Postal Explorer > Mailing Standards of the United States Postal Service, International Mail Manual > 4 Treatment of Outbound Mail > 440 Mailpiece Refused by an Air Carrier
When an air carrier refuses a mailpiece containing nonmailable, hazardous, or perishable material, Postal Service employees will follow the standards in section 727.2 or 742.3 of Publication 52, Hazardous, Restricted, and Perishable Mail. In such an instance, the customer may be eligible for refund of postage consistent with IMM 941, IMM 942, and DMM 604.9.