Fatal Airs: The Deadly History and Apocalyptic Future of Lethal Gases That Threaten Our World relates the fascinatingÑand appallingÑstories of the discovery, development, applications, and occupational and public health hazards of natural and man-made gases. Some of these gases have figured in mass extinctions. Others have created havoc through their use in chemical warfare or their accidental release. Among the hundreds of man-made lethal gases, several have been singled out for attention, including chlorine, phosgene, mustard gas, lewisite, hydrogen cyanide, and the nerve agents tabun, sar.