ToxFAQs™ for for Blister Agents:
HN-1, HN-2, HN-3 (Nitrogen Mustards)
Spanish: Agentes que Causan Ampollas: Mostazas de Nitrógeno (HN-1, HN-2,
CAS#: 538-07-8 (HN-1); 51-75-2 (HN-2); 555-77-1 (HN-3)
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This fact sheet answers the most frequently
asked health questions about nitrogen mustards. 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 public will be exposed to nitrogen mustards agents HN-1, HN-2, and HN-3. Exposure to vapors of nitrogen mustards can damage the respiratory airways. Contact with the skin or eyes may cause burns. When nitrogen mustards are absorbed by the body, they may cause damage to bone marrow and the immune system. Exposure to high levels can cause death. Nitrogen mustards HN-1, HN-2, and HN-3 have not been identified in any of the 1,585 National Priorities List sites identified by the Environmental Protection Agency (EPA).
What are nitrogen mustards?
Nitrogen mustards (HN-1, HN-2, HN-3)
are colorless to yellow, oily liquids that evaporate very
slowly. HN-1 has a faint, fishy or musty odor. HN-2 has a
soapy odor at low concentrations and a fruity odor at higher
concentrations. HN-3 may smell like butter almond.
Although nitrogen mustards could be used
in chemical warfare, there are presently no records of such
use. HN-1 has been used to remove warts in the past, and HN-2
has been used sparingly in chemotherapy.
What happens to nitrogen mustards when they enter the environment?
- Nitrogen mustards HN-1, HN-2, and HN-3 could enter the
environment from an accidental release.
- When released to air, nitrogen mustards 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.
- Nitrogen mustards will be broken down in water quickly,
and only small amounts may evaporate.
- Nitrogen mustards will be broken down in moist soil quickly,
and only small amounts may evaporate.
- Nitrogen mustards do not accumulate in the food chain.
How might I be exposed to nitrogen mustards?
- The general population will not be exposed to nitrogen
- The nitrogen mustards HN-1, HN-2, and HN-3 are not manufactured
in significant commercial quantities in the United States.
Although several of the nitrogen mustards have medicinal
uses and as chemical warfare agents, they were never stockpiled
as part of the U.S. chemical warfare inventory.
How can nitrogen mustards affect my health?
If you breathe nitrogen mustard vapors,
you will likely experience such effects as nasal and sinus
pain or discomfort, pharyngitis, laryngitis, cough, and shortness
of breath. Damage to cells lining your airways may begin within
hours and get worse over the next several days. Exposure to
high levels could cause death.
Skin contact with nitrogen mustard vapors
or liquid, will likely cause initial swelling and rash, followed
by blistering. Contact with high levels of nitrogen mustards
can result in second- and third-degree burns. If nitrogen
mustards touch the eye, you may experience eye inflammation,
pain, swelling, corneal damage, burns, and even blindness.
If you swallow nitrogen mustards, you
will probably experience burning of the mouth, esophagus,
When nitrogen mustards are absorbed by
the body, they may cause damage to your immune system and
There is some evidence that nitrogen
mustard treatment in humans may result in decreased fertility.
How likely are nitrogen mustards to cause cancer?
The International Agency for Research
on Cancer (IARC) has classified nitrogen mustard HN-2 as probably
carcinogenic to humans, based on evidence that it causes leukemia
in humans and cancers of the lung, liver, uterus, and large
intestine in animals.
How can nitrogen mustards affect children?
Children exposed to nitrogen mustards
would probably experience the same effects seen in exposed
adults. But we do not know whether children differ from adults
in their susceptibility to nitrogen mustards.
A few case reports have linked treatment
with HN-2 in pregnant mothers to changes in the unborn child.
Nitrogen mustards have been shown to cause damage to the fetus
How can families reduce the risk of exposure to nitrogen mustards?
Families are not likely to be exposed
to nitrogen mustards.
Is there a medical test to show whether I've been exposed to nitrogen mustards?
There are no specific tests to indicate
whether you have been exposed to nitrogen mustards.
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 HN-1 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: HN-1, HN-2, HN-3 (Nitrogen
Mustards). 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
Office of Innovation and Analytics, Toxicology Section
4770 Buford Highway
Chamblee, GA 30341-3717
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.