Editor's note: This story has been updated with a response from the Texas Commission on Environmental Quality.  

Within a decade, Texas will lead the nation in sicknesses linked to ozone-forming pollutants from oil and gas activity, according to a new analysis from a pair of environmental groups released Wednesday. 

In the 2025 “ozone season,” those pollutants will trigger more than 144,000 childhood asthma attacks, nearly 106,000 lost school days and 313 total asthma-related emergency room visits in Texas, the research said. (The study defined ozone season as May 1 through September 30.)

The conclusions from Clean Air Task Force and Earthworks — national environmental groups based in Massachusetts and Washington, D.C. respectively —added fuel to a debate about how much oil and gas activity contribute to smog troubles that plague some Texas cities.

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“This is really the first time we know of that anyone has looked at the national health impacts of ozone-smog produced by pollution from the oil and gas industry,” said Lesley Fleischman, a Clean Air Task Force analyst who led the study. “So we think it’s important to separate out the health impacts we’re seeing directly from this industry."

The Dallas-Fort Worth region — home of the gas-rich Barnett Shale — would see roughly a third of the Texas cases of asthma, school days lost and emergency room visits linked to oil and gas activity, the study said.  

Petroleum industry officials sought to discredit the study, which is not peer-reviewed. Steve Everley, a spokesman for industry-funded group North Texans for Natural Gas, pointed to separate research and opinions from Texas environmental regulators downplaying health affects from oil and gas drilling.

“The claim that oil and gas development is a major contributor to Texas ozone levels has been repeatedly disproven with state data, and these groups know it,” Everley said.

Ozone forms when emissions from cars, industrial plants and other activities mix with other airborne compounds in sunlight. It can worsen asthma, lung disease and heart conditions. This study focused specifically on what the oil and gas sector contributes: volatile organic compounds and methane from production, natural gas processing, leaking pipelines and storage facilities, for instance.

To calculate the industry’s ozone contribution, researchers largely relied on U.S. Environmental Protection Agency data — the agency’s emissions inventory. They also used the same mapping tools and methodology the federal agency uses to calculate the health impacts of new regulations.

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The study suggests the pollution can affect folks who live far away from Texas oilfields.

“Emissions are released into the atmosphere, and they can stay in the atmosphere for a very long time, and they can travel great distances,” Fleischman said.

Debate has long simmered in Texas about how much oil and gas activity contributes to ozone — a difficult, costly problem to address. Those questions are most pressing in the Dallas-Fort Worth region, and around San Antonio, metropolitan hub of the Eagle Ford Shale.

A few years ago, research by the Alamo Area Council of Governments suggested shale drilling played a sizable role in the San Antonio’s ozone problems. Amid a recent slowdown in the oil patch, however, the group’s experts believe the industry’s role has shrunk. 

The Texas Commission on Environmental Quality — which has fought federal regulations to lower ozone limits, calling them unnecessary and burdensome to industry — has downplayed drilling’s contribution to ozone, saying that traffic and tailpipe emissions are the biggest culprits.

“Emissions from oil and gas operations are sporadic; They’re localized in nature rather than widespread,” commission Chairman Bryan Shaw told a San Antonio gathering last November, citing research he described as "preliminary." 

His agency said authors of the Clean Air Task Force report "provided insufficient detail" — such as proper labels on figures and tables — for its scientists to review the findings. 

"In addition, the report fails to recognize the extensive steps taken by the TCEQ to evaluate, account for, and control emissions associated with oil and gas production," spokeswoman Andrea Morrow said in an emailed statement Wednesday afternoon.

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In the Dallas-Fort Worth region, the agency's modeling suggests that oil and gas emissions contribute just 1.8 parts per billion to ozone levels on high ozone days, compared with 14.1 parts per billion from cars and trucks, Morrow said. 

In their report, the environmental groups called for strong regulations in the oil patch that would force operators to find and fix more pipeline leaks, reducing venting from oil wells and other equipment, among other actions.

New federal limits on methane from the oil patch would require some of those actions. Texas is challenging them in court

Industry groups insist that operators are doing enough to limit methane and other pollutants.

Everley pointed to a peer-reviewed University of Texas at Arlington study that found air contamination from various substances “highly variable” around oil and gas sites in the Eagle Ford Shale — the result of operational inefficiencies rather than inherent characteristics of the industry. And he said the environmental group's proposals for the industry were either already being carried out or were not applicable to some drilling regions. 

"These groups know how to blame oil and gas development, but they really don’t understand the industry they’re criticizing," he said. 

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