GHS / HazCom term · Glossary
Explosive
Verified vs OSHA sources · 2026-10-05
As a GHS/HazCom physical hazard class, an explosive is a solid or liquid chemical that is itself capable, by chemical reaction, of producing gas at such a temperature, pressure, and speed as to cause damage to the surroundings — as defined in Appendix B.1 of 29 CFR 1910.1200. The class is organized into six divisions (1.1 through 1.6) by the type and severity of the explosion hazard, plus a separate 'unstable explosive' designation for chemicals too thermally unstable or sensitive for normal handling. Explosives carry the exploding-bomb pictogram (GHS01).
Also known as: explosive substance, explosive chemical, GHS explosives class
Explosive at a glance
- Defined in 29 CFR 1910.1200 Appendix B.1 (GHS physical hazard class).
- Division 1.1 — mass explosion hazard (nearly the entire quantity detonates virtually instantaneously).
- Division 1.2 — projection hazard but not a mass explosion hazard.
- Division 1.3 — fire hazard with a minor blast and/or minor projection hazard.
- Division 1.4 — no significant hazard; effects largely confined to the package.
- Division 1.5 — very insensitive but with a mass explosion hazard; Division 1.6 — extremely insensitive, no mass explosion hazard.
- 'Unstable explosive' = thermally unstable and/or too sensitive for normal handling, transport, or use.
- Pictogram: GHS01 (exploding bomb); signal word 'Danger' for the hazardous divisions.
In plain English
A chemical that can blow up — react so fast it produces a burst of hot gas that damages everything around it. GHS sorts explosives into six 'divisions' by how they explode: whether the whole mass goes off at once, just throws fragments, mainly burns, or is so insensitive it barely reacts. The most unstable ones, too touchy to handle normally, get a special 'unstable explosive' label.
What the source says, in summary
An explosive chemical is a solid or liquid chemical which is in itself capable by chemical reaction of producing gas at such a temperature and pressure and at such a speed as to cause damage to the surroundings. Pyrotechnic chemicals are included even when they do not evolve gases.
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.1Read on eCFR / OSHA.gov
- 29 CFR 1910.1200Read on eCFR / OSHA.gov
Example
A manufacturer classifying a new energetic compound runs the GHS test series and finds that a small initiating stimulus causes nearly the entire sample to react at once — a mass explosion. The chemical is assigned to Division 1.1, labeled with the GHS01 exploding-bomb pictogram and the signal word 'Danger,' and its SDS Section 2 states the explosive hazard. By contrast, a consumer sparkler composition that mainly burns with only a minor projection risk would fall in Division 1.3, and a compound rendered insensitive by added phlegmatizer might instead be classified as a desensitized explosive.
Why it matters
The explosives class covers the most immediately catastrophic physical hazard in GHS — one that can kill instantly and destroy a facility. Correct division assignment drives storage, quantity limits, compatibility, and emergency planning, and it connects to DOT transport classification (which uses the same 1.1–1.6 divisions). Misclassifying an explosive — or overlooking that a self-reactive substance or organic peroxide has explosive properties — removes the very warnings that keep the material from being handled like an ordinary chemical.
Explosive vs. desensitized explosive vs. self-reactive
These related classes are easy to blur. An EXPLOSIVE (App B.1) is capable of a damaging gas-producing reaction and is sorted into divisions 1.1–1.6. A DESENSITIZED EXPLOSIVE (App B.17) is an explosive that has been wetted or diluted (phlegmatized) to suppress its explosive properties for handling — it is a separate class precisely because the desensitization changes the hazard. A SELF-REACTIVE substance (App B.8) is thermally unstable and undergoes exothermic decomposition without needing oxygen, and some self-reactives (Types A/B) have explosive properties too. The distinctions matter because each class has its own tests, pictograms, and controls.
GHS Explosive Divisions (29 CFR 1910.1200 App B.1)
| Division | Hazard |
|---|---|
| 1.1 | Mass explosion hazard (entire quantity detonates virtually at once) |
| 1.2 | Projection hazard, but not a mass explosion |
| 1.3 | Fire hazard with minor blast and/or projection |
| 1.4 | No significant hazard; effects confined to the package |
| 1.5 | Very insensitive, but has a mass explosion hazard |
| 1.6 | Extremely insensitive; no mass explosion hazard |
Explosive: frequently asked questions
- What are the six explosive divisions in GHS?
- Division 1.1 has a mass explosion hazard (almost the whole quantity detonates at once); 1.2 has a projection hazard but not a mass explosion; 1.3 has a fire hazard with minor blast or projection; 1.4 presents no significant hazard beyond the package; 1.5 is a very insensitive substance that still has a mass explosion hazard; and 1.6 is extremely insensitive with no mass explosion hazard. These are the same divisions used in DOT/UN transport classification.
- What is an 'unstable explosive'?
- An unstable explosive is an explosive chemical that is thermally unstable and/or too sensitive for normal handling, transport, or use. Under GHS it is flagged separately from the 1.1–1.6 divisions because its instability demands the most stringent controls. Unstable explosives carry the exploding-bomb pictogram (GHS01) and the signal word 'Danger.'
- Which pictogram and signal word do explosives use?
- Explosives use the GHS01 pictogram — the exploding bomb — and the signal word 'Danger' for the hazardous divisions. (Division 1.4, 1.5, and 1.6 materials carry reduced label elements appropriate to their lower hazard.) The exploding-bomb pictogram is also shared with self-reactive substances and organic peroxides that have explosive properties.
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.1 (eCFR / OSHA.gov)
- 29 CFR 1910.1200 (eCFR / OSHA.gov)
- OSHA — 1910.1200 Appendix B.1 (Explosives)
- 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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