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PUBLIC HEALTH STATEMENT 

DIISOPROPYL METHYLPHOSPHONATE 

CAS#: 1445-75-6 

Division of Toxicology August 1998 

This Public Health Statement is the summary 

chapter from the Toxicological Profile for 

Diisopropyl methylphosphonate. 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 public health statement tells you about 

diisopropyl methylphosphonate and the effects of 

exposure. 

The Environmental Protection Agency (EPA) 

identifies the most serious hazardous waste sites in 

the nation. These sites make up the National 

Priorities List (NPL) and are the sites targeted for 

long-term federal clean-up. Diisopropyl 

methylphosphonate has been found in at least 2 of 

the 1,416 current or former NPL sites. However, 

it's unknown how many NPL sites have been 

evaluated for this substance. This is important 

because exposure to this substance may harm you 

and because these sites may be sources of exposure. 

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 are 

exposed to a substance only when you come in 

contact with it. You may be exposed by breathing, 

eating, or drinking the substance or by skin contact. 

If you are exposed to diisopropyl 

methylphosphonate, many factors determine 

whether you'll be harmed. These factors include the 

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

you come in contact with it. You must also 

consider the other chemicals you're exposed to and 

your age, sex, diet, family traits, lifestyle, and state 

of health. 

1.1 WHAT IS DIISOPROPYL 

METHYLPHOSPHONATE? 

Diisopropyl methylphosphonate is a colorless liquid 

at normal temperatures. It is also known as methyl-

,bis-(1-methyl-ethyl)ester, phosphonic acid, and 

methyl-diisopropyl ester. 

Diisopropyl methylphosphonate, or DIMP, is a 

chemical by-product resulting from the manufacture 

and detoxification of GB (also called Sarin), a nerve 

gas that the Army produced from 1953 to 1957. A 

chemical by-product is a chemical that is formed 

while making another substance. You might find 

diisopropyl methylphosphonate in places where GB 

has been produced, stored, or used, for example, the 

Rocky Mountain Arsenal (RMA) outside of Denver, 

Colorado. The RMA is where GB was produced for 

loading into chemical warfare munitions. 

Production of GB was discontinued in 1957, and it 

is not likely that GB, or diisopropyl 

methylphosphonate, will be produced in the United 

States in the future because of signing of a chemical 

treaty that bans not only the use but also the 

production and stockpiling of poison gases. 

Diisopropyl methylphosphonate is a colorless 

liquid. A small amount (0.1%, or 1g of DIMP in 

1,000 mL of water) of it dissolves in water, but 

some scientists have found it to be more soluble 

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 

DIISOPROPYL METHYLPHOSPHONATE 

CAS#: 1445-75-6 

Division of Toxicology August 1998 

(8%). Once it is dissolved, little, if any, evaporates 

into the air. 

1.2 WHAT HAPPENS TO DIISOPROPYL 

METHYLPHOSPHONATE WHEN IT 

ENTERS THE ENVIRONMENT? 

Diisopropyl methylphosphonate was released into 

the environment at the RMA between 1953 and 

1957. While most discharged diisopropyl 

methylphosphonate entered the groundwater at the 

RMA, some also entered the surface water and 

soils. It is unlikely that diisopropyl 

methylphosphonate escaped to the air because it 

does not evaporate easily. Diisopropyl 

methylphosphonate does not break down in the 

environment very quickly and can remain in water 

and soil for years. The flow of water during 

irrigation can carry diisopropyl methylphosphonate 

through the soil. Plants can take up diisopropyl 

methylphosphonate and store or accumulate it in 

leaves and DIMP may enter the food chain when 

animals eat these plants. However, because DIMP 

is rapidly changed to isopropyl methylphosphonic 

acid (IMPA) by animals that eat it, it is unlikely that 

DIMP will be present further up the food chain. 

Human exposure may also occur by consumption of 

home-grown fruits and vegetables irrigated by 

DIMP-contaminated water. 

1.3 HOW MIGHT I BE EXPOSED TO 

DIISOPROPYL 

METHYLPHOSPHONATE? 

Exposure of the general population to diisopropyl 

methylphosphonate is expected to be rare and even 

then in small amounts. Only people living near a 

site where DIMP is found (such as RMA) may be 

exposed to this substance. 

Drinking or showering with water containing 

diisopropyl methylphosphonate, or eating 

vegetables irrigated with it are the most likely ways 

that a person can be exposed to it. Water 

contaminated with DIMP has been found only at or 

near the RMA. In 1974 diisopropyl 

methylphosphonate was first measured in the 

groundwater at RMA. The reported amounts 

ranged from 0.5 parts per billion (ppb) to 44,000 

ppb (1 ppb is equivalent to one part by weight of 

diisopropyl methylphosphonate in a billion parts by 

volume of water or soil). In 1989, soil samples 

from some areas in the RMA were reported to 

contain approximately 50 ppb to 240 ppb of 

diisopropyl methylphosphonate. During the most 

recent comprehensive groundwater sampling at 

RMA in 1995, diisopropyl methylphosphonate 

concentrations in groundwater were reported to 

range from less than 0.110 ppb to 965 ppb. It is 

possible that exposure to diisopropyl 

methylphosphonate might occur by eating plants 

that absorbed it from water or soil. 

1.4 HOW CAN DIISOPROPYL 

METHYLPHOSPHONATE ENTER AND 

LEAVE MY BODY? 

Diisopropyl methylphosphonate may enter your 

body after drinking water contaminated with it or it 

may enter through your skin. You could be exposed 

to diisopropyl methylphosphonate if you drink 

water that contains the chemical near the RMA. 

Exposure of the general population to diisopropyl 

methylphosphonate is not likely to occur. Studies 

in animals show that diisopropyl 

methylphosphonate enters the bloodstream 

relatively quickly following oral exposure. Animal 

studies also show that once diisopropyl 

methylphosphonate is inside the body, it is changed 

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 

DIISOPROPYL METHYLPHOSPHONATE 

CAS#: 1445-75-6 

Division of Toxicology August 1998 

almost completely into isopropyl methylphosphonic 

acid (IMPA) and leaves the body in the urine. 

1.5 HOW CAN DIISOPROPYL 

METHYLPHOSPHONATE AFFECT MY 

HEALTH? 

Scientists use many tests to protect the public from 

the harmful effects of toxic chemicals and to find 

ways to treat people who have been harmed. 

One way to see if a chemical will hurt people is to 

learn how the chemical is absorbed, changed, and 

released by the body; for some chemicals, animal 

testing may be necessary. Animal testing may also 

be used to identify health effects such as cancer or 

birth defects. Without laboratory animals, scientists 

would lose a basic method to get information 

needed to make wise decisions to protect public 

health. Scientists have the responsibility to treat 

research animals with care and compassion. Laws 

today protect the welfare of research animals, and 

scientists must comply with strict animal care 

guidelines. 

Little is known about the human health effects of 

diisopropyl methylphosphonate. Skin rashes and 

other signs of irritation have been reported in some 

people who handled dead animals near a pond 

containing diisopropyl methylphosphonate and 

other chemicals, but it is not known which 

substances caused these effects. 

Drinking large amounts of diisopropyl 

methylphosphonate kills animals. The amount 

needed to cause death in humans is not known for 

sure. Animal studies have shown no evidence that 

drinking or eating diisopropyl methylphosphonate 

causes fertility problems or birth defects. Animal 

studies have shown that eating diisopropyl 

methylphosphonate can affect some liver enzymes 

(indicating a response by the liver). However, test 

animals showed no liver disease. While most 

animal studies have shown only minimal toxic 

effects below a certain level of exposure, there is 

some evidence that diisopropyl methylphosphonate 

can cause effects on the blood and nervous systems 

at high levels. Overall, however, it is not a very 

toxic chemical. 

1.6 IS THERE A MEDICAL TEST TO 

DETERMINE WHETHER I HAVE BEEN 

EXPOSED TO DIISOPROPYL 

METHYLPHOSPHONATE? 

Once inside the body, diisopropyl 

methylphosphonate is rapidly converted to 

isopropyl methylphosphonic acid (IMPA), which is 

rapidly cleared from the blood. Laboratory tests 

can determine the amount of IMPA in the blood or 

urine. However, because IMPA leaves the body 

rapidly, these tests are useful only for recent 

exposure. It is helpful for your doctor to know 

whether there are other chemicals to which you 

have been exposed. 

1.7 WHAT RECOMMENDATIONS HAS THE 

FEDERAL GOVERNMENT MADE TO 

PROTECT HUMAN HEALTH? 

The federal government develops regulations and 

recommendations to protect public health. 

Regulations can be enforced by law. Federal 

agencies that develop regulations for toxic 

substances include the Environmental Protection 

Agency (EPA), the Occupational Safety and Health 

Administration (OSHA), and the Food and Drug 

Administration (FDA). Recommendations provide 

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 

DIISOPROPYL METHYLPHOSPHONATE 

CAS#: 1445-75-6 

Division of Toxicology August 1998 

valuable guidelines to protect public health but 

cannot be enforced by law. Federal organizations 

that develop recommendations for toxic substances 

include the Agency for Toxic Substances and 

Disease Registry (ATSDR) and the National 

Institute for Occupational Safety and Health 

(NIOSH). 

Regulations and recommendations can be expressed 

in not-to-exceed levels in air, water, soil, or food 

that are usually based on levels that affect animals, 

then they are adjusted to help protect people. 

Sometimes these not-to-exceed levels differ among 

federal organizations because of different exposure 

times (an 8-hour workday or a 24-hour day), the use 

of different animal studies, or other factors. 

Recommendations and regulations are also 

periodically updated as more information becomes 

available. For the most current information, check 

with the federal agency or organization that 

provides it. Some regulations and 

recommendations for diisopropyl 

methylphosphonate include the following: 

The EPA has issued guidelines concerning 

recommendations for levels of diisopropyl 

methylphosphonate that may be in drinking water, 

including Health Advisories. It has concluded that 

a lifetime of exposure to drinking water containing 

0.6 mg/L (1 mg/L = 1 milligram of diisopropyl 

methylphosphonate in 1 liter of water) of 

diisopropyl methylphosphonate would not result in 

any noncancer harmful health effects. This amount, 

0.6 mg/L, is the same as 600 parts per billion parts 

of water. The EPA has determined that diisopropyl 

methylphosphonate is unclassifiable as to its ability 

to cause cancer in humans, that is, there are not 

enough data to classify the ability of diisopropyl 

methylphosphonate to cause cancer in humans. 

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). 1998. Toxicological profile for 

diisopropyl methylphosphonate. 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