I've used these in an experiment before, I remember toasting them in the oven. I think I used it in a cider, this was before I took brewing notes though. I'd start with the same oaking rates as you would normal oak chips.
I would think you could use them, but I'm just guessing. It seems to me that if they are safe for cooking food, they would be safe for brewing. I would probably toast them and then soak them in Jack or another good quality whiskey or bourbon.