GHS / HazCom term · Glossary
Aerosol
Verified vs OSHA sources · 2026-10-05
As a GHS/HazCom hazard class, an aerosol is a non-refillable pressurized container (an aerosol dispenser) — a can holding a gas compressed, liquefied, or dissolved under pressure, fitted with a release valve that ejects the contents as a spray, foam, paste, powder, liquid, or gas. HazCom classifies aerosols into three categories by their flammable content and heat of combustion: Category 1 (extremely flammable), Category 2 (flammable), and Category 3 (non-flammable).
Also known as: aerosol dispenser, aerosol can, spray can
Aerosol at a glance
- The hazard class refers to the pressurized dispenser (the can), not just the mist it produces.
- Category 1 (extremely flammable): ≥ 85% flammable components and heat of combustion ≥ 30 kJ/g (or meets ignition-distance/foam tests).
- Category 2 (flammable): > 1% flammable components or heat of combustion ≥ 20 kJ/g, meeting defined spray/foam test thresholds.
- Category 3 (non-flammable): ≤ 1% flammable components and heat of combustion < 20 kJ/g.
In plain English
A pressurized spray can — think spray paint, aerosol lubricant, or hairspray. Because many contain flammable propellants, GHS rates them Category 1 (extremely flammable), 2 (flammable), or 3 (non-flammable).
What the rule says
“Aerosol means any non-refillable receptacle containing a gas compressed, liquefied or dissolved under pressure, and fitted with a release device allowing the contents to be ejected as particles in suspension in a gas, or as a foam, paste, powder, liquid or gas.”
In context
A classification or labeling concept from the UN Globally Harmonized System, adopted into US law through OSHA's Hazard Communication Standard (29 CFR 1910.1200) and its appendices.
Where this is written in OSHA's rules
- 29 CFR 1910.1200 App B.3Read on eCFR / OSHA.gov
Example
A can of spray paint with a hydrocarbon propellant is typically Aerosol Category 1 (extremely flammable) and carries the GHS02 flame pictogram plus a pressurized-container warning. A water-based aerosol with almost no flammable content would be Category 3 (non-flammable).
Why it matters
Aerosols combine two hazards in one package — flammable contents and stored pressure — so a heated or punctured can can rupture or flash. The three-category system tells you which cans demand flame-free storage and heat protection, and it drives the label pictogram and storage segregation.
Two meanings of “aerosol”
In everyday and industrial-hygiene use, an “aerosol” is any fine solid/liquid particles suspended in air (a mist or dust cloud). In GHS/HazCom hazard classification, “aerosol” means the pressurized dispenser can itself. This glossary entry covers the GHS hazard class — the spray can — not the airborne-particle sense.
GHS aerosol categories
| Category | Flammability | Basis |
|---|---|---|
| 1 | Extremely flammable | ≥ 85% flammable, heat ≥ 30 kJ/g (or test criteria) |
| 2 | Flammable | > 1% flammable or heat ≥ 20 kJ/g (with test thresholds) |
| 3 | Non-flammable | ≤ 1% flammable and heat < 20 kJ/g |
Aerosol: frequently asked questions
- What is an aerosol in GHS terms?
- A non-refillable pressurized container (aerosol dispenser) that ejects its contents as a spray, foam, paste, powder, liquid, or gas. HazCom classifies aerosols as Category 1 (extremely flammable), 2 (flammable), or 3 (non-flammable).
- What makes an aerosol Category 1?
- A high flammable content — generally ≥ 85% flammable components with a heat of combustion ≥ 30 kJ/g (or meeting the ignition-distance/foam flammability tests). Category 1 is labeled “extremely flammable.”
- Isn't an aerosol just airborne particles?
- That's the general/industrial-hygiene meaning. In GHS hazard classification, “aerosol” refers specifically to the pressurized dispenser can — which is what determines the flammability category and label.
Related terms
Free tools for this
Governing OSHA standards
More GHS terms
A GHS health-hazard class for the harmful effects that follow a single dose, several doses within 24 hours, or a 4-hour inhalation exposure. Chemicals are sorted into categories by route (oral, dermal, inhalation) using LD50/LC50 cut-offs — Category 1 is the most toxic. OSHA's HazCom standard uses Categories 1–4.
Aspiration HazardA GHS health-hazard class for chemicals that can be fatal if swallowed and then enter the airways — directly or by vomiting — causing chemical pneumonia or lung injury. Thin, low-viscosity hydrocarbons (gasoline, kerosene, lamp oil) are the classic example. It is Category 1, with the health-hazard pictogram (GHS08) and signal word “Danger.”
CarcinogenicityA GHS health-hazard class for chemicals that cause cancer or increase its incidence. GHS (and OSHA's HazCom standard) sorts carcinogens into Category 1A (known human carcinogen), 1B (presumed, from animal evidence), and Category 2 (suspected). Carcinogens carry the health-hazard pictogram (GHS08) and a hazard statement such as H350 (“May cause cancer”).
Chemicals Under PressureA physical-hazard class added by OSHA's 2024 HCS update (aligning with GHS Revision 7) for liquids or solids pressurized with a gas, held in pressure receptacles other than aerosol dispensers and not classified as gases under pressure. It is categorized by the flammability of its contents and always carries the gas-cylinder pictogram (GHS04) for the pressure hazard.
ClassificationThe process of evaluating the available scientific evidence for a chemical against the GHS criteria to decide whether it is hazardous and, if so, the hazard class and category of each effect. Classification is the first step in HazCom — its result determines every label element (pictogram, signal word, hazard and precautionary statements) and SDS content.
Corrosive to MetalsA GHS physical-hazard class for chemicals that, by chemical action, will materially damage or even destroy metals. It is a single category (Category 1), determined by corrosion-rate testing on steel and aluminum, and uses the corrosion pictogram (GHS05) with the hazard statement H290. It is a separate hazard from skin corrosion, even though both use GHS05.
Desensitized ExplosivesA physical-hazard class added by OSHA's 2024 HCS update (GHS Revision 7) for solid or liquid explosives that have been phlegmatized — wetted or diluted — to suppress their explosive properties for safe transport and storage. It has four categories based on the corrected burning rate, and uses the flame pictogram (GHS02), not the exploding-bomb.
Globally Harmonized System (GHS)An internationally agreed framework created by the United Nations (first adopted in 2003) that standardizes how chemical hazards are classified and communicated — using common hazard classes, pictograms, signal words (Danger / Warning), and coded hazard (H) and precautionary (P) statements on labels and safety data sheets. The US adopted GHS into law through OSHA's 2012 Hazard Communication Standard update.
Sources & verification
- 29 CFR 1910.1200 App B.3 (eCFR / OSHA.gov)
- OSHA — 1910.1200 Appendix B.3 (Aerosols)
- OSHA — Hazard Communication (Physical Hazards)
Reviewed by HazComFast against eCFR, OSHA.gov, NIOSH, and the Federal Register. Last reviewed 2026-10-05. This glossary is general information, not legal advice; OSHA State-Plan states (e.g. California, Michigan) may adopt stricter requirements.
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