Tesla CEO Elon Musk is threatening to ban his employees from taking Apple devices into their workplaces after Apple CEO Tim Cook announced a partnership on Monday to integrate OpenAI’s artificial intelligence technology into its operating systems. 

On Monday evening, Musk wrote on his social media platform X that adding OpenAI’s tech into Apple’s systems “is an unacceptable security violation.” He added that visitors to his businesses, which also include SpaceX, “will have to check their Apple devices at the door, where they will be stored in a Faraday cage.”

Musk’s threat to ban Apple devices at his workplaces, which employ more than 100,000 workers across Tesla, SpaceX and X alone, comes amid a legal battle between the Tesla CEO and OpenAI. In March, Musk sued OpenAI and its CEO, Sam Altman, alleging that the artificial intelligence company had violated its original mission statement by putting profits over benefiting humanity. 

Apple’s announcement of its partnership with OpenAI emphasized that users’ personal data would remain private, even as the iPhone maker integrates AI into operating systems including iOS 18 and macOS Sequoia. The tech giant said it won’t collect data on users or search their personal data stored on their devices when they use the AI system.

Yet Musk expressed skepticism that that Apple users’ personal data will remain private. 

“It’s patently absurd that Apple isn’t smart enough to make their own AI, yet is somehow capable of ensuring that OpenAI will protect your security & privacy!” Musk wrote on X. “Apple has no clue what’s actually going on once they hand your data over to OpenAI. They’re selling you down the river.”

Apple didn’t immediately respond to a request for comment. 

Musk helped found OpenAI in 2015, but stepped down from its board in 2018. At the same time, he is working to build a rival AI company, xAI, which has recruited researchers from OpenAI and other top tech firms with the mission to “maximally benefit all of humanity.”