Memorandum establishes Agency-wide policy to limit lead changes from EPA to potentially responsible parties in the middle of discrete phases of the Superfund process, such as remedial investigation/feasibility study (RI/FS), remedial design (RD), and remedial action (RA), except in situations where the lead change would not cause undue delay. OSWER Directive No. 9800.1-01. Issued 11/14/1991.You may need a PDF reader to view some of the files on this page. See EPA’s About PDF page to learn more.