Final Rule To Amend the Final Water Quality Guidance for the Great Lakes System To Prohibit Mixing Zones for Bioaccumulative Chemicals of Concern

Today EPA is promulgating the final rule to amend the Final Water Quality Guidance for the Great Lakes System (Guidance) to prohibit mixing zones for bioaccumulative chemicals of concern (BCCs) in the Great Lakes System, subject to certain exceptions for existing discharges. For existing discharges, the regulation prohibits mixing zones for BCCs starting 10 years after the publication date of the final BCC mixing zone rule. New discharges of BCCs are subject to the mixing zone prohibition immediately upon commencing discharge. EPA had promulgated a mixing zone provision similar to this regulation on March 23, 1995, as part of the Guidance required by section 118(c)(2) of the Clean Water Act. The provision was vacated by the U.S. Court of Appeals for the District of Columbia Circuit in the case of American Iron & Steel Institute v. EPA, 115 F.3d 979 (D.C. Cir. 1997), and was remanded to the Agency for further consideration. In response to the Court's remand, EPA published a proposal on October 4, 1999, to amend the Guidance to reinstate the provision to prohibit mixing zones for BCCs (64 FR 53632). EPA received many comments from stakeholders throughout the United States on its proposal to prohibit mixing zones for BCCs in the Great Lakes Basin. This final rule reflects EPA's reconsideration of the factual record in response to the Court's remand and public comments received on its proposal.