To handle dangerous goods safely you must be able to say what kind of danger they have. The Regulations sort dangerous goods into nine classes. This lesson covers the classes and the codes used to describe a product.
The nine classes
- Class 1: Explosives. Ammunition, fireworks, blasting products.
- Class 2: Gases. Divided into 2.1 flammable gases (propane), 2.2 non-flammable and non-toxic gases (nitrogen), and 2.3 toxic gases (chlorine).
- Class 3: Flammable liquids. Gasoline, many paints, solvents, alcohol-based products.
- Class 4: Flammable solids; substances liable to spontaneous combustion; water-reactive substances. These are split into 4.1, 4.2 and 4.3. A 4.3 product gives off flammable gas when it touches water.
- Class 5: Oxidizing substances and organic peroxides. 5.1 oxidizers help other materials burn; 5.2 organic peroxides can burn fiercely or decompose.
- Class 6: Toxic and infectious substances. 6.1 toxic substances such as many pesticides; 6.2 infectious substances such as some laboratory samples.
- Class 7: Radioactive materials.
- Class 8: Corrosives. Battery acid, drain cleaners, strong cleaning chemicals.
- Class 9: Miscellaneous products, substances or organisms. Lithium batteries, dry ice and some environmentally hazardous goods.
Four things that describe a product
Learn to read these four items. You will see them again on documents and on labels.
- UN number. A four-digit number that identifies the substance, written with the letters UN, for example UN1203. The same number is used around the world.
- Shipping name. The proper name from Schedule 1, for example GASOLINE. It is written in capital letters on shipping documents. You must use the name from the Regulations, not a trade name.
- Class. The primary class number, such as 3.
- Packing group (PG). Roman numerals show the degree of danger for many goods: PG I is great danger, PG II is medium danger, PG III is minor danger. Class 2 gases and Class 7 radioactive materials have no packing group, and all explosives are in Packing Group II.
Example: UN1203, GASOLINE, 3, PG II.
Primary and subsidiary classes
Some goods have more than one danger. A flammable liquid may also be toxic. The Regulations decide which class is the primary class by an order of precedence, and the other danger is a subsidiary class. On a shipping document the subsidiary class is written in parentheses after the primary class. Labels are needed for the primary class and for each subsidiary class on small containers.
Who classifies the goods
Under section 2.2, the consignor must determine the classification before a carrier takes possession of the goods. The consignor must keep proof of classification (a test report, laboratory report or a document explaining how the goods were classified) for five years from the date on the shipping document.
If a carrier notices what looks like a classification error while the goods are in transport, it must not simply carry on: it must tell the consignor and stop transporting the goods until the consignor verifies or corrects the classification (section 2.2(6)). If you handle the goods and something looks wrong, tell your supervisor.
Where to look things up
- Schedule 1 of the Regulations lists dangerous goods by UN number, with shipping name, class and packing group.
- The Emergency Response Guidebook (ERG) uses the UN number to give the first steps for an emergency. Drivers should have one in the cab.
- The Safety Data Sheet (SDS) from the supplier gives product details, though an SDS is a WHMIS document and does not replace the TDG shipping document.
Class colours
Labels and placards use colours and symbols so the class can be recognized at a distance. Orange is used for explosives, red with a flame for flammable gases and flammable liquids, green for non-flammable gases, white with a skull for toxic gases and toxic substances, yellow for oxidizers, blue for water-reactive goods, and black and white for corrosives. Do not rely on the colour alone: always read the class number at the bottom of the diamond.
Key points to remember
- Nine classes. Know the main examples of each.
- UN number, shipping name, class and packing group describe the goods.
- The consignor classifies. A doubt about classification stops the shipment until it is resolved.