The United States chemical industry is one of the most highly regulated of all national business categories, primarily through the auspices of the Environmental Protection Agency (EPA) Toxic Substances Control Act (TSCA). The Chemical Abstract Service (CAS)—a division of the American Chemical Society—maintains a registry of nearly 130 million records for unique organic and inorganic chemicals, and each registered chemical is assigned a unique identification number. However, there is no assigned CAS number for metalworking fluids (MWFs), with the exception of some purified mineral oils. MWF products are complex chemical mixtures with proprietary formulations produced by many companies, and no given fluid is truly representative of the thousands of unique products in commercial channels. The regulatory aspects of MWFs are numerous, due primarily to the chemical complexity of MWF products and governmental efforts to protect human health and safety, and reduce environmental impacts.