Many common, everyday items are classified as hazardous materials. Determining the mailability of hazardous materials requires the consideration of a number of factors and can be very challenging. Please check with your local U.S. Postal Service® officials before attempting to mail any items that could be considered hazardous. Improper mailing of hazardous materials may subject you to civil and/or criminal liability.
Ensuring that no hazardous material is mailed unless it is permitted under Postal Service™ mailing standards in Mailing Standards of the United States Postal Service, Domestic Mail Manual (DMM®) 601.10 and the Mailing Standards of the United States Postal Service, International Mail Manual (IMM®).