If it is contaminated, it is not to the same degree as rice flour (because of the gluten in the commercial mills). We know this because ds will get car sick (throws up) if we feed him a flour based rice product and then go for about a 45 minute ride (he throws up about 1/2 an hour into the journey). However, he can eat a whole bowl of rice and not be sick at all. (Also, it says 'may contain trace amounts of wheat' on the bag of rice flour.)

I don't grind my rice up, I just cook it and reduce the liquids used. I'm still working on a lot of stuff but am not being too impatient because we don't really need a whole lot of grain in our diets.