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ToxFAQs™ for for Blister Agents:
Lewisite (L), Mustard-Lewisite Mixture (HL)

(Agentes que Causan Ampollas: Lewisita (L), Mezcla de Mostaza-Lewisita (HL))

April 2002

CAS#: 541-25-3 (Lewisite); (Mustard-Lewisite Mixture CAS# Not Available)

ToxFAQs™ PDF PDF Version, 43 KB

This fact sheet answers the most frequently asked health questions about lewisite and mustard-lewisite. For more information, you may call the ATSDR Information Center at 1-888-422-8737. This fact sheet is one in a series of summaries about hazardous substances and their health effects. It is important you understand this information because this substance may harm you. The effects of exposure to any hazardous substance depend on the dose, the duration, how you are exposed, personal traits and habits, and whether other chemicals are present.


It is unlikely that the general population will be exposed to blister agents Lewisite or Mustard-Lewisite. People who breathe in vapors of Lewisite or Mustard-Lewisite may experience damage to the respiratory system. Contact with the skin or eye can result in serious burns. Lewisite or Mustard-Lewisite also can cause damage to bone marrow and blood vessels. Exposure to high levels may be fatal. Blister agents Lewisite and Mustard-Lewisite have not been found in any of the 1,585 National Priorities List sites identified by the Environmental Protection Agency (EPA).

What are lewisite and mustard-lewisite?

Lewisite is an oily, colorless liquid with an odor like geraniums. Mustard-Lewisite Mixture is a liquid with a garlic-like odor. Mustard-Lewisite is a mixture of Lewisite and a sulfur mustard known as HD.

Lewisite might have been used as a chemical weapon by Japan against Chinese forces in the 1930s, but such reports have not been confirmed. Any stored Lewisite in the United States must be destroyed before April 2007, as mandated by the Chemical Weapons Convention.

What happens to lewisite and mustard-lewisite when it enters the environment?

  • Blister agents Lewisite and Mustard-Lewisite could enter the environment from an accidental release.
  • In air, blister agents Lewisite and Mustard-Lewisite will be broken down by compounds that are found in the air, but they may persist in air for a few days before being broken down.
  • Lewisite and Mustard-Lewisite will be broken down in water quickly, but small amounts may evaporate.
  • Lewisite and Mustard-Lewisite will be broken down in moist soil quickly, but small amounts may evaporate.
  • Lewisite and Mustard-Lewisite do not accumulate in the food chain.

How might I be exposed to lewisite and mustard-lewisite?

  • The general population will not be exposed to blister agents Lewisite or Mustard-Lewisite.
  • Lewisite and Mustard-Lewisite are no longer produced in the United States.
  • It is used in many industries and in hospitals and laboratories.
  • People that are potentially exposed to Lewisite or Mustard-Lewisite are soldiers who might be exposed to chemical weapons or people who work at military sites where these compounds are stored.

How can lewisite and mustard-lewisite affect my health?

If you breathe Lewisite or Mustard-Lewisite vapors, your airways will immediately become irritated. You could experience burning pain in the nose and sinuses, laryngitis, cough, shortness of breath, nausea, and vomiting. You could also experience airway tissue damage and accumulation of fluid in your lungs, which could result in death.

Contact of the skin with Lewisite or Mustard-Lewisite vapors or liquid will result in local pain, swelling, and rash, followed by blistering that might be delayed for hours. If Lewisite or Mustard-Lewisite vapors or liquid contact your eyes, you will suffer immediate pain and rapid swelling, as well as serious damage to the cornea and other parts of the eye.

Ingestion of Lewisite or Mustard-Lewisite will burn your mouth and throat, will cause severe stomach pain, nausea, vomiting, and bloody stools.

If some of the Lewisite and Mustard-Lewisite that you breathe, touch, or ingest, pass to your blood stream, it can cause bone marrow damage and fluid loss from your blood vessels, which could result in low blood pressure and damage to the rest of your body.

We do not know if exposure to Lewisite or Mustard-Lewisite causes reproductive effects in humans.

How likely are lewisite and mustard-lewisite to cause cancer?

The Department of Health and Human Services (DHHS), the International Agency for Research on Cancer (IARC), and the EPA have not classified Lewisite as to its carcinogenicity. Both the DHHS and IARC have classified the blister agent H/HD (the sulfur mustard used in the Mustard-Lewisite mixture) as a human carcinogen. We to not know whether the Mustard-Lewisite mixture might also be a human carcinogen.

How does lewisite and mustard-lewisite affect children?

There is no information on children exposed to Lewisite or Mustard-Lewisite, but children would probably be affected in the same ways as adults. We do not know whether children differ from adults in their susceptibility to these blister agents.

We do not know whether Lewisite or Mustard-Lewisite can cause developmental effects in humans.

How can families reduce the risk of exposure to lewisite and mustard-lewisite?

It is unlikely that families will be exposed to Lewisite or Mustard-Lewisite.

Is there a medical test to show whether I've been exposed to lewisite and mustard-lewisite?

There are no specific tests to indicate whether you have been exposed to Lewisite or Mustard-Lewisite. The presence of arsenic in the urine could indicate if you have been exposed to one of these blister agents.

Has the federal government made recommendations to protect human health?

An Airborne Exposure Limit (as recommended by the Surgeon General's Working Group, U.S. Department of Health and Human Services) of 0.003 milligrams of Lewisite and Mustard-Lewisite per cubic meter of air (0.003 mg/m³) has been established as a time-weighted average (TWA) for the workplace.


Agency for Toxic Substances and Disease Registry (ATSDR). 2002. Managing Hazardous Materials Incidents. Volume III – Medical Management Guidelines for Acute Chemical Exposures: Blister Agents: Lewisite (L), Mustard-Lewisite Mixture (HL). Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.

Where can I get more information?

If you have questions or concerns, please contact your community or state health or environmental quality department or:

For more information, contact:
Agency for Toxic Substances and Disease Registry
Division of Toxicology and Human Health Sciences
1600 Clifton Road NE, Mailstop F-57
Atlanta, GA 30329-4027
Phone: 1-800-CDC-INFO · 888-232-6348 (TTY)
Email: Contact CDC-INFO

ATSDR can also tell you the location of occupational and environmental health clinics. These clinics specialize in recognizing, evaluating, and treating illnesses resulting from exposure to hazardous substances.

Information line and technical assistance:
Phone: 888-422-8737

To order toxicological profiles, contact:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Phone: 800-553-6847 or 703-605-6000

Some PDF files may be electronic conversions from paper copy or other electronic ASCII text files. This conversion may have resulted in character translation or format errors. Users are referred to the original paper copy of the toxicological profile for the official text, figures, and tables. Original paper copies can be obtained via the directions on the toxicological profile home page, which also contains other important information about the profiles.

The information contained here was correct at the time of publication. Please check with the appropriate agency for any changes to the regulations or guidelines cited.

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