Substance profile
Nitric acid
Nitric acid is a transparent, colorless, or yellowish, fuming, hygroscopic, corrosive liquid with a characteristic choking odor.
01 · Identification
What Nitric acid is
Nitric acid is a transparent, colorless, or yellowish, fuming, hygroscopic, corrosive liquid with a characteristic choking odor. It boils at 83 °C, melts at -41.6 °C, is very soluble in water.
Under the GHS it carries the signal word Danger. It is classed as corrosives.
02 · Identifiers
Nitric acid identifiers and molecular data
Nitric acid CAS number and EC number
Nitric acid molecular formula and molecular weight
Other names for Nitric acid
- aqua fortis
- HNO3
- Azotic Acid
- Hydrogen Nitrate
- Nital
- Nitric Acid (Conc 80% Or Greater)
- Nitric Acid (Hono2)
- Nitric Acid, Fuming
- Nitric Acid, Red Fuming
- Nitryl Hydroxide
- Nitric Acid, Other Than Red Fuming
- nitric acid ...% [C > 70 %]
03 · GHS classification
Nitric acid hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Nitric acid pictograms and signal word
Nitric acid hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Oxidising liquids or Oxidising solids | Category 2 or 3 | H272 | GHS03 |
| Acute toxicity - inhalation GHS chapter 3.1 | Category 1 or 2 | H330 | GHS06 |
| Skin corrosion/irritation GHS chapter 3.2 | Category 1A or 1B or 1C | H314 | GHS05 |
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.
Nitric acid hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H272 | May intensify fire; oxidiser. |
| H330 | Fatal if inhaled. |
| H314 | Causes severe skin burns and eye damage. |
Nitric acid supplemental EU statements (EUH)
| Code | Statement |
|---|---|
| EUH071 | Corrosive to the respiratory tract. |
This page lists only the codes assigned to Nitric acid. 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 Nitric acid
Our own Nitric acid 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
Nitric acid precautionary statements
CLP Annex VI assigns 7 precautionary statements to Nitric acid. 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
Nitric acid 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 | This edition prints the paired entry’s qualifier here. The Bulgarian edition prints the qualifier "[C ≤ 70 %]" here, which belongs to the paired entry 007-030-00-3. Every other edition prints "[C > 70 %]", and the classification in this same row is the one for the concentrated acid. Regulation (EU) 2020/1182, OJ L 261, 11.8.2020, p. 11 азотна киселина ...% [C ≤ 70 %] |
| Spanish español | Ácido nítrico...% [C > 70 %] |
| Czech čeština | kyselina dusičná …% [C > 70 %] |
| Danish dansk | salpetersyre …% [C > 70 %] |
| German Deutsch | Salpetersäure … % [C > 70 %] |
| Estonian eesti | Lämmastikhape kontsentratsiooniga … % [C > 70 %] |
| Greek ελληνικά | νιτρικό οξύ...% [C > 70 %] |
| English English | nitric acid …% [C > 70 %] |
| French français | acide nitrique …% [C > 70 %] |
| Croatian hrvatski | dušična kiselina ...% [C > 70 %] |
| Italian italiano | acido nitrico … % [C > 70 %] |
| Latvian latviešu | slāpekļskābe, … % [C > 70 %] |
| Lithuanian lietuvių | nitrato rūgštis...% [C > 70 %] |
| Hungarian magyar | … %-os salétromsav [C > 70 %] |
| Maltese Malti | aċidu nitriku … % [C > 70 %] |
| Dutch Nederlands | salpeterzuur … % [C > 70 %] |
| Polish polski | kwas azotowy …% [C > 70 %] |
| Portuguese português | ácido nítrico a ... % [C > 70%] |
| Romanian română | acid azotic … % [C > 70 %] |
| Slovak slovenčina | kyselina dusičná …% [C > 70 %] |
| Slovenian slovenščina | dušikova kislina ...% [C > 70 %] |
| Finnish suomi | typpihappo, ...% [C > 70 %] |
| Swedish svenska | salpetersyra ...% [C > 70 %] |
One or more lines above are flagged. In those language editions the Regulation as published in the Official Journal prints something that the rest of the same row contradicts — a name belonging to a different entry, or the qualifier of a paired entry. Each flag cites the amending act and the Official Journal page, so the wording can be checked at source. The lines are reproduced as printed, because Art. 18(2) points at Annex VI and not at our reading of it; the note beside each one says what the row’s own EC and CAS numbers identify.
The part in square brackets is not an editorial comment. Annex VI Part 1 §1.1.1.4 makes a reference of that kind part of the name itself, which means it has to be printed on the label together with the name.
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
Nitric acid GHS label elements
Everything CLP Annex VI fixes for Nitric acid, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Nitric acid
- May intensify fire; oxidiser.
- Fatal if inhaled.
- Causes severe skin burns and eye damage.
- Corrosive to the respiratory tract.
- Do not breathe dust/fume/gas/mist/vapours/spray.
- Use only outdoors or in a well-ventilated area.
- Wear protective gloves/protective clothing/eye protection/face protection/hearing protection/…
- IF SWALLOWED:
- IF INHALED:
- Immediately call a POISON CENTER/doctor/…
- Do NOT induce vomiting.
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Nitric acid in the GHS label constructor →
07 · Health hazards
Nitric acid health hazards and exposure limits
Nitric acid hazard summary
Liquid causes second or third degree burns after short contact; [CHRIS] Solutions >30% are highly corrosive to skin; Solutions <30% are corrosive; [Quick CPC] Nitrogen dioxide and nitric oxide are usually present as hazards whenever nitric acid is used. Occupational exposure may lead to acute pneumonitis and pulmonary edema. [ACGIH] May cause erosion of teeth enamel; [ICSC]
Source: Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
Nitric acid occupational exposure limits
| Limit | Value | Source |
|---|---|---|
| PEL | 2.0 [ppm] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| PEL | 2 ppm (5 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| PEL | TWA 2 ppm (5 mg/m3) See Appendix G | The National Institute for Occupational Safety and Health (NIOSH) |
| REL | 2 ppm (5 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| REL | 4 ppm (10 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| REL | TWA 2 ppm (5 mg/m3) ST 4 ppm (10 mg/m3) | The National Institute for Occupational Safety and Health (NIOSH) |
| IDLH | 25 ppm (NIOSH, 2024) | CAMEO Chemicals |
| IDLH | 25.0 [ppm] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| IDLH | Excerpts from Documentation for IDLHs: Other animal data: Rats receiving a single exposure to 63 mg/m3 nitric acid (24 ppm) exhibited no apparent adverse effects [Diggle and Gage 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
Nitric acid 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.
Nitric acid boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | 83 °C (181.4 °F) | HSDB | |
| 82.78 °C (181 °F) | NIOSH | ||
| 82.78 °C (181 °F) | at 760 mmHg | CAMEO |
Nitric acid melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | -41.6 °C (-42.9 °F) | HSDB | |
| -37.62 °C (-35.7 °F) | HSDB | ||
| -42.22 °C (-44 °F) | NIOSH |
Nitric acid density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 1.5129 g/cm³ | at 20 °C | HSDB |
| 1.5 g/cm³ | at 25 °C | CAMEO |
Nitric acid solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Very soluble in water | HSDB | |
| Miscible with water | HSDB | ||
| Miscible | NIOSH |
Nitric acid vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 48 mmHg | NIOSH | |
| 63.1 mmHg | at 25 °C | HSDB |
Nitric acid lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | Not combustible | HSDB | |
| Noncombustible Liquid, but increases the flammability of combustible materials. | NIOSH |
Nitric acid vapor density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor density | 2.2 (air = 1) | ICSC |
Nitric acid odor threshold
| Property | Value | Conditions | Source |
|---|---|---|---|
| Odor threshold | Odor low: 0.75 mg/cu m; Odor high: 2.50 mg/cu m; Irritating concn: 155.0 mg/cu m. | HSDB | |
| Odor Threshold Low: 0.27 [ppm] | Haz-Map | ||
| Odor threshold from AIHA | Haz-Map |
Nitric acid corrosivity
| Property | Value | Conditions | Source |
|---|---|---|---|
| Corrosivity | IN PRESENCE OF TRACES OF OXIDES IT ATTACKS ALL BASE METALS EXCEPT ALUMINUM & SPECIAL CHROMIUM STEELS | HSDB | |
| Nitric acid will attack some forms of plastics, rubber, and coatings. | HSDB | ||
| Caustic and corrosive | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
Nitric acid 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.
Nitric acid fire potential
Contact of concentrated nitric acid with combustible materials may increase the hazard from fire and may lead to an explosion.
Source: Hazardous Substances Data Bank (HSDB)
10 · Handling and storage
Nitric acid storage and handling
Nitric acid reactive group
CAMEO Chemicals places Nitric acid in the reactive group Acids, Strong Oxidizing. 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.
Nitric acid safe storage
Separated from combustible substances, reducing agents, bases, organic chemicals and food and feedstuffs. Cool. Dry. Keep in a well-ventilated room. Store only in original container.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Nitric acid storage conditions
As a rule, nitric acid is stored in stainless steel tanks and transported in stainless steel containers.
Source: Hazardous Substances Data Bank (HSDB)
Nitric acid incompatible materials
Reacts violently with combustible or readily oxidizable materials such as alcohols, turpentine, charcoal, organic refuse. Reacts with most metals to release hydrogen gas.
Source: Hazardous Substances Data Bank (HSDB)
Planning storage for a mix of chemicals? Check Nitric acid in the storage compatibility matrix →
11 · Questions
Nitric acid — frequently asked questions
What is the CAS number of Nitric acid?
The CAS number of Nitric acid is 7697-37-2. Its EC number is 231-714-2.
What does a Nitric acid label have to show?
Under CLP Annex VI the label for Nitric acid carries the pictograms Flame over circle, Skull and crossbones and Corrosion and the signal word is Danger.
Is Nitric acid flammable?
CLP Annex VI assigns Nitric acid 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 Nitric acid a carcinogen?
CLP Annex VI records no harmonised carcinogenicity classification for Nitric acid. 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 Nitric acid?
The US occupational exposure limit reported for Nitric acid is 2.0 [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 Nitric acid?
The boiling point reported for Nitric acid is 83 °C (181.4 °F) (HSDB).
What is the melting point of Nitric acid?
The melting point reported for Nitric acid is -41.6 °C (-42.9 °F) (HSDB).
How should Nitric acid be stored?
As a rule, nitric acid is stored in stainless steel tanks and transported in stainless steel containers. (Hazardous Substances Data Bank (HSDB))
Nearby
Substances next to Nitric acid
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