Memorandum presents results of evalauation of the selection process EPA uses in issuing unilateral administrative orders (UAOs) to potentially responsible parties (PRPs) for remedial design/remedial action (RD/RA) under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA, commonly referred to as Superfund). OSWER Directive No. 9833.2c. Issued 6/20/1991.You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.