The Environmental Protection Agency isn't saying which areas of the country are not complying with the Obama administration's 2015 national air quality standards for smog-forming ozone just yet.

“The ozone designation process is complex and requires ongoing and extensive conversations with state and local agencies," said EPA administrator Scott Pruitt. "As we move forward, the agency will be able to prioritize, be more responsive to local needs, and move forward on a case-by-case basis.”

The EPA is required under the Clean Air Act to designate non-attainment areas of the country under the ozone rule by Oct. 1. These are areas of the country that cannot meet the regulations. Once the non-attainment areas are designated, the clock begins to tick down for states to develop and submit plans for meeting that standards.

Manufacturing and business groups had argued the original version of the updated ozone regulations would place much of the country in non-attainment, stifling heavy industry, and energy development. Critics say even pristine national parks would not be able to meet the standard.

EPA's final regulation was less strict, but industry and states continue to argue they have yet to comply with the previous 2008 ozone standards. A GOP-backed bill on Capitol Hill looks to block the 2015 rules from going into effect until states have met the previous rules.

The Trump EPA argues it is following the law in implementing the ozone standard, though it missed the Oct. 1 deadline. It is doing so by designating those areas that are in compliance with the ozone rules before moving on to the non-attainment areas, according to the agency.

"Consistent with states’ and tribes’ recommendations, EPA finds that most areas of the country — 2,646 of the more than 3,100 counties in the United States -- meet the standards for ground-level ozone," the agency said Monday. "These areas do not have any increased compliance burdens."

EPA continues to examine how other areas are "meeting attainment thresholds," saying peer-reviewed science indicates "international emissions and background ozone" can result in higher ozone pollution levels, suggesting it will seek to account for those distortions before making final assessments.

"The agency intends to address these areas in a separate future action."