(a) Except as provided in subsection (b) of this section, corrective action management units for RCRA hazardous waste, or for management of both RCRA and non-RCRA hazardous wastes in the same unit are subject to the requirements of section 66264.552. Corrective action management units for hazardous waste that is solely non-RCRA are subject to the requirements of section 66264.552.5.

(b) Corrective action management units for RCRA hazardous wastes that were approved before April 22, 2002, or for which substantially complete applications (or equivalents) were submitted to the Department on or before November 20, 2000, are subject to the requirements in section 66264.551 for grandfathered corrective action management units; corrective action management unit waste, activities, and design will not be subject to the standards in section 66264.552, so long as the waste, activities, and design remain within the general scope of the corrective action management unit as approved.