The placarding requirements are found in Part 172.500 of the Hazardous Materials Regulations. The general rule is going to be: If in bulk, you always need a placard. If non-bulk, then it depends on if the hazard class is in Table 1 or 2, and the amount that is being shipped.

Where should placards be placed?

They must be on all 4 sides – placards need to be displayed on all four sides of a transport vehicle or bulk packaging. They must always be displayed in the square-on-point configuration and be located at least 3 inches away from any other marking that may reduce its effectiveness.

Where do we use the DOT placard system?

DOT Hazmat Placards The United States Department of Transportation (DOT) requires that vehicles transporting dangerous goods must display the appropriate DOT hazard class placard and that placards must be displayed on all sides of the transporting vehicle.