Thimerosal

Thimerosal is an organometallic compound containing mercury, commonly used as a preservative. It is found in cosmetics, including makeup removers, eye moisturizers, and mascaras. Some other places in which Thimerosal may be found include: soap-free cleansers; nose, eye, and ear drops; eye ointments; topical medications; and antiseptic sprays. It is also found in cleaning fluids that are used for contact lenses. Thimerosal is also used widely as a preservative in antitoxins, tuberculin tests, desensitization solutions and vaccines, most controversially including those widely administered to children. Its chemical formula is C9H9HgNaO2S. It has been in use since the 1930s.

Other names for thimerosal:
Thimerosol, Merthiolate, Sodium ethylmercurithiosalicylate, Mercurothiolate, Thiomersal, Thiomersalate, Thiomersalan, Ethyl (2-mercaptobenzoato-S) mercury sodium salt, [(o-carboxyphenyl)thio] Ethylmercury sodium salt