Thankfully, it is illegal for private companies to do that.

Unless you work in a pharmacy. Or you’re a ‘mall-cop’. Or literally any employee anywhere who is suspected of fraud or embezzlement or any “incident that resulted in a specific economic loss to the employer”.

Unfortunately, that doesn't really prevent companies from doing things being illegal if they turn out to be profitable enough. You could use a multispectral hidden camera and an mmwave radar fed into 'AI' to simulate a lie detector - you can definitely get pulse and breathing rate out of it, probably also perspiration..