Substance profile
Zinc oxide
Zinc oxide is white or yellowish-white powder; hexagonal crystals and is odorless.
01 · Identification
What Zinc oxide is
Zinc oxide is white or yellowish-white powder; hexagonal crystals and is odorless. Its molecular formula is OZn and its molecular weight is 81.4 g/mol. It melts at 1974 °C.
Under the GHS it carries the signal word Warning.
02 · Identifiers
Zinc oxide identifiers and molecular data
Zinc oxide CAS number and EC number
Zinc oxide molecular formula and molecular weight
Other names for Zinc oxide
- ZnO
- Zinc Oxide, Crude
- Zinc Peroxide
03 · GHS classification
Zinc oxide hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Zinc oxide pictograms and signal word
Zinc oxide hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Hazardous to the aquatic environment - acute GHS chapter 4.1 | Category 1 | H400 | GHS09 |
| Hazardous to the aquatic environment - chronic GHS chapter 4.1 | Category 1 | H410 | GHS09 |
Zinc oxide hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H400 | Very toxic to aquatic life. |
| H410 | Very toxic to aquatic life with long lasting effects. |
This page lists only the codes assigned to Zinc oxide. 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 Zinc oxide
Our own Zinc oxide 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
Zinc oxide precautionary statements
CLP Annex VI assigns 3 precautionary statements to Zinc oxide. 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.
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
Zinc oxide 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 | цинков оксид |
| Spanish español | Óxido de cinc |
| Czech čeština | oxid zinečnatý |
| Danish dansk | zinkoxid |
| German Deutsch | Zinkoxid |
| Estonian eesti | tsinkoksiid |
| Greek ελληνικά | οξείδιο του ψευδαργύρου |
| English English | zinc oxide |
| French français | oxyde de zinc |
| Croatian hrvatski | cinkov oksid |
| Italian italiano | ossido di zinco |
| Latvian latviešu | cinka oksīds |
| Lithuanian lietuvių | cinko oksidas |
| Hungarian magyar | cink-oxid |
| Maltese Malti | ossidu taż-żingu |
| Dutch Nederlands | zinkoxide |
| Polish polski | tlenek cynku |
| Portuguese português | óxido de zinco |
| Romanian română | oxid de zinc |
| Slovak slovenčina | oxid zinočnatý |
| Slovenian slovenščina | cinkov oksid |
| Finnish suomi | sinkkioksidi |
| Swedish svenska | zinkoxid |
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
Zinc oxide GHS label elements
Everything CLP Annex VI fixes for Zinc oxide, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Warning
Zinc oxide
- Very toxic to aquatic life.
- Very toxic to aquatic life with long lasting effects.
- Avoid release to the environment.
- Collect spillage.
- Dispose of contents/container to …
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Zinc oxide in the GHS label constructor →
07 · Health hazards
Zinc oxide health hazards and exposure limits
Zinc oxide hazard summary
Causes metal fume fever; [Rom, p. 404-6] See Zinc.
Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
Zinc oxide carcinogenicity classification
CLASSIFICATION: D; not classifiable as to human carcinogenicity. BASIS FOR CLASSIFICATION: Based on inadequate evidence in humans and animals. HUMAN CARCINOGENICITY DATA: Inadequate. ANIMAL CARCINOGENICITY DATA: Inadequate. /Zinc and compounds/
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.
Zinc oxide occupational exposure limits
| Limit | Value | Source |
|---|---|---|
| PEL | 5.0 [mg/m3](fume and respirable fraction), 15 mg/m3(total dust) | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| PEL | 5 mg/m³ | Occupational Safety and Health Administration (OSHA) |
| PEL | TWA 5 mg/m3 (fume) TWA 15 mg/m3 (total dust) TWA 5 mg/m3 (resp dust) See Appendix G | The National Institute for Occupational Safety and Health (NIOSH) |
| REL | 5 mg/m³ | Occupational Safety and Health Administration (OSHA) |
| REL | 10 mg/m³ | Occupational Safety and Health Administration (OSHA) |
| REL | Dust: TWA 5 mg/m3 C 15 mg/m3 | The National Institute for Occupational Safety and Health (NIOSH) |
| IDLH | 500 mg/m3 (NIOSH, 2024) | CAMEO Chemicals |
| IDLH | 500.0 [mg/m3] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| IDLH | 500 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
Zinc oxide 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.
Zinc oxide melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | 1974 °C (3585.2 °F) | HSDB | |
| 1975 °C (3587 °F) | NIOSH |
Zinc oxide density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 5.6 g/cm³ | HSDB | |
| 5.61 g/cm³ | NIOSH |
Zinc oxide solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Insoluble in water | HSDB | |
| Soluble in dilute acid | HSDB | ||
| Slowly decomposed by water | decomposes | HSDB |
Zinc oxide vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 0 mmHg | approx | HSDB |
Zinc oxide lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | Noncombustible Solid | NIOSH |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
Zinc oxide 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.
Zinc oxide fire potential
Not combustible.
Source: Hazardous Substances Data Bank (HSDB)
10 · Handling and storage
Zinc oxide storage and handling
Zinc oxide reactive group
CAMEO Chemicals places Zinc oxide in the reactive group Salts, Basic. 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.
Zinc oxide safe storage
Separated from incompatible materials. See Chemical Dangers. Provision to contain effluent from fire extinguishing.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Zinc oxide storage conditions
Store in airtight containers.
Source: Hazardous Substances Data Bank (HSDB)
Zinc oxide incompatible materials
Slow addition of zinc white (a voluminous oxide containing much air) to cover the surface of linseed oil varnish caused generation of heat and ignition. Lithopone, a denser (air-free) grade of oxide did not cause heating.
Source: Hazardous Substances Data Bank (HSDB)
Zinc oxide reactivity
ZINC OXIDE is insoluble in water. What little solubility it has yields aqueous solutions that are neutral in pH. Intimate mixtures of zinc oxide and chlorinated rubber with or without hydrocarbons or chlorinated solvent react violently, even explosively upon heating [Chem. Trade J., 1962, 151, 672]. Slow addition of zinc oxide to cover the surface of linseed oil varnish caused generation of heat and ignition, [Chem. Trade J., 1933, 92, 278].
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Zinc oxide in the storage compatibility matrix →
11 · Questions
Zinc oxide — frequently asked questions
What is the CAS number of Zinc oxide?
The CAS number of Zinc oxide is 1314-13-2. Its EC number is 215-222-5.
What is the chemical formula of Zinc oxide?
The molecular formula of Zinc oxide is OZn and its molecular weight is 81.4 g/mol.
What does a Zinc oxide label have to show?
Under CLP Annex VI the label for Zinc oxide carries the pictogram Environment and the signal word is Warning.
Is Zinc oxide flammable?
CLP Annex VI assigns Zinc oxide 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.
Is Zinc oxide a carcinogen?
CLP Annex VI records no harmonised carcinogenicity classification for Zinc oxide. 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 Zinc oxide?
The US occupational exposure limit reported for Zinc oxide is 5.0 [mg/m3](fume and respirable fraction), 15 mg/m3(total dust) (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 melting point of Zinc oxide?
The melting point reported for Zinc oxide is 1974 °C (3585.2 °F) (HSDB).
How should Zinc oxide be stored?
Store in airtight containers. (Hazardous Substances Data Bank (HSDB))
Nearby
Substances next to Zinc oxide
Keep going: substances starting with Z, or search the whole database by name, CAS number, pictogram or signal word.
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