Class | Name of Hazard Class (and Division when applicable) | Domestic Mail | International Mail and APO/FPO/DPO Mail |
Air Transportation | Surface Transportation |
1 | Explosives |
| Division 1.1: Mass Explosive Hazard | Prohibited | Prohibited | Prohibited |
Division 1.2: Projection Hazard | Prohibited | Prohibited | Prohibited |
Division 1.3: Fire and/or Minor Blast/Minor Projection Hazard | Prohibited | Prohibited | Prohibited |
Division 1.4: Minor Explosion Hazard | Prohibited | Only with prior HQ approval per 341.2c | Prohibited |
Division 1.5: Very Insensitive With Mass Explosion Hazard | Prohibited | Prohibited | Prohibited |
Division 1.6: Extremely Insensitive; No Mass Explosion Hazard | Prohibited | Prohibited | Prohibited |
2 | Gases |
| Division 2.1: Flammable Gases | Prohibited | Only Limited Quantity Surface material per 342 | Prohibited |
Division 2.2: Nonflammable Gases | ID8000 material per 342 | Only Limited Quantity Surface material per 342 | Prohibited |
Division 2.3: Toxic Gases | Prohibited | Prohibited | Prohibited |
3 | Flammable and Combustible Liquids |
| All Flammable Liquids | Prohibited | Only Limited Quantity Surface material per 343 | Prohibited |
All Combustible Liquids | ID8000 material per 343 | Only Limited Quantity Surface material per 343 | Prohibited |
4 | Flammable Solids |
| Division 4.1: Flammable Solids | Prohibited | Only Limited Quantity Surface material per 344 | Prohibited |
Division 4.2: Spontaneously Combustible | Prohibited | Only Limited Quantity Surface material per 344 | Prohibited |
Division 4.3: Dangerous When Wet | Prohibited | Only Limited Quantity Surface material per 344 | Prohibited |
5 | Oxidizing Substances, Organic Peroxides |
| Division 5.1: Oxidizing Substances | Only Limited Quantity Air material per 345 | Only Limited Quantity Surface material per 345 | Prohibited |
Division 5.2: Organic Peroxides | Only Limited Quantity Air material material per 345 | Only Limited Quantity Surface material per 345 | Prohibited |
6 | Toxic Substances and Infectious Substances |
| Division 6.1: Toxic Substances | ID8000 material per 346; other poisons as permitted in 346.231 | Only Limited Quantity Surface material per 346; other poisons as permitted in 346.231 | Prohibited |
| Division 6.2: Infectious Substances | Only as permitted in 346 | Only as permitted in 346 | Only First-Class Package International Service with Registered Mail service per 622 |
7 | Radioactive Material | Prohibited | Only per 347 | Only First-Class Package International Service with Registered Mail service per 622 |
8 | Corrosives (Liquids And Solids) | Only Limited Quantity Air material per 348 | Only Limited Quantity Surface material per 348 | Prohibited |
9 | Miscellaneous Hazardous Materials ID8000 materials, UN3077, UN3082, UN3334, or UN3335 materials | ID8000 material and other materials as permitted in 349 | Only Limited Quantity Surface material and other materials as permitted in 349 | Prohibited, except for magnetized materials per 349 and 622.4 and lithium batteries per 622.5 |