EPA dubs Colorado a “serious” violator of federal air quality standards

The state has until 2021 to come into compliance with air quality standards or face another downgrade

Photo of smoggy downtown Denver skyline via the Colorado Department of Public Health and Environment, Air Pollution Control Division, Technical Services Program, Wednesday, March 6, 2019.
Photo of smoggy downtown Denver skyline via the Colorado Department of Public Health and Environment, Air Pollution Control Division, Technical Services Program, Wednesday, March 6, 2019. The EPA downgraded the region to a "serious" violator of the Clean Air Act on Dec. 16, 2019.

The Environmental Protection Agency on Monday formally designated Colorado a “serious” violator of federal air quality standards designed to protect public health, kicking off a process that likely will lead to a crackdown on polluters in the northern Front Range. 

The nine-county region, stretching from Douglas County to the southern half of Weld County, has failed federal health standards for ground-level ozone for more than a decade. Ground-level ozone, also known as smog, is linked to respiratory ailments such as asthma and heart attacks. 

Smog in Colorado’s Front Range is generally formed when volatile organic compound emissions from oil and gas operations and nitrogen oxide emissions from automobile tailpipes mix with sunlight. 

The downgrade, which moves Colorado from a “moderate” violator to a “serious” violator of federal air quality standards, means polluters that emit 50 tons of VOCs per year will have to comply with more stringent air pollution permit requirements. This is a reduction from the current 100 tons per year threshold, which means it will apply to more polluters. This could include requiring some companies to offset their emissions. 

The state has until July 20, 2021 to come into compliance with the 2008 standard for ozone of 75 parts per billion, which is less rigorous than the current 2015 standard of 70 parts per billion. This summer, monitors across the state measured ozone concentrations of 79 parts per billion. 

“The department is on it,” said Jill Hunsaker Ryan, the executive director of the Colorado Department of Public Health and Environment, in a statement. 

The downgrade has long been controversial in Colorado. Industry has raised concerns about the cost of complying with additional regulations to curb emissions. Health and environmental advocates have condemned state and federal health officials for not acting sooner.

“The air in beautiful Colorado has been unsafe to breathe for far too long,” said Robert Ukeiley, a senior attorney with the Center for Biological Diversity’s environmental health program, in a statement. “This important decision means the region’s oil and fracked gas polluters are one step closer to finally being required to clean up their dangerous emissions.”

Defend Colorado, a group representing oil and gas companies, long has fought the downgrade, arguing that much of Colorado’s emissions waft in from other states and countries. The Colorado Independent sought comment from the Colorado Oil and Gas Association and Defend Colorado. The groups’ comments will be added, if provided. 

Former Gov. John Hickenlooper, now a candidate for U.S. Senate, in 2018 requested that the EPA give the state another year to come into compliance with the ozone standard, in part because of the effect the designation would have on industries and the wildfires in 2017 that helped knock the state out of compliance. 

In March, Gov. Jared Polis withdrew the request, saying “There’s too much smog in our air, and instead of hiding behind bureaucracy and paperwork that delay action, we are moving forward to make our air cleaner now.” 

In April, the governor signed into law Senate Bill 181, which requires state air quality regulators to reduce emissions from oil and gas operations. The Air Quality Control Commission this week likely will adopt new rules to require oil and gas companies to check for leaks and repair them more frequently. Also, in August, the commission adopted a requirement that by 2023, at least 5% of automobiles sold in Colorado be zero-emission vehicles.

The World Health Organization recommends an ozone concentration limit of about 50 parts per billion. The American Lung Association gave several counties in the Front Range region an “F” grade for poor air quality. 


  1. Good luck with getting cleaner air anytime soon. The Governor’s push for 5% ZEV sales by 2023 will utterly fail to improve air quality since is does nothing to address all the emissions of the much cheaper ICE vehicles rolling around the metro area. Something like 75% of vehicles are now SUVs or pickup trucks, many of them burning diesel rather incompletely judging by the stink they emit. As long as gas is dirt cheap and there is no disincentive to buying bigger vehicles Denver metro will continue to enjoy Los Angeles quality air.


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