• For a large means of containment, a placard, or a placard and UN number, must be displayed on each side and each end.

Dangerous goods safety marks are required to be displayed on a means of containment containing dangerous goods in transport, according to Canada’s Transportation of Dangerous Goods (TDG) Regulations. These marks include labels, placards, orange panels, signs, marine pollutant marks, numbers, letters, abbreviations, and words used to identify dangerous goods and show the nature of the danger they pose.

The marks quickly identify dangerous goods in an emergency situation such as an accident or accidental release of dangerous goods from a means of containment.

Dangerous goods safety marks are also an awareness tool for people involved in transportation, including truck drivers, train crews, loading dock workers, reception personnel at a lab or hospital, and aircraft loading personnel.

Placarding exemption for 500 kg or less gross mass of dangerous goods

A placard is not required on a road vehicle or railway vehicle if the dangerous goods in or on that vehicle have a gross mass less than or equal to 500 kg.

The placarding exemption cannot be used for dangerous goods:

• Requiring an Emergency Response Assistance Plan (ERAP), or
• Requiring the display of subsidiary class placards.

The exemption also cannot be used for certain dangerous goods in the following classes:

• Class 1, Explosives (with some exceptions, see 4.16.1(2)(c);
• Class 2.1, Flammable Gases, if the road vehicle or railway vehicle is to be transported by vessel;
• Class 2.3, Toxic Gases;
• Class 4.3, Water-reactive Substances;
• Class 5.2, Organic Peroxides, Type B, liquid or solid, that require a control or emergency temperature;
• Class 6.1, Toxic Substances, that are subject to special provision 23; or
• Class 7, Radioactive Materials, that require a Category III – Yellow label.

Placards and UN numbers on a large means of containment A placard, or a placard and UN number, must be displayed on each side and each end of a large means of containment.

There are some exceptions, however:

Where must placards be placed?

The primary class placard for each of the dangerous goods contained in a large means of containment, other than a vessel or aircraft, must be displayed on each side and each end of the large means of containment.

If two or more dangerous goods have different UN numbers but are identified by the same placard or placards, the placard or placards are required to be displayed only once on each side and each end of a large means of containment.

The following applies to visibility of placards and UN numbers on large means of containment:

Placard specifications

Each side of a placard must be at least 250 mm in length and, except for the DANGER placard, have a line running 12.5 mm inside the edge.

However, except for dangerous goods included in Class 7, Radioactive Materials, if that size placard cannot be displayed because of the irregular shape or size of the large means of containment, each side of the placard may be reduced in length by the same amount to the point where the placard will fit that large means of containment, but must not be reduced to less than 100 mm.

If the size of a label or placard is reduced, every symbol, letter, and number required on that label or placard must be reduced proportionally.

If a large means of containment contains dangerous goods included in Class 7, Radioactive Materials, and a Class 7 placard is required to be displayed in accordance with Part 4, the means of containment must have displayed on it the Class 7 placard required or the appropriate optional Class 7 placard illustrated in the appendix to Part 4.

Compartmentalized large means of containment

If dangerous goods of different primary classes are transported in different compartments of a compartmentalized large means of containment:

• The primary class placard and UN number for dangerous goods in each compartment must be displayed on each side of that compartment; and
• Each placard and UN number displayed must be displayed on each end of the compartmentalized large means of containment, but each specific placard need only be displayed once on each end.

If all compartments in a compartmentalized large means of containment contain dangerous goods included in the same primary class:

• The primary class placard must be displayed on each side and each end of the compartmentalized large means of containment; and

• The UN number of the dangerous goods in a compartment must be displayed on each side of that compartment and each end of the compartmentalized large means of containment, except that, if all dangerous goods are included in Class 3, Flammable Liquids, only the UN number of the dangerous goods with the lowest flash point is required to be displayed on each side and each end of the compartmentalized large means of containment.

If a compartmentalized large means of containment contains UN3475, ETHANOL AND GASOLINE MIXTURE, the number “3475” must be displayed, in addition to the UN number — without the prefix “UN” — of the dangerous goods with the lowest flash point, on each side and each end of the compartmentalized large means of containment.