Hazard cargoes classification
Information on this graphic changes depending on which, "Division" of explosive is shipped. Explosive Dangerous Goods have compatibility group letters assigned to facilitate segregation during transport. The letters used range from A to S excluding the letters I, M, O, P, Q and R. The example above shows an explosive with a compatibility group "A" (shown as 1.1A). The actual letter shown would depend on the specific properties of the substance being transported.
For example, the Canadian Transportation of Dangerous Goods Regulations provides a description of compatibility groups.
subclass 1.1 Explosives with a mass explosion hazard. Ex: TNT, dynamite, nitroglycerine.
subclass 1.2 Explosives with a severe projection hazard.
subclass 1.3 Explosives with a fire, blast or projection hazard but not a mass explosion hazard.
subclass 1.4 Minor fire or projection hazard (includes ammunition and most consumer fireworks).
subclass 1.5 An insensitive substance with a mass explosion hazard (explosion similar to 1.1).
subclass 1.6 Extremely insensitive articles.
The United States Department of Transportation (DOT) regulates hazmat transportation within the territory of the US.
subclass 1.1 Explosives with a mass explosion hazard. (nitroglycerin/dynamite).
subclass 1.2 Explosives with a blast/projection hazard.
subclass 1.3 Explosives with a minor blast hazard. (rocket propellant, display fireworks).
subclass 1.4 Explosives with a major fire hazard. (consumer fireworks, ammunition).
subclass 1.5 Blasting agents.
subclass 1.6 Extremely insensitive explosives.
Gases which are compressed, liquefied or dissolved under pressure as detailed below. Some gases have subsidiary risk classes; poisonous or corrosive.
2.1 Flammable Gas: gases which ignite on contact with an ignition source, such as acetylene and hydrogen.
2.2 Non-Flammable Gases: gases which are neither flammable nor poisonous. Includes the cryogenic gases/liquids (temperatures of below -100°C) used for cryopreservation and rocket fuels, such as nitrogen and neon.
2.3 Poisonous Gases: gases liable to cause death or serious injury to human health if inhaled; examples are fluorine, chlorine, and hydrogen cyanide.
Flammable liquids included in Class 3 are included in one of the following packing groups:
Packing Group I, if they have an initial boiling point of 35°C or less at an absolute pressure of 101.3 kPa and any flash point, such as diethyl ether or carbon disulfide;
Packing Group II, if they have an initial boiling point greater than 35°C at an absolute pressure of 101.3 kPa and a flash point less than 23°C, such as gasoline (petrol) and acetone;
Packing Group III, if the criteria for inclusion in Packing Group I or II are not met, such as kerosene and diesel.
Note: For further details, check the Dangerous Goods Transportation Regulations of the country of interest.
4.1 Flammable Solids: Solid substances that are easily ignited and readily combustible (nitrocellulose, magnesium, safety or strike-anywhere matches).
4.2 Spontaneously Combustible: Solid substances that ignite spontaneously (aluminium alkyls, white phosphorus).
4.3 Dangerous when Wet: Solid substances that emit a flammable gas when wet or react violently with water (sodium, calcium, potassium, calcium carbide).
6.1a Toxic substances which are liable to cause death or serious injury to human health if inhaled, swallowed or by skin absorption (potassium cyanide, mercuric chloride).
6.1b (Now PGIII) Toxic substances which are harmful to human health (N.B this symbol is no longer authorized by the United Nations) (pesticides, methylene chloride).
6.2 Biohazardous substances; the World Health Organization (WHO) divides this class into two categories: Category A: Infectious; and Category B: Samples (virus cultures, pathology specimens, used intravenous needles).