w h a t e v e r c h e m i s t r y ! !: PHOSGENE

Have u ever heard about phosgene before? Phosgene is a chemical used to make plastics and pesticides. At room temperature (70°F), phosgene is a poisonous gas. With cooling and pressure, phosgene gas can be changed into a liquid so that it can be shipped and stored. When liquid phosgene is released, it quickly turns into a gas that stays close to the ground and spreads rapidly.

Phosgene gas may appear colorless or as a white to pale yellow cloud. At low level of concentrations, it has a pleasant odor of newly mown hay or green corn, but its odor may not be noticed by all people. At high level of concentrations, the odor may be strong and unpleasant.

Phosgene was used during World War I as a choking (pulmonary) agent. Among the chemicals used in the war, phosgene was responsible for the large majority of deaths.

PHOSGENE

Molecular formula: CCl₂O

Appearance: colourless gas

Melting point: -118 C

Boiling point: 8.2 C

Vapour density: 3.48 (air = 1)
Vapour pressure: 22.6 psi at 20 C
Density (g cm^-3): 1.37
Water solubility: decomposes
Stability: Stable. Incompatible with water, ammonia, primary amines, alkalies, active metals.

Toxicology: Highly toxic. Severe poison. Inhalation may be fatal. Odour does not give sufficient warning of lethal concentrations. Symptoms may be delayed up to 24 hours. Concentrations down to levels below 1 ppm may be harmful. Severe eye and skin irritant. Corrosive - may cause burns. Decomposes to further toxic compounds in the presence of water.

Where phosgene is found and how it is used?

Phosgene is not found naturally in the environment. Phosgene is used in industry to produce many other chemicals such as pesticides. Phosgene can be formed when chlorinated hydrocarbon compounds are exposed to high temperatures. Chlorinated hydrocarbon compounds are substances sometimes used or created in industry that contain the elements chlorine, hydrogen, and carbon. The vapors of chlorinated solvents exposed to high temperatures have been known to produce phosgene. Chlorinated solvents are chlorine-containing chemicals that are typically used in industrial processes to dissolve or clean other materials, such as in paint stripping, metal cleaning, and dry cleaning. Phosgene gas is heavier than air, so it would be more likely found in low-lying areas.

How people are exposed to phosgene?

People's risk for exposure depends on how close they are to the place where the phosgene was released. If phosgene gas is released into the air, people may be exposed through skin contact or eye contact. They may also be exposed by breathing air that contains phosgene. If phosgene liquid is released into water, people may be exposed by touching or drinking water that contains phosgene. If phosgene liquid comes into contact with food, people may be exposed by eating the contaminated food.

Phosgene as a weapon: Phosgene can be an “agent of opportunity.” This means that someone could explode the vehicle of transportation (truck, train) that is being used to ship the chemical, or destroy tanks that store the chemical. Phosgene would then be released into the air.

Signs and symptoms?

During or immediately after exposure to dangerous concentrations of phosgene, the following signs and symptoms may develop:

· Coughing

· Burning sensation in the throat and eyes

· Watery eyes

· Blurred vision

· Difficulty breathing or shortness of breath

· Nausea and vomiting

· Skin contact can result in lesions similar to those from frostbite or burns

Following exposure to high concentrations of phosgene, a person may develop fluid in the lungs (pulmonary edema) within 2 to 6 hours. Exposure to phosgene may cause delayed effects that may not be apparent for up to 48 hours after exposure, even if the person feels better or appears well following removal from exposure. Therefore, people who have been exposed to phosgene should be monitored for 48 hours afterward. Delayed effects that can appear for up to 48 hours include the following:

· Difficulty breathing

· Coughing up white to pink-tinged fluid (a sign of pulmonary edema)

· Low blood pressure

· Heart failure

Treatment for phosgene?

Prevention of illness after contact: Leave the area where the phosgene was released and move to fresh air.

Remove clothing.

§ Quickly take off clothing that may have phosgene on it. If possible, any clothing that has to be pulled over the head should be cut off the body instead so the chemical does not get near the eyes, mouth or nose. If helping other people remove their clothing, try to avoid touching any contaminated areas.

Wash affected areas.

§ As quickly as possible, wash any phosgene from the skin with lots of soap and water.

§ If the eyes are burning or vision is blurred, rinse your eyes with plain water for 10 to 15 minutes.

§ If contact lenses are worn, remove them and put them with the contaminated clothing. Do not put the contacts back in. If eyeglasses are worn, wash them with soap and water. Eyeglasses can be put back on after they are washed.

§ If you are wearing jewelry that you can wash with soap and water, wash it and put it back on. If it cannot be washed, put it with the contaminated clothing.

Discard contaminated items.

§ Place the clothing and any other contaminated items inside a plastic bag. Avoid touching contaminated areas of the clothing. If you can't avoid touching contaminated areas, or you aren't sure where the contaminated areas are, wear rubber gloves or use tongs, sticks or similar objects. Anything that touches the contaminated clothing should also be placed in the bag.

§ Seal the bag, and then seal that bag inside another plastic bag.

§ Call the local county health department right away. (Visit www.idph.state.il.us//local/alpha.htm for a listing of all county health departments in Illinois or check your local phone book.)

§ When the local or state health department or emergency personnel arrive, tell them what you did with your clothes. The health department or emergency personnel will arrange for further disposal. Do not handle the plastic bags yourself.

If someone has swallowed phosgene, do not make the person vomit or give fluids to drink. Seek medical attention right away.

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