Air quality alerts that popped up on Oklahomans’ phones over the weekend reflected Professor Xiao-Ming Hu’s research findings in real time.
Hu is an air quality researcher at the National Weather Center at the University of Oklahoma. His work focuses on ozone pollutants from fossil fuel-burning power plants and how tropical storms in the Atlantic can push those pollutants across the state.
Tropical cyclone Isaias hit the East Coast Friday, Oct. 9, and while Oklahomans weren’t directly affected by torrential rain, they were hit with a blast of invisible pollutants. Winds moving inland carried coal emissions from northeast power plants into Oklahoma City.
Hu said that as more data centers are planned across the state, emissions from those coal-burning plants will only increase. Data centers require immense amounts of electricity and water to operate around the clock, straining electrical grids and water resources.
But those intensive heating and cooling processes are on the cusp of dramatic change. Moving from water cooling to refrigerant could shrink data centers and eliminate the heat island effect.
In June, the U.S. Department of Energy awarded the Grand River Dam Authority $28.5 million to upgrade its coal-fired plant. And only a fraction of data centers use refrigerant-based cooling.
Hu said building new data centers reliant on those power plants will create a vicious cycle. The data centers will require more energy, so more coal will be burned, contributing to ozone pollution that can not only directly harm people living in the surrounding area, but also contribute to climate change, intensifying the effects of those tropical storms.
Cooling a data center
The Pryor Creek Google data center withdrew 1,397 million gallons of water in 2025 and consumed 1,081 million gallons, about 3 million gallons per day. The data center discharged the other 316 million gallons back into the Neosho River after filtering it through its on-site water filtration system.
The data center uses evaporative cooling towers to cool its computer servers. The towers work as the server’s sweat glands, moving water through the building, extracting the heat and carrying it away. In this instance, “consumed” means evaporated.
Ardeshir Moftakhari, an assistant professor of mechanical and aerospace engineering at Oklahoma State University, said data centers used to rely on air cooling, but that’s not good enough anymore.
He said that artificial intelligence in particular has higher computational demands and takes much more energy out of CPUs and GPUs, which creates more heat and necessitates more efficient cooling.
The next step was liquid cooling: water mixed with chemicals to prevent degradation moves through the system and evaporates. Both air cooling and liquid cooling use water and can put communities in a tight spot if they’re already in a drought. Another concern is ensuring evaporation and discharge are free of pollutants.
Data centers in Oklahoma are closely monitored by the Department of Environmental Quality. They test the Pryor center yearly for chlorination level. They also test for residual oxidants and pH weekly and continually monitor the amount of water passing through the system.
From September 2024 to September 2025, the Pryor Google data center discharged almost no chlorine; the water's pH ranged from 6 to 9, which is safe and drinkable.
While the discharged water is clean, it represents only a fraction of the water lost to evaporation during the cooling process.
Suzie Shin, manager of Google’s data center sustainability programs, said the evaporation from the cooling towers contains no pollutants. Only water is lost and the chemicals left behind ensure nothing grows in the plumbing. The system continuously cycles water to keep the chemicals from becoming too concentrated.
Shin said once the heat is removed from the servers, it needs somewhere to go. So a common setup in Google data centers is an internal closed-loop system in the data center and an external evaporative system. Closed-loop systems recycle the same water continuously, lessening the strain on local resources.
Moftakhari’s research focuses on using refrigerant as a direct cooling medium, which he says would eliminate data centers' heat island effect. Refrigerant cooling systems can also make data centers smaller because they use smaller tubes. His research also aims to reduce the likelihood of a cooling failure. This would prevent the use of backup generators, which most recently in Virginia forced residents out of their homes after running for 24 hours straight.
The emissions from those backup generators are particularly harmful and can cause increased heart disease, stroke, respiratory illness, asthma exacerbation and premature death, according to a Harvard study.
Pros and cons
Last summer, the Mayes Emergency Services Trust Authority in Pryor received a call from the data center. A security guard had been exposed to refrigerant and was found barely conscious. Shortly after dispatching a team, the operator received more calls from the data center.
Fourteen people were exposed to R-410A through an accidental HVAC leak for an unknown amount of time.
The guards' symptoms included fainting, difficulty breathing, headaches, dizziness, nausea, and numbness in the lower extremities.
The Pryor Fire Department, MESTA and Mayes County Emergency Management worked with Google’s onsite medical team to treat the guard.
Erik Dickover, MESTA's executive director, said such instances happen.
“This was definitely a learning experience for all of us regarding initial contact, control, notifications, ongoing communications, and treatment,” Dickover said. “We held an after-action review to address what went wrong, what could have been better, and what went right.”
Google declined to comment on the event due to litigation.
One Mayes County Commissioner, Steve Grossman, even said he’d welcome more data centers. Just a few months ago, Google invested $500,000 in Mayes County schools and nonprofits.
Grossman said data centers create thousands of jobs when they’re being built, restaurant and hotel patronage increases and there are a few hundred job openings when the systems are up and running.
He offered personal, anecdotal evidence of the data center’s safety, saying his cows are near a data center and are fine, and that a pack of feral hogs has been highly active, rooting around the runway lights at the nearby airport and in the area around Google’s Pryor Creek facility.
“They’re multiplying like crazy,” he said.
David Stewart, the chief administrative officer for the MidAmerica Industrial Park, said the hogs are a problem. The Google Pryor center is in the MidAmerica Industrial Park, where they plan to build another data center.
Stewart said their on-site water filtration system is big enough to handle another data center. Google receives electricity from the Grand River Dam Authority’s energy center that has both coal- and gas-fired units. Stewart said the new data center would do the same, since it doesn’t have an on-campus power plant.
So what
Moftakhari said that as data centers increase, they are leaning more often toward on-site power plants. New data center models require so much energy that it’s more feasible to build their own power plants instead of drawing from an existing source.
Xiao-Ming Hu said that will make his job more difficult. He and his fellow researchers already struggle to receive adequate funding for data-collection instruments. If data centers start building their own power plants scattered across the state, it would be harder to map pollutant movement.
“We need more data to measure both pollutants and also quantify their health impact,” Hu said.
Rep. Mark Chapman, R-Broken Arrow, who recently led an interim study on the pros and cons of data centers, said Oklahoma should explore alternatives for backup generation. Other industrial sites also have backup generators, he said, and they don’t use them often.
In the interim study, Chapman said Oklahoma should hold off on statewide legislation on data centers. Instead, municipalities should consider their unique situations when deciding whether to welcome a data center.
“We support the oil and gas industry and they haven’t been perfect,” Chapman said. “But that doesn’t mean we strangle the industry.”
Moftakhari said some groups at Oklahoma State University are working to give residents and legislators as much information as possible when considering whether to accept a data center in their communities.
“If data centers are bringing something good like a tax incentive, they’re welcomed,” Moftakhari said. “But it has to be done carefully.”
Oklahoma Watch, at oklahomawatch.org, is a nonprofit, nonpartisan news organization that covers public-policy issues facing the state.
