Cyanide is a rapidly acting, potentially deadly chemical that interferes with the body's ability to use oxygen. Cyanide can be a colorless gas or liquid, such as hydrogen cyanide (HCN) or cyanogen chloride (CNCl). Cyanide can also be a crystal (solid) form such as sodium cyanide (NaCN) or potassium cyanide (KCN).
Cyanide is a very poisonous chemical. Exposure to high levels of cyanide harms the brain and heart, and may cause coma and death. Exposure to lower levels may result in breathing difficulties, heart pains, vomiting, blood changes, headaches, and enlargement of the thyroid gland. Cyanide has been found in at least 415 of the 1,430 National Priorities List sites …