This October, nations will gather in Japan to sign the Minamata convention, a treaty to address the toxic effects of mercury in the environment. The agreement will become binding once ratified by at least 50 nations. The convention is timely and welcome in that it places controls and limitations on products, processes, and industries that increase the level of exposure of people and the environment to mercury, a naturally occurring element. Mercury bioaccumulates in the form of methylmercury, a powerful neurotoxin that can affect wildlife, domestic animals, and humans alike. Symptoms of mercury poisoning can range from numbness in the hands and feet and muscle weakness in mild cases, to insanity and death.