Question About Safety of MoM \ Grey Market Shake

I have been browsing online delivery options for lower prices. One thing that caught my eye, which I think is too good to be true, is an Oz. bag of trimmings and shake for a ridiculous deal.

The website says that the bag may contain perlite and styrofoam though. Perlite should be easy to notice and remove, but I have serious reservations about burning the styrofoam. Is this safe to consume?

The obvious answer is that one would be trading price for health concerns, but I was unable to find a discussion online about this topic and thought this would be one of the better places to ask.