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PUBLIC HEALTH STATEMENT 

HMX 

CAS#: 2691-41-0 

Division of Toxicology September 1997 

This Public Health Statement is the summary 

chapter from the Toxicological Profile for HMX. It 

is one in a series of Public Health Statements about 

hazardous substances and their health effects. A 

shorter version, the ToxFAQsTM, is also available. 

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. For 

more information, call the ATSDR Information 

Center at 1-888-422-8737. 

_______________________________________ 

This Statement was prepared to give you 

information about HMX and to emphasize the 

human health effects that may result from exposure 

to it. The Environmental Protection Agency (EPA) 

has identified 1,416 hazardous waste sites as the 

most serious in the nation. These sites make up the 

National Priorities List (NPL) and are the sites 

targeted for long-term federal cleanup activities. 

HMX has been found in at least 10 of the sites on 

the NPL. However, the number of NPL sites 

evaluated for HMX is not known. As EPA evaluates 

more sites, the number of sites at which HMX is 

found may increase. This information is important 

because exposure to HMX may cause harmful 

health effects and because these sites are potential 

or actual sources of human exposure to HMX. 

When a substance is released from a large area, 

such as an industrial plant, or from a container, such 

as a drum or bottle, it enters the environment. This 

release does not always lead to exposure. You can 

be exposed to a substance only when you come in 

contact with it. You may be exposed by breathing, 

eating, or drinking substances containing the 

substance or by skin contact with it. 

If you are exposed to a substance such as HMX, 

many factors will determine whether harmful health 

effects will occur and what the type and severity of 

those health effects will be. These factors include 

the dose (how much), the duration (how long), the 

route or pathway by which you are exposed 

(breathing, eating, drinking, or skin contact), the 

other chemicals to which you are exposed, and your 

individual characteristics such as age, gender, 

nutritional status, family traits, life-style, and state 

of health. 

1.1 WHAT IS HMX? 

HMX, an acronym for High Melting eXplosive, is 

also known as octogen and cyclotetramethylenetetranitramine, as well as by other names. It is a 

colorless solid that dissolves slightly in water. Only 

a very small amount of HMX will evaporate into 

the air; however, it can occur in air attached to 

suspended particles or dust. The taste and smell of 

HMX are not known. 

HMX is a manmade chemical and does not occur 

naturally in the environment. It is made from other 

chemicals known as hexamine, ammonium nitrate, 

nitric acid, and acetic acid. HMX explodes violently 

at high temperatures (534°F and above). Because of 

this property, HMX is used in nuclear devices, 

plastic explosives, rocket fuels, and burster 

chargers. A small amount of HMX is also formed in 

making cyclotrimethylene-trinitramine (RDX), 

another explosive similar in structure to HMX. The 

amount of HMX made and used in the United States 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 
 

 

 

 

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PUBLIC HEALTH STATEMENT 

HMX 

CAS#: 2691-41-0 

Division of Toxicology September 1997 

at present is not known, but it is believed to be 

greater than 30 million pounds per year. 

1.2 WHAT HAPPENS TO HMX WHEN IT 

ENTERS THE ENVIRONMENT? 

Most of the HMX that enters the environment is 

released into waste water from places that make or 

use HMX. A small amount of HMX can be released 

to the air as dust or ash from facilities that burn 

waste contaminated with HMX. Some HMX may 

be released to soil as a result of accidental spills, the 

settling of HMX-containing dust particles from the 

air, or the disposal of waste that contains HMX in 

landfills. 

Dust particles containing HMX may be carried by 

the wind for some distance. The distance depends 

on a number of factors, including particle size, wind 

velocity, and weather conditions. Eventually, these 

particles settle to the earth, depositing on soil and 

surface waters. The length of time that HMX 

remains in the air is not known. 

In surface water, HMX does not evaporate or bind 

to sediments to any large extent. Sunlight breaks 

down most of the HMX in surface water into other 

compounds, usually in a matter of days to weeks. 

The amount of time HMX remains in surface water 

depends on how much light-absorbing material is 

present. A small amount of HMX may also be 

broken down by bacteria in the water. Some of the 

breakdown products of HMX (nitrite, nitrate, 

formaldehyde, 1,1-dimethylhydrazine) are also 

harmful to your health, although the amounts you 

may be exposed to as a result of HMX in your 

drinking water are not expected to be above trace 

levels. 

Laboratory studies show that HMX is likely to 

move from soil into groundwater, particularly in 

sandy soils. For most soils, however, the movement 

of HMX into groundwater is expected to be slow. 

Bacteria in the soil are not expected to break down 

HMX to any large extent. Exactly how long HMX 

will remain in the environment is not known; 

however, HMX in soil and groundwater is expected 

to stay there for a long time. It is not known if 

plants, fish, or animals living in areas contaminated 

with HMX build up high levels of the chemical in 

their tissues. 

1.3 HOW MIGHT I BE EXPOSED TO HMX? 

There is no information on how often you might be 

exposed to HMX in the environment or to how 

much. Most people, however, probably won't be 

exposed to HMX from the environment. People 

who work at facilities that make or use HMX or 

RDX, such as military personnel, may be exposed. 

These workers may be exposed by inhaling dusts 

that contain HMX or by getting HMX-containing 

liquids on their skin. People who live near facilities 

that make or use HMX, or near hazardous waste 

sites that contain HMX, may also be exposed. For 

these residents, exposure (if any) is most likely to 

occur from contaminated groundwater. However, 

exposures to small amounts of HMX from 

contaminated surface water, soil, and air are also 

possible. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 
 

 

 

 

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PUBLIC HEALTH STATEMENT 

HMX 

CAS#: 2691-41-0 

Division of Toxicology September 1997 

1.4 HOW CAN HMX ENTER AND LEAVE MY 

BODY? 

HMX can enter your body if you breathe 

contaminated air, swallow contaminated water or 

soil, or get substances that contain HMX on your 

skin. Very little is known about how much and how 

fast HMX enters your body after you are exposed. 

Limited information from laboratory studies in 

animals suggests that if you swallow HMX, only a 

small amount (less than 5 percent) will be absorbed 

into your blood. The rest of the HMX that is not 

absorbed leaves your body in your feces, usually 

within a day or two after you are exposed. Your 

blood carries the small amount of absorbed HMX to 

your tissues. Animal studies suggest that the 

resulting concentrations of HMX in your lungs, 

liver, heart, and kidneys may be slightly higher than 

the concentrations in other tissues. 

HMX does not remain in any of your tissues for 

very long. Information from animal studies suggests 

that your body can transform HMX into other 

compounds called metabolites. At present, the 

identity and toxicity of these metabolites are not 

known. Most of these metabolites leave your body 

in your urine, usually within a few days after you 

are exposed. Smaller amounts of these metabolites 

may be released in your feces or in the air you 

breathe out. 

1.5 HOW CAN HMX AFFECT MY HEALTH? 

Information on the adverse health effects of HMX is 

limited. In one human study, no adverse effects 

were reported in workers exposed to HMX in air. 

However, the concentrations of HMX in the 

workplace air were not reported in this study, and 

only a small number of workers and effects were 

investigated. 

Studies in rats, mice, and rabbits indicate that HMX 

may be harmful to your liver and central nervous 

system if it is swallowed or gets on your skin. The 

lowest dose producing any effects in animals was 

100 milligrams per kilogram of body weight per day 

(mg/kg/day) orally and 165 mg/kg/day on the skin. 

Limited evidence suggests that even a single 

exposure to these dose levels harmed rabbits. The 

mechanism by which HMX causes adverse effects 

on the liver and nervous system is not understood. 

The reproductive and developmental effects of 

HMX have not been well studied in humans or 

animals. At present, the information needed to 

determine if HMX causes cancer is insufficient. 

Due to the lack of information, EPA has determined 

that HMX is not classifiable as to its human 

carcinogenicity. 

1.6 IS THERE A MEDICAL TEST TO 

DETERMINE WHETHER I HAVE BEEN 

EXPOSED TO HMX? 

You can find out if you have been exposed to HMX 

by having your blood, urine, or feces tested for 

HMX. Since HMX is poorly absorbed after it is 

swallowed, the levels of HMX in your blood and 

urine are likely to be lower than those in your feces. 

For best results, tests for HMX should be done 

within a few days after you are exposed. These tests 

cannot be used to tell how much HMX you have 

been exposed to or to predict whether or not you 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov 
 

 

 

 

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PUBLIC HEALTH STATEMENT 

HMX 

CAS#: 2691-41-0 

Division of Toxicology September 1997 

will experience adverse health effects. These tests 

are not usually done in a doctor's office, but require 

that the samples be sent to a laboratory for testing. 

1.7 WHAT RECOMMENDATIONS HAS THE 

FEDERAL GOVERNMENT MADE TO 

PROTECT HUMAN HEALTH? 

The federal government has made several 

regulations and guidelines to protect human health. 

EPA recommends that the concentration of HMX in 

an adult's drinking water be less than 0.40 

milligrams per liter (mg/L) for a lifetime exposure. 

EPA regulates waste containing HMX as hazardous 

and has set restrictions on its disposal in landfills. 

The Department of State regulates the exportation 

of HMX, and the Department of Transportation 

regulates its transportation. The Bureau of Alcohol, 

Tobacco, and Firearms regulates the importation, 

manufacture, distribution, and storage of HMX. 

1.8 WHERE CAN I GET MORE 

INFORMATION? 

If you have any more questions or concerns, please 

contact your community or state health or 

environmental quality department or: 

Agency for Toxic Substances and Disease Registry 

Division of Toxicology 

1600 Clifton Road NE, Mailstop F-32 

Atlanta, GA 30333 

Information line and technical assistance: 

Phone: 888-422-8737 

FAX: (770)-488-4178 

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. 

To order toxicological profiles, contact: 

National Technical Information Service 

5285 Port Royal Road 

Springfield, VA 22161 

Phone: 800-553-6847 or 703-605-6000 

Reference 

Agency for Toxic Substances and Disease Registry 

(ATSDR). 1997. Toxicological profile for HMX. 

Atlanta, GA: U.S. Department of Health and 

Human Services, Public Health Service. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-888-422-8737 Fax: 770-488-4178 E-Mail: atsdric@cdc.gov