How are Packing Group II and Packing Group III distinguished in practice?

• A. PG II indicates a lower hazard level than PG III.
• B. PG II and PG III are assigned randomly.
• C. PG II indicates a higher hazard level than PG III; the assigned PG depends on the substance as given in the DG List and PI.
• D. They are unrelated to hazard.

Answer: (C)

Packing Groups convey how hazardous a substance is within its hazard class. In practice, a substance assigned to Packing Group II is more hazardous than one in Packing Group III, and the exact group is determined for each substance by its properties and listed in the Dangerous Goods List and the Packing Instructions (PI). This means you don’t guess or pick at random—the DG List and PI specify whether a substance falls into II or III (or another group) based on factors like flammability, toxicity, reactivity, and other hazard characteristics. Because the hazard level differs, the required packaging, labeling, and handling rules are more stringent for Packing Group II than for Packing Group III. The other statements don’t fit: hazard levels aren’t opposite in that way, they aren’t assigned randomly, and they’re not unrelated to hazard.