The Environmental Protection Agency (EPA or the Agency) is promulgating mandatory criteria for the environmentally protective use of chat in transportation projects carried out, in whole or in part, with Federal funds. Specifically, chat used in such transportation projects will be safe and environmentally protective if it is used in asphalt concrete, in slurry seals, microsurfacing, or in epoxy seals for anti-skid on bridge decking. Chat used in such transportation projects will also meet EPA's criteria if it is used in Portland cement concrete, flowable fill, stabilized base, chip seals, or as road base providing, on a case-by-case basis, either: Synthetic Precipitation Leaching Procedure (SPLP, EPA SW-846 Method 1312) tests are conducted on the proposed material and the leachate testing results show that concentrations in the leachate do not exceed the Drinking Water Standards for lead and cadmium and the fresh water chronic National Recommended Water Quality Criterion for zinc of 120 ug/l; or EPA (or a State environmental Agency, if it chooses to do so) has determined, based on a site-specific risk assessment and after notice and opportunity for public comment, that the releases from the chat mixture in its proposed use will not cause an exceedance of the National Primary Drinking Water Standards for lead and cadmium in potential drinking water sources and the fresh water chronic National Recommended Water Quality Criterion for zinc of 120 ug/l in surface water. Furthermore, this rule also establishes a criterion that other uses of chat will be safe and environmentally protective and are acceptable if they are part of, and otherwise authorized by, a State or Federal response action undertaken in accordance with Federal or State environmental laws, with consideration of a site-specific risk assessment. This rule does not require that chat be sized (dry or wet) prior to its use, as long as this rule's criteria are complied with. EPA is also establishing recommende