The D.C. Circuit denied petitions for review of EPA decisions regarding nonattainment designations under the 2008 ozone NAAQS. Several states, counties, industrial entities, and environmental…

The D.C. Circuit held that EPA's regulations implementing the 2008 NAAQS for ozone exceed the Agency’s authority under the CAA. In 2008, EPA revised and strengthened the standards for ozone…

The D.C. Circuit upheld EPA’s decision to defer adopting new secondary NAAQS for oxides of sulfur (SOx) and nitrogen (NOx) pending further scientific study. Citing doubts about the accuracy of its…

The D.C. Circuit denied industry groups' petition for review challenging EPA's 2013 primary NAAQS for fine particulate matter. In the final rule, EPA lowered the level of the particulate…

A district court denied industry groups' motion to intervene in a CAA citizen suit concerning EPA's alleged failure to review the ozone NAAQS in a timely manner. The underlying lawsuit…

The D.C. Circuit remanded for reconsideration EPA's revisions to the secondary, welfare-based NAAQS for ozone, but denied petitions challenging revisions to the primary, health-based ozone…

The D.C. Circuit dismissed petitions challenging EPA's primary NAAQS for sulfur dioxide (SO2). The petitioners—several states, state regulatory agencies, corporations, and industrial…

The D.C. Circuit denied petitions challenging EPA's one-hour primary NAAQS for nitrogen dioxide (NOx). The new one-hour primary NAAQS requires that “the three-year average of the annual 98th…

A district court held that EPA does not have a mandatory duty to review and, if necessary, promulgate new PSD rules for ozone simply because the NAAQS for ozone has been revised. The history of…

The court affirms a February 2001, district court order requiring the U.S. Environmental Protection Agency (EPA) to make an air quality attainment status determination for the St. Louis, Missouri…