| name | nine-hazmat-classes |
| description | Use when classifying a material for shipping or understanding placarding. Covers the 9 hazard classes, their divisions, the visual identifier patterns, and the hierarchy when multiple hazards apply.
|
Nine Hazmat Classes
DOT classifies all hazardous materials into 9 numbered classes. Class 1 (explosives) is most regulated; Class 9 (miscellaneous) is least. Most carriers see Class 3 (flammable liquids) and Class 8 (corrosives) most often.
Class 1 — Explosives
Divisions: 1.1 (mass explosion), 1.2 (projection), 1.3 (fire + minor), 1.4 (minor), 1.5 (very insensitive), 1.6 (extremely insensitive). Most regulated. Special routing required.
Class 2 — Gases
2.1 flammable (propane, hydrogen). 2.2 non-flammable (oxygen, nitrogen). 2.3 toxic (chlorine, ammonia). Cylinder + tank rules vary by division.
Class 3 — Flammable liquids
Gasoline, diesel, ethanol, paint, alcohol. Most common hazmat carriers haul. Flashpoint ≤ 140°F.
Class 4 — Flammable solids
4.1 (flammable solids), 4.2 (spontaneously combustible), 4.3 (dangerous when wet — sodium, calcium carbide).
Class 5 — Oxidizers
5.1 oxidizers (ammonium nitrate, hydrogen peroxide). 5.2 organic peroxides.
Class 6 — Toxic + infectious
6.1 toxic substances. 6.2 infectious (medical waste, biological). Different rules each.
Class 7 — Radioactive
Three categories (I, II, III) based on radiation level. Specialized carriers only.
Class 8 — Corrosive
Acids + bases. Battery acid, sodium hydroxide, hydrochloric acid. Common for industrial freight.
Class 9 — Miscellaneous
Lithium batteries (now huge — every iPhone container ships under Class 9), elevated-temperature materials, environmental hazards.
Multiple hazards
Material may have a primary + subsidiary hazard. Placard shows primary; shipping papers note both.
Where this fits in X3 Compass
Applied in the X3 Compass Hazmat Center — the vertical add-on for hazmat-hauling motor carriers.
