RSPA is proposing to regulate materials which pose a hazard due to their being offered for transportation or transported at elevated temperatures. Materials would include those in a liquid phase having temperatures at or above 212 °F (100 °C) and materials in a solid phase having temperatures at or above 464 °F (240 °C). RSPA is also proposing to regulate, as flammable liquids, materials in a liquid phase with flash points at or above 100 °F (37.8 °C) which are offered for transportation or transported at or above their flash points. The proposed changes to the Hazardous Materials Regulations (HMR; 49 CFR parts 171-179) would communicate the hazards of these elevated temperature materials by means of marking, shipping papers and placarding, and would prescribe package requirements. The proposed changes are necessary to provide notice to the public and alert emergency response personnel concerning the risk presented by such materials and to specify minimum levels of packaging.