Whether a district court's equitable allocation of environmental response costs pursuant to Section 113(f)(1) of CERCLA is properly reviewed on appeal for clear error or abuse of discretion

QUESTION PRESENTED Whether a district court’s equitable allocation of environmental response costs pursuant to Section 113@)(1) of the Comprehensive Environmental Response, Compensation, and _ Liability Act (CERCLA), 42 U.S.C. § 9613(f)(1), is properly reviewed on appeal only for clear error, as the Fourth, Fifth, and Ninth Circuits have held, or for abuse of discretion, as the First, Second, Third, Sixth, Seventh, Tenth, and D.C. Circuits have held.