Compressed gases hazard categories

Some bromine compounds are covered specifically under Hazardous Materials Regulations. Other compounds may usually be shipped under the classification of chemicals, not otherwise indexed by name, without special requirements unless from their nature they would fall under a category such as combustible liquid, compressed gas, corrosive liquid (or solid), disinfectant liquid (or solid), dmg, dye intermediate (liquid), fire extinguisher, flammable gas (liquid or solid), insecticide, medicine, oxidizer or oxidizing material, poisonous liquid (gas or solid), solvent, or tear gas. Specific provisions apply to each of these categories and appropriate packaging and labeling are required. 

Physical hazard—name for a chemical that statistically falls into one of the following categories combustible liquid, compressed gas, explosive or flammable, organic peroxide, oxidizer, pyrophoric, unstable, or water reactive. 

The proper and safe disposition of unserviceable compressed gas cylinders is important because substantial hazards can exist that must be recognized and evaluated. Where the contents of the cylinder are unknown and there is no ready means for identifying its properties, the hazard is especially great. The disposal of cylinders with unknown contents is a very complex subject and should only be attempted by specially trained experts. For cylinders in this category, the supplier should be contacted immediately. The user should never attempt to dispose of a cylinder with unknown contents. The disposal of unserviceable compressed gas cylinders is potentially hazardous because they may contain ... 

Physical hazards. A substance can be classified as a physical hazard if it is a flammable or combustible liquid, a compressed gas, an explosive, an oxidizer, or is unstable or water-reactive. Many physical hazards are also health hazards, but substances are grouped in this category because they have the capability ofjcausing physical damage to material. 

The most common transportation labels warn against the chemical hazards of flammability (including explosion and oxidizer hazards), corrosiveness, toxicity, or pressure (compressed gas). These labels are shown in Figure App. 3.7. At times, shipments may consist of material that can present a hazard in more than one shipping hazard category. In such cases, DOT regulations specify how these packages are to be labeled (49 Cre 172.402). 

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