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PUBLIC HEALTH STATEMENT 

Heptachlor and Heptachlor Epoxide 

CAS#: 76-44-8 and 1024-57-3 

Division of Toxicology and Environmental Medicine August 2007 

This Public Health Statement is the summary 

chapter from the Toxicological Profile for 

Heptachlor and Heptachlor Epoxide. It is one in a 

series of Public Health Statements about hazardous 

substances and their health effects. A shorter 

version, the ToxFAQs, is also available. This 

information is important because these substances 

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 1-800-232-4636. 

This public health statement tells you about 

heptachlor and heptachlor epoxide and the effects of 

exposure to them. 

The Environmental Protection Agency (EPA) 

identifies the most serious hazardous waste sites in 

the nation. These sites are then placed on the 

National Priorities List (NPL) and are targeted for 

long-term federal clean-up activities. Heptachlor 

has been found in at least 210 of the 1,684 current 

or former NPL sites. Heptachlor epoxide has been 

found in at least 200 NPL sites. Although the total 

number of NPL sites evaluated for these substances 

is not known, the possibility exists that heptachlor 

and heptachlor epoxide may be found in the future 

as more sites are evaluated. This information is 

important because these sites may be sources of 

exposure and exposure to these substances may 

harm you. 

When a substance is released either from a large 

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

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

Such a 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 the substance, or by 

skin contact. 

If you are exposed to heptachlor or heptachlor 

epoxide, many factors will determine whether you 

will be harmed. These factors include the dose 

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

come in contact with them. You must also consider 

any other chemicals you are exposed to and your 

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

health. 

1.1 WHAT ARE HEPTACHLOR AND 

HEPTACHLOR EPOXIDE? 

Heptachlor is a manufactured chemical that was 

used in the past for killing insects in homes, in 

buildings, and on food crops. It has not been used 

for these purposes since 1988. There are no natural 

sources of heptachlor or heptachlor epoxide. Trade 

names for heptachlor include Heptagran®, 

Heptamul®, Heptagranox®, Heptamak®, Basaklor®, 

Drinox®, Soleptax®, Gold Crest H-60®, Termide®, 

and Velsicol 104®. Heptachlor is both a breakdown 

product and a component of the pesticide chlordane 

(approximately 10% by weight). Pure heptachlor is 

a white powder. Technical-grade heptachlor is a tan 

powder and has a lower level of purity than pure 

heptachlor. Technical-grade heptachlor was the 

form of heptachlor used most often as a pesticide. 

Heptachlor smells somewhat like camphor. 

Heptachlor does not burn easily and does not 

explode. It does not dissolve easily in water. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-800-232-4636 Fax: 770-488-4178 E-Mail: cdcinfo@cdc.gov 
 

 

 

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PUBLIC HEALTH STATEMENT 

Heptachlor and Heptachlor Epoxide 

CAS#: 76-44-8 and 1024-57-3 

Division of Toxicology and Environmental Medicine August 2007 

Like pure heptachlor, heptachlor epoxide is a white 

powder that does not explode easily. It was not 

manufactured and was not used as an insecticide 

like heptachlor. Bacteria and animals break down 

heptachlor to form heptachlor epoxide. This profile 

describes these two chemicals together because 

about 20% of heptachlor is changed within hours 

into heptachlor epoxide in the environment and in 

your body. 

You might find heptachlor or heptachlor epoxide in 

the soil or air of homes treated for termites, 

dissolved in surface water or groundwater, or in the 

air near hazardous waste sites. You might also find 

heptachlor or its byproduct, heptachlor epoxide, in 

plants and animals near hazardous waste sites. 

Heptachlor can no longer be used to kill insects on 

crops or in homes and buildings. However, 

heptachlor is still approved by EPA for killing fire 

ants in buried power transformers, although it is 

unclear whether or not it is still being used for this 

purpose in the United States. 

1.2 WHAT HAPPENS TO HEPTACHLOR 

AND HEPTACHLOR EPOXIDE WHEN 

THEY ENTER THE ENVIRONMENT? 

From 1953 to 1974, heptachlor entered the soil and 

surface water when farmers used it to kill insects in 

seed grains and on crops. It also entered the air and 

soil when homeowners and professional insect 

exterminators used it to kill termites. Today, 

heptachlor is no longer used by homeowners to kill 

termites or other insects. However, exterminators 

can still use existing stocks of heptachlor to kill fire 

ants in underground power transformers. 

Heptachlor and heptachlor epoxide can enter the air, 

soil, groundwater, and surface water from leaks at 

hazardous waste sites or landfills. Heptachlor sticks 

to soil very strongly and evaporates slowly into the 

air. Heptachlor does not dissolve easily in water. 

Heptachlor epoxide dissolves more easily in water 

than heptachlor does and evaporates slowly from 

water. Like heptachlor, heptachlor epoxide sticks to 

soil. 

Both heptachlor and heptachlor epoxide can travel 

long distances in the wind from places where they 

are released, such as treated fields or manufacturing 

sites. In soil and water, heptachlor is changed by 

bacteria into the more harmful substance, 

heptachlor epoxide, or into other less harmful 

substances. Plants can absorb heptachlor through 

their roots from the soil. Heptachlor in the air can 

be deposited on plant leaves and enter the plant 

from contaminated soil. 

Animals that eat plants containing heptachlor can 

also absorb it. Animals can also change heptachlor 

to heptachlor epoxide in their bodies. Heptachlor 

epoxide breaks down very slowly in the 

environment. It can stay in soil and water for many 

years. Both heptachlor and heptachlor epoxide 

build up in fish and in cattle. People store 

heptachlor epoxide in their fatty tissue. Some 

studies show that heptachlor epoxide can still be 

measured in fatty tissue 3 years after a person is 

exposed to it. 

Most of the breakdown products of heptachlor are 

thought to be less harmful than heptachlor itself. 

However, in laboratory animals, heptachlor epoxide 

is more harmful than heptachlor. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-800-232-4636 Fax: 770-488-4178 E-Mail: cdcinfo@cdc.gov 
 

 

 

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PUBLIC HEALTH STATEMENT 

Heptachlor and Heptachlor Epoxide 

CAS#: 76-44-8 and 1024-57-3 

Division of Toxicology and Environmental Medicine August 2007 

1.3 HOW MIGHT I BE EXPOSED TO 

HEPTACHLOR AND HEPTACHLOR 

EPOXIDE? 

Exposure to heptachlor and heptachlor epoxide 

most commonly occurs when you eat food 

contaminated with those chemicals. Contaminated 

foods might include fish, shellfish (such as clams), 

dairy products, meat, and poultry. Children and 

toddlers drink large amounts of milk and may have 

greater exposure if the milk is contaminated with 

heptachlor or heptachlor epoxide. Infants can be 

exposed to these compounds from drinking 

breastmilk or cow's milk. 

Exposure can also occur when you drink water, 

breathe air, or touch contaminated soil at hazardous 

waste sites that contain heptachlor or heptachlor 

epoxide. People whose homes have been treated 

with heptachlor to kill termites can be exposed by 

breathing heptachlor in the air. After heptachlor is 

changed to heptachlor epoxide in the soil, it can get 

into the air. People who breathe this air will be 

exposed to heptachlor epoxide. Workers who use 

heptachlor to kill fire ants are exposed if they 

breathe in the heptachlor or get it on their skin. 

Background levels of a substance are levels found 

in the environment that cannot be traced to a 

specific source. Information on background levels 

of heptachlor and heptachlor epoxide in the air was 

not found. In one survey, the background levels of 

heptachlor in drinking water and groundwater in the 

United States ranged from 20 to 800 parts of 

heptachlor in one trillion parts of water (ppt). 

Heptachlor was found in less than 2% of U.S. 

groundwater samples that are known to be contaminated from pesticide application. The average level 

of heptachlor in the contaminated groundwater 

samples was 800 ppt. No information was found 

for levels of heptachlor epoxide in groundwater or 

drinking water. Heptachlor epoxide has been found 

in surface water (river, lakes) at levels between 

0.1 and 10 parts of heptachlor epoxide in one billion 

parts of water (ppb, 1 ppb is 1 thousand times more 

than 1 ppt). 

Heptachlor and heptachlor epoxide stick to 

sediment and soil. Sediment in stream beds is likely 

to contain a lot of the heptachlor that enters the 

water. Heptachlor and heptachlor epoxide were 

found in less than 0.7 and 1.8% of river bed 

sediments that were tested from 2003 to 2005. 

Contaminated fish and shellfish have been found to 

contain 2–750 ppb heptachlor and 0.1–480 ppb 

heptachlor epoxide. Heptachlor epoxide has been 

found in human milk samples at levels ranging from 

0.13 to 128 ppb. 

1.4 HOW CAN HEPTACHLOR AND 

HEPTACHLOR EPOXIDE ENTER AND 

LEAVE MY BODY? 

When you breathe air containing heptachlor or 

heptachlor epoxide, both can enter your 

bloodstream through your lungs. It is not known 

how fast these compounds enter and remain in the 

bloodstream. Both heptachlor and heptachlor 

epoxide can also enter your body through your 

stomach after you eat food or drink water or milk 

containing them. Most of the heptachlor that is 

swallowed passes through your stomach into your 

blood. It can also enter your body through your 

skin. Heptachlor and heptachlor epoxide can pass 

directly from a mother's blood to an unborn baby 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-800-232-4636 Fax: 770-488-4178 E-Mail: cdcinfo@cdc.gov 
 

 

 

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PUBLIC HEALTH STATEMENT 

Heptachlor and Heptachlor Epoxide 

CAS#: 76-44-8 and 1024-57-3 

Division of Toxicology and Environmental Medicine August 2007 

through the placenta. It can also pass from the 

mother to an infant through breast milk. 

Once inside your body, heptachlor is changed to 

heptachlor epoxide and other related chemicals. 

Most of the heptachlor, heptachlor epoxide, and 

other breakdown products leave your body in the 

feces within a few days after exposure. Some 

breakdown products can also leave in the urine. 

Some heptachlor and heptachlor epoxide are stored 

in your body fat for long periods after exposure has 

occurred. The heptachlor and heptachlor epoxide 

that have been stored in fat leave your body much 

more slowly. 

1.5 HOW CAN HEPTACHLOR AND 

HEPTACHLOR EPOXIDE AFFECT MY 

HEALTH? 

Scientists use many tests to protect the public from 

harmful effects of toxic chemicals and to find ways 

for treating persons who have been harmed. 

One way to learn whether a chemical will harm 

people is to determine how the body absorbs, uses, 

and releases the chemical. For some chemicals, 

animal testing may be necessary. Animal testing 

may also help identify health effects such as cancer 

or birth defects. Without laboratory animals, 

scientists would lose a basic method for getting 

information needed to make wise decisions that 

protect public health. Scientists have the 

responsibility to treat research animals with care 

and compassion. Scientists must comply with strict 

animal care guidelines because laws today protect 

the welfare of research animals. 

People can begin to smell heptachlor or heptachlor 

epoxide at around 0.3 milligrams in a cubic meter of 

air (0.3 mg/m3). No reliable studies in humans were 

found that show whether harmful health effects 

occur as a result of breathing heptachlor or 

heptachlor epoxide. No animal studies examining 

the harmful effects resulting from breathing air that 

contains heptachlor or heptachlor epoxide were 

found. 

In addition, no reliable human studies were found 

that show whether harmful effects occur from 

eating contaminated foods or by drinking liquids 

contaminated with heptachlor or heptachlor 

epoxide. Studies have shown a number of harmful 

health effects when animals were fed heptachlor or 

heptachlor epoxide. These effects were more 

harmful when the exposure levels were high or 

when exposure lasted many weeks. The effects 

observed in animals include damage to the liver, 

excitability, and decreases in fertility. 

Animals fed heptachlor throughout their lifetime 

had more liver tumors than animals that ate food 

without heptachlor. EPA and the International 

Agency for Research on Cancer have classified 

heptachlor as a possible human carcinogen. EPA 

also considers heptachlor epoxide as a possible 

human carcinogen. 

1.6 HOW CAN HEPTACHLOR AND 

HEPTACHLOR EPOXIDE AFFECT 

CHILDREN? 

This section discusses potential health effects in 

humans from exposures during the period from 

conception to maturity at 18 years of age. 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-800-232-4636 Fax: 770-488-4178 E-Mail: cdcinfo@cdc.gov 
 

 

 

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PUBLIC HEALTH STATEMENT 

Heptachlor and Heptachlor Epoxide 

CAS#: 76-44-8 and 1024-57-3 

Division of Toxicology and Environmental Medicine August 2007 

Some studies in animals suggest that young animals 

exposed during gestation and infancy may be very 

sensitive to heptachlor and heptachlor epoxide. 

Changes in nervous system and immune function 

were found in these animals. There is some 

evidence that similar effects may occur in humans, 

but a study that found some changes in performance 

on some tests that measure nervous system function 

is not conclusive and exposure to other chemicals 

cannot be ruled out. Exposure to higher doses of 

heptachlor in animals can also result in decreases in 

body weight and death in animal newborn babies. 

1.7 HOW CAN FAMILIES REDUCE THE 

RISK OF EXPOSURE TO 

HEPTACHLOR AND HEPTACHLOR 

EPOXIDE? 

If your doctor finds that you have been exposed to 

substantial amounts of heptachlor and heptachlor 

epoxide, ask whether your children might also have 

been exposed. Your doctor might need to ask your 

state health department to investigate. 

Heptachlor is no longer used in the United States 

except to control fire ants; therefore, exposure 

should be limited. Before the use of heptachlor was 

cancelled in 1988, it was used on various 

agricultural crops, in homes for the treatment of 

termites, and in power lines for fire ant control. 

However, because of the persistence of both 

heptachlor and heptachlor epoxide, exposure to the 

general population can occur from contaminated 

water, soil, and air. People who live in homes 

where heptachlor was used for termite control or on 

farms where heptachlor was used on crops may 

have a higher risk of exposure through 

contaminated crops, soil, water, and air. To avoid 

exposure from contaminated soil, you should 

discourage your children from eating or playing 

with dirt near home or barn foundations. Make sure 

they wash their hands frequently and before eating. 

Discourage children from putting their hands in 

their mouths or other hand-to-mouth activities. 

Heptachlor and heptachlor epoxide are also 

persistent in food and milk. Eating fish from 

contaminated water can increase exposure to 

heptachlor. Avoid eating fish from contaminated 

water. Local fishing advisories can tell you if the 

water is contaminated. 

1.8 IS THERE A MEDICAL TEST TO 

DETERMINE WHETHER I HAVE BEEN 

EXPOSED TO HEPTACHLOR AND 

HEPTACHLOR EPOXIDE? 

Laboratory tests can detect heptachlor and 

heptachlor epoxide in blood, fat, breast milk, and 

body tissues after exposure to high levels of these 

chemicals. These tests are not commonly available 

at your doctor's office. Most often, the test for 

heptachlor epoxide is used because heptachlor is 

quickly changed into heptachlor epoxide in your 

body. Blood samples are used most often because 

they are easy to collect. These tests are specific for 

heptachlor and heptachlor epoxide. However, 

heptachlor is both a breakdown product and a 

component of chlordane, another pesticide. So if 

heptachlor and heptachlor epoxide are measured in 

the blood, the actual exposure could have been to 

chlordane. Methods for measuring heptachlor and 

heptachlor epoxide in body fat are more precise and 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-800-232-4636 Fax: 770-488-4178 E-Mail: cdcinfo@cdc.gov 
 

 

 

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PUBLIC HEALTH STATEMENT 

Heptachlor and Heptachlor Epoxide 

CAS#: 76-44-8 and 1024-57-3 

Division of Toxicology and Environmental Medicine August 2007 

can detect lower levels than tests that measure 

levels in blood. If heptachlor or heptachlor epoxide 

is found in your blood or fat, it is not possible to tell 

when you were exposed to these chemicals or if 

harmful health effects will occur. 

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. The EPA, the 

Occupational Safety and Health Administration 

(OSHA), and the Food and Drug Administration 

(FDA) are some federal agencies that develop 

regulations for toxic substances. Recommendations 

provide valuable guidelines to protect public health, 

but cannot be enforced by law. The Agency for 

Toxic Substances and Disease Registry (ATSDR) 

and the National Institute for Occupational Safety 

and Health (NIOSH) are two federal organizations 

that develop recommendations for toxic substances. 

Regulations and recommendations can be expressed 

as “not-to-exceed” levels, that is, levels of a toxic 

substance in air, water, soil, or food that do not 

exceed a critical value that is usually based on 

levels that affect animals; they are then adjusted to 

levels that will help protect humans. Sometimes 

these not-to-exceed levels differ among federal 

organizations because they used different exposure 

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

different animal studies, or other factors. 

Recommendations and regulations are also updated 

periodically 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 

heptachlor and heptachlor epoxide include the 

following: 

For exposures of up to 10 days, EPA recommends 

that a child weighing 22 pounds or less not drink 

water containing more than 0.01 mg heptachlor or 

heptachlor epoxide per liter of water (0.01 mg/L or 

0.01 ppm). EPA requires that drinking water should 

not contain more than 0.0004 mg/L (0.0004 ppm) 

heptachlor and 0.0002 mg/L (0.0002 ppm) of 

heptachlor epoxide. 

FDA controls the amount of heptachlor and 

heptachlor epoxide on raw food crops and on edible 

seafood. The limit for most food crops is 0.01 parts 

heptachlor per million parts food (0.01 ppm). The 

limit in milk is 0.1 parts heptachlor per million parts 

of milk fat. The limit on edible seafood is 0.3 ppm. 

OSHA has set a limit of 0.5 mg/m3 for heptachlor in 

workplace air over an 8-hour workday for a 40-hour 

workweek. 

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 contact 

ATSDR at the address and phone number below. 

ATSDR can also tell you the location of 

occupational and environmental health clinics. 

These clinics specialize in recognizing, evaluating, 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-800-232-4636 Fax: 770-488-4178 E-Mail: cdcinfo@cdc.gov 
 

 

 

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PUBLIC HEALTH STATEMENT 

Heptachlor and Heptachlor Epoxide 

CAS#: 76-44-8 and 1024-57-3 

Division of Toxicology and Environmental Medicine August 2007 

and treating illnesses that result from exposure to 

hazardous substances. 

Toxicological profiles are also available on-line at 

www.atsdr.cdc.gov and on CD-ROM. You may 

request a copy of the ATSDR ToxProfilesTM 

CD-ROM by calling the toll-free information and 

technical assistance number at 1-800-CDCINFO 

(1-800-232-4636), by e-mail at cdcinfo@cdc.gov, 

or by writing to: 

Agency for Toxic Substances and Disease Registry 

Division of Toxicology and Environmental 

Medicine 

1600 Clifton Road NE 

Mailstop F-32 

Atlanta, GA 30333 

Fax: 1-770-488-4178 

Organizations for-profit may request copies of final 

Toxicological Profiles from the following: 

National Technical Information Service (NTIS) 

5285 Port Royal Road 

Springfield, VA 22161 

Phone: 1-800-553-6847 or 1-703-605-6000 

Web site: http://www.ntis.gov/ 

DEPARTMENT of HEALTH AND HUMAN SERVICES, Public Health Service
 

Agency for Toxic Substances and Disease Registry 

www.atsdr.cdc.gov/ Telephone: 1-800-232-4636 Fax: 770-488-4178 E-Mail: cdcinfo@cdc.gov