Last week, the 3rd Circuit Court of Appeals vacated EPA’s approval of Pennsylvania’s SIP for attaining the 2008 NAAQS for NOx. Specifically, the Court found that EPA’s approval was arbitrary and capricious with respect to three separate, but related, provisions of the SIP.
The flawed provisions were:
Earlier this week, the 9th Circuit Court of Appeals rejected challenges to the Federal Implementation Plan EPA promulgated after finding that Arizona’s regional haze State Implementation Plan was inadequate. 
I think that the result is both correct and unsurprising.
However, one part of the opinion – a recitation of black-letter law – caught my eye. In discussing the standard of review, the court noted that the arbitrary and capricious standard is “highly deferential.” No surprise there. … More
Earlier this week, the 9th Circuit denied Arizona’s challenge to EPA’s decision to reject Arizona’s SIP addressing regional haze 
requirements and instead promulgate its own federal implementation plan. The decision has a number of interesting elements and is well worth a read, but it’s most notable for its treatment of the deference issue.
We all know that courts defer to reasonable agency decision-making. … More