Substance profile
Methyl ethyl ketone
Methyl ethyl ketone is a colorless liquid with an acetone-like odor.
01 · Identification
What Methyl ethyl ketone is
Methyl ethyl ketone is a colorless liquid with an acetone-like odor. Its molecular formula is C4H8O and its molecular weight is 72.11 g/mol. It boils at 79.6 °C, melts at -86.7 °C.
Under the GHS it carries the signal word Danger. It is classed as hazardous Air Pollutants (HAPs).
02 · Identifiers
Methyl ethyl ketone identifiers and molecular data
Methyl ethyl ketone CAS number and EC number
Methyl ethyl ketone molecular formula and molecular weight
Other names for Methyl ethyl ketone
- MEK
- butanone
- 2-butanone
- 3-Butanone
- Ethyl Methyl Ketone
- Ketone, Ethyl Methyl
- Meetco
- Methyl Acetone
- Methyl Ethyl Ketone (Mek)
- ethyl methyl ketone
03 · GHS classification
Methyl ethyl ketone hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Methyl ethyl ketone pictograms and signal word
Methyl ethyl ketone hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Flammable liquids GHS chapter 2.6 | Category 2 | H225 | GHS02 |
| Serious eye damage/eye irritation GHS chapter 3.3 | Category 2A | H319 | GHS07 |
| Specific target organ toxicity - single exposure GHS chapter 3.8 | Category 3 narcotic | H336 | GHS07 |
Methyl ethyl ketone hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H225 | Highly flammable liquid and vapour. |
| H336 | May cause drowsiness or dizziness. |
| H319 | Causes serious eye irritation. |
Methyl ethyl ketone supplemental EU statements (EUH)
| Code | Statement |
|---|---|
| EUH066 | Repeated exposure may cause skin dryness or cracking. |
This page lists only the codes assigned to Methyl ethyl ketone. 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 Methyl ethyl ketone
Our own Methyl ethyl ketone safety data sheet walks through all sixteen sections of the published data. What it is not is the document an inspector asks for: an SDS is issued for a product by its supplier, so the sheet covering the grade actually standing in your store exists only in that supplier’s version. Collecting those and keeping them current as suppliers revise them is a separate job.
04 · Precautionary statements
Methyl ethyl ketone precautionary statements
CLP Annex VI assigns 11 precautionary statements to Methyl ethyl ketone. 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
Methyl ethyl ketone 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 | бутанон етилметилкетон |
| Spanish español | Butanona etilmetilcetona |
| Czech čeština | butanon ethyl(methyl)keton |
| Danish dansk | butanon ethylmethylketon |
| German Deutsch | Butanon Ethylmethylketon |
| Estonian eesti | butanoon metüületüülketoon |
| Greek ελληνικά | βουτανόνη μεθυλαιθυλοκετόνη |
| English English | butanone ethyl methyl ketone |
| French français | butanone éthylméthylcétone |
| Croatian hrvatski | butanon etil-metil-keton |
| Italian italiano | butanone metiletilchetone |
| Latvian latviešu | butanons etilmetilketons |
| Lithuanian lietuvių | butanonas etilmetilketonas |
| Hungarian magyar | butanon etil-metil-keton |
| Maltese Malti | butanon keton tal-metil tal-etil |
| Dutch Nederlands | butanon ethylmethylketon |
| Polish polski | butanon keton etylowo-metylowy |
| Portuguese português | butanona etilmetilcetona |
| Romanian română | butanonă etil-metil-cetonă |
| Slovak slovenčina | butanón etyl(metyl)ketón |
| Slovenian slovenščina | butanon etil metil keton |
| Finnish suomi | butanoni etyylimetyyliketoni |
| Swedish svenska | butanon etylmetylketon |
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
Methyl ethyl ketone GHS label elements
Everything CLP Annex VI fixes for Methyl ethyl ketone, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Methyl ethyl ketone
- Highly flammable liquid and vapour.
- May cause drowsiness or dizziness.
- Causes serious eye irritation.
- Repeated exposure may cause skin dryness or cracking.
- 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.
- Wash … thoroughly after handling.
- Wear protective gloves/protective clothing/eye protection/face protection/hearing protection/…
- IF IN EYES:
- Get medical advice/attention.
- If eye irritation persists:
- Remove contact lenses, if present and easy to do. Continue rinsing.
- Store in a well-ventilated place.
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Methyl ethyl ketone in the GHS label constructor →
07 · Health hazards
Methyl ethyl ketone health hazards and exposure limits
Methyl ethyl ketone hazard summary
2-Butanone is a manufactured chemical but it is also present in the environment from natural sources. It is a colorless liquid with a sharp, sweet odor. It is also known as methyl ethyl ketone (MEK). 2-Butanone is produced in large quantities. Nearly half of its use is in paints and other coatings because it will quickly evaporate into the air and it dissolves many substances. It is also used in glues and as a cleaning agent. 2-Butanone occurs as a natural product. It is made by some trees and found in some fruits and vegetables in small amounts. It is also released to the air from car and truck exhausts.
Source: Agency for Toxic Substances and Disease Registry (ATSDR)
Methyl ethyl ketone carcinogenicity classification
Cancer Classification: Group D Not Classifiable as to Human Carcinogenicity
Source: Hazardous Substances Data Bank (HSDB)
CLASSIFICATION: D; not classifiable as to human carcinogenicity. BASIS FOR CLASSIFICATION: Based on no human carcinogenicity data and inadequate animal data. HUMAN CARCINOGENICITY DATA: None. ANIMAL CARCINOGENICITY DATA: Inadequate.
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.
Methyl ethyl ketone occupational exposure limits
| Limit | Value | Source |
|---|---|---|
| PEL | 200.0 [ppm] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| PEL | 200 ppm (590 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| PEL | TWA 200 ppm (590 mg/m3) See Appendix G | The National Institute for Occupational Safety and Health (NIOSH) |
| REL | 200 ppm (500 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| REL | 300 ppm (885 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| REL | TWA 200 ppm (590 mg/m3) ST 300 ppm (885 mg/m3) | The National Institute for Occupational Safety and Health (NIOSH) |
| IDLH | 3000 ppm (NIOSH, 2024) | CAMEO Chemicals |
| IDLH | 3000.0 [ppm] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| IDLH | Excerpts from Documentation for IDLHs: It has been reported that 3,000 ppm is irritating to the eyes and nose [Patty et al. 1935]. | 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
Methyl ethyl ketone 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.
Methyl ethyl ketone boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 79.59 °C (175.3 °F) | HSDB | |
| 79.44 °C (175 °F) | NIOSH | ||
| 79.61 °C (175.3 °F) | at 760 mmHg | CAMEO |
Methyl ethyl ketone melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | -86.67 °C (-124 °F) | HSDB | |
| -86.11 °C (-123 °F) | NIOSH | ||
| -86.28 °C (-123.3 °F) | CAMEO |
Methyl ethyl ketone density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 0.81 g/cm³ | NIOSH | |
| 0.805 g/cm³ | at 20 °C | HSDB | |
| 0.804 g/cm³ | at 20 °C | HSDB |
Methyl ethyl ketone solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Soluble in benzene, alcohol, and ether; miscible with oils | HSDB | |
| Constant boiling mixture with water, BP 73.4 °C, contains 88.7% methyl ethyl ketone (MEK); Solubility of water in MEK is 12.5% at 25 °C | at 25 °C | HSDB | |
| In water, 2.23X10+5 mg/L at 25 °C | at 25 °C | HSDB |
Methyl ethyl ketone vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 78 mmHg | NIOSH | |
| 77.5 mmHg | at 20 °C | CAMEO | |
| 90.6 mmHg | at 25 °C | HSDB |
Methyl ethyl ketone flash point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Flash point | -8.89 °C (16 °F) | HSDB | |
| -9 °C (15.8 °F) | closed cup | HSDB |
Methyl ethyl ketone autoignition temperature
| Property | Value | Conditions | Source |
|---|---|---|---|
| Autoignition temperature | 505 °C (941 °F) | HSDB | |
| 516.11 °C (961 °F) | CAMEO |
Methyl ethyl ketone lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | 1.8 % by volume | CAMEO |
Methyl ethyl ketone upper explosive limit (UEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Upper explosive limit (UEL) | 10 % by volume | CAMEO | |
| 11.5 % by volume | ICSC | ||
| 11.4 % by volume | at 93.33 °C | HSDB |
Methyl ethyl ketone vapor density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor density | 2.41 (air = 1) | HSDB | |
| 2.42 (air = 1) | CAMEO |
Methyl ethyl ketone odor threshold
| Property | Value | Conditions | Source |
|---|---|---|---|
| Odor threshold | Odor low= 0.7375 mg/cu m; Odor high= 147.5 mg/cu m. | HSDB | |
| Detection limit in water: 5.00x10+1 ppm (purity not specified) | HSDB | ||
| Recognition in air: 1.00x10+1 ppm (chemically pure) | HSDB |
Methyl ethyl ketone critical temperature and pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Critical temperature and pressure | 263.55 °C (506.4 °F) | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
Methyl ethyl ketone 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.
Methyl ethyl ketone fire potential
Highly flammable liquid.
Source: Hazardous Substances Data Bank (HSDB)
10 · Handling and storage
Methyl ethyl ketone storage and handling
Methyl ethyl ketone reactive group
CAMEO Chemicals places Methyl ethyl ketone in the reactive group Ketones. Compatibility with other chemicals is worked out from the group, not from the individual substance — which is why two substances you have never seen react can still be flagged as a pair that must be separated.
A reactive group is a CAMEO Chemicals (US NOAA) grouping, not a GHS hazard class: it has no code, no category and no legal force. It is what the storage compatibility matrix on this site computes from.
Methyl ethyl ketone peroxide formation
B*: Compounds that form peroxides on concentration (distillation/evaporation)
Source: Lab and Research Safety, University of Minnesota
Methyl ethyl ketone safe storage
Fireproof. Separated from strong oxidants and strong acids. Cool. Well closed. Store in an area without drain or sewer access.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Methyl ethyl ketone storage conditions
Methyl ethyl ketone must be stored to avoid contact with strong oxidizers (such as chlorine, bromine, and fluorine) since violent reactions may occur. Store in tightly closed containers in a cool, well ventilated area away from sources of heat, sparks, or flame. Sources of ignition such as smoking and open flames are prohibited where methyl ethyl ketone is handled, used or stored in a manner that could create a potential fire or explosion hazard. Metal containers involving the transfer of 5 gallons or more of diethyl ketone should be grounded and bonded. Drums must be equipped with self-closing valves, pressure vacuum bungs, and flame arresters. Use only non-sparking tools and equipment, especially when opening and closing containers of methyl ethyl ketone.
Source: Hazardous Substances Data Bank (HSDB)
Methyl ethyl ketone incompatible materials
Reacts violently with strong oxidants and inorganic acids causing fire and explosion hazard. Attacks some plastic.
Source: Hazardous Substances Data Bank (HSDB)
Methyl ethyl ketone reactivity
METHYL ETHYL KETONE is explosive in the form of vapor when exposed to heat, flame or sparks. Ignition on contact with potassium tert-butoxide. Reactive with strong oxidizing materials, and will dissolve or soften some plastics. Mixture with 2-propanol will form explosive peroxides during storage. Vigorous reaction with chloroform in the presence of alkali (sodium hydroxide, potassium hydroxide), chlorosulfonic acid, fuming sulfuric acid (oleum) [Lewis, 3rd ed., 1993, p. 855]. Reaction with hydrogen peroxide in the presence of nitric acid forms heat- and shock-sensitive explosive acetone peroxides. [Bjorklund, G. H. et al., Trans. R. Soc. Can, 1950, 44, p. 25].
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Methyl ethyl ketone in the storage compatibility matrix →
11 · Transport
Methyl ethyl ketone 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.
Methyl ethyl ketone under UN 1193 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| ETHYL METHYL KETONE (METHYL ETHYL KETONE) | 3 | F1 | II | |
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) |
|---|---|---|---|
| Ethyl methyl ketone or Methyl ethyl ketone | 3 | II | |
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
Methyl ethyl ketone — frequently asked questions
What is the CAS number of Methyl ethyl ketone?
The CAS number of Methyl ethyl ketone is 78-93-3. Its EC number is 201-159-0.
What is the chemical formula of Methyl ethyl ketone?
The molecular formula of Methyl ethyl ketone is C4H8O and its molecular weight is 72.11 g/mol.
What does a Methyl ethyl ketone label have to show?
Under CLP Annex VI the label for Methyl ethyl ketone carries the pictograms Flame and Exclamation mark and the signal word is Danger.
Is Methyl ethyl ketone flammable?
Yes. CLP Annex VI assigns Methyl ethyl ketone H225 — highly flammable liquid and vapour. The flash point reported for it is -8.89 °C (16 °F) (HSDB).
Is Methyl ethyl ketone a carcinogen?
CLP Annex VI records no harmonised carcinogenicity classification for Methyl ethyl ketone. 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 exposure limit for Methyl ethyl ketone?
The US occupational exposure limit reported for Methyl ethyl ketone is 200.0 [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 Methyl ethyl ketone?
The boiling point reported for Methyl ethyl ketone is 79.59 °C (175.3 °F) (HSDB).
What is the melting point of Methyl ethyl ketone?
The melting point reported for Methyl ethyl ketone is -86.67 °C (-124 °F) (HSDB).
How should Methyl ethyl ketone be stored?
CLP Annex VI assigns Methyl ethyl ketone the storage statement P403. Methyl ethyl ketone must be stored to avoid contact with strong oxidizers (such as chlorine, bromine, and fluorine) since violent reactions may occur. Store in tightly closed containers in a cool, well ventilated area away from sources of heat, sparks, or flame. Sources of ignition such as smoking and open flames are prohibited where methyl ethyl ketone is handled, used or stored in a manner that could create a potential fire or explosion hazard. Metal containers involving the transfer of 5 gallons or more of diethyl ketone should be grounded and bonded. Drums must be equipped with self-closing valves, pressure vacuum bungs, and flame arresters. Use only non-sparking tools and equipment, especially when opening and closing containers of methyl ethyl ketone. (Hazardous Substances Data Bank (HSDB))
Nearby
Substances next to Methyl ethyl ketone
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