1 year after approving Project Blue, Pima County releases data center health impact study

People are not just worried about data centers raising their water and energy bills, they’re also worried about potential impacts to their health.

This is true in Pima County, where Tucson officials unanimously rejected the first large scale data center request from Beale Infrastructure last August.

A month before that, Pima County officials approved a zoning change for Beale’s Project Blue on unincorporated county land near the Pima County Fairgrounds.

The 300-acre project, which is now easily moving through permitting, will include 10 data center buildings powered by Tucson Electric Power and a fleet of heavy-duty diesel backup generators. The first phase of development is expected to use 286 megawatts of power, enough to electrify roughly 60,000 homes.

At full buildout, Project Blue could end up using a gigawatt of power, which is equivalent to a large city’s energy demands.

Diesel fuels emit nitrogen oxides and fine particulate matter known as PM2.5, both of which can contribute to respiratory and heart diseases. But there are many other parts of data center operations that could impact public health and the environment.

Late last year, the Pima County Board of Health directed its health department to determine these other impacts and put them in context for Southern Arizona.

Their first study, done in partnership with the Johns Hopkins Bloomberg School of Public Health, shows how large scale data centers could exacerbate existing community vulnerabilities, worsen air quality, and strain or contaminate water supplies in Pima County.

They could raise energy bills, too — a growing health concern for the county, which is vulnerable to extreme heat and has a lower median household income compared to the state and nation.

John Neatherlin, deputy director of the Pima County Health Department, says there was little to go off of when they received the study request.

“We did not have an environmental health program here, we had no expertise, and there was no evaluation tool or framework that existed,” he said.

He says the department had a concept of what to include in the assessment, and it was the university researchers who largely built the final framework.

“We were more in line with, you know, does this meet our requirements, does what they’re developing make sense in the local context? And sort of keeping it real, instead of theoretical,” Neatherlin said.

An extensive review of available literature on data center health impacts and development metrics was done, but Neatherlin says there was a lot left to be desired.

“I’m not saying there were no tools, but I think the hunger for this was really apparent in our search and in the work we were doing,” Neatherlin said.

“There’s a lot of opinions, but you know, when we’re actually looking for empirical evidence in the scientific literature, it’s coming up a little short for us,” he added.

The team settled on breaking out all of the potential concerns associated with data center development into four life-cycle phases: project siting, construction, operation and decommissioning.

Within these phases, the team described different pathways and outcomes for public health, assuming a data center follows what they found to be rather standard ways of building, today.

“If there are going to be diesel backup generators that are being tested frequently or being used to supplement power requirements, obviously that is going to have an impact on the air quality in that area,” he said.

They consider this a primary concern, given that Pima County is currently in EPA attainment for air quality, but additional stressors could push them out of that, which would open up several health considerations.

“We have high rates of adult asthma here, higher than the national average,” Neatherlin said.

Data center cooling systems and backup generators continuously generate heat. A global study the team cited found thermal plumes from data centers can extend 6 miles, raising ambient air and surface temperatures between 4 and 16 degrees Fahrenheit.

“Obviously, we are heat stressed — as is Phoenix, right? So, the potential of adding heat to our community you know puts us — we’re already vulnerable there. So, what is our tolerance for that?” he said.

Neatherlin says the department did not have the resources to do a site-specific study, say, for the already approved Project Blue. Instead, they were directed by the board to do a more broad, county-wide assessment that could be tailored down the line.

“We didn’t want to make a one and done tool,” he said. “We wanted to make a tool that could be used over and over and standardized and adapted to a site-specific context.”

However, the report did include some references to Project Blue, specifically around its planned water consumption and management. The authors shared that Project Blue plans to use around 143 million gallons of reclaimed water per year for on-site cooling. But some amount of that recycled water will have to be discharged and refilled. That’s because as data center cooling water gets reused, it becomes concentrated with minerals that can damage equipment.

The authors say that could open up risk of contaminating local groundwater supplies with PFAS “forever chemicals” or refrigerants.

The authors also pointed out that Pima County is considered extremely high risk for water stress, according to the World Resources Institute’s Aqueduct Water Risk Atlas. So although Project Blue plans to use reclaimed water, the authors say facilities on site may still use potable water for other operations.

“In a region where Tucson Water delivers 30 billion gallons of potable water annually to around 722,000 customers, even a single new industrial user could appreciably shift demand patterns and impact pricing, supply infrastructure, and sustainability,” wrote the authors.

Neatherlin says further research or directives to study a specific data center project will be left up to the Pima County Board of Health.