Substance profile
Maleic Anhydride
Maleic Anhydride is orthorhombic needles from chloroform; commercial grades furnished in fused form with a pungent odor.
01 · Identification
What Maleic Anhydride is
Maleic Anhydride is orthorhombic needles from chloroform; commercial grades furnished in fused form with a pungent odor. Its molecular formula is C4H2O3 and its molecular weight is 98.06 g/mol. It boils at 202 °C, melts at 52.6 °C, is soluble in water.
Under the GHS it carries the signal word Danger. It is classed as hazardous Air Pollutants (HAPs).
02 · Identifiers
Maleic Anhydride identifiers and molecular data
Maleic Anhydride CAS number and EC number
Maleic Anhydride molecular formula and molecular weight
03 · GHS classification
Maleic Anhydride hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Maleic Anhydride pictograms and signal word
Maleic Anhydride hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Acute toxicity - oral GHS chapter 3.1 | Category 4 | H302 | GHS07 |
| Skin corrosion/irritation GHS chapter 3.2 | Category 1A or 1B or 1C | H314 | GHS05 |
| Serious eye damage/eye irritation GHS chapter 3.3 | Category 1 | H318 | GHS05 |
| Respiratory sensitisation GHS chapter 3.4 | Category 1 or 1A or 1B | H334 | GHS08 |
| Skin sensitisation GHS chapter 3.4 | Category 1 or 1A or 1B | H317 | GHS07 |
| Specific target organ toxicity - repeated exposure GHS chapter 3.9 | Category 1 | H372 | 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.
Maleic Anhydride hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H302 | Harmful if swallowed. |
| H372 | Causes 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>. |
| H314 | Causes severe skin burns and eye damage. |
| H318 | Causes serious eye damage. |
| H334 | May cause allergy or asthma symptoms or breathing difficulties if inhaled. |
| H317 | May cause an allergic skin reaction. |
Maleic Anhydride supplemental EU statements (EUH)
| Code | Statement |
|---|---|
| EUH071 | Corrosive to the respiratory tract. |
This page lists only the codes assigned to Maleic Anhydride. 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 Maleic Anhydride
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 Maleic Anhydride 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
Maleic Anhydride precautionary statements
CLP Annex VI assigns 15 precautionary statements to Maleic Anhydride. 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
Maleic Anhydride 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 | малеинов анхидрид |
| Spanish español | Anhídrido maleico |
| Czech čeština | maleinanhydrid |
| Danish dansk | maleinsyreanhydrid |
| German Deutsch | Maleinsäureanhydrid |
| Estonian eesti | maleanhüdriid |
| Greek ελληνικά | μηλεϊνικός ανυδρίτης |
| English English | maleic anhydride |
| French français | anhydride maléique |
| Croatian hrvatski | anhidrid maleinske kiseline |
| Italian italiano | anidride maleica |
| Latvian latviešu | maleīnskābes anhidrīds |
| Lithuanian lietuvių | maleino rūgšties anhidridas |
| Hungarian magyar | maleinsav-anhidrid |
| Maltese Malti | anidride malejku |
| Dutch Nederlands | maleïnezuuranhydride |
| Polish polski | bezwodnik maleinowy |
| Portuguese português | anidrido maleico |
| Romanian română | anhidridă maleică |
| Slovak slovenčina | anhydrid kyseliny maleínovej |
| Slovenian slovenščina | anhidrid maleinske kisline |
| Finnish suomi | maleiinianhydridi |
| Swedish svenska | maleinsyraanhydrid |
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
Maleic Anhydride GHS label elements
Everything CLP Annex VI fixes for Maleic Anhydride, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Maleic Anhydride
- Harmful if swallowed.
- Causes 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>.
- Causes severe skin burns and eye damage.
- Causes serious eye damage.
- May cause allergy or asthma symptoms or breathing difficulties if inhaled.
- May cause an allergic skin reaction.
- Corrosive to the respiratory tract.
- Do not breathe dust/fume/gas/mist/vapours/spray.
- Avoid breathing dust/fume/gas/mist/vapours/spray.
- Do not eat, drink or smoke when using this product.
- Contaminated work clothing should not be allowed out of the workplace.
- Wear protective gloves/protective clothing/eye protection/face protection/hearing protection/…
- IF SWALLOWED:
- IF IN EYES:
- Immediately call a POISON CENTER/doctor/…
- Call a POISON CENTER/doctor/… if you feel unwell.
- Get medical advice/attention.
- Get medical advice/attention if you feel unwell.
- Rinse mouth.
- Do NOT induce vomiting.
- If skin irritation or rash occurs:
- Remove contact lenses, if present and easy to do. Continue rinsing.
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Maleic Anhydride in the GHS label constructor →
07 · Health hazards
Maleic Anhydride health hazards and exposure limits
Maleic Anhydride hazard summary
Maleic anhydride is used in the formulation of resins. Exposure to maleic anhydride may occur from accidental releases to the environment or in workplaces where it is produced or used. Acute (short-term) inhalation exposure of humans to maleic anhydride has been observed to cause irritation of the respiratory tract and eye irritation. Chronic (long-term) exposure to maleic anhydride has been observed to cause chronic bronchitis, asthma-like attacks, and upper respiratory tract and eye irritation in workers. In some people, allergies have developed so that lower concentrations can no longer be tolerated. Kidney effects were observed in rats chronically exposed to maleic anhydride via gavage (experimentally placing the chemical in the stomach). EPA has not classified maleic anhydride for carcinogenicity.
Source: EPA Hazardous Air Pollutants
Maleic Anhydride occupational exposure limits
| Limit | Value | Source |
|---|---|---|
| PEL | 1.0 [mg/m3] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| PEL | 0.25 ppm (1 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| PEL | TWA 1 mg/m3 (0.25 ppm) | The National Institute for Occupational Safety and Health (NIOSH) |
| REL | 0.25 ppm (1 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| REL | TWA 1 mg/m3 (0.25 ppm) | The National Institute for Occupational Safety and Health (NIOSH) |
| IDLH | 10 mg/m3 (NIOSH, 2024) | CAMEO Chemicals |
| IDLH | 10.0 [mg/m3] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| IDLH | 10 mg/cu m | 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
Maleic Anhydride 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.
Maleic Anhydride boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 202 °C (395.6 °F) | at 760 mmHg | HSDB |
| 202.22 °C (396 °F) | NIOSH | ||
| 202 °C (395.6 °F) | ICSC |
Maleic Anhydride melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | 52.56 °C (126.6 °F) | HSDB | |
| 52.78 °C (127 °F) | NIOSH |
Maleic Anhydride density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 1.48 g/cm³ | NIOSH | |
| 1.5 g/cm³ | ICSC | ||
| 0.934 g/cm³ | at 20 °C | HSDB |
Maleic Anhydride solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | In water: reaction with water | HSDB | |
| Soluble in water, forming maleic acids | HSDB | ||
| Soluble; decomposes in hot solvent (NTP, 1992) | decomposes | CAMEO |
Maleic Anhydride vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 0.2 mmHg | NIOSH | |
| 0.25 mmHg | at 25 °C | HSDB |
Maleic Anhydride flash point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Flash point | 102 °C (215.6 °F) | closed cup | HSDB |
| 110 °C (230 °F) | open cup | HSDB | |
| 103.33 °C (218 °F) | NIOSH |
Maleic Anhydride autoignition temperature
| Property | Value | Conditions | Source |
|---|---|---|---|
| Autoignition temperature | 477 °C (890.6 °F) | HSDB | |
| 470 °C (878 °F) | CAMEO |
Maleic Anhydride lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | 7.1 % by volume | Upper | HSDB |
| 1.4 % by volume | HSDB |
Maleic Anhydride upper explosive limit (UEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Upper explosive limit (UEL) | 7.1 % by volume | HSDB |
Maleic Anhydride vapor density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor density | 3.38 (air = 1) | HSDB | |
| 3.4 (air = 1) | ICSC |
Maleic Anhydride odor threshold
| Property | Value | Conditions | Source |
|---|---|---|---|
| Odor threshold | Odor low: 1.84 mg/mL; Odor high: 1.96 mg/mL | HSDB | |
| Odor threshold 0.3 ppm (0.001223 mg/L)... reported for off-gases in manufacture. | HSDB | ||
| Odor Threshold Low: 0.25 [mg/m3] | Haz-Map |
Maleic Anhydride corrosivity
| Property | Value | Conditions | Source |
|---|---|---|---|
| Corrosivity | Corrosive material. | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
Maleic Anhydride 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.
Maleic Anhydride fire potential
Great care must be taken with the molten and vapor as material in this state is flammable. The material is a combustible solid... .
Source: Hazardous Substances Data Bank (HSDB)
10 · Handling and storage
Maleic Anhydride storage and handling
Maleic Anhydride safe storage
Fireproof. Store only in original container. Separated from strong oxidants, strong reducing agents and incompatible materials. Dry. Store in an area without drain or sewer access.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Maleic Anhydride storage conditions
Keep container tightly closed in a dry and well-ventilated place. Moisture sensitive. Storage class (TRGS 510): Non-combustible, corrosive hazardous materials
Source: Hazardous Substances Data Bank (HSDB)
Maleic Anhydride incompatible materials
Incompatible with alkali metals, caustics, and amines at greater than 150 °F.
Source: Hazardous Substances Data Bank (HSDB)
Planning storage for a mix of chemicals? Check Maleic Anhydride in the storage compatibility matrix →
11 · Transport
Maleic Anhydride 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.
Maleic Anhydride under UN 2215 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| MALEIC ANHYDRIDE, MOLTEN | 8 | C3 | III | |
| MALEIC ANHYDRIDE | 8 | C4 | III | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 8 is “Corrosive 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) |
|---|---|---|---|
| Maleic anhydride | 8 | III | |
| Maleic anhydride, molten | 8 | III | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 8 is “Corrosive material” (49 CFR 173.2).
12 · Questions
Maleic Anhydride — frequently asked questions
What is the CAS number of Maleic Anhydride?
The CAS number of Maleic Anhydride is 108-31-6. Its EC number is 203-571-6.
What is the chemical formula of Maleic Anhydride?
The molecular formula of Maleic Anhydride is C4H2O3 and its molecular weight is 98.06 g/mol.
What does a Maleic Anhydride label have to show?
Under CLP Annex VI the label for Maleic Anhydride carries the pictograms Exclamation mark, Health hazard and Corrosion and the signal word is Danger.
Is Maleic Anhydride flammable?
CLP Annex VI assigns Maleic Anhydride 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 102 °C (215.6 °F), closed cup (HSDB).
Is Maleic Anhydride a carcinogen?
CLP Annex VI records no harmonised carcinogenicity classification for Maleic Anhydride. 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 Maleic Anhydride?
The US occupational exposure limit reported for Maleic Anhydride is 1.0 [mg/m3] (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 Maleic Anhydride?
The boiling point reported for Maleic Anhydride is 202 °C (395.6 °F), at 760 mmHg (HSDB).
What is the melting point of Maleic Anhydride?
The melting point reported for Maleic Anhydride is 52.56 °C (126.6 °F) (HSDB).
How should Maleic Anhydride be stored?
Keep container tightly closed in a dry and well-ventilated place. Moisture sensitive. Storage class (TRGS 510): Non-combustible, corrosive hazardous materials (Hazardous Substances Data Bank (HSDB))
Nearby
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