A Minnesota appellate court affirmed the Minnesota Pollution Control Agency's (MPCA's) decision to issue a CWA §401 certification for the Line 3 crude oil pipeline replacement project.

The D.C. Circuit denied a challenge to EPA's 2015 rule updating the standards under which the Agency audits wood-burning heaters' compliance with CAA emissions limits.

The Second Circuit denied two petitions to review EPA's final rule restricting access by customers to methylene chloride.

The Ninth Circuit granted in part and denied in part a petition to review EPA's final rule approving California's SIP for meeting the air quality standard for ozone in the San Joaquin Valley.

A district court vacated and remanded EPA's and the Army Corps of Engineers' Navigable Waters Protection Rule, which established a new definition of "waters of the United States" under the CWA.