Tungsten, at atomic number 74,'s the heaviest element known to be used by any living organism, with the next heaviest being iodine (Z = 53). On 20 August 2002, officials representing the U.S.-based Centers for Disease Control and Prevention announced that urine tests on leukemia patient families and control group families in the Fallon, Nevada area had shown elevated levels of tungsten in the bodies of both groups. Sixteen recent cases of cancer in children were discovered in the Fallon area,… (More on Tungsten)