PFAS, or per- and polyfluoroalkyl, chemicals have been shown to harm human health and the environment. In 2024, the Environmental Protection Agency determined that there is no safe level of exposure to PFAS chemicals given how toxic they can be to humans and the environment. Some PFAS chemicals are classified as carcinogenic by the World Health Organization. Nevertheless, the Trump administration is considering relaxing rules on some PFAS chemicals because of their use in data centers.
Computers in data centers run hot, and they need to be kept from overheating. Excess water is often used to keep them cool. So are PFAS chemicals.
“This is the most common way of cooling in data centers,” says Norbert Conrad, deputy director of the High Performance Computing Center in Stuttgart, Germany. “It's similar to how a fridge is cooled, just much bigger. You use a compressor and gases to cool air or water for the computers.”
These gases can escape into the air, where they accelerate climate change. Some PFAS gases used in cooling of data centers have global warming potential that is thousands of times higher than CO2's.
PFAS chemicals can also be used in a different form of cooling, using immersion. Computers are submerged in a chemical fluid to which the heat transfers. PFAS fluids for applications like this can leak or seep into water sources, where they find their way to drinking water or are used in agriculture. The alternatives to cooling in data centers are explosive propane or ammonia gases.
Read more about the PFAS contamination risks associated with data centers in Tom Cassauwers May article in Sierra Magazine and check out the recording from a July webinar about PFAS and Data Centers hosted by the Great Lakes PFAS Action Network.