Hazard Classes

CAMEO Chemicals' UN/NA datasheets include information on hazard classes and divisions from the Hazmat Table (49 CFRCode of Federal Regulations (www.govinfo.gov/app/collection/cfr/). 172.101), including representative placards.

The U.S. Department of Transportation divides regulated hazardous materials into the following nine classes, most of which are further divided into divisions:

Class Number Division Number Name of Class or Division UN/NA Datasheet Examples
1* 1.1 Explosives which have a mass explosionA chemical or physical process in which the rate at which energy is being generated exceeds its ability to escape to its surrounding environment. The hazards of an explosion can include a shock wave (especially near the point of explosion) and projectiles generated by the shock wave. hazard black powder, dynamite, TNT
1.2 Explosives which have a projection hazard (but NOT as mass explosion hazard)  detonating cord, fireworks, grenades
1.3 Explosives which have a fire hazardA hazard category that includes chemicals described as flammable, combustible liquid, pyrophoric, or oxidizers (as defined by 29 CFR 1910.1200). AND either a minor blast hazard or a minor projection hazard or both (but NOT a mass explosion hazard) dinitrosobenzene, liquid-fueled rocket motors, surface flares
1.4 Explosives which present no significant blast hazard line-throwing rockets, practice ammunition, signal cartridges
1.5 Very insensitive explosives with a mass explosion hazard ammonium nitrate-fuel oil mixture, type E blasting agent
1.6 Extremely insensitive articles which do NOT have a mass explosion hazard extremely insensitive explosive articles
2 2.1 FlammableEasy to ignite and burns readily. gas ethane, methyl chloride, propane
2.2 NonflammableDifficult to ignite., non-poisonous gas carbon dioxide, compressed nitrogen, cryogenic argon
2.3 Poisonous gas arsine, chlorine, methyl bromide
3 -- Flammable liquids (and combustibleCan be ignited and burned. liquids [U.S.]) fuel oil, gasoline, xylene
4 4.1 Flammable solid magnesium, zirconium hydride
4.2 Spontaneously combustible molten white phosphorus, sodium methylate, thiourea dioxide
4.3 Dangerous when wet calcium carbide, magnesium powder, sodium hydride
5 5.1 OxidizerOr oxidizing agent. A material that can cause or enhance the combustion of other materials, usually by providing oxygen. ammonium nitrate, barium permanganate, potassium superoxide
5.2 OrganicGenerally, compounds that contain the element carbon, except for some carbon-containing compounds that are considered to be inorganic (carbon oxides, carbides, carbon disulfide, phosgene, the cyanides of the metals, and carbonyl sulfide). peroxide liquid organic peroxide type D
6 6.1 Poison aniline, arsenic bromide, nickel carbonyl
6.2 Infectious substance regulated medical waste
7 -- RadioactiveSpontaneously and continuously emitting ions or ionizing radiation. Radioactivity isn't a chemical property, but an additional hazard apart from other properties of a material. uranium hexafluoride radioactive material
8 -- CorrosiveLiquid or solid that can destroy human skin or lung tissue or corrode metals. nitric acid, solid sodium hydroxide, sulfuric acid
9 -- Miscellaneous hazardous material acetaldehyde ammonia, ammonium nitrate based fertilizer, liquid PCBs

Compatibility Groups

Note (*): Class 1 materials (explosives) may have a compatibility group listed as part of the division (for example, 1.1A). The following summary information on this topic comes from the Emergency Response Guidebook.

Letters identify explosives that are deemed to be compatible. The definition of these Compatibility Groups from the ERG Glossary are intended to be descriptive. Please consult the transportation of dangerous goods/hazardous materials or explosives regulations of your jurisdiction for the exact wording of the definitions. Class 1 materials are considered to be "compatible" if they can be transported together without significantly increasing either the probability of an incident or, for a given quantity, the magnitude of the effects of such an incident.

  • A – Substances which are expected to mass detonate very soon after fire reaches them.
  • B – Articles which are expected to mass detonate very soon after fire reaches them.
  • C – Substances or articles which may be readily ignited and burn violently without necessarily exploding.
  • D – Substances or articles which may mass detonate (with blast and/or fragment hazard) when exposed to fire.
  • E & F – Articles which may mass detonate in a fire.
  • G – Substances and articles which may mass explode and give off smoke or toxicPoisonous; can injure or kill people or other organisms. gases.
  • H – Articles which in a fire may eject hazardous projectiles and dense white smoke.
  • J – Articles which may mass explode.
  • K – Articles which in a fire may eject hazardous projectiles and toxic gases.
  • L – Substances and articles which present a special risk and could be activated by exposure to air or water.
  • N – Articles which contain only extremely insensitive detonating substances and demonstrate a negligible probability of accidental ignition or propagation.
  • S – Packaged substances or articles which, if accidentally initiated, produce effects that are usually confined to the immediate vicinity.