An Arizona court overturned the state's issuance of an air permit for a proposed open-pit copper mine. An environmental group argued that the state's approval of the permit was arbitrary and capricious because the mine has the potential to violate NAAQS. They also claimed that the mine's modeling re...

The Ninth Circuit denied an environmental group's petition challenging EPA's approval of a revision to California's SIP. The revision provided alternative "not less stringent" controls to what is required in CAA §185's antibacksliding measures, which require that major stationary sources of polluti...

The Ninth Circuit upheld the dismissal of a trucking association's federal preemption challenge to a California environmental regulation on diesel trucks. The regulation requires heavy-duty diesel trucks, whose emissions contribute significantly to particulate matter and ozone pollution, to be upgra...