All hazardous materials warning labels and markings, including markings required by other federal regulatory agencies, must be displayed on the address side of the package, including the proper shipping name and UN identification numbers, unless otherwise specified. If there is insufficient space, DOT labels or markings may be placed on an adjacent side but must never be placed on the bottom of a package or envelope.
DOT hazardous materials warning labels and markings must be:
- Placed on the same surface as the proper shipping name and, when multiple labels are needed, they must be displayed within 6 inches of one another.
- Printed on or affixed to a background of contrasting color or feature a dotted or solid line outer boundary.
- Durable, weather-resistant, clearly visible, and unobscured.
- Oriented as diamonds (diamond-shaped) and measure at least 100 mm (3.9 inches) on each side, unless otherwise specified by postal regulations.
- Printed with solid line inner border at least 5 mm inside and parallel to the edge, with border widths of at least 2 mm.
Markings such as Limited Quantity or UN3373, Biological Substances, may be displayed within the shipping label at a reduced size if special authorization is obtained from the director, Product Classification (refer to 214 for contact information).
Surface mailpieces containing hazardous materials must include one of the following endorsements:
- "Address Service Requested"
- "Forwarding Service Requested"
- "Return Service Requested"
The endorsement "Change Service Requested" is not permitted for mailpieces containing hazardous materials.
The DOT warning labels shown in Exhibit 325.3 are prohibited in Postal Service networks because they contain hazardous materials-or quantities of hazardous materials-that possess too great a risk to be safely handled in the mail. These labels are prohibited in Postal Service networks unless special authorization is granted by the director, Product Classification (refer to 214 for contact information).
Exhibit 325.3
DOT Hazardous Materials Warning Labels: PROHIBITED IN THE MAIL
Packages containing hazardous materials must display the appropriate DOT hazardous materials warning label(s) and marking(s) as outlined in 49 CFR § 172.407 through 172.446.
Only the following hazardous materials warning labels in Exhibit 325.4a, Exhibit 325.4b, and Exhibit 325.5 are permitted in Postal Service networks. Division 5.1, 5.2, Class 8, and Class 9 labels are permitted only when used in conjunction with a Limited Quantity air mark.
Note: The sizes and colors of the labels shown in exhibits are for reference only and do not meet DOT size and color standards unless explicitly noted.
Exhibit 325.4a
DOT Hazardous Materials Warning Labels-PERMITTED ON MAILABLE HAZARDOUS MATERIALS
Exhibit 325.4b
DOT Hazardous Material Warning Labels-PERMITTED FOR MAILABLE LIMITED QUANTITIES ONLY
When required, the DOT Limited Quantity markings for air or surface transportation must meet the following conditions:
- The diamond-shaped marking must have black top and bottom portions with a white or contrasting center background. Refer to Exhibit 325.5.
- Markings must be durable, legible, and unobstructed.
- The minimum dimension of each side of the marking must be 100 mm (3.9 inches), with a border at least 2 mm (0.08 inches) wide, unless the package size requires a reduced size marking of no less than 50 mm (1.97 inches) on each side.
- Incorporating a reduced-size (50 mm or 25 mm with a DOT Special Permit) limited quantity mark within the package shipping label requires prior written approval from the director, Product Classification (refer to 214 for contact information).
- For transportation by aircraft, the air Limited Quantity mark must include a black ‘‘Y‘‘ in the center of the diamond-shaped mark and be clearly visible. Mailpieces intended for air transport must also display the proper shipping name, identification number, and appropriate DOT-associated marking when required for the hazard class shipped in accordance with this publication.
- For surface transportation, a Limited Quantity ground mark (diamond-shaped) is not required to include the proper shipping name and identification number.
Exhibit 325.5
DOT Hazardous Material Warning Labels-PERMITTED FOR LIMITED QUANTITY
Hazardous materials eligible to be shipped under the excepted quantity provision, as described in 49 CFR § 173.4a and 337.2, must be prepared following Packaging Instruction 10B in Appendix C. Each package must display a DOT-approved excepted quantity marking, shown in Exhibit 325.6, under the following conditions:
- The "*" is replaced by the primary hazard class or division of each of the hazardous material in the package.
- The "**" is replaced by the name of the mail owner or mail service provider if it does not appear elsewhere on the package.
- The marking must be at least 100 mm x 100 mm (3.9 inches) and placed durably and unobstructed on the address side of the mailpiece.
Exhibit 325.6
Excepted Quantity Marking
