This fact sheet answers the most frequently asked health questions about sulfur mustard blister agents H/HD and HT. 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. This information is important 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.

Sulfur mustards H/HD and HT are manufactured compounds. They are colorless when pure, but are typically yellow to brown oily liquids with a slight garlic or mustard odor. Agent H contains about 20-30% impurities. The nearly pure substance is called HD. HT is a mixture of 60% HD and 40% of another substance called agent T. They do not dissolve much in water, but dissolve easily in oils, fats, and other solvents. They are stable at ambient temperatures.

Sulfur mustards were introduced as chemical warfare agents during World War I. More than a dozen countries have sulfur mustard agents in their chemical arsenals. Destruction of U.S. stockpiles of chemical agents, including sulfur mustards, was mandated by the Chemical Weapons Convention to take place before April 2007.

• Sulfur mustards are no longer produced in the United States.
• People who might be exposed to chemical weapons or who work at military sites where these compounds are stored have the potential of being exposed to these chemicals.

• The primary routes of potential human exposure to sulfur mustards are inhalation and dermal contact. Sulfur mustards are chemical warfare agents that can cause skin burns and blisters and damage to the respiratory airways. Sulfur mustards burn your skin and cause blisters within a few days of exposure. Exposure is particularly harmful around sweaty parts of the body. It is also more harmful to the skin on hot, humid days, or in tropical climates. Sulfur mustards make your eyes burn, your eyelids swell, and cause you to blink a lot.
• If you breath sulfur mustards, it can cause coughing, bronchitis, and long-term respiratory disease. If you are exposed to large amounts of sulfur mustards, you can eventually die from it.
• Sulfur mustards did not affect reproduction in rats that breathed it. We do not know if sulfur mustards can affect people's ability to reproduce.

The primary routes of potential human exposure to sulfur mustards are inhalation and dermal contact. Sulfur mustards are chemical warfare agents that can cause skin burns and blisters and damage to the respiratory airways. Sulfur mustards burn your skin and cause blisters within a few days of exposure. Exposure is particularly harmful around sweaty parts of the body. It is also more harmful to the skin on hot, humid days, or in tropical climates. Sulfur mustards make your eyes burn, your eyelids swell, and cause you to blink a lot.

If you breath sulfur mustards, it can cause coughing, bronchitis, and long-term respiratory disease. If you are exposed to large amounts of sulfur mustards, you can eventually die from it.

Sulfur mustards did not affect reproduction in rats that breathed it. We do not know if sulfur mustards can affect people's ability to reproduce.

The Department of Heath and Human Services (DHHS) has determined that blister agent H/HD is a known human carcinogen. The International Agency for Research on Cancer (IARC) has classified agent H/HD as carcinogenic to humans. Studies in humans indicate that long-term exposure to sulfur mustards may lead to cancer of the upper respiratory airways.

There are no studies of children exposed to sulfur mustard agents H/HD or HT. Children exposed to sulfur mustard agents H/HD or HT are likely to experience the same toxic effects experienced by exposed adults. In general, children may be more vulnerable to corrosive agents than adults because of the smaller diameter of their airways.

Sulfur mustards did not cause birth defects in rats that breathed it. We do not know if these substances can cause birth defects or other developmental effects in humans.

It is unlikely that the general population will be exposed to sulfur mustard agents H/HD or HT.

There is no effective medical test to determine if you have been exposed to sulfur mustards. A breakdown product of sulfur mustards can be measured in urine, but this chemical can also be found in people who have not been exposed to sulfur mustards.

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 H/HD or HT 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: Sulfur Mustard Agent H/HD, Sulfur Mustard Agent HT. Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service.

ATSDR can tell you where to find occupational and environmental health clinics. Their specialists can recognize, evaluate, and treat illnesses resulting from exposure to hazardous substances. You can also contact your community or state health or environmental quality department if you have any more questions or concerns.

For more information, contact:

Agency for Toxic Substances and Disease Registry
Division of Toxicology
1600 Clifton Road NE, Mailstop F-32
Atlanta, GA 30333
Phone: 1-888-42-ATSDR (1-888-422-8737)
FAX:   (770)-488-4178
Email: ATSDRIC@cdc.gov