Methyldichloroarsine

Methyldichloroarsine (MDA) is a chemical warfare agent classified as a vesicant, or blister agent. It is a member of the lewisite family of organometallic compounds, which are known for their potent and lethal effects on the human body.

Chemical Structure and Properties

Methyldichloroarsine is an organoarsenic compound with the formula CH3AsCl2. It is a colorless, oily liquid that is not naturally occurring. It has a pungent, garlic-like odor and is soluble in organic solvents but only slightly soluble in water.

History

Methyldichloroarsine was first synthesized in the early 20th century and was used as a chemical warfare agent during World War I. It was primarily used by the German forces, who referred to it as "Blue Cross" due to the blue cross symbol that was used to mark the shells containing this agent.

Effects on the Human Body

When inhaled or absorbed through the skin, methyldichloroarsine can cause severe blistering, eye and lung damage, and can be fatal in high concentrations. The effects are typically immediate and include burning sensation, coughing, and difficulty breathing. Long-term exposure can lead to chronic respiratory problems and can damage the liver and kidneys.

Treatment

Treatment for exposure to methyldichloroarsine is primarily supportive and includes decontamination, administration of oxygen, and treatment of any secondary infections that may occur as a result of the blistering. There is no specific antidote for methyldichloroarsine exposure.

Prevention and Protection

Prevention of exposure to methyldichloroarsine includes the use of protective clothing and gas masks. In the event of a suspected release of this agent, immediate evacuation of the area is recommended.

See Also

• Chemical warfare
• Vesicant
• Lewisite
• World War I