Like all hexavalent chromium compounds, sodium dichromate is carcinogenic. From a health standpoint, trivalent chromium is intrinsically less toxic than hexavalent chromium. This is typical of all redox reactions where hexavalent chromium is reduced to trivalent chromium. Reduction of toxicity of hexavalent chromium involves methods using chemicals, microbes and plants. Hexavalent chromium pollution here is associated with industrial waste. Hexavalent chromium is a constituent of tobacco smoke. Hexavalent chromium is used for metal finishes to prevent corrosion. In solution, the chrome exists as chromic acid, known as hexavalent chromium. Approximately of hexavalent chromium, mainly sodium dichromate, were produced in 1985. However, these treatments use hexavalent chromium chemicals that are extremely toxic. In 1998 the EPA released a toxicological review of hexavalent chromium. Workers in many occupations are exposed to hexavalent chromium. Primer paint containing hexavalent chromium is widely used in aerospace and automobile refinishing applications. Approximately of hexavalent chromium were produced in 1985. As with all hexavalent chromium compounds, it is acutely and chronically harmful to health.