Is used as a preservative in vaccines, cosmetics, tattoo inks, eye drops. The toxicity of mercury and its compounds is extensively documented in scientific literature. Some mercury compounds can be absorbed through the skin on topical application and accumulate in the body. Depending on the form of mercury, exposure to sufficiently high concentrations can result in allergic reactions, skin irritation, or neurotoxicity. FDA banned mercury in most cosmetics in 1974. The FDA has determined that mercury compounds may be used in cosmetic products only in trace amounts as a preservative.