A small quantity refers to the maximum amount of a specific hazardous material that is eligible for domestic highway and rail transportation. These materials are exempt from most DOT requirements (e.g., packaging, marking, labeling) under 49 CFR § 173.4. Classes 1, 2, and 7, and Division 6.2 materials are not permitted to be sent as small quantity in Postal networks. This provision applies only to domestic highway and rail transportation mail and its use is prohibited to international or APO/FPO/DPO destinations.
Only the following categories of hazardous materials are eligible to be sent under the small-quantity provision in domestic highway or rail transportation:
- Class 3.
- Division 4.1.
- Division 4.2 (Packing Groups II and III).
- Division 4.3 (Packing Groups II and III).
- Division 5.1.
- Division 5.2.
- Division 6.1 (Packing Group III).
- Class 8.
- Class 9.
Materials identified in Appendix A as prohibited under table columns (e), Domestic Mail Air and (f) Domestic Mail Surface, are ineligible for mailing under the small-quantity provision, regardless of their hazard class, division, or packing group.
Each primary receptacle for eligible hazardous materials mailed under the small-quantity provision must be limited to:
- 30 g (1 ounce) or less for solids.
- 30 ml (1 ounce) or less for liquids.
Eligible hazardous materials shipped under the small-quantity provision must adhere to 49 CFR § 173.4 and 338.2 and Packaging Instruction 10A in Appendix C. Each mailpiece must be clearly marked on the address side with the following words: "This package conforms to 49 CFR § 173.4 for domestic highway or rail transport only."
