Substance profile
Tetrahydrofuran
Tetrahydrofuran is colorless, mobile liquid with an ether-like odor.
01 · Identification
What Tetrahydrofuran is
Tetrahydrofuran is colorless, mobile liquid with an ether-like odor. Its molecular formula is C4H8O and its molecular weight is 72.11 g/mol. It boils at 65 °C, melts at -108 °C.
Under the GHS it carries the signal word Danger. It is classed as flammable agents - 3rd degree.
02 · Identifiers
Tetrahydrofuran identifiers and molecular data
Tetrahydrofuran CAS number and EC number
Tetrahydrofuran molecular formula and molecular weight
Other names for Tetrahydrofuran
- THF
- Butane Alpha,Delta-Oxide
- Butane, 1,4-Epoxy-
- Butylene Oxide
- Cyclotetramethylene Oxide
- Diethylene Oxide
- 1,4-Epoxybutane
- Furan, Tetrahydro-
- Furanidine
- Hydrofuran
- Oxacyclopentane
- Oxolane
- Tetramethylene Oxide
03 · GHS classification
Tetrahydrofuran hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Tetrahydrofuran pictograms and signal word
Tetrahydrofuran 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 |
| Carcinogenicity GHS chapter 3.6 | Category 2 | H351 | GHS08 |
| Specific target organ toxicity - single exposure GHS chapter 3.8 | Category 3 | H335 | GHS07 |
Tetrahydrofuran hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H225 | Highly flammable liquid and vapour. |
| H351 | Suspected of causing cancer <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>. |
| H335 | May cause respiratory irritation. |
| H319 | Causes serious eye irritation. |
Tetrahydrofuran supplemental EU statements (EUH)
| Code | Statement |
|---|---|
| EUH019 | May form explosive peroxides. |
This page lists only the codes assigned to Tetrahydrofuran. 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 Tetrahydrofuran
Our own Tetrahydrofuran 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
Tetrahydrofuran precautionary statements
CLP Annex VI assigns 13 precautionary statements to Tetrahydrofuran. 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
Tetrahydrofuran 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 | тетрахидрофуран |
| Spanish español | Tetrahidrofurano |
| Czech čeština | tetrahydrofuran |
| Danish dansk | tetrahydrofuran |
| German Deutsch | Tetrahydrofuran |
| Estonian eesti | tetrahüdrofuraan |
| Greek ελληνικά | τετραϋδροφουράνιο |
| English English | tetrahydrofuran |
| French français | tétrahydrofurane |
| Croatian hrvatski | tetrahidrofuran |
| Italian italiano | tetraidrofurano |
| Latvian latviešu | tetrahidrofurāns |
| Lithuanian lietuvių | tetrahidrofuranas |
| Hungarian magyar | tetrahidrofurán |
| Maltese Malti | tetraidrofuran |
| Dutch Nederlands | tetrahydrofuran |
| Polish polski | tetrahydrofuran |
| Portuguese português | tetra-hidrofurano |
| Romanian română | tetrahidrofuran |
| Slovak slovenčina | tetrahydrofurán |
| Slovenian slovenščina | tetrahidrofuran |
| Finnish suomi | tetrahydrofuraani |
| Swedish svenska | tetrahydrofuran |
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
Tetrahydrofuran GHS label elements
Everything CLP Annex VI fixes for Tetrahydrofuran, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Tetrahydrofuran
- Highly flammable liquid and vapour.
- Suspected of causing cancer <state route of exposure if it is conclusively proven that no other routes of exposure cause the hazard>.
- May cause respiratory irritation.
- Causes serious eye irritation.
- May form explosive peroxides.
- 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.
- Wash … thoroughly after handling.
- Wear protective gloves/protective clothing/eye protection/face protection/hearing protection/…
- IF IN EYES:
- IF exposed or concerned:
- 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 Tetrahydrofuran in the GHS label constructor →
07 · Health hazards
Tetrahydrofuran health hazards and exposure limits
Tetrahydrofuran carcinogenicity classification
Under the conditions of these 2-year inhalation studies, there was some evidence of carcinogenic activity of tetrahydrofuran in male F344/N rats based on increased incidences of renal tubule adenoma or carcinoma (combined). There was no evidence of carcinogenic activity of tetrahydrofuran in female F344/N rats exposed to 200, 600, or 1,800 ppm or male B6C3F1 mice exposed to 200, 600, or 1,800 ppm. There was clear evidence of carcinogenic activity of tetrahydrofuran in female B6C3F1 mice based on increased incidences of hepatocellular neoplasms.
Source: US National Toxicology Program · TR-475: Toxicology and Carcinogenesis Studies of Tetrahydrofuran (CASRN 109-99-9) in F344/N Rats and B6C3F1 Mice (Inhalation Studies) (1998 )
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.
Tetrahydrofuran 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 (590 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| REL | 250 ppm (735 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| REL | TWA 200 ppm (590 mg/m3) ST 250 ppm (735 mg/m3) | The National Institute for Occupational Safety and Health (NIOSH) |
| IDLH | 2000 ppm ; Based on 10% of the lower explosive limit. (NIOSH, 2024) | CAMEO Chemicals |
| IDLH | 2000.0 [ppm] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| IDLH | Excerpts from Documentation for IDLHs: Human data: It has been reported that exposure to 25,000 ppm will cause anesthesia and 17,000 ppm appears to be safe for 3 hours [Hofmann and Oettel 1954]. | 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
Tetrahydrofuran 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.
Tetrahydrofuran boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 65 °C (149 °F) | HSDB | |
| 66.11 °C (151 °F) | NIOSH | ||
| 66.11 °C (151 °F) | at 760 mmHg | CAMEO |
Tetrahydrofuran melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | -108.44 °C (-163.2 °F) | HSDB | |
| -108.33 °C (-163 °F) | NIOSH | ||
| -108.5 °C (-163.3 °F) | CAMEO |
Tetrahydrofuran density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 0.89 g/cm³ | NIOSH | |
| 0.888 g/cm³ | at 20 °C | CAMEO | |
| 0.8833 g/cm³ | at 25 °C | HSDB |
Tetrahydrofuran solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Miscible with alcohols, ketones, esters, hydrocarbons, and ethers. | HSDB | |
| Very soluble in acetone, benzene, ether, ethanol, and chloroform | HSDB | ||
| 30% IN WATER AT 25 °C | at 25 °C | HSDB |
Tetrahydrofuran vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 132 mmHg | NIOSH | |
| 144.762 mmHg | at 20 °C | ICSC | |
| 162 mmHg | at 25 °C | HSDB |
Tetrahydrofuran flash point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Flash point | -14.44 °C (6 °F) | HSDB | |
| -14.5 °C (5.9 °F) | closed cup | HSDB |
Tetrahydrofuran autoignition temperature
| Property | Value | Conditions | Source |
|---|---|---|---|
| Autoignition temperature | 321 °C (609.8 °F) | HSDB | |
| 321.11 °C (610 °F) | CAMEO |
Tetrahydrofuran lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | 2 % by volume | % by vol | HSDB |
| 2 % by volume | NIOSH | ||
| 1.8 % by volume | CAMEO |
Tetrahydrofuran upper explosive limit (UEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Upper explosive limit (UEL) | 11.8 % by volume | % by vol | HSDB |
| 11.8 % by volume | NIOSH |
Tetrahydrofuran vapor density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor density | 2.5 (air = 1) | HSDB |
Tetrahydrofuran odor threshold
| Property | Value | Conditions | Source |
|---|---|---|---|
| Odor threshold | 20-50 ppm @3.8 M | HSDB | |
| 7.3-10.2 mg/cu m (recognition in air) | HSDB | ||
| Low: 7.37 mg/cu m; High: 177.0 mg/cu m | From table | HSDB |
Tetrahydrofuran critical temperature and pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Critical temperature and pressure | 268 °C (514.4 °F) | HSDB |
Tetrahydrofuran corrosivity
| Property | Value | Conditions | Source |
|---|---|---|---|
| Corrosivity | Tetrahydrofuran will attack some forms of plastics, rubber, and coatings. | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
Tetrahydrofuran 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.
Tetrahydrofuran fire potential
Flammable liquid. A very dangerous fire hazard when exposed to heat, flames, oxidizers.
Source: Hazardous Substances Data Bank (HSDB)
10 · Handling and storage
Tetrahydrofuran storage and handling
Tetrahydrofuran reactive group
CAMEO Chemicals places Tetrahydrofuran in the reactive group Ethers. 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.
Tetrahydrofuran peroxide formation
B: Compounds that form peroxides on concentration (distillation/evaporation)
Source: Lab and Research Safety, University of Minnesota
Tetrahydrofuran safe storage
Fireproof. Well closed. Separated from : see Chemical Dangers.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Tetrahydrofuran storage conditions
Store in a cool, dry, well-ventilated location. Store away from heat, oxidizing materials, and sunlight. Outside or detached storage is preferred. Inside storage should be in a standard flammable liquids storage warehouse, room, or cabinet.
Source: Hazardous Substances Data Bank (HSDB)
Tetrahydrofuran incompatible materials
Reacts with lithium tetrahydroaluminate or borane to form explosive hydrogen gas. Violent reaction with metal halides (e.g., hafnium tetrachloride, titanium tetrachloride, zirconium tetrachloride). Vigorous reaction with bromine, calcium hydride + heat. Can react with oxidizing materials.
Source: Hazardous Substances Data Bank (HSDB)
Tetrahydrofuran reactivity
TETRAHYDROFURAN reacts violently with oxidizing agents leading to fires and explosions [Handling Chemicals Safely 1980. p. 891]. Subject to peroxidation in the air. Peroxides or their products react exothermically with lithium aluminum hydride [MCA Guide for Safety 1973]. Thus, use as a solvent for lithium aluminum hydride has led to fires. Using potassium hydroxide or sodium hydroxide to dry impure tetrahydrofuran that contains peroxides has resulted in explosions. A violent explosion occurred during the preparation of sodium aluminum hydride from sodium and aluminum in a medium of tetrahydrofuran [Chem. Eng. News 39(40):57. 1961]. THF forms explosive products with 2-aminophenol [Lewis 3227].
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Tetrahydrofuran in the storage compatibility matrix →
11 · Transport
Tetrahydrofuran 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.
Tetrahydrofuran under UN 2056 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| TETRAHYDROFURAN | 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) |
|---|---|---|---|
| Tetrahydrofuran | 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
Tetrahydrofuran — frequently asked questions
What is the CAS number of Tetrahydrofuran?
The CAS number of Tetrahydrofuran is 109-99-9. Its EC number is 203-726-8.
What is the chemical formula of Tetrahydrofuran?
The molecular formula of Tetrahydrofuran is C4H8O and its molecular weight is 72.11 g/mol.
What does a Tetrahydrofuran label have to show?
Under CLP Annex VI the label for Tetrahydrofuran carries the pictograms Flame, Exclamation mark and Health hazard and the signal word is Danger.
Is Tetrahydrofuran flammable?
Yes. CLP Annex VI assigns Tetrahydrofuran H225 — highly flammable liquid and vapour. The flash point reported for it is -14.44 °C (6 °F) (HSDB).
Is Tetrahydrofuran a carcinogen?
CLP Annex VI assigns Tetrahydrofuran H351 — suspected of causing cancer. That is category 2: the evidence points that way but is not conclusive. IARC places it in Group 2B: possibly carcinogenic to humans.
What is the exposure limit for Tetrahydrofuran?
The US occupational exposure limit reported for Tetrahydrofuran 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 Tetrahydrofuran?
The boiling point reported for Tetrahydrofuran is 65 °C (149 °F) (HSDB).
What is the melting point of Tetrahydrofuran?
The melting point reported for Tetrahydrofuran is -108.44 °C (-163.2 °F) (HSDB).
How should Tetrahydrofuran be stored?
CLP Annex VI assigns Tetrahydrofuran the storage statement P403. Store in a cool, dry, well-ventilated location. Store away from heat, oxidizing materials, and sunlight. Outside or detached storage is preferred. Inside storage should be in a standard flammable liquids storage warehouse, room, or cabinet. (Hazardous Substances Data Bank (HSDB))
Nearby
Substances next to Tetrahydrofuran
Keep going: substances starting with T, or search the whole database by name, CAS number, pictogram or signal word.
Next