CAS RN: 75-44-5

Toxicity Summary

Human exposure in both the general population and occupational setting is primarily by inhalation. ... The primary route of exposure is by inhalation, the gas penetrates into the tissues of the respiratory tract and so only minimal amounts of phosgene are distributed in the body. The very short half-life (0.026 seconds) in aqueous solutions precludes a significant retention of phosgene in the body. ... The hydrolytic products of phosgene, i.e., hydrochloric acid and carbon dioxide, are disposed of by the body through normal physiological processes. Phosgene exerts its toxicity through acylation of proteins, as well as through the production of hydrochloric acid. The amino, hydroxyl and sulfhydryl groups in the protein appear to be the target for acylation leading to marked inhibition of several enzymes related to energy metabolism and a breakdown of the blood:air barrier. In all species studied, the lung is the major target organ. ... In all species the characteristic pathological feature is the delayed clinical manifestation of pulmonary edema, which is dose-dependent. Pathological changes in the terminal bronchioles and alveoli at low concentrations are typical of a pulmonary irritant, whereas at higher exposures pulmonary edema occurs, leading to interference with gas exchange and death. ... Phosgene exposure can result in eye and skin irritation. ... The target organ in humans, as in experimental animals, is the lung. After exposure to phosgene levels between 120 and 1200 mg/cu m-min, three distinct clinical clinicopathological phases have been reported. The initial phase consists of pain in the eyes and throat and tightness in the chest, often with shortness of breath, wheezing, and coughing; hypotension, bradycardia and rarely sinus arrhythmias can occur. The second or latent phase, which is often asymptomatic, can last as long as 24 hr depending upon the level and duration of exposure. In the third phase, pulmonary edema may develop, leading to death in some cases. Populations exposed to phosgene after industrial accidents have reported a wide variety of symptoms, including headache, nausea, cough, dyspnea, fatigue, pharyngeal pain, chest tightness and pain, intense pain in the eye and severe lacrimation. ... In view of the lack of exposure data ... the conclusions regarding the chronic effects of phosgene that can be drawn are limited.
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