Answer: Placards probably wouldn’t be required at all. If the used antifreeze is considered hazardous it would be a Class 9 material in most cases. Section 172.504(f)(9) exempts placarding requirements for Class 9 materials when transported domestically.

Used antifreeze can be considered a hazardous waste and, even if it is not a hazardous waste, some states might require a hazardous waste manifest to be used when transporting used antifreeze.

Once a hazardous waste manifest is required, that automatically makes it regulated by the Hazardous Materials Regulations. At this point it depends on how the shipper classifies the used antifreeze. From the choices in the hazmat table, most shippers would use: Environmentally Hazardous Substance Liquid n.o.s. or Hazardous Waste Liquid n.o.s., which are both Class 9 (shown in column 3 of the HMT) and, as mentioned above, not required to be placarded domestically.

If the shipper classifies the used antifreeze as something else, such as a Class 3, then the package type (bulk or non-bulk) and weight become factors:

• If the chosen hazard class falls into Table 1, placarding is required when transporting any amount.
• If the chosen hazard class falls into Table 2, placarding is required for bulk packages, or non-bulk packages when the total weight meets or exceeds 1,001 pounds.