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. Native American tribes and environmental groups challenged the decision, arguing the MPCA failed to consider alter...

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. EPA and the Corps sought voluntary remand of the rule without vacatur to give them time to revise or repla...

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. An environmental group argued the SIP's contingency measure was inadequate because it provided only a nomina...

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. An industry group argued the rule was invalid because, unlike the 1988 rule, it authorized testing at other labs and neither account...