Cadmium has many common used in manufacturing. Cadmium metal can be found in batteries and is often a byproduct of smelting lead, zinc and other ores. In everyday life, most cadmium exposure comes through cigarette smoke. According to recent studies, about 512,000 workers in the United States work in environments where they may be exposed to cadmium at high levels. This concerns health and environmental officials because the silver-white metal can cause health problems if workers are exposed in high doses. Immediate reaction in high does may be lung irritation that causes the individual to cough. Long-term exposure may result in kidney problems and in some cases in renal failure - which is fatal. Health officials have studied whether or not cadmium can cause cancer after long-term exposure, particularly lung cancer. However, none of those studies have been conclusive and the Environmental Protection Agency lists the metal as a probable human carcinogen.