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PUBLIC HEALTH STATEMENT 

ENDRIN 

CAS#: 72-20-8 

Division of Toxicology August 1996 

This Public Health Statement is the summary 

chapter from the Toxicological Profile for Endrin. 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 endrin and to emphasize the 

human health effects that may result from exposure 

to it. 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 activities. Endrin has 

been found in at least 120 (8.4%) of the current or 

former NPL sites. Endrin ketone has been found in 

at least 37 sites of the current or former sites on the 

NPL. However, the number of NPL sites evaluated 

for endrin ketone is not known. As the EPA 

evaluates more sites, the number of sites at which 

endrin ketone is found may increase. This 

information is important because exposure to endrin 

may cause harmful health effects and because these 

sites are potential or actual sources of human 

exposure to endrin. 

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 endrin, 

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, sex, 

nutritional status, family traits, lifestyle, and state of 

health. 

1.1 WHAT IS ENDRIN? 

This toxicological profile focuses on endrin, but 

because of its close association to both endrin 

aldehyde and endrin ketone, the profile includes 

studies with data relevant to human exposure to 

these compounds when available. 

Endrin is a solid, white, almost odorless substance 

that was used as a pesticide to control insects, 

rodents, and birds. Endrin has not been produced or 

sold for general use in the United States since 1986. 

Little is known about the properties of endrin 

aldehyde, an impurity and breakdown product of 

endrin, or endrin ketone, which is a product of 

endrin when it is exposed to light. 

1.2 WHAT HAPPENS TO ENDRIN WHEN IT 

ENTERS THE ENVIRONMENT? 

Endrin does not dissolve very well in water. It has 

been found in ground water and surface water, but 

only at very low levels. It is more likely to cling to 

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 

ENDRIN 

CAS#: 72-20-8 

Division of Toxicology August 1996 

the bottom sediments of rivers, lakes, and other 

bodies of water. Endrin is generally not found in the 

air except when it was applied to fields during 

agricultural applications. 

The persistence of endrin in the environment 

depends highly on local conditions. Some estimates 

indicate that endrin can stay in soil for over 10 

years. Endrin may also be broken down by exposure 

to high temperatures (230°C) or light to form 

primarily endrin ketone and endrin aldehyde. 

It is not known what happens to endrin aldehyde or 

endrin ketone once they are released to the 

environment; however, the amount of endrin broken 

down to endrin aldehyde or endrin ketone is very 

small (less than 5%). 

1.3 HOW MIGHT I BE EXPOSED TO 

ENDRIN? 

Since endrin is no longer produced or used in the 

United States, you can probably be exposed to it 

only in areas where it is concentrated, such as a 

hazardous waste site. You may be exposed to endrin 

in air, water, or soil if you live near a hazardous 

waste site. Endrin has been detected at 120 (8.4%) 

such sites. Children living near hazardous waste 

sites could be exposed to endrin in contaminated 

soils, if they eat dirt. Detection of endrin in ground 

water or drinking water is rare. In the U.S. EPA 

1989 National Pesticide in Groundwater Study, in 

which ground water was collected from areas with 

significant agricultural land uses as well as urban 

areas, only two wells were found with detectable 

levels of endrin. In wells drilled to access ground 

water near hazardous waste sites, 1.3% of 156 

Resource Conservation and Recovery Act (RCRA) 

sites and 0.9% of 178 Comprehensive 

Environmental Response, Compensation, and 

Liability Act of 1980 (CERCLA) or Superfund sites 

had detectable levels of endrin in the early 1980s. 

No information about the presence of endrin 

aldehyde or endrin ketone in the environment was 

found. 

You may also be exposed to endrin by eating foods 

that contain endrin. Before cancellation of endrin 

use, reported concentrations of endrin in domestic 

and imported food samples ranged from 0.05 to 

0.50 parts per million (ppm; where 1 ppm = 1 

microgram per gram (μg/g) of food). However, no 

endrin was detected in food samples from a Texas 

survey and only 0.084% of over 13,000 food 

samples were found to contain endrin in 1989 after 

cancellation of endrin use. Endrin was found in less 

than 1% of all food sampled by the U.S. Food and 

Drug Administration (FDA) in 1991. Because 

endrin is no longer used in the United States, 

residues on imported foods are the main source of 

potential human exposure in food. The levels of 

endrin aldehyde or endrin ketone in foods are not 

known. 

Endrin levels can build up (bioaccumulate) in the 

tissues of organisms that live in water. In the 1986 

EPA National Study of Chemical Residues in Fish, 

concentrations of endrin were found in fish at 11% 

of 362 sites surveyed (average 1.69 parts per billion 

[ppb; where 1 ppb = 1 nanogram per gram (ng/g) of 

food]; maximum 162 ppb). Endrin was also 

detected in 21 of 31 samples of 2 commercial 

shrimp species from a Gulf Coast estuary receiving 

both industrial discharges, and urban and 

agricultural runoff. The average concentration was 

1,070 and the maximum concentration was 9,470 

ppb. Levels of endrin have probably declined, even 

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 

ENDRIN 

CAS#: 72-20-8 

Division of Toxicology August 1996 

in such polluted areas, since using endrin was 

banned. 

Endrin has been detected in human breast milk 

(0.02-6.24 milligrams endrin in each kilogram milk 

fat [mg/kg]); this may be a route of exposure for 

nursing infants. However, no studies of endrin in 

breast milk in United States or Canadian 

populations have been conducted. 

1.4 HOW CAN ENDRIN ENTER AND LEAVE 

MY BODY? 

Endrin and endrin aldehyde can enter your body 

when you eat foods or drink beverages or breathe 

air that contain this substance, or when it comes in 

contact with your skin. When endrin enters your 

body in any of these ways, it is rapidly changed into 

other substances. Endrin and its metabolic 

breakdown products are rapidly removed from the 

body, usually within a few days, through the urine 

and feces. There is some evidence that small 

amounts of endrin may remain in the fatty tissue of 

your body when you are exposed to high levels. No 

information is known about how endrin aldehyde or 

endrin ketone leaves the body. 

1.5 HOW CAN ENDRIN AFFECT MY 

HEALTH? 

Exposure to endrin can cause various harmful 

effects including death and severe central nervous 

system (brain and spinal cord) injury. Swallowing 

large amounts of endrin (more than 0.2 mg/kg of 

body weight) may cause convulsions and kill you in 

a few minutes or hours. 

Symptoms that may result from endrin poisoning 

are headache, dizziness, nervousness, confusion, 

nausea, vomiting, and convulsions. Some of these 

symptoms may continue for weeks after exposure to 

high doses of endrin. 

No long-term health effects have been noted in 

workers, either in factories or during field 

applications, who have been exposed to endrin by 

breathing or touching it. 

Studies in animals confirm that endrin's main target 

is the nervous system, probably because the brain 

and other parts of the nervous system contain much 

fatty tissue, and endrin tends to stay in those tissues. 

Birth defects, especially abnormal bone formation, 

have been seen in some animal studies. While there 

are no human data on birth defects, evidence in 

rodents suggests that exposure to high doses of 

endrin during pregnancy could be a health risk to 

developing fetuses. 

In studies using rats, mice, and dogs, endrin did not 

produce cancer. However, most of these studies did 

not accurately evaluate the ability of endrin to cause 

cancer. No significant excess of cancer has been 

found in exposed factory workers, although endrin 

metabolites have been detected in their urine. The 

EPA has determined that endrin is not classifiable 

as to its human carcinogenicity because there is not 

enough information to allow classification. Endrin 

has also not been classified for carcinogenic effects 

by the Department of Health and Human Services 

(DHHS) or the International Agency for Research 

on Cancer (IARC). 

One study in rodents suggests that exposure to 

endrin aldehyde or endrin ketone may cause liver 

disease. No other studies were found on how endrin 

aldehyde or endrin ketone can affect your health. 

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 

ENDRIN 

CAS#: 72-20-8 

Division of Toxicology August 1996 

1.6 IS THERE A MEDICAL TEST TO 

DETERMINE WHETHER I HAVE BEEN 

EXPOSED TO ENDRIN? 

If you are exposed to endrin, the chemical can be 

detected in your blood, breast milk, or fatty tissue. 

Tests can measure endrin in the blood or fat of 

people recently exposed. Endrin is cleared from the 

blood rapidly, so samples should be taken within 1­

2 weeks of exposure. Since special analytical 

equipment is needed, these tests are not routinely 

performed in doctors' offices. Although these tests 

can be used to confirm that a person has been 

exposed to endrin, it is not yet possible to use those 

tests to predict the type or severity of any health 

effects that might occur. Endrin metabolites have 

been found in urine (0.001-0.14 micrograms per 

milliliter [μg/mL]; where 1 μg/mL = 1 ppm) and 

feces of workers exposed to endrin. 

No information is available on tests for exposure to 

endrin aldehyde or endrin ketone. 

1.7 WHAT RECOMMENDATIONS HAS THE 

FEDERAL GOVERNMENT MADE TO 

PROTECT HUMAN HEALTH? 

In order to protect people from potential health 

effects, the EPA banned the production and use of 

endrin in the United States in 1986. The EPA's 

proposed maximum contaminant level (MCL) in 

drinking water is 0.0002 milligrams per liter (mg/L; 

1 mg/L = 1 ppm). The EPA has also set health 

advisories which are levels of a chemical in water 

that are safe. The 1-day and 10-day health 

advisories for endrin are 0.02 mg endrin per liter of 

water for both children and adults. The longer-term 

health advisories for children and adults are 0.003 

mg/L and 0.01 mg/L, respectively. The lifetime 

health advisory for children and adults is 0.002 

mg/L. The EPA recommends an ambient water 

quality criteria level of 0.001 mg/L to protect 

human health. 

The National Institute of Occupational Safety and 

Health (NIOSH) and the Occupational Safety and 

Health Administration (OSHA) have established a 

limit of 0.1 mg endrin per cubic meter of air (0.1 

mg/m3) averaged over an 8-hour day in an 

occupational setting for a 40-hour work week. In 

addition, NIOSH considers that a person could 

escape within 30 minutes from a concentration of 

2,000 mg/m3 without respiratory protection and 

without experiencing any escape-impairing or 

irreversible health effects. 

No information can be found on government 

regulations for endrin aldehyde or endrin ketone. 

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. 

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 

ENDRIN 

CAS#: 72-20-8 

Division of Toxicology August 1996 

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). 1996. Toxicological profile for endrin. 

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