Elon Musk raced to build Colossus, the world’s largest supercomputer, in Memphis, Tennessee. He bragged that construction only took 122 days and expected that his biggest AI rivals would struggle to catch up.

Now xAI is facing calls to shut down gas turbines that power the supercomputer, as Memphis residents in historically Black communities—which have long suffered from industrial pollution causing poor air quality and decreasing life expectancy—allege that xAI has been secretly running more turbines than the local government knows, without permits.