Wikipedia
Specially denatured alcohol
A specially denatured alcohol (SDA) is one of many types of denatured alcohol specified under the US Code of Federal Regulations Title 27 Section 21.151. A specially denatured alcohol is a combination of ethanol and another chemical, e.g. ethyl acetate in SDA 29, 35, and 35A, added to render the mixture unsuitable for drinking. Often an SDA is used in cosmetic products but can also be used in chemical manufacturing, pharmaceuticals, and solvents. The use of denatured, non-beverage suitable, alcohol in the USA avoids excise taxes on alcohol