Applicability of EPCRA §§302 and 304 to EHSs produced on-site

If an extremely hazardous substance is not stored on-site but is produced in a process such as incineration, is it exempt from both threshold planning quantity calculation and release reporting if the release is covered by a Clean Air Act permit?

If the hazardous substance is produced on-site in a process such as incineration, it is considered present at the facility and subject to Section 302 reporting requirements provided, of course, that the amount on site exceeds the threshold planning quantity at any one time.  However, if the release is federally permitted under Section 101(10) of CERCLA, which includes permitted emissions into the air under the Clean Air Act, then the release need not be reported under Section 304.