Phosgene oxime

Phosgene oxime (CX) is a colorless liquid or solid with a disagreeable odor. It is a urticant/nettle gas whose primary sites of action are the skin, eyes and upper respiratory system. The mechanism of action of CX is not completely understood, but its toxicity is probably mediated via binding to sulfhydryl and the NH2 group, and it is no longer considered a major chemical threat.

There is a characteristic pain suggestive of stinging nettles with a central white area surrounded by erythema in the area of CX exposure. Within an hour there is urticaria-like edema with blistering after 24 hours, and later there is significant tissue necrosis that may take months to heal. Affected individuals are first decontaminated with copious amounts of water and a mild base such as sodium bicarbonate solution, followed by routine therapies used for burns.

Phosgene should not be confused with phosgene (CG), which is primarily a pulmonary toxicant leading to injury of the respiratory tract and suffocation.