Specially Denatured Alcohol (SDA) is alcohol to which denaturing materials have been added. Manufacturers may use SDA in the manufacture of any product that is not intended for consumption. Generally, SDA is used in cosmetic products but its use extends to pharmaceuticals, chemical manufacturing, and products where SDA is the solvent or reactant.
Completely Denatured Alcohol (CDA) is alcohol that has been so thoroughly denatured that the product is utterly unfit for beverage use, and the denaturants used are very nearly inseparable from the alcohol. The use of CDA is authorized without permit restrictions because of the reduced risk that the pure alcohol can be extracted and diverted to beverage use.