PUBLIC HEALTH STATEMENT 

 Hexachlorobenzene CAS#: 118-74-1 

Division of Toxicology September 2002 

__________________________________________________________________________________________

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 

This Public Health Statement is the summary 

chapter from the Toxicological Profile for 

Hexachlorobenzene. 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 

hexachlorobenzene 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 cleanup activities. 

Hexachlorobenzene has been found in at least 107 

of the 1,613 current or former NPL sites. However, 

the total number of NPL sites evaluated for this 

substance is not known. As more sites are 

evaluated, the sites at which hexachlorobenzene is 

found may increase. This information 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 hexachlorobenzene, 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 HEXACHLOROBENZENE? 

Hexachlorobenzene is a white crystalline solid. This 

compound does not occur naturally. It is formed as 

a by-product during the manufacture of chemicals 

used as solvents (substances used to dissolve other 

substances), other chlorine-containing compounds, 

and pesticides. Small amounts of 

hexachlorobenzene can also be produced during 

combustion processes such as burning of city 

wastes. It may also be produced as a by-product in 

waste streams of chlor-alkali and wood- preserving 

plants. Hexachlorobenzene was widely used as a 

pesticide until 1965. It was also used to make 

fireworks, ammunition, and synthetic rubber. 

Currently, the substance is not used commercially in 

the United States. 

 

1.2 WHAT HAPPENS TO 

HEXACHLOROBENZENE WHEN IT 

ENTERS THE ENVIRONMENT? 

Hexachlorobenzene tends to remain in the 

environment for a long time. If it is released to the 

soil, it has a half-life of 3-6 years. This means that 

half of the total amount will disappear after 3-6 

years, half of the remaining amount will disappear 

in another 3-6 years, and this process will continue 

each 3-6 years thereafter. If it is released to surface 

waters such as lakes, rivers, and streams, the halflife is 2.7-5.7 years, and if it is released to 
 PUBLIC HEALTH STATEMENT 

 Hexachlorobenzene CAS#: 118-74-1 

Division of Toxicology September 2002 

__________________________________________________________________________________________

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 

groundwater, the half-life is 5.3-11.4 years. Since 

hexachlorobenzene does not dissolve in water very 

well, most of it will remain in particles on the 

bottom of lakes, rivers, or streams. The evaporation 

of hexachlorobenzene into the air is not significant 

under ordinary conditions. Once in the air, it can be 

carried over wide geographic areas. Its half-life in 

air ranges from 0.63 to 6.28 years. 

 

1.3 HOW MIGHT I BE EXPOSED TO 

HEXACHLOROBENZENE? 

 

You may be exposed to hexachlorobenzene if you 

live near an industrial site where it is produced as an 

unintentional by-product or as a minor part of 

another chemical product. You may also be exposed 

if you live near a hazardous waste site where 

hexachlorobenzene has been discarded. At these 

sites, hexachlorobenzene may be carried in the air 

on dust particles. The levels of it in the air around 

these sites are not known. The amount you might 

breathe in urban air is very small, about 0.00003 

parts per million (ppm). If you work in an industry 

that uses or produces it unintentionally as a byproduct, you may also breathe in 

hexachlorobenzene particles or dust that carries it, 

and it may touch your skin. In workplaces where 

hexachlorobenzene is used or disposed, an 

estimated 1-1.4 ppm of this substance has been 

measured in the air. You can also be exposed to it 

through contact with soil or dust particles 

contaminated with hexachlorobenzene, or by 

breathing air contaminated by industrial releases 

into the environment. 

Because it does not dissolve easily in water, this 

substance is usually not present in high 

concentrations in drinking water. Based on a 

national survey, it was detected at very low levels in 

surface water and groundwater systems. Drinking 

water in three cities contained only trace amounts of 

hexachlorobenzene. Therefore, exposure to this 

substance through drinking water is limited. 

Eating foods such as shellfish, fish, and certain 

vegetables can also expose people to 

hexachlorobenzene. Additionally, you can be 

exposed to hexachlorobenzene by eating and 

drinking foods and liquids, such as milk, other dairy 

products, meat, and poultry, if the animals from 

which these products are obtained have been 

exposed to it through their feed or other sources of 

contamination. Additionally, fat and oil in food may 

increase the amount of hexachlorobenzene that 

enters the body from food. 

Low levels of hexachlorobenzene have been found 

in the fatty tissues of almost all people tested. These 

amounts are most likely the result of low levels in 

food. An estimated average yearly uptake of 1 

microgram per kilogram (μg/kg) of body weight has 

been calculated for exposure to contaminated food. 

Exposure by breathing contaminated air is estimated 

to be 0.01 μg/kg/year. This is 100 times less than 

the exposure from eating contaminated foods. 

Drinking contaminated water is estimated to 

contribute only very small amounts (0.00085 

μg/kg/year). 

 

1.4 HOW CAN HEXACHLOROBENZENE 

ENTER AND LEAVE MY BODY? 

Hexachlorobenzene can enter your body when you 

eat food contaminated with it, when you breathe 

particles of it in the air, or when it gets on your skin. 

After it enters your body, it rapidly spreads through 

your blood to many tissues in the body, especially 

to fat. This probably happens within a few hours. 
 PUBLIC HEALTH STATEMENT 

 Hexachlorobenzene CAS#: 118-74-1 

Division of Toxicology September 2002 

__________________________________________________________________________________________

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 

Based on the results of a survey of this substance in 

people's tissues, it will remain in your body, 

especially in fat, for years. A large portion of 

hexachlorobenzene in the fat of a mother can be 

transferred to her baby in breast milk. During 

pregnancy, this substance can transfer to the unborn 

child through the mother's blood. Most of it leaves 

your body in the feces; smaller amounts are found 

in urine. 

 

1.5 HOW CAN HEXACHLOROBENZENE 

AFFECT MY HEALTH? 

 

To protect the public from the harmful effects of 

toxic chemicals and to find ways to treat people 

who have been harmed, scientists use many tests. 

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

learn how the chemical is absorbed, used, 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. 

A study of people in Turkey who, over a period of 

several years, ate grain that was accidentally 

contaminated with hexachlorobenzene, showed a 

high death rate in young children of mothers who 

ate it and in young children who ate it themselves. 

Nursing infants may be in particular danger from 

the transfer of hexachlorobenzene through breast 

milk if their mothers have been exposed. Unborn 

children may also be at particular risk because of 

the transfer of hexachlorobenzene through the 

mother's blood during pregnancy. This has been 

confirmed by experiments in animals. 

People in Turkey who, over a long time, ate grain 

that was accidentally contaminated with 

hexachlorobenzene suffered from a liver disease 

called porphyria cutanea tarda. The main effect of 

porphyria is slowed or stopped formation of heme, 

the oxygen-carrying part of the hemoglobin 

molecule found in red blood cells and an important 

chemical in the body. Porphyria is identified by 

elevation of heme precursors called porphyrins in 

the blood, urine, and stool. This disease can cause 

red-colored urine, skin sores, change in skin color, 

arthritis, and problems of the liver, nervous system, 

and stomach. Studies in animals also show that 

eating hexachlorobenzene for a long time can harm 

mostly the liver, thyroid, and nervous systems; the 

studies in animals also show that eating 

hexachlorobenzene for months or years can damage 

bones, kidneys, and blood, and the immune, 

endocrine (hormone-releasing), and nervous 

systems. Unborn children and young children may 

be more sensitive to these effects than adults. 

Studies in animals also suggest that eating this 

substance for months or years can cause cancer of 

the liver, kidney, and thyroid, but there is no strong 

evidence that the substance causes cancer in people. 

The U.S. Department of Health and Human 

Services (DHHS) has determined that the substance 

may reasonably be anticipated to be a human 

carcinogen. The International Agency for Research 

on Cancer (IARC) has determined that 

hexachlorobenzene is possibly carcinogenic to 

humans. EPA has determined that 

hexachlorobenzene is a probable human carcinogen. 
 PUBLIC HEALTH STATEMENT 

 Hexachlorobenzene CAS#: 118-74-1 

Division of Toxicology September 2002 

__________________________________________________________________________________________

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 

There is no information on levels of 

hexachlorobenzene in air that affect people. No 

information is available on the taste or lowest levels 

at which you can taste or smell it in air or water. 

Therefore, people may not know when 

hexachlorobenzene is present in air or water. 

Studies conducted with rats indicate that breathing 

hexachlorobenzene may harm the immune system. 

The health effects from getting it on your skin are 

not known. 

1.6 HOW CAN HEXACHLOROBENZENE 

AFFECT CHILDREN? 

This section discusses potential health effects from 

exposures during the period from conception to 

maturity at 18 years of age in humans. 

Infants and young children appeared to be 

especially sensitive to the effects of 

hexachlorobenzene in the Turkish grain poisoning 

epidemic. Breast-fed infants of mothers known to 

have ingested the contaminated bread developed a 

disease known as pembe yara or "pink sore." The 

disease was named for the skin lesions that were 

produced. Other symptoms were weakness and 

convulsions. Many of the sickened infants died 

from this disease. Young children beyond 2 years of 

age did not get pink sore, but they did develop 

numerous skin, nervous system, and bone 

abnormalities later in life. 

One study found higher levels of 

hexachlorobenzene in mother's milk in babies who 

had ear infections than in the milk of babies without 

ear infections. Another study found higher levels of 

hexachlorobenzene in the fat of boys with a specific 

type of birth defect, undescended testis, than in the 

fat of normal boys. We do not know if 

hexachlorobenzene caused the infection or the birth 

defect. 

Animal studies support the suggestion that young 

animals exposed to hexachlorobenzene before and 

soon after birth are especially sensitive to 

hexachlorobenzene. Effects on the liver, nervous 

system, and immune function occurred at lower 

doses in the young developing animals than in 

adults. Animal studies also showed that 

hexachlorobenzene has effects on various endocrine 

organs, including the thyroid gland 

(hypothyroidism), parathyroid gland 

(hyperparathyroidism), adrenal gland, and ovaries. 

These tissues produce hormones that are important 

to normal growth and development of the organism. 

1.7 HOW CAN FAMILIES REDUCE THE 

RISK OF EXPOSURE TO 

HEXACHLOROBENZENE? 

 

If your doctor finds that you have been exposed to 

significant amounts of hexachlorobenzene, ask 

whether your children might also be exposed. Your 

doctor might need to ask your state health 

department to investigate. 

The primary way most people are exposed is 

through food. Fatty food may be higher in 

hexachlorobenzene than less fatty food. 

Additionally, when hexachlorobenzene is present in 

food, more may be absorbed when the food is fatty 

than when the food is less fatty. Therefore, eating 

less fatty food may reduce the risk of exposure to 

hexachlorobenzene. 

If you live near an industrial site where 

hexachlorobenzene was produced or is produced as 

an unintentional by-product or you live near a 
 PUBLIC HEALTH STATEMENT 

 Hexachlorobenzene CAS#: 118-74-1 

Division of Toxicology September 2002 

__________________________________________________________________________________________

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 

hazardous waste site where it has been discarded, 

there may be high levels of hexachlorobenzene in 

the water and soil. Substituting cleaner sources of 

water and limiting contact with soil (for example, 

through use of a dense ground cover or thick lawn) 

would reduce family exposure to 

hexachlorobenzene. Produce grown in contaminated 

soil should not be eaten. By paying careful attention 

to dust and dirt control in the home (air filters, 

frequent cleaning), you can reduce family exposure 

to contaminated dirt. Some children eat a lot of dirt. 

You should prevent your children from eating dirt. 

You should discourage your children from putting 

objects in their mouths. Make sure that they wash 

their hands frequently and before eating. 

Discourage your children from putting their hands 

in their mouths or from other hand-to-mouth 

activity. 

It is sometimes possible to carry hexachlorobenzene 

from work on your clothing, skin, hair, tools, or 

other objects removed from the workplace. This is 

particularly likely if you work in the chemical or 

pesticide industries. You may contaminate your car, 

home, or other locations outside work where 

children might be exposed to hexachlorobenzene. 

You should know about this possibility if you work 

where hexachlorobenzene exposure may occur. 

Your occupational health and safety officer at work 

can and should tell you whether chemicals you 

work with are dangerous and likely to be carried 

home on your clothes, body, or tools and whether 

you should be showering and changing clothes 

before you leave work, storing your street clothes in 

a separate area of the workplace, or laundering your 

work clothes at home separately from other clothes. 

Material safety data sheets (MSDS) for many 

chemicals used should be found at your place of 

work, as required by the Occupational Safety and 

Health Administration (OSHA) in the U.S. 

Department of Labor. MSDS information should 

include chemical names and hazardous ingredients, 

and important properties, such as fire and explosion 

data, potential health effects, how you get the 

chemical(s) in your body, how to properly handle 

the materials, and what to do in the case of 

emergencies. Your employer is legally responsible 

for providing a safe workplace and should freely 

answer your questions about hazardous chemicals. 

Your state OSHA-approved occupational safety and 

health program or OSHA itself can answer any 

further questions and help your employer identify 

and correct problems with hazardous substances. 

Your state OSHA-approved occupational safety and 

health program or OSHA will listen to your formal 

complaints about workplace health hazards and 

inspect your workplace when necessary. Employees 

have a right to seek safety and health on the job 

without fear of punishment. 

1.8 IS THERE A MEDICAL TEST TO 

DETERMINE WHETHER I HAVE BEEN 

EXPOSED TO HEXACHLOROBENZENE? 

Blood, breast milk, urine, and feces may be tested to 

determine if you have ever been exposed to 

hexachlorobenzene. These tests are not usually 

available at a doctor's office because they require 

special equipment found at county, state, university, 

and independent analytical laboratories. Because 

this compound can collect and remain in human fat 

for several years, the test for this substance in breast 

milk can tell you only that you have been exposed, 

but not when or to how much. The blood, urine, and 

feces tests can indicate more recent exposure. 

However, the levels measured cannot be used to 

predict what health effects might occur in people. 
 PUBLIC HEALTH STATEMENT 

 Hexachlorobenzene CAS#: 118-74-1 

Division of Toxicology September 2002 

__________________________________________________________________________________________

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 

Blood, urine, and feces can also be monitored for 

porphyrins. High porphyrin levels indicate slowed 

formation of heme, which is a major effect of 

hexachlorobenzene in the body. The usefulness of 

this test as a sign of hexachlorobenzene exposure is 

limited, however, because there are many other 

potential causes of high porphyrin levels. 

1.9 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 

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 hexachlorobenzene include the following: 

EPA has developed advisories to protect people 

from the potential health effects of exposure to 

hexachlorobenzene in drinking water. EPA has 

proposed that drinking water should not contain 

more than 0.05 parts of hexachlorobenzene per 

million parts of water (ppm) in water that children 

drink, and should not exceed 0.2 ppm in water that 

adults drink for longer periods (approximately 7 

years). No other health standards or 

recommendations exist for this substance. 

 

1.10 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. 
 PUBLIC HEALTH STATEMENT 

 Hexachlorobenzene CAS#: 118-74-1 

Division of Toxicology September 2002 

__________________________________________________________________________________________

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 

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). 2002. Toxicological profile for 

hexachlorobenzene. Atlanta, GA: U.S. Department 

of Health and Human Services, Public Health 

Service.