What type of store can one buy Diatomaceous Earth to try to get rid of roach infestation?

swimming pool supply stores sell it for filter pumps - but avoid breathing the dust - use outdoors only or in cabinets (some lungs disorders have been linked to DE with silica content) - food grade DE is safer and can be bought at commercial restaurant supply stores (used for grease filters) - either type is just as effective on roaches, throw in a dash of boric acid powder (available at pharmacies) for even better effectiveness.