Several modern industrial processes produce cyanide containing wastes, including metal plating, case hardening of steel, and refining of gold and silver ores. Wastewater from these processes that contains even trace amounts of cyanide must be treated before discharge into sewage systems. Cyanide wastewater treatment is critical, because cyanide wastes are toxic to living organisms. Specifically, cyanide may reduce or eliminate oxygen utilization in organisms, including human beings, making cyanide poisoning potentially fatal. Aquatic life, including microorganisms involved in natural water purification streams, is particularly susceptible to cyanide poisoning.