Substance profile
Ammonia
Ammonia is a colorless gas with a sharp, cloying, repellent odor.
01 · Identification
What Ammonia is
Ammonia is a colorless gas with a sharp, cloying, repellent odor. It boils at -33.3 °C, melts at -77.7 °C.
Under the GHS it carries the signal word Danger. It is classed as corrosives.
02 · Identifiers
Ammonia identifiers and molecular data
Ammonia CAS number and EC number
Ammonia molecular formula and molecular weight
Other names for Ammonia
- anhydrous ammonia
- NH3
- Ammonia Solutions (Containing More Than 35% But Not More Than 50% Ammonia)
- R 717
- R717
- Am-Fol
- Ammonia (Anhydrous)
- Ammonia (Anhydrous) (Liquefied)
- Ammonia Gas
- Ammonia Solution, With More Than 50% Ammonia
- Ammonia, Anhydrous
- Ammonia, Anhydrous, Liquefied
- Ammonia-14N
- Anhydrous Ammonia, Liquefied
- ammonia, anhydrous
03 · GHS classification
Ammonia hazard classification
Harmonised classification under CLP Annex VI. This is the legally binding classification in the EU; other jurisdictions may differ.
Ammonia pictograms and signal word
Ammonia hazard class and category
| Hazard class | Category | From code | Pictogram |
|---|---|---|---|
| Flammable gases GHS chapter 2.2 | Category 1B or 2 | H221 | GHS02 |
| Acute toxicity - inhalation GHS chapter 3.1 | Category 3 | H331 | GHS06 |
| Skin corrosion/irritation GHS chapter 3.2 | Category 1A or 1B or 1C | H314 | GHS05 |
| Hazardous to the aquatic environment - acute GHS chapter 4.1 | Category 1 | H400 | GHS09 |
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.
Ammonia hazard statements (H-codes)
| Code | Hazard statement |
|---|---|
| H221 | Flammable gas. |
| H331 | Toxic if inhaled. |
| H314 | Causes severe skin burns and eye damage. |
| H400 | Very toxic to aquatic life. |
This page lists only the codes assigned to Ammonia. 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 Ammonia
Our own Ammonia 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
Ammonia precautionary statements
CLP Annex VI assigns 13 precautionary statements to Ammonia. 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.
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
Ammonia 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 | амоняк, безводен |
| Spanish español | Amoniaco anhidro |
| Czech čeština | amoniak, bezvodý |
| Danish dansk | ammoniak, vandfri |
| German Deutsch | Ammoniak, wasserfrei |
| Estonian eesti | ammoniaak, veevaba |
| Greek ελληνικά | αμμωνία, άνυδρη |
| English English | ammonia, anhydrous |
| French français | ammoniac, anhydre |
| Croatian hrvatski | amonijak, bezvodni |
| Italian italiano | ammoniaca, anidra |
| Latvian latviešu | amonjaks, bezūdens |
| Lithuanian lietuvių | amoniakas, bevandenis |
| Hungarian magyar | ammónia, vízmentes |
| Maltese Malti | ammonijaku, anidru |
| Dutch Nederlands | ammoniak, watervrij |
| Polish polski | amoniak bezwodny |
| Portuguese português | amoníaco, anidro |
| Romanian română | amoniac, anhidru |
| Slovak slovenčina | amoniak, bezvodý |
| Slovenian slovenščina | amonijak, brezvodni |
| Finnish suomi | ammoniakki, vedetön |
| Swedish svenska | ammoniak, vattenfri |
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
Ammonia GHS label elements
Everything CLP Annex VI fixes for Ammonia, laid out the way it appears on a label. The greyed lines are the parts only the supplier can fill in.
Danger
Ammonia
- Flammable gas.
- Toxic if inhaled.
- Causes severe skin burns and eye damage.
- Very toxic to aquatic life.
- Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
- Keep container tightly closed.
- Do not breathe dust/fume/gas/mist/vapours/spray.
- Use only outdoors or in a well-ventilated area.
- Avoid release to the environment.
- 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.
- Collect spillage.
- Store in a well-ventilated place.
- Dispose of contents/container to …
Supplier name, address and telephone number· Product identifier·Nominal quantity
Need this as an actual label? Open Ammonia in the GHS label constructor →
07 · Health hazards
Ammonia health hazards and exposure limits
Ammonia hazard summary
Ammonia occurs naturally and is produced by human activity. It is an important source of nitrogen which is needed by plants and animals. Bacteria found in the intestines can produce ammonia. Ammonia is a colorless gas with a very distinct odor. This odor is familiar to many people because ammonia is used in smelling salts, many household and industrial cleaners, and window-cleaning products. Ammonia gas can be dissolved in water. This kind of ammonia is called liquid ammonia or aqueous ammonia. Once exposed to open air, liquid ammonia quickly turns into a gas. Ammonia is applied directly into soil on farm fields, and is used to make fertilizers for farm crops, lawns, and plants. Many household and industrial cleaners contain ammonia.
Source: Agency for Toxic Substances and Disease Registry (ATSDR)
Ammonia occupational exposure limits
| Limit | Value | Source |
|---|---|---|
| PEL | 50.0 [ppm] | Haz-Map, Information on Hazardous Chemicals and Occupational Diseases |
| PEL | 50 ppm (35 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| PEL | TWA 50 ppm (35 mg/m3) See Appendix G | The National Institute for Occupational Safety and Health (NIOSH) |
| REL | 25 ppm (18 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| REL | 35 ppm (27 mg/m³) | Occupational Safety and Health Administration (OSHA) |
| REL | TWA 25 ppm (18 mg/m3) ST 35 ppm (27 mg/m3) | The National Institute for Occupational Safety and Health (NIOSH) |
| IDLH | 300 ppm [From NPG: Ammonia] (NIOSH, 2024) | CAMEO Chemicals |
| IDLH | 300 ppm (NIOSH, 2024) | CAMEO Chemicals |
| IDLH | 300.0 [ppm] | 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
Ammonia 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.
Ammonia boiling point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Boiling point | -33.35 °C (-28 °F) | at 760 mmHg | HSDB |
| -33.33 °C (-28 °F) | NIOSH |
Ammonia melting point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Melting point | -77.7 °C (-107.9 °F) | HSDB | |
| -77.78 °C (-108 °F) | NIOSH | ||
| -77.72 °C (-107.9 °F) | CAMEO |
Ammonia density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Density | 0.0007 g/cm³ | HSDB | |
| 0.771 g/cm³ | at 25 °C | DOE PAC | |
| 0.7 g/cm³ | at -33 °C | ICSC |
Ammonia solubility
| Property | Value | Conditions | Source |
|---|---|---|---|
| Solubility | Soluble in water forming alkaline solutions; soluble in oxygenated solvents. | HSDB | |
| In water, 4.82X10+5 mg/L at 24 °C | at 24 °C | HSDB | |
| 15% in 95% alcohol at 20 °C; 11% in alcohol at 30 °C | at 20 °C | HSDB |
Ammonia vapor pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor pressure | 6460 mmHg | NIOSH | |
| 7500 mmHg | at 25 °C | HSDB | |
| 7598 mmHg | at 26 °C | ICSC |
Ammonia flash point
| Property | Value | Conditions | Source |
|---|---|---|---|
| Flash point | 132 °C (269.6 °F) | HSDB | |
| NA (Gas) | NIOSH |
Ammonia autoignition temperature
| Property | Value | Conditions | Source |
|---|---|---|---|
| Autoignition temperature | 651.11 °C (1204 °F) | HSDB | |
| 630 °C (1166 °F) | ICSC |
Ammonia lower explosive limit (LEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Lower explosive limit (LEL) | 15 % by volume | HSDB | |
| 13 % by volume | HSDB |
Ammonia upper explosive limit (UEL)
| Property | Value | Conditions | Source |
|---|---|---|---|
| Upper explosive limit (UEL) | 28 % by volume | HSDB |
Ammonia vapor density
| Property | Value | Conditions | Source |
|---|---|---|---|
| Vapor density | 0.597 (air = 1) | HSDB | |
| 0.6 (air = 1) | CAMEO |
Ammonia odor threshold
| Property | Value | Conditions | Source |
|---|---|---|---|
| Odor threshold | Water: 1.5 mg/L; air: 5.2 uL/L; odor safety class C; C = < 50% of distracted persons perceive warning of TLV. | HSDB | |
| Odor recognition of pure ammonia in air is 4.68 x 10+1 ppm. | HSDB | ||
| Sharp, cloying, repellent; low threshold = 0.0266 mg/cu m; high threshold = 39.60 mg/cu m; irritating concn = 72.00 mg/cu m. | HSDB |
Ammonia critical temperature and pressure
| Property | Value | Conditions | Source |
|---|---|---|---|
| Critical temperature and pressure | 132.4 °C (270.3 °F) | HSDB |
Ammonia corrosivity
| Property | Value | Conditions | Source |
|---|---|---|---|
| Corrosivity | Corrosive gas | HSDB | |
| Corrosive to copper and galvanized surfaces | HSDB |
Values compiled from PubChem Laboratory Chemical Safety Summary. Temperatures converted to Fahrenheit for reference.
09 · Fire and explosion
Ammonia 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.
Ammonia fire potential
Not flammable.
Source: Hazardous Substances Data Bank (HSDB)
10 · Handling and storage
Ammonia storage and handling
Ammonia reactive group
CAMEO Chemicals places Ammonia in the reactive group Bases, Weak. 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.
Ammonia safe storage
Fireproof. Separated from oxidants, acids and halogens. Cool. Keep in a well-ventilated room.
Source: ILO-WHO International Chemical Safety Cards (ICSCs)
Ammonia storage conditions
Keep container tightly closed in a dry and well-ventilated place. Contents under pressure. Storage class (TRGS 510): Gases
Source: Hazardous Substances Data Bank (HSDB)
Ammonia incompatible materials
Incompatible materials: Oxidizing agents, iron, zinc, copper, silver/silver oxides, cadmium/cadmium oxides, alcohols, acids, halogens, aldehydes.
Source: Hazardous Substances Data Bank (HSDB)
Ammonia reactivity
AMMONIA SOLUTION is basic. Reacts exothermically with acids to produce water and ammonium salts, which, being generally water-soluble, stay in the solution. The heat can cause evolution of quantities of unreacted ammonia as a corrosive, irritating gas. Heating ammonia solutions or treating them with strong bases also causes evolution of gaseous ammonia. Salts with oxidizing acids (such as ammonium chlorate) may explode if obtained in dry or nearly dry form [Kirk-Othmer, 3rd ed., Vol. 2, 1978, p. 470]. Intense sources of ignition can cause air/ammonia mixtures to burn or explode, but the conditions are so specialized that ammonia is generally regarded as nonflammable. Mixing of bleaching powder (hypochlorite solution) with ammonia solutions produces toxic/explosive ammonia trichloride vapors.
Source: CAMEO Chemicals
Planning storage for a mix of chemicals? Check Ammonia in the storage compatibility matrix →
11 · Transport
Ammonia 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.
The same CAS number is shipped under more than one UN number. Which entry applies follows from the form and the concentration of the consignment — read the proper shipping name, not the CAS.
Ammonia under UN 1005 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| AMMONIA, ANHYDROUS | 2 | 2TC | — | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 2 is “Gases” (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) |
|---|---|---|---|
| Ammonia, anhydrous | 2.3 | — | |
| Ammonia, anhydrous | 2.2 | — | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 2.3 is “Poisonous gas” (49 CFR 173.2).
Ammonia under UN 2073 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| AMMONIA SOLUTION, relative density less than 0.880 at 15 °C in water, with more than 35 % but not more than 50 % ammonia | 2 | 4A | — | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 2 is “Gases” (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) |
|---|---|---|---|
| Ammonia solution, relative density less than 0.880 at 15 degrees C in water, with more than 35 percent but not more than 50 percent ammonia | 2.2 | — | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 2.2 is “Non-flammable compressed gas” (49 CFR 173.2).
Ammonia under UN 2672 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| AMMONIA SOLUTION, relative density between 0.880 and 0.957 at 15 °C in water, with more than 10 % but not more than 35 % ammonia | 8 | C5 | 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) |
|---|---|---|---|
| Ammonia solution, relative density between 0.880 and 0.957 at 15 degrees C in water, with more than 10 percent but not more than 35 percent ammonia | 8 | III | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 8 is “Corrosive material” (49 CFR 173.2).
Ammonia under UN 3318 — shipping name, class and packing group
Europe · ADR 2025, Table A
| Proper shipping name (3.1.2) | Class | Classification code | PG | Labels (column 5) |
|---|---|---|---|---|
| AMMONIA SOLUTION, relative density less than 0.880 at 15 °C in water, with more than 50 % ammonia | 2 | 4TC | — | |
Source: ADR 2025, Table A of Chapter 3.2 · ECE/TRANS/352 Vol. I (UNECE). Class 2 is “Gases” (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) |
|---|---|---|---|
| Ammonia solution, relative density less than 0.880 at 15 degrees C in water, with more than 50 percent ammonia | 2.3 | — | |
| Ammonia solution, relative density less than 0.880 at 15 degrees C in water, with more than 50 percent ammonia | 2.2 | — | |
Source: 49 CFR 172.101 Hazardous Materials Table · eCFR, revision 2026-08-03. Class 2.3 is “Poisonous gas” (49 CFR 173.2).
12 · Questions
Ammonia — frequently asked questions
What is the CAS number of Ammonia?
The CAS number of Ammonia is 7664-41-7. Its EC number is 231-635-3.
What does a Ammonia label have to show?
Under CLP Annex VI the label for Ammonia carries the pictograms Gas cylinder, Skull and crossbones, Corrosion and Environment and the signal word is Danger.
Is Ammonia flammable?
Yes. CLP Annex VI assigns Ammonia H221 — flammable gas. The flash point reported for it is 132 °C (269.6 °F) (HSDB).
Is Ammonia a carcinogen?
CLP Annex VI records no harmonised carcinogenicity classification for Ammonia. 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 Ammonia?
The US occupational exposure limit reported for Ammonia is 50.0 [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 Ammonia?
The boiling point reported for Ammonia is -33.35 °C (-28 °F), at 760 mmHg (HSDB).
What is the melting point of Ammonia?
The melting point reported for Ammonia is -77.7 °C (-107.9 °F) (HSDB).
How should Ammonia be stored?
CLP Annex VI assigns Ammonia the storage statement P403. Keep container tightly closed in a dry and well-ventilated place. Contents under pressure. Storage class (TRGS 510): Gases (Hazardous Substances Data Bank (HSDB))
Nearby
Substances next to Ammonia
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