Mercury is a metal that is a liquid at room temperature. Mercury has a long and interesting history deriving from its use in medicine and industry, with the resultant toxicity produced. In high enough doses, all forms of mercury can produce toxicity. The most devastating tragedies related to mercury toxicity in recent history include Minamata Bay and Niagata, Japan in the 1950s, and Iraq in the 1970s. More recent mercury toxicity issues include the extreme toxicity of the dimethylmercury compound noted in 1998, the possible toxicity related to dental amalgams, and the disproved relationship between vaccines and autism related to the presence of the mercury-containing preservative, thimerosal.