Appendix A, “Hazardous Materials Table: Postal Service Mailability Guide,” contains a modified version of the DOT Hazardous Materials Table found in 49 CFR 172.101. Appendix A lists the hazardous materials from 49 CFR and identifies eligibility for mailing in the domestic mail via air and surface transportation. The table can be used to determine the mailability of a hazardous material if the proper shipping name of the material is known. When only the UN number is known, Appendix B, “Numerical Listing of Proper Shipping Names by Identification (ID) Number,” can be used to locate a proper shipping name for cross referencing back to Appendix A.
The mailability information in Appendix A is based on the Department of Transportation requirements in this publication and past Postal Service mailability rulings. The table does not include specific information for international mail because almost all hazardous materials are prohibited in international mail. See Chapter 6 for the specific requirements that apply to international mail.