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USPS Packaging Instruction 6F

Forensic Material

Forensic material containing a biological material, such as tissue, body fluid, excreta, or secreta, and sent on behalf of a federal, state, local, or Indian tribal government agency must be packaged under 346.325 when it is not known or suspected to contain a Category A or Category B infectious substance. Forensic material known or suspected to contain a Category A infectious substance is not mailable. Forensic material known or suspected to contain a Category B infectious substance as identified in 346.321 is mailable via air transportation, when triple-packaged in a primary receptacle, secondary container, and a rigid outer shipping container.

Proper Shipping Name


Required Packaging

  • Must be triple-packaged, meeting the packaging requirements in 49 CFR 173.199. Such materials must be properly packaged to withstand shocks, pressure changes, and other conditions related to ordinary handling in transit, and surrounded by absorbent material sufficient to protect the primary receptacle and to absorb the total amount of liquid should the primary receptacle leak or break.
Primary Receptacle (Container)
Cushioning and Absorbent Material
Secondary Container
Outer Shipping Container
International Mail

Substances identified in IMM 135.11b must be sent only by authorized laboratories to their foreign counterparts in those countries that have indicated a willingness to accept them.

Note: Countries distinguish between infectious and noninfectious (nonregulated) biological substances and may prohibit one or the other or both. See “Prohibitions” in the Individual Country Listings.