Opinion ID: 4020089
Heading Depth: 3
Heading Rank: 1

Heading: EPA’s Selection of GACT Standards

Text: for Non-Hg Metals The Environmental Petitioners argue that the EPA failed to support its decision-making when it established MACT standards for Hg and POM emissions from some coal-fired boilers but declined to regulate non-Hg emissions under the MACT standard from the same boilers. We agree. Although the EPA thoroughly explained why it chose to impose one GACT standard instead of another, nothing in the record explains why the EPA decided to impose GACT standards instead of MACT standards in the first place. Despite the Agency’s broad discretion, we cannot sustain its action in the absence of some explanation for why GACT standards are more appropriate than MACT standards for these sources and types of pollutants. See Transactive Corp., 91 F.3d at 236. For this reason, we remand (but do not vacate) the EPA’s choice of GACT standards for non-Hg emissions from coal127 fired boilers. See Sierra Club, 167 F.3d at 664; Nat’l Lime Ass’n, 233 F.3d at 634-35.