The Environmental Protection Agency (EPA) is proposing Effluent Limitations Guidelines and New Source Performance Standards for discharges associated with the use of synthetic-based drilling fluids (SBFs) and other non-aqueous drilling fluids in portions of the Offshore Subcategory and Cook Inlet portion of the Coastal Subcategory of the Oil and Gas Extraction Point Source Category under the authority of Sections 301, 304 (b), (c), and (e), 306, 307, 308, 402, and 501 of the Clean Water Act (CWA) (the Federal Water Pollution Control Act); 33 U.S.C. 1311, 1314 (b), (c), and (e), 1316, 1317, 1318, 11342, and 1361. The proposed regulation and supporting technical information is presented in the proceeding chapters of this document.