When spills of a reportable quantity occur, the responsibility to report it lays with either the driver or _________.

Appendix A to 172.101 Hazardous Substances and Reportable Quantities:
DOT and EPA need to know about any spills of hazardous substances named in the List of Hazardous Substances and Reportable Quantities. Column 2 shows each product's reportable quantity (RQ).
When these materials are being transported in a reportable quantity or greater in one package, the shipper displays the letters RQ on the shipping paper and package. The letters RQ may appear before or after the basic description. You or your employer must report any spill of these materials that occurs in a reportable quantity.