It's easy to assume that the word "cyanide" is always synonymous with a deadly poison. Chemically speaking, however, cyanide describes a triple bond between carbon and nitrogen atoms. This carbon-nitrogen combination can be combined with metals or other elements to form any number of compounds or salts, such as potassium cyanide, sodium cyanide or hydrogen cyanide. It is also found naturally in sugars, cassava roots, large fruit pits and tobacco leaves.
Different cyanide salts are used to process film, remove gold from ore, electroplate or clean metals, and make paper or plastic. In gas form, hydrogen cyanide is used to fumigate warehouses and the cargo areas of ships. The compounds can be stored in liquid, solid or gas form. The infamous "suicide pills" used by spies were often derived from prussic acid, a solid form of the compound.
Perhaps its most insidious use occurred during World War II. Charged with the gruesome task of exterminating large groups of Jewish captives, German concentration camp directors ordered canisters of hydrogen cyanide, sold under the brand name Zyklon B. Victims were ordered into airtight chambers, ostensibly for showers, and the gas would be introduced through the ventilation system. There have also been claims that former Iraqi president Saddam Hussein used this gas to kill thousands of Kurds during an uprising in the late 1980s.
Because cyanide, especially hydrogen cyanide, is produced naturally, it is very difficult for humans to avoid exposure completely. It is not considered to be carcinogenic (cancer-causing) however, and the gas evaporates quickly from groundwater. Long-term exposure to smoke, as in forest fires or cigarettes, is considered dangerous, since this gas is a natural by-product of smoke production. Liquid cyanide products such as insecticides and industrial cleaners can cause localized rashes and blister on exposed skin.
Hydrogen cyanide gas causes death and sickness by preventing normal oxygen absorption by blood cells. As the ions block the oxygen in the blood, the heart and brain suffer major damage. If the concentration of gas is heavy enough, death will occur within minutes of exposure. Victims of cyanide poisoning can be treated at a hospital if transported in time. Lower level exposure can cause dizziness, rapid heart rate, overall weakness and breathing difficulties. Evacuation to a source of fresh air is usually the first response, followed by decontamination and oxygen treatments.