EPA is finalizing significant new use rules (SNURs) under the Toxic Substances Control Act (TSCA) for the chemical substances rutile, tin zinc, calcium-doped (CAS No. 389623-01-2) and rutile, tin zinc, sodium-doped (CAS No. 389623-07-8) which were the subject of premanufacture notices (PMNs P-06-36 and P-06-37) and a TSCA consent order issued by EPA. This action requires persons who intend to manufacture, import, or process either of the chemical substances for an activity that is designated as a significant new use by this final rule to notify EPA at least 90 days before commencing that activity. EPA believes that this action is necessary because new uses of the chemical substances may be hazardous to human health. The required notification would provide EPA with the opportunity to evaluate the intended use and, if necessary, to prohibit or limit the activity before it occurs.