• Some dangerous goods are categorized into a packing group, which indicates the level of danger (high to low) that the dangerous goods present.

Some dangerous goods are further subdivided into packing groups. The packing group indicates the degree of danger presented by the dangerous goods.

• Packing Group I — high danger
• Packing Group II — medium danger
• Packing Group III — low danger

Packing groups have been developed for dangerous goods in Class 3, Class 4, Division 5.1, Division 6.1 and Class 8 materials. Some hazardous materials are assigned more than one packing group. Because packing groups impact the type of packaging that can be used, it is critical that each material is assigned to the correct one. The criteria for determining packing groups are included in the International Air Transport Association’s (IATA) Dangerous Goods Regulations (DGR) as follows:

• Section 3.3 — Class 3 (flammable liquid) materials
• Section 3.4 — Class 4 (flammable solid) materials
• Section 3.5 — Division 5.1 (oxidizing) materials
• Section 3.6 — Division 6.1 (poisonous) materials
• Section 3.8 — Class 8 (corrosive) materials

Some substances in Class 9, liquids in Division 5.1, and waste in Division 6.2 have been assigned packing groups according to the List of Dangerous Goods. Requirements for a specific packaging performance level can be found in the applicable packing instruction.