Is the mercury in thimerosal (ethylmercury) the same as the kind found in certain fish (methylmercury)?
No. Thimerosal is a very effective preservative that contains a form of mercury called ethylmercury. Thimerosal contains approximately 49% ethylmercury. Thimerosal has been used in some vaccines and other products since the 1930’s to help keep them safe from bacterial contamination. In contrast, methyl mercury is an environmental contaminant. In March 2004, the Food and Drug Administration (FDA) and the Environmental Protection Agency (EPA) released a joint advisory for the consumption of fish for women who may become pregnant, pregnant women, nursing mothers, and young children. The advisory is based on an EPA standard of 0.1 mcg/kg per day of methylmercury which is not a component of thimerosal.
