The prisoner is restrained in a hermetically sealed steel chamber below which is a pan. Upon a signal, the executioner opens a valve, flowing hydrochloric acid into the pan. On a second signal, about 8 ounces of potassium cyanide crystals or tablets are dropped mechanically into the acid, producing hydrocyanic gas, which destroys the ability of blood hemoglobin to perform.(The root word of cyanide, CYAN, denotes a blue color, descriptive of the body's hue). Unconciousness occurs within a few seconds if the prisoner takes a deep breath, and longer if he or she holds their breath. Death usually occurs within six to eighteen minutes. After pronouncement of death, the chamber is evacuated through carbon and neutralizing filters. Gas-masked crews decontaminate the body with a bleach solution and outgassed prior to release. An unwary undertaker could be killed if this is not done.