Dive Brief:

• The Environmental Protection Agency (EPA) will not seek to weaken regulations for ground-level ozone, a major respiratory irritant, the agency said in a court filing this week. 
• The Obama administration set national standards for ozone at 70 parts per billion (ppb) in 2015, but the rule was challenged by industrial and fossil fuel interests in the D.C. Circuit Court. The court put a hold on the case while the Trump EPA considered changes to the rule, but this week the Justice Department told the court that "at this time, EPA does not intend to revisit the 2015 Rule."
• The decision means the industry lawsuits will move forward at the D.C. Circuit, leaving the Trump DOJ to defend the ozone rules. Separately, environmental groups sued the EPA this week over its decision this year to not list some counties outside Chicago, Milwaukee and St. Louis as being in violation of the ozone rules.  

Dive Insight:

Ground-level ozone, or smog, is formed when fossil fuel emissions meet sunlight and heat. It can cause serious breathing problems, particularly in at-risk populations like the children or the elderly. 

In 2015, the Obama EPA completed its five-year review of the regulations, setting them at 70 ppb, the most lenient standard recommended by the agency's scientific advisory board. 

Industry groups including the U.S. Chamber of Commerce and coal companies sued, arguing the new regulation would impose undue costs on them. The EPA last year asked the D.C. Circuit to hold the case in abeyance while it considered changes to the rules, which it agreed to do. 

But on Aug. 1, the court reopened the case, telling parties to file new motions by Aug. 22. In response, EPA said it had intensively reviewed the ozone standards and decided not to challenge them at this time. 

The agency said it is still considering changes to the ozone standards for its next review, slated to be complete by 2020. That will involve input from the agency's Clean Air Scientific Advisory Committee, which will soon have new members after the EPA put out a request for nominations late last month. 

The ozone case brought by industry groups is not the only one EPA faces. The Environmental Law and Policy Center and the Respiratory Heath Association also sued the agency over its decision this spring to not list a group of counties around Midwestern metropolitan areas as in non-attainment of the ozone standards. 

A dozen counties were slated for nonattainment on an initial EPA finding, but had their designations changed to attainment or partial attainment in the final rule, raising concerns of political influence over the rulemaking process.