Is it legal (in CA) for a company to blackball, for life, everyone it lays off?

I know CA is a 'right to work' state. But, there are still many labor regulations. I'm familiar, for instance, with many companies that will let temporary workers go, and not re-hire them for a period of time, to avoid laws that would require them to make temporary positions permanent.

What I heard today, though, was new to me. I have never heard of a company discriminating against former employees across the board and in perpetuity like this. I hope what I heard isn't true, but if anyone knows were the law is on this sort of thing, I'd like to hear it.