(Carbonyl chloride; chloroformyl chloride; carbon oxychloride)

CAS 75-44-5





Physical Properties

Colorless gas

bp 8.2 °C, mp -128 °C

Decomposes in water with formation of HCl



Sweet, hay-like odor at lower levels, pungent at higher levels; detectable at 0.1 to 5.7 ppm


Vapor Density

3.4 at bp (air = 1.0)


Vapor Pressure

1180 mmHg at 20 °C


Toxicity Data

LC50 inhal (rat)

341 ppm (1364 mg/m3; 30 min)



0.1 ppm (0.4 mg/m3)



0.1 ppm (0.4 mg/m3)

Major Hazards

Highly toxic, irritating, and corrosive gas; inhalation can cause fatal respiratory damage.



Phosgene is severely irritating and corrosive to all body tissues. Irritation of the throat occurs immediately at 3 ppm, while 4 ppm causes immediate eye irritation. Exposure to 20 to 30 ppm for as little as 1 min may cause severe irritation of the upper and lower respiratory tract, with symptoms including burning throat, nausea, vomiting, chest pain, coughing, shortness of breath, and headache. Brief exposure to 50 ppm can be fatal within a few hours. Severe respiratory distress may not develop for 4 to 72 hours after exposure, at which point pulmonary edema progressing to pneumonia and cardiac failure may occur. Phosgene vapor is irritating to the eyes, and the liquid can cause severe burns to the eyes and skin. Phosgene is not regarded as a substance with adequate warning properties.

Phosgene has not been found to be carcinogenic or to show reproductive or developmental toxicity in humans.


Flammability and Explosibility



Reactivity and Incompatibility

Phosgene reacts with water to form HCl and carbon dioxide.


Storage and Handling

Because of its corrosivity and high acute toxicity, phosgene should be handled using the "basic prudent practices" of Chapter 5.C, supplemented by the additional precautions for work with compounds of high toxicity (Chapter 5.D). In particular, work with phosgene should be conducted in a fume hood to prevent exposure by inhalation, and splash goggles


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