Cobalt-60 Nuclear Generating Station. The cobalt targets are substituted here for a small number of fuel assemblies. After entering a living mammal (such as a human being), some of the is excreted in feces. The remainder is taken up by tissues, mainly the liver, kidneys, and bones, where the prolonged exposure to gamma radiation can cause cancer. Over time, the absorbed cobalt is eliminated in urine. Cobalt is an element used to make steel. Uncontrolled disposal of in scrap metal is responsible for the radioactivity found in several iron-based products. In August 2012, Petco recalled several models of steel pet food
Cobalt stable cobalt isotope and the only isotope that exists naturally on Earth. Twenty-two radioisotopes have been characterized; the most stable, Co has a half-life of 5.2714 years, and Co has a half-life of 271.8 days, Co a half-life of 77.27 days, and Co a half-life of 70.86 days. All the other radioactive isotopes of cobalt have half-lives shorter than 18 hours, and in most cases shorter than 1 second. This element also has 4 meta states, all of which have half-lives shorter than 15 minutes. The isotopes of cobalt range in atomic weight from 50 u (Co) to 73 u