PHOSGENE

Phosgene
(Carbonyl chloride; chloroformyl chloride; carbon oxychloride)
CAS 75-44-5

COCl₂

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

3.4 at bp (air = 1.0)

1180 mmHg at 20 °C

LC₅₀ inhal (rat) 341 ppm (1364 mg/m³; 30 min)

PEL (OSHA) 0.1 ppm (0.4 mg/m³)

TLV-TWA (ACGIH) 0.1 ppm (0.4 mg/m³)

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.

Noncombustible.

Phosgene reacts with water to form HCl and carbon dioxide.

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 and impermeable gloves should be worn at all times to prevent eye and skin contact. Containers of phosgene solutions should be stored in secondary containers, and phosgene cylinders should be stored in a cool, well-ventilated area separate from incompatible materials.

In the event of skin contact, immediately wash with soap and water and remove contaminated clothing. In case of eye contact, promptly wash with copious amounts of water for 15 min (lifting upper and lower lids occasionally) and obtain medical attention. If phosgene is ingested, obtain medical attention immediately. If phosgene is inhaled, move the person to fresh air and seek medical attention at once.

In case of the accidental release of phosgene gas, such as from a leaking cylinder or associated apparatus, evacuate the area and eliminate the source of the leak if this can be done safely. Remove cylinder to a fume hood or remote area if it cannot be shut off. In the event of a spill of a phosgene solution, soak up the solution with a spill pillow or absorbent material, place in an appropriate container, and dispose of properly. Full respiratory protection and protective clothing will be necessary in the event of a spill or release in a confined area.

Excess phosgene and waste material containing this substance should be placed in an appropriate container, clearly labeled, and handled according to your institution's waste disposal guidelines.

The information in this LCSS has been compiled by a committee of the National Research Council from literature sources and Material Safety Data Sheets and is believed to be accurate as of July 1994. This summary is intended for use by trained laboratory personnel in conjunction with the NRC report Prudent Practices in the Laboratory: Handling and Disposal of Chemicals. This LCSS presents a concise summary of safety information that should be adequate for most laboratory uses of the title substance, but in some cases it may be advisable to consult more comprehensive references. This information should not be used as a guide to the nonlaboratory use of this chemical.

Copyright 1995 National Academy of Sciences. All rights reserved.