Responding to a court order, the U.S. Environmental Protection Agency on Wednesday officially designated Bexar County as noncompliant with a new and stricter federal standard for ozone levels passed under the Obama administration.

The announcement prompted praise from environmental groups, which have argued that the health of San Antonio-area residents is on the line, and outrage from state and local officials, who say the designation — which will come with far more regulatory scrutiny — will harm the economy and ignores recent efforts at the local level to reduce ozone levels.

“We look forward to supporting Texas as they work to improve air quality and foster economic opportunity,” Acting EPA Administrator Andrew Wheeler said in a statement. “Information provided by the state indicates that the San Antonio area is on the path toward attainment, and we expect Bexar County will be able to demonstrate that it meets the standard well in advance of the attainment date in 2021.”

Wheeler added that a state analysis of how “international emissions” from Mexico are adversely impacting air quality in the region and the forthcoming closure of a coal-fired power plant run by San Antonio’s city-owned utility “will help ensure that implementation of this standard has minimal burdens on economic development.”

San Antonio had been the largest city in the United States that was still in compliance with federal ozone standards. It would have passed muster under the older standard of 75 parts per billion, but the Obama administration lowered the maximum to 70 parts per billion — a standard many scientists and public health experts believe is still too lenient.

Ground level ozone, a key component of smog, forms when emissions from cars, coal plants and the like mix with other airborne compounds in the presence of sunlight. High ozone levels exacerbate conditions such as asthma, lung disease and heart disease, and may even lead to premature death.

Republican-dominated Texas led the charge against the more stringent ozone standard, which then-EPA Administrator Scott Pruitt — who resigned earlier this month — chose to delay until this year. (Pruitt had sued over the rule as Oklahoma's attorney general.)

Democratic-led states and public health and environmental groups, including the Environmental Defense Fund, successfully sued the EPA after Pruitt missed an October 2017 designation deadline in hopes of speeding up the process.

“This is a positive first step for reducing air pollution in Bexar County,” said Elena Craft, a senior health scientist at the EDF. “It could prevent dozens of preventable deaths and thousands of hospitalizations each year.”

But she also said that “San Antonio families need EPA to do more to limit air pollution from oil and gas development in neighboring counties, which is likely contributing to the unhealthy smog levels in Bexar County.”

Various studies have linked San Antonio's ozone levels to dozens of deaths annually. And state data shows that the number of children hospitalized for asthma in the nation's seventh-largest city is significantly higher than the statewide average.

In a scathing statement, the Texas Commission on Environmental Quality said it disagreed with the EPA's decision "as this action creates an unnecessary burden on the residents, industry, and governing bodies of Bexar County without any associated benefit from an air quality perspective."

The statement noted that Gov. Greg Abbott had recommended designating Bexar County as compliant with the older standard.

"The EPA’s blatant disregard for cooperative federalism in not supporting Governor Abbott’s recommendation shows the disconnect between states and Washington D.C.," the statement said.

Local officials have also been opposed to a designation, but not because they — unlike the TCEQ and the state’s Republican leadership — don’t believe in the overwhelming scientific consensus that smog can significantly impact human health. Rather, they have argued that the additional regulations will adversely impact the local economy.

A February 2017 report by the Alamo Area Council of Governments found that the stricter federal oversight that would come with a nonattainment designation could have a total economic impact of as much as $36.2 billion.

In response to an impending designation, the city had enacted an anti-idling ordinance for heavy vehicles as well as other measures and vowed to continue its efforts even as Pruitt announced he would delay enactment of the new standard.

San Antonio Mayor Ron Nirenberg said in a statement that “The EPA air quality designation is no surprise. The science showed clearly for several years that our region has been teetering on the edge of non-attainment because of stricter federal standards. We had evaded a non-attainment designation, in large part due to cooperative regional efforts."

Still, he said, “As this designation loomed, we made great progress in achieving better air quality, and we will continue to strive for cleaner air. The region’s ozone levels are down significantly from where they were a decade ago."

Bexar County Judge Nelson W. Wolff was more direct.

"The EPA's nonattainment designation will cost Bexar County residents hundreds of millions of dollars," he said in a statement. "The EPA ignored a long track record of improving air quality in Bexar County. We are extremely disappointed and will examine every possible remedy."

Disclosure: The Environmental Defense Fund has been a financial supporter of The Texas Tribune, a nonprofit, nonpartisan news organization that is funded in part by donations from members, foundations and corporate sponsors. Financial supporters play no role in the Tribune's journalism. Find a complete list of them here.