WELD COUNTY, Colo.— In response to legal objections filed by the Center for Biological Diversity, the Environmental Protection Agency has ruled that Colorado failed to ensure flaring at a large gas processing plant north of Denver effectively reduces smog-forming emissions.

Tuesday’s ruling comes on the heels of a similar EPA decision in January, rejecting state-issued air permits for the oil and gas industry in Colorado. The latest order continues to call into question the Colorado Department of Public Health and Environment’s oversight of the industry and whether it is effectively controlling air pollution by burning it with flares in the Denver Metro-North Front Range region.

“Colorado still allows tens of thousands of oil and gas facilities to guestimate how much toxic air pollution they’re putting into the air we breathe,” said Ryan Maher, a staff attorney at the Center for Biological Diversity and co-author of the petition. “Blocking this permit is a positive step forward toward the kind of transparency and accountability the oil and gas industry has fought hard to avoid. Colorado’s weak permitting has routinely enabled them to do so.”

The order comes in response to a petition filed in September by the Center challenging a new air pollution permit allowing DCP Operating Company to operate a gas processing plant near the town of Platteville.

Tanks, engines, gas venting and processing, and leaking pipes at DCP’s processing plant emit large amounts of toxic gases, including nitrogen oxides, volatile organic compounds, particulate matter, benzene and formaldehyde. Flares are used to burn off some of this toxic pollution.

Nitrogen oxides and volatile organic compounds form ground-level ozone, the key ingredient of smog. The DCP processing plant is located in an area of Colorado that includes Denver and other Front Range communities, and is home to more than 4 million people. The region has suffered from ozone pollution in excess of the EPA’s health standard for more than 15 years.

The petition targeted the Colorado Department of Public Health and Environment’s failure to ensure adequate testing and monitoring of flares. While the department widely assumes the oil and gas industry reduces smog-forming pollution by 95% or more using flares, reports indicate flares often fail meet this level of control.

In its ruling, the EPA found, “it is unclear…how the monitoring requirements assure that the [flares] continually achieve the specific 95 percent control efficiency in the Permit.”

The petition also targeted the failure of the Department of Public Health and Environment to ensure protection of health-based ambient air quality standards and to ensure reporting of air pollution monitoring data. Although the EPA denied these issues, the agency still objected to the issuance of the permit.

Smog pollution linked to oil and gas extraction is linked to human health problems like asthma attacks, cardiovascular issues and premature death. Those most at risk include older adults, children and people who work outdoors. The harm smog does to plants can damage entire ecosystems and reduce biodiversity.

Under the Clean Air Act, Colorado officials have 90 days to respond to the EPA’s ruling and revise the flawed air pollution permit.

More information about the Center’s fight against air pollution is available at Protecting Air Quality Under the Clean Air Act.