541-25-3

Colorless liquid when pure; geraniumlike odor. Impurities lead to colors ranging from violet to brown, decomposed by water and alkalies. Inactivated by bleaching powder. Antidote is dimercaptopropanol.

Chemical warfare agent.

Vesicant gas, a poison. See arsenic.

Dr Wilford Lee Lewis first synthesized lewisite in 1918 for use as a vesicant chemical warfare agent. This synthesis was based on the thesis work of Julius Arthur Nieuwland at the Catholic University of America. Its discovery was made too late for use during World War I, but was later weaponized and garnered the nickname ‘Dew of Death.’ Several countries have manufactured and stockpiled lewisite; however, none have officially reported its battlefield use.

Lewisite is also a systemic poison, which can result in pulmonary edema, diarrhea, restlessness, weakness, subnormal temperature, and low blood pressure. Severity of symptoms, in order of appearance, are blister agent, toxic lung irritant, tissue absorption, and systemic poison. If inhaled in high enough concentrations, lewisite can cause death in as little as 10 min. Common routes of exposure into the body are through the eyes, skin, and inhalation. Lewisite is an oily colorless liquid when pure. “War gas” is amber to dark brown in color with a geranium-like odor; pure lewisite has little, if any, odor. Lewisite is much more volatile than mustard agents. Often, lewisite is mixed with mustard to lower the boiling point of the mixture. The military designation for the mustard/lewisite mixture is (HL). Lewisite is insoluble in water and has a specific gravity, which makes it heavier than water. It has a vapor density more than seven times heavier than air. Lewisite has a low level of flammability, with no flash point or flammable range identified.

Lewisite is an arsenic-based chemical warfare agent used in form of a blister gas. Further research showed that it can be used as an antidote against a variety of toxic metals. Additionally, it was used in the treatment of Wilson disease, which is a chronic disease in which the body retains excess amounts of copper. Heavy-metal poisoning often results from the coordination of the metal to sulfhydryl groups of enzymes, which means that these enzymes are blocked for their activity. BAL also contains sulfhydryl groups and basically competes with the enzymes for the coordination of the metal. The chelated complex is then excreted in the urine. Whilst BAL removes a range of heavy metals, it also seems to increase the concentration of some metals in the human body and therefore limits its use. It is not indicated as an antidote for cadmium (increased levels are found in the kidneys after treatment), selenium or iron poisoning.

Those involved in the manufacture oruse of this chemical warfare agent which is a vesicant. L-1,L-2, and L-3 have been used as a blister-agent-type wargas.Mustard-lewisite mixture was developed to achieve alower freezing point for ground dispersal and aerialspraying.

If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least30 min, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediately with soap and water. Speed in removing material from skinis of extreme importance. Seek medical attention immediately. If this chemical has been inhaled, remove from exposure, begin rescue breathing (using universal precautions,including resuscitation mask) if breathing has stopped andCPR if heart action has stopped. Transfer promptly to amedical facility. When this chemical has been swallowed,get medical attention. Give large quantities of water andinduce vomiting. Do not make an unconscious personvomit. Medical observation is recommended for 24-48 hafter breathing overexposure, as pulmonary edema may bedelayed. As first aid for pulmonary edema, a doctor orauthorized paramedic may consider administering a corticosteroid spray. Keep victim quiet and maintain normal bodytemperature. Effects may be delayed; keep victim underobservation.Note to physician: For severe poisoning BAL [British AntiLewisite, dimercaprol, dithiopropanol (C3H8OS2)] has beenused to treat toxic symptoms of certain heavy metals poisoning including arsenic. Although BAL is reported to havea large margin of safety, caution must be exercised, becausetoxic effects may be caused by excessive dosage. Most canbe prevented by premedication with 1-ephedrine sulfate(CAS: 134-72-5). For milder poisoning penicillamine (notpenicillin) has been used, both with mixed success. Sideeffects occur with such treatment and it is never a substitutefor controlling exposure. It can only be done under strictmedical care.

Color Code—Red Stripe (UN3162): FlammabilityHazard: Store separately from all other flammable materials. Color Code—Blue (UN2810): Health Hazard/Poison:Store in a secure poison location. Prior to working with thischemical you should be trained on its proper handling andstorage. Store in tightly closed containers in a cool, wellventilated area away from alkalis.

Toxic, liquids, organic, n.o.s. [Inhalation hazard,Packing Group I, Zone A] requires a shipping label of“POISONOUS/TOXIC MATERIALS.” Inhalation Hazard.Technical name required.

The exact mechanism of lewisite toxicity is not very well understood. It is hypothesized that the trivalent arsenic in lewisite combines with the thiol groups in many enzymes, leading to toxicity. It is easily absorbed by the skin, eyes, and respiratory tract; lewisite can also enter the body through ingestion of contaminated material. Areas that come into direct contact with this agent, such as the skin and mucous membranes, will form blisters. Once absorbed into the body, lewisite causes an increase in capillary permeability, which can induce hypovolemia, shock, and organ damage. This reaction is known as ‘lewisite shock.’ In contrast to the mustard agents, lewisite vapor or liquid causes immediate pain or irritation, although the full effects of exposure are not observed until up to 18-h following exposure.

Lewisite reacts with water and sweat;and, as it breaks down in water or sweat, it producesarsenic-containing materials which are less dangerous thanlewisite but still dangerous. Heating causes lewisite to yieldarsenic trichloride, tris-(2-chlorovinyl)arsine, and bis-(2-chlorovinyl)chloroarsine. Mustard-lewisite mixture is rapidly corrosive to brass at 65℃ and will corrode steel at arate of 0.0001 in. of steel per month at 65℃. It will hydrolyze into hydrochloric acid, thiodiglycol, and nonvesicantarsenic compounds.