Lewisite

Background

Lewisite, known as "L" in the military, is a type of chemical warfare agent. It was produced in 1918 to be used in World War I. However, its production was too late for it to be used in the war.

As a vesicant or blistering agent, it causes blistering of the skin and mucous membranes (eyes, nose, throat, etc.) on contact.

Lewisite is an oily, colorless liquid in its pure form and can appear amber to black in its impure form. It has a smell like geraniums and contains arsenic, a poisonous element.

Where it is found

Lewisite is not found naturally in the environment. It is used only as a chemical warfare agent and has no medical or other practical use.

How it works

Lewisite is a powerful irritant and blistering agent that immediately damages the skin, eyes, and respiratory (breathing) tract.

Because it contains arsenic, lewisite has some effects that are similar to arsenic poisoning, including stomach illness and low blood pressure.

Signs and symptoms

Effects of lewisite depend on the amount people are exposed to, how they are exposed, and how long they are exposed. Most information on the health effects of lewisite is based on animal studies.

Signs and symptoms happen immediately after lewisite exposure. Lewisite has different effects on specific parts of the body.

Showing these signs and symptoms does not necessarily mean that a person has been exposed to lewisite.

Skin

Pain and irritation can start within seconds to minutes. Within 15 to 30 minutes, redness can begin. Within several hours, blisters can appear. The blister begins as a small blister in the middle of the red areas. The blister then grows to cover the entire reddened area.

The lesions (sores) from lewisite heal much faster than lesions caused by the other blistering agents (sulfur mustard and nitrogen mustards). The discoloring of the skin that occurs later is much less noticeable as well.

Eyes

Signs and symptoms of contact with eyes include:

• Irritation
• Pain
• Swelling
• Tearing

Respiratory Tract

Respiratory (breathing) tract signs and symptoms include:

• Coughing
• Hoarseness
• Runny or bloody nose
• Shortness of breath
• Sinus pain
• Sneezing

Digestive tract

Digestive tract signs and symptoms include:

• Diarrhea
• Nausea
• Vomiting

Cardiovascular

Cardiovascular (heart-related system) signs and symptoms include "Lewisite shock" or low blood pressure.

Exposure

People's risk for exposure depends on how close they are to the place where the lewisite was released.

Lewisite gas is heavier than air, so it will settle in lower areas. Lewisite is a liquid under a wide range of environmental conditions, from below freezing to very hot temperatures. Therefore, it could last for a long time in the environment.

Air

If lewisite 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 lewisite.

Food

If lewisite liquid comes into contact with food, people may be exposed by eating the contaminated food.

Water

People may be exposed by drinking water that contains lewisite or by getting the water on their bodies.

What to do if you are exposed

Get away

Get fresh air by leaving the area where the lewisite is. Moving to an area with fresh air is a good way to reduce the possibility of death from lewisite.

If lewisite was released outside, move away from the area. Go to the highest ground possible, because lewisite is heavier than air and will sink to lower areas.

If lewisite was released indoors, get out of the building.

Take your clothes off

Remove the clothing with liquid lewisite as quickly as possible. Cut clothes off instead of pulling it over the head.

If you are helping others, do not touch unsafe areas and take off the clothes quickly.

Wash your body

As quickly as possible, wash any liquid lewisite from your skin with lots of soap water. Washing with soap and water will protect you from any chemicals on your body.

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

If you wear contacts, remove them and put them with the dirty clothing. Do not put the contacts back in your eyes (even if they are not disposable contacts).

If you wear eyeglasses, wash them with soap and water. You can put your eyeglasses back on after you wash them.

Throw your clothes away

If possible, put the clothing in a plastic bag. Then put the first plastic bag in a second plastic bag. Throwing away your clothes this way helps protect you and others from any chemicals that might be on your clothes.

If you placed your clothes in plastic bags, tell the local or state health department or emergency personnel when they arrive. Do not handle the plastic bags.

Treatment

Treatment involves removing lewisite from the body as soon as possible and providing supportive medical care in a hospital.

An antidote (cure for poisons) for lewisite is available and is most useful if given as soon as possible after exposure.

Long-term health effects

Breathing in large amounts of lewisite gas may cause long-term respiratory (breathing) disease.

If the eye is exposed for a long time, it may cause permanent blindness.

Lewisite is not known to affect the immune system. Severe skin burning is also less likely.

More information

You can contact one of the following:

• Regional poison control center: 1-800-222-1222
• Centers for Disease Control and Prevention (CDC) Public Response Hotline
  • Phone: 800-CDC-INFO
  • Teletypewriter (TTY): 888-232-6348
  • E-mail inquiries: cdcinfo@cdc.gov

The Centers for Disease Control and Prevention (CDC) protects people's health and safety by preventing and controlling diseases and injuries; enhances health decisions by providing credible information on critical health issues; and promotes healthy living through strong partnerships with local, national, and international organizations.