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PUBLIC HEALTH STATEMENT 

1,2-DIPHENYLHYDRAZINE 

CAS#: 122-66-7 

Division of Toxicology December 1990 

This Public Health Statement is the summary 

chapter from the Toxicological Profile for 1,2-

Diphenylhydrazine. 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 1,2-diphenylhydrazine and to 

emphasize the human health effects that may result 

from exposure to it. The Environmental Protection 

Agency (EPA) has identified 1,177 sites on its 

National Priorities List (NPL). 1,2-

Diphenylhydrazine has been found at seven of these 

sites. However, we do not know how many of the 

1,177 NPL sites have been evaluated for 1,2-

diphenylhydrazine. As EPA evaluates more sites, 

the number of site at which 1,2-diphenylhydrazine 

is found may change. The information is important 

for you because 1,2-diphenylhydrazine may cause 

harmful health effects and because these sites are 

potential or actual sources of human exposure to 

1,2-diphenylhydrazine. 

When a chemical 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 as a 

chemical emission. This emission, which is also 

called a release, does not always lead to exposure. 

You can be exposed to a chemical only when you 

come into contact with the chemical. You may be 

exposed to it in the environment by breathing, 

eating, or drinking substances containing the 

chemical or from skin contact with it. 

If you are exposed to a hazardous substance such as 

1,2-diphenylhydrazine several 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, sex, 

nutritional status, family traits, life style, and state 

of health. 

1.1 WHAT IS 1,2-DIPHENYLHYDRAZINE? 

1,2-Diphenylhydrazine is a white solid. It dissolves 

only slightly in water and does not change into a gas 

unless it is heated to very high temperatures. It 

sticks to soil and can be carried into the air along 

with windblown dust. Once in water or exposed to 

air it is changed into other chemicals within 

minutes. These chemicals include the toxic 

chemicals azobenzene and benzidine. 

1,2-Diphenylhydrazine is used to make fabric dyes 

in other countries, and to make certain medicines. 

There are no other major anthropogenic or natural 

sources of 1,2-diphenylhydrazine. 

1.2 HOW MIGHT I BE EXPOSED TO 1,2-

DIPHENYLHYDRAZINE? 

1,2-Diphenylhydrazine does not dissolve in water 

easily and reacts quickly when present in water. 

Therefore, it is extremely unlikely that you would 

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 

1,2-DIPHENYLHYDRAZINE 

CAS#: 122-66-7 

Division of Toxicology December 1990 

be exposed to it by drinking water. Also, 1,2-

diphenylhydrazine does not change to a gas at 

normal outside temperatures. Therefore, it is 

extremely unlikely that you would be exposed to it 

by breathing air even if you live near a hazardous 

waste site. Because 1,2-diphenylhydrazine may 

stick to soil, it is possible that you could breathe in 

dust coated with 1,2-diphenylhydrazine if you 

entered a hazardous waste site in which it had been 

recently spilled on the ground. It is also possible 

that children playing at this hazardous waste site 

could be exposed by eating dirt or smearing dirt on 

their skin. It would have to be a site in which the 

1,2-diphenylhydrazine was recently spilled on the 

ground, since once exposed to air, 1,2-

diphenylhydrazine changes into other substances 

within minutes. 

You also could be exposed to 1,2-

diphenylhydrazine if you work in an industry in 

which it is used. For example, while working, you 

could be exposed to dust containing 1,2-

diphenylhydrazine when it is moved from one place 

to another. It has not been found in food or in air or 

natural soils. If 1,2-diphenylhydrazine exists at all 

in lakes or streams, it is probably at levels that are 

less than 1 part 1,2-diphenylhydrazine in 1,000,000 

parts water (1 ppm). 

1.3 HOW CAN 1,2-DIPHENYLHYDRAZINE 

ENTER AND LEAVE MY BODY? 

If you were to breathe in dust coated with 1,2-

diphenylhydrazine you would probably breathe out 

most of it within a few minutes; however, some of it 

might enter your body. Also, if you were to eat dust 

or dirt coated with 1,2-diphenylhydrazine, some of 

it might enter your body. However, we do not know 

how much or how long it would take for the 1,2-

diphenylhydrazine that you breathe in or eat to enter 

your body. It is not known if 1,2-diphenylhydrazine 

would enter your body if you were to spill it on 

your skin or if you were to get dirt coated with it on 

your skin. Some, maybe most of 1,2-

diphenylhydrazine that enters your body leaves your 

body in the urine. It is not known how long it takes 

for 1,2-diphenylhydrazine to leave the body in the 

urine. 

1.4 HOW CAN 1,2-DIPHENYLHYDRAZINE 

AFFECT MY HEALTH? 

It is not known if 1,2-diphenylhydrazine would 

affect your health if you were to breathe it in or eat 

it. The health effects of 1,2-diphenylhydrazine in 

humans have not been studied. Animals die if they 

swallow large amounts of 1,2-diphenylhydrazine 

and develop liver disease if they eat small amounts 

of 1,2-diphenylhydrazine for more than a year. 

Therefore, it is possible that if you were to eat large 

amounts of 1,2-diphenylhydrazine for a long time 

you might experience liver damage or die. 

It is not known whether 1,2-diphenylhydrazine 

would harm you if you were to spill it on you skin. 

It is not known if 1,2-diphenylhydrazine causes 

birth defects or affects fertility. It is not known if 

1,2-diphenylhydrazine causes cancer in humans; 

however, it has been shown to cause cancer in rats 

and mice that have eaten it in food for most of their 

lifetime. Therefore, the U.S. Environmental 

Protection Agency (EPA) has determined 1,2-

diphenylhydrazine to be a probable human 

carcinogen. 

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 

1,2-DIPHENYLHYDRAZINE 

CAS#: 122-66-7 

Division of Toxicology December 1990 

1.5 WHAT LEVELS OF EXPOSURE HAVE 

RESULTED IN HARMFUL HEALTH 

EFFECTS? 

It is not known what levels of 1,2-

diphenylhydrazine result in harmful health effects in 

people or animals. 

1.6 IS THERE A MEDICAL TEST TO 

DETERMINE WHETHER I HAVE BEEN 

EXPOSED TO 1,2-

DIPHENYLHYDRAZINE? 

There is no test to determine if you have been 

exposed to 1,2-diphenylhydrazine. 

1.7 WHAT RECOMMENDATIONS HAS THE 

FEDERAL GOVERNMENT MADE TO 

PROTECT HUMAN HEALTH? 

The EPA recommends that levels of 1,2-

diphenylhydrazine in lakes and streams should be 

limited to 0.041 parts per billion (0.041 ppb) to 

prevent possible human health effects from drinking 

water or eating fish contaminated with this 

chemical. Any release to the environment greater 

than 10 pounds of 1,2-diphenylhydrazine must be 

reported to the EPA. 

The federal recommendations have been updated as 

of July 1999. 

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). 1990. Toxicological profile for 1,2-

diphenylhydrazine. 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