On April 19, 1996, EPA proposed revisions for air emission standards for certain hazardous waste combustion units. Today's rule finalizes some elements of that proposal. These elements include a conditional exclusion from RCRA for fuels which are produced from a hazardous waste, but which are comparable to some currently used fossil fuels; a new RCRA permit modification provision which is intended to make it easier for facilities to make changes to their existing RCRA permits when adding air pollution control equipment or making other changes in equipment or operation needed to comply with the upcoming air emission standards; notification requirements for sources which intend to comply with the final rule; and allowances for extensions to the compliance period to promote the installation of cost effective pollution prevention technologies to replace or supplement emission control technologies for meeting the emission standards.