The United States, unlike other countries, is very strict in having all parties follow the provisions of US CFR 49. With no exception, this is imposed upon the shippers that all shipments must conform to all the US State Variations. Airlines are of no exception, and in State Variation USG-13 (a), it is specifically written that: “A package prepared in accordance with these Regulations for transport to, from or within the United States must not be accepted unless the operator also ensures that the shipper has complied with all applicable United States variations included in these Regulations. (see 9.1.2)”.
The airline is also obligated to double check that the shipper has screened USG-04 and that the declaration and the shipment are in order. A shipper’s approval does not translate to an automatic airline approval. The substance in question, UN 1210 CL 3 PG III PI Y344 is not listed in Appendix A of 49 CFR 172.101 spelled out in USG-04 (1) Hazardous substances, therefore, there is no need to indicate the letters “RQ”. USG-04 may appear to be directed to the shipper, but USG-13 does not exempt airlines from abiding with USG-04.
For shipments destined to, or from, or move within the United States, Appendix A to 172.101 - List of Hazardous Substances and Reportable Quantity (Table 1 to Appendix A - Hazardous Substances other than Radionuclides) is a mandatory document that an airline should carry. There is a web address shown below 1 (b) of USG-04. Download the list and make the check routine. It will be a service to your shippers.