What Chloromethane is
Chloromethane is a colorless compressed gas or liquid with a faint sweet ethereal odor. Its molecular formula is CH3Cl and its molecular weight is 50.49 g/mol. It boils at -23.7 °C, melts at -97.6 °C.
Under the GHS it carries the signal word Danger. It is classed as hazardous Air Pollutants (HAPs).
02 · Identifiers
Chloromethane identifiers and molecular data
Chloromethane CAS number and EC number
Chloromethane molecular formula and molecular weight
Other names for Chloromethane
- methyl chloride
03 · GHS classification
Chloromethane hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Chloromethane pictograms and signal word
Chloromethane hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Flammable gases GHS chapter 2.2 | Category 1A | H220 | GHS02 |
| Carcinogenicity GHS chapter 3.6 | Category 2 | H351 | GHS08 |
| Specific target organ toxicity - repeated exposure GHS chapter 3.9 | Category 2 | H373 | GHS08 |
Chloromethane hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H220 | Extremely flammable gas. |
| H351 | Suspected of causing cancer <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>. |
| H373 | May cause damage to organs <or state all organs affected, if known> through prolonged or repeated exposure <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 Chloromethane. 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 Chloromethane
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 Chloromethane 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
Chloromethane precautionary statements
CLP Annex VI assigns 10 precautionary statements to Chloromethane. 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
Chloromethane 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 | хлорометан метилхлорид |
| Spanish español | Clorometano cloruro de metilo |
| Czech čeština | chlormethan methylchlorid |
| Danish dansk | chlormethan methylchlorid |
| German Deutsch | Chlormethan Methylchlorid |
| Estonian eesti | klorometaan metüülkloriid |
| Greek ελληνικά | χλωρομεθάνιο μεθυλοχλωρίδιο |
| English English | chloromethane methyl chloride |
| French français | chlorométhane chlorure de méthyle |
| Croatian hrvatski | klormetan metil-klorid |
| Italian italiano | clorometano metile cloruro |
| Latvian latviešu | hlormetāns metilhlorīds |
| Lithuanian lietuvių | chlormetanas metilchloridas |
| Hungarian magyar | klór-metán metil-klorid |
| Maltese Malti | klorometan klorur tal-metil |
| Dutch Nederlands | chloormethaan methylchloride |
| Polish polski | chlorometan chlorek metylu |
| Portuguese português | clorometano cloreto de metilo |
| Romanian română | clormetan clorură de metil |
| Slovak slovenčina | chlórmetán metylchlorid |
| Slovenian slovenščina | klorometan metil klorid |
| Finnish suomi | metyylikloridi kloorimetaani |
| Swedish svenska | klormetan metylklorid |
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
Chloromethane GHS label elements
Everything CLP Annex VI fixes for Chloromethane, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Chloromethane
- Extremely flammable gas.
- Suspected of causing cancer <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>.
- May cause damage to organs <or state all organs affected, if known> through prolonged or repeated exposure <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>.
- Obtain special instructions before use.
- Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
- Keep container tightly closed.
- Do not breathe dust/fume/gas/mist/vapours/spray.
- Do not eat, drink or smoke when using this product.
- Wear protective gloves/protective clothing/eye protection/face protection/hearing protection/…
- IF exposed or concerned:
- Get medical advice/attention.
- Get medical advice/attention if you feel unwell.
- Store in a well-ventilated place.
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Chloromethane in the GHS label constructor →
07 · Health hazards
Chloromethane health hazards and exposure limits
Chloromethane hazard summary
Chloromethane is also known as methyl chloride. It is a clear, colorless gas. It has a faint, sweet odor that is noticeable only at levels that may be toxic. It is heavier than air, and it is extremely flammable.
Source: Agency for Toxic Substances and Disease Registry (ATSDR)
Chloromethane carcinogenicity classification
The Human Health Assessment Group in EPA's Office of Health and Environmental Assessment has evaluated methyl chloride for carcinogenicity. According to their analysis, the weight-of-evidence for methyl chloride is group C, which is based on limited evidence in animals. No data are available for humans. As a group C chemical, methyl chloride is considered possibly carcinogenic to humans.
Source: Hazardous Substances Data Bank (HSDB)
Evaluation: There is inadequate evidence for the carcinogenicity of methyl chloride in humans. There is inadequate evidence for the carcinogenicity of methyl chloride in experimental animals. Overall evaluation: Methyl chloride is not classifiable as to its carcinogenicity to humans (Group 3).
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.
Chloromethane occupational exposure limits
| Limit | Value | Source |
|---|---|---|
| PEL | 100.0 [ppm], Ceiling(OSHA) = 200 ppm(300 ppm for 5-min peak in any 3 hrs) | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| PEL | 100 ppm (210 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| PEL | 200 ppm; 300 ppm (Peak - 5 min in any 3 hrs) | Occupational Safety and Health Administration (OSHA) |
| REL | Ca See Appendix A | The National Institute for Occupational Safety and Health (NIOSH) |
| IDLH | 2000 ppm ; A potential occupational carcinogen. (NIOSH, 2024) | CAMEO Chemicals |
| IDLH | 2000.0 [ppm] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| IDLH | NIOSH considers methyl chloride 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
Chloromethane 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.
Chloromethane boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | -23.7 °C (-10.7 °F) | HSDB | |
| -24.44 °C (-12 °F) | NIOSH | ||
| -24.22 °C (-11.6 °F) | at 760 mmHg | CAMEO |
Chloromethane melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | -97.6 °C (-143.7 °F) | HSDB | |
| -97.78 °C (-144 °F) | NIOSH | ||
| -97.22 °C (-143 °F) | CAMEO |
Chloromethane density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 0.91 g/cm³ | ICSC | |
| 0.9203 g/cm³ | at 20 °C | HSDB | |
| 0.911 g/cm³ | at 25 °C, at 760 mmHg | HSDB |
Chloromethane solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Soluble in ethanol; miscible with ethyl ether, acetone, benzene and chloroform | HSDB | |
| Solubility at 20 °C (mL/100 mL): benzene 4723, carbon tetrachloride 3756, glacial acetic acid 3679, ethanol 3740; miscible with chloroform, ether | at 20 °C | HSDB | |
| In water, 5040 mg/L at 25 °C | at 25 °C | HSDB |
Chloromethane vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 3800 mmHg | NIOSH | |
| 4300 mmHg | at 25 °C | HSDB | |
| 4298 mmHg | at 25 °C | ICSC |
Chloromethane flash point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Flash point | -45.56 °C (-50 °F) | HSDB | |
| -45.5 °C (-49.9 °F) | CAMEO | ||
| -45 °C (-49 °F) | OSHA |
Chloromethane autoignition temperature
| Property | Value | Conditions | Source |
|---|---|---|---|
| Autoignition temperature | 632.22 °C (1170 °F) | HSDB | |
| 632 °C (1169.6 °F) | ICSC |
Chloromethane lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | 8.1 % by volume | HSDB |
Chloromethane upper explosive limit (UEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Upper explosive limit (UEL) | 17.4 % by volume | HSDB | |
| 17 % by volume | HSDB |
Chloromethane vapor density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor density | 1.8 (air = 1) | HSDB | |
| 2.47 (air = 1) | ICSC |
Chloromethane odor threshold
| Property | Value | Conditions | Source |
|---|---|---|---|
| Odor threshold | Odor recognition in air: 1.00x10+1 ppm (chemically pure) | HSDB | |
| Odor ... not noticeable at dangerous concentrations. | HSDB | ||
| Odor Threshold (air) 21 mg/cu m | HSDB |
Chloromethane critical temperature and pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Critical temperature and pressure | 143.1 °C (289.6 °F) | HSDB |
Chloromethane corrosivity
| Property | Value | Conditions | Source |
|---|---|---|---|
| Corrosivity | Methyl chloride will attack some forms of plastics, rubber and coatings. | HSDB | |
| Attacks aluminum, magnesium, and zinc. | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
Chloromethane 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.
Chloromethane fire potential
Flammable gas. Very dangerous fire hazard when exposed to heat, flame or powerful oxidizers. ... May ignite on contact with aluminum chloride or powdered aluminum.
Source: Hazardous Substances Data Bank (HSDB)
10 · Handling and storage
Chloromethane storage and handling
Chloromethane safe storage
Fireproof. Ventilation along the floor.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Chloromethane storage conditions
Keep container tightly closed in a dry and well-ventilated place. Contents under pressure. Moisture sensitive. Storage class (TRGS 510): Gases
Source: Hazardous Substances Data Bank (HSDB)
Chloromethane incompatible materials
Incompatible materials: Strong oxidizing agents, Iron
Source: Hazardous Substances Data Bank (HSDB)
Chloromethane reactivity
METHYL CHLORIDE can react vigorously with oxidizing agents. May react explosively with sodium, potassium, sodium-potassium alloy, magnesium, zinc. Reacts with aluminum powder in the presence of catalytic amounts of aluminum chloride to form pyrophoric trimethylaluminum. When heated to decomposition, it emits highly toxic fumes of chlorine [Bretherick, 5th ed., 1995, p. 176].
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Chloromethane in the storage compatibility matrix →
11 · Transport
Chloromethane 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.
Chloromethane under UN 1063 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| METHYL CHLORIDE (REFRIGERANT GAS R 40) | 2 | 2F | — | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 2 is “Gases” (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) |
|---|---|---|---|
| Methyl chloride or Refrigerant gas R 40 | 2.1 | — | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 2.1 is “Flammable gas” (49 CFR 173.2).
12 · Questions
Chloromethane — frequently asked questions
What is the CAS number of Chloromethane?
The CAS number of Chloromethane is 74-87-3. Its EC number is 200-817-4.
What is the chemical formula of Chloromethane?
The molecular formula of Chloromethane is CH3Cl and its molecular weight is 50.49 g/mol.
What does a Chloromethane label have to show?
Under CLP Annex VI the label for Chloromethane carries the pictograms Flame, Gas cylinder and Health hazard and the signal word is Danger.
Is Chloromethane flammable?
Yes. CLP Annex VI assigns Chloromethane H220 — extremely flammable gas. The flash point reported for it is -45.56 °C (-50 °F) (HSDB).
Is Chloromethane a carcinogen?
CLP Annex VI assigns Chloromethane H351 — suspected of causing cancer. That is category 2: the evidence points that way but is not conclusive. IARC places it in Group 3: not classifiable as to its carcinogenicity to humans.
What is the exposure limit for Chloromethane?
The US occupational exposure limit reported for Chloromethane is 100.0 [ppm], Ceiling(OSHA) = 200 ppm(300 ppm for 5-min peak in any 3 hrs) (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 Chloromethane?
The boiling point reported for Chloromethane is -23.7 °C (-10.7 °F) (HSDB).
What is the melting point of Chloromethane?
The melting point reported for Chloromethane is -97.6 °C (-143.7 °F) (HSDB).
How should Chloromethane be stored?
CLP Annex VI assigns Chloromethane the storage statement P403. Keep container tightly closed in a dry and well-ventilated place. Contents under pressure. Moisture sensitive. Storage class (TRGS 510): Gases (Hazardous Substances Data Bank (HSDB))
Nearby
Substances next to Chloromethane
Keep going: substances starting with C, or search the whole database by name, CAS number, pictogram or signal word.