Two volume guidance on potentially responsible parties (PRPs) conducting remedial investigation feasibility studies (RI/RS) under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA, commonly referred to as Superfund). OSWER Directive No. 9835.1(c). Publication No. EPA 540-G-91-010a. Issued 7/1/1991.

Volume 1 addresses oversight of RI/FS conducted by potentially responsible parties (PRPs) at Superfund enforcement-lead sites.
Volume 2 describes oversight of sampling and analysis activity and of well-drilling and installation activity conducted by PRPs during a remedial investigation.

• Guidance on Oversight of Potentially Responsible Party Remedial Inveestigations and Feasibility Studies, Final, Volume 1 (PDF)(121 pp, 4 MB)
• Guidance on Oversight of Potentially Responsible Party Remedial Inveestigations and Feasibility Studies, Final, Volume 2 (PDF)(193 pp, 5 MB)