Synonyms and Trade Names (partial list): Compound 269, Endrex, Hexadrin, Isodrin Epoxide, MEndrin, NEndrin.
Appearance: White, odourless, crystalline solid when pure; light tan colour with faint chemical odour for technical grade.


Endrin is a foliar insecticide used mainly on field crops such as cotton and grains. It has also been used as a rodenticide to control mice and voles. It is rapidly metabolised by animals and does not accumulate in fat to the same extent as other compounds with similar structures. It can enter the atmosphere by volatilization, and can contaminate surface water from soil run-off.

Endrin is banned in many countries, including Belgium, Cyprus, Ecuador, Finland, Israel, Philippines, Singapore, Thailand, and Togo. Its use is severely restricted in many countries, including Argentina, Canada, Chile, Colombia, the EU, India, Japan, New Zealand, Pakistan, USA, and Venezuela.

Usage in South East Asia


Used or Found in Country?

Years of Usage

Regulatory Controls



1950-92 Present?




Banned in 1992



Withdrawn by company




Banned in 1981



Never registered for use



Banned from import in 1989

Viet Nam


Banned in 1992

(table references)

Potential Effects on Humans

A study of workers involved in the production of Aldrin, Dieldrin and Endrin did not find Endrin in the blood of workers, except in cases of accidental, acute over-exposure. These findings are in agreement with results of a study of 71 workers in an Endrin plant in the USA. Data on absenteeism, results of liver function tests, blood chemistry, blood morphology, urine analysis, occurrence of sensitization, and the incidence and pattern of diseases, including the occurrence of malignant growth, showed no difference between workers exposed to Endrin and other chemical plant operators. A study of workers involved in the manufacture of Aldrin, Dieldrin and Endrin found a statistically significant increase in liver and biliary tract cancers, although the study did have some limitations such as a lack of quantitative exposure information. There is limited evidence that cyclodienes such as Endrin may also depress immune responses.

IARC has concluded that there is inadequate evidence for the carcinogenicity of Endrin in humans, and there is only limited evidence in experimental animals. Endrin is therefore not classifiable as to its carcinogenicity in humans (Group 3).

Potential Effects on Animals

Endrin is metabolised rapidly by animals, and very little is accumulated in fat compared to compounds of similar structure (including its stereoisomer - Dieldrin). The formation of anti-12-hydroxyEndrin is considered to be the major route of metabolism of Endrin.

The acute oral LD50 of Endrin is in the range of 3 mg/kg body weight in monkeys to 36 mg/kg in guinea pigs.

Male and female Long-Evans rats were fed Endrin in their diet over three generations. No difference in appearance, behaviour, body weight, or number or size of litters was observed. The weights of liver, kidneys and brain were normal, and no histopathological abnormalities were observed in third generation weanlings. Significant increased mortality of pups in the second and third generations of rats fed 3 mg/kg was noted. Endrin was not teratogenic at levels that did not cause maternal toxicity.

Endrin is highly toxic to fish, with most LC50 values below 1.0 µg/L. Sheepshead minnow embryos exposed for 23 weeks to 0.31 and 0.72 µg/L hatched early, and all those exposed to 0.72 µg/L died by the ninth day of their exposure, while those exposed at 0.31 µg/L were initially stunted and some died. The reproductive ability of the survivors of the 0.31 µg/L was impaired. No significant effects were observed at an exposure concentration of 0.12 µg/L. The lowest observed adverse effect level (LOAEL) for aquatic organisms was 30 ng/L over 20 days for reproduction in mysid shrimp. Reproduction in male and female mallard ducks was not impaired by diets containing 0, 0.5 or 3.0 mg/kg.

Accumulation Characteristics

The half life of Endrin in soil may be up to 12 years, depending on local conditions. This persistence, combined with a high partition coefficient (log KOW = 3.21-5.340), provides the necessary conditions for Endrin to bioconcentrate in organisms.

A bioconcentration factor of 6,400 was recorded for sheepshead minnows exposed to Endrin from embryonic stage through adulthood.

Bluegill sunfish exposed to water containing 14C-labelled Endrin took up 91% of the radio-labelled Endrin with in 48 hours, with a half life of loss from the tissues of approximately four weeks. Leiostomus xantharus exposed to 0.05 µg/L for 5 months had a tissue residue level of 78 µg/kg tissue. After 18 days in uncontaminated water, no residues were detected, suggesting that Endrin disappears rapidly from this organism.

The chemical properties of Endrin (low water solubility, high stability in the environment, and semi-volatility) favour its long range transport, and it has been detected in Arctic freshwater. The main source of Endrin exposure to the general population is residues in food, however, contemporary intake is generally below the acceptable daily intake of 0.0002 mg/kg body weight recommended by the Joint FAO/WHO Meeting on Pesticide Residues (JMPR). Recent food surveys have generally not included Endrin, and hence recent monitoring data are not available.


For more information:

Adapted from Persistent Organic Pollutants: Information on POPs, their alternatives and alternative approaches (United Nations Environmental Programme (UNEP) 1995).

Endrin container
Source: Washington State University
Hatfield Consultants The World Bank funded by the Canadian POPs Trust Fund through the      
Canadian International Development Agency
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