The Sixth Circuit granted the Commonwealth of Kentucky's and business groups' motions to preliminarily enjoin EPA's and the Army Corps of Engineers' 2023 rule revising the definition of "waters of the United States" under the CWA. A district court had denied the motions, concluding plaintiffs lacked...

The D.C. Circuit vacated EPA's withdrawal of its determination to regulate perchlorate in drinking water. An environmental group argued EPA lacked the authority to withdraw the determination under the SDWA, and that even if it did have such authority, it acted arbitrarily and capriciously in doing s...

In an unpublished order, the Fifth Circuit, 2-1, stayed EPA's disapproval of SIPs submitted by Texas and Louisiana following the Agency's 2015 revision to the ozone NAAQS. The states moved for a stay pending review of EPA's disapproval. The court found a stay was appropriate because the states made ...