Hazard Class 5 consists of two divisions:
- Division 5.1, Oxidizing Substances. A material that may, generally by yielding oxygen, cause or enhance the combustion of other materials.
- Division 5.2, Organic Peroxides. Any organic compound that contains oxygen in the bivalent structure and that may be considered a derivative of hydrogen peroxide, where one or more of the hydrogen atoms have been replaced by organic radicals.
Examples of Class 5 materials (not all of which are mailable) include ferric nitrate, hydrogen peroxide, lead perchlorate, lithium nitrate, organic peroxide solids or liquids, and some swimming–pool chemicals.
The following conditions apply:
- International Mail. All oxidizing substances and organic peroxides are prohibited.
- Domestic Mail via Air or Surface Transportation. An oxidizing substance or an organic peroxide that can qualify as an ORM–D material is permitted.
345.21 Nonmailable Class 5 Materials
When nonmailable Class 5 materials are found in the mailstream, the procedures in POM 139.117 must be followed if the materials present an immediate threat to persons or property. The procedures in POM 139.118 are followed when there is no immediate threat to persons or property.
The following Class 5 materials are nonmailable:
- Division 5.1, Oxidizing Substances.
- Chlorine dioxide hydrate, frozen.
- Hydrogen peroxide solution (more than 20 percent).
- Perchloric acid.
- Potassium peroxide.
- Sodium chlorite.
- Tetranitromethane.
- Zinc ammonium nitrate.
- Division 5.2, Organic Peroxides. Organic peroxides are nonmailable unless they can qualify as ORM–D materials.
345.22 Mailable Class 5 Materials
The following Class 5 materials are mailable:
- ORM–D Material. A Division 5.1 or 5.2 material that can be reclassified as an ORM–D material is mailable within the requirements in 345.2b.
- Hydrogen Peroxide. There are no restrictions on Division 5.1 hydrogen peroxide solutions up to 8 percent. Solutions of hydrogen peroxide exceeding 8 percent and up to 20 percent are permitted if they can qualify as an ORM–D material.
All mailable Division 5.1 and 5.2 materials must be prepared following the conditions for Packaging Instruction 5A in Appendix C.
For air transportation, a parcel containing a mailable Division 5.1 or 5.2 material must be plainly and durably marked on the address side with “ORM–D AIR” immediately following or below the proper shipping name (e.g., Consumer Commodity). A properly completed shipper’s declaration for dangerous goods prepared in triplicate must be affixed to the outside of the mailpiece.
For surface transportation, a parcel containing a mailable Division 5.1 or 5.2 material must be plainly and durably marked on the address side with “Surface Only” or “Surface Mail Only” and “ORM–D” immediately following or below the proper shipping name (e.g., Consumer Commodity). A shipper’s declaration for dangerous goods is not required for a mailable Division 5.1 or 5.2 material sent via surface transportation.
