Petitioners first alleged that EPA acted contrary to the CAA and abused its discretion in failing to require Arizona to perform and include updated analyses of BACM and MSM in the Five Percent Plan.
The Ninth Circuit first held that, given the lack of any contrary statutory command in the CAA and given EPA's reasonable explanation for its approach, EPA did not abuse its discretion or act contrary to law by declining to require updated demonstrations of BACM or MSM in the Five Percent Plan.
(29) Contrary to Petitioners' argument, the court found that nothing required EPA to review and approve windblown dust control measures as BACM before determining that dust is reasonably well controlled in a given area.
Petitioners argued this requirement did not qualify as the BACM required for serious PM-10 non-attainment areas, reasoning that the state had determined all thirty-four BMPs to be feasible.
Reviewing the plan, EPA did not address Arizona's concerns regarding the cost of CARB diesel, but approved the plan anyway as a BACM on the grounds that Arizona's plan was among the most stringent and extensive programs in the nation.