As franeli points out there are similar dangers in breathing in sand as there are in breathing in DE. Don't breath those products, wear a dust mask when messing with them. There are very few things we mess with every day that are good for us to inhale aside from fresh air and the minute particulates in the air are not much better than either sand or DE. Talcum Powder, Corn Starch, Baking Soda, Flour, Sugar, Corn Meal, salt, pepper all are carcinogens in your respiratory system, but you don't not use them because they are.