Chlordane, is an organochlorine compound with the molecular formula C10H6Cl8, used as a pesticide in the United States from 1948 to 1988. It is sometimes referred to by the trade names Octachlor® and Velsicol 1068®. It is a thick liquid whose colour ranges from colourless to amber, depending on its purity. It may have no smell or a mild, irritating smell. Chlordane is not a single chemical, but is a mixture of many related chemicals, of which about 10 are major components. Some of the major components are trans-chlordane, cis-chlordane, beta-chlordene, heptachlor, and trans-nonachlor. Chlordane does not dissolve in water. Therefore, before it can be used as a spray, it must be placed in water with emulsifiers (soap-like substances), which results in a milky-looking mixture. [1,2]

Uses [3,4]

Chlordane was used as a pesticide in the United States from 1948 to 1988. In 1988, all approved uses of chlordane in the United States were cancelled. From 1983 to 1988, chlordane’s only approved use was to control termites in homes. The pesticide was applied underground around the foundation of homes. Before 1978, chlordane was also used as a pesticide on agricultural crops, lawns, and gardens and as a fumigating agent. In 1978, EPA cancelled the use of chlordane on food crops and phased out other above ground uses over the following 5 years. Chlordane still can be legally manufactured in the United States, but it can only be sold to or used by foreign countries. Although chlordane can be used to control fire ants in the United States, no products are currently registered for this use (5, 6).

In the Environment [2]

When used as a pesticide on crops, on lawns and gardens, and to control termites in houses, chlordane enters the environment. In soil, it attaches strongly to particles in the upper layers of soil and is unlikely to enter into groundwater. It is not known whether chlordane breaks down in most soils. If breakdown occurs, it is very slow. Chlordane is known to remain in some soils for over 20 years. Persistence is greater in heavy, clayey or organic soil than in sandy soil. Most chlordane is lost from soil by evaporation. Evaporation is more rapid from light, sandy soils than from heavy soils. Half of the chlordane applied to the soil surface may evaporate in 2 to 3 days. Evaporation is much slower after chlordane penetrates into the soil. In water, some chlordane attaches strongly to sediment and particles in the water column and some is lost by evaporation. It is not known whether much breakdown of chlordane occurs in water or in sediment. Chlordane breaks down in the atmosphere by reacting with light and with some chemicals in the atmosphere. However, it is sufficiently long lived that it may travel long distances and be deposited on land or in water far from its source. Chlordane or the chemicals that chlordane changes into accumulate in fish, birds, and mammals. Chlordane stays in the environment for many years and is still found in food, air, water, and soil. Chlordane is still commonly found in some form in the fat of fish, birds, mammals, and almost all humans.

Sources & Routes of Exposure

Sources of Exposure [3]

  • Before 1988, exposure to chlordane may have occurred in the workplace; persons involved in the manufacture, formulation, or application of chlordane, such as farmers, lawn-care workers, and pest-control workers may have been exposed.
  • Studies on chlordane levels in indoor air reported levels ranging from < 1 to 610,000 nanograms per cubic metre (ng/m3).
  • Currently, exposure to chlordane appears to be highest for those persons living in homes that were treated for termites with chlordane. Chlordane may be found in the air in these homes for many years after treatment.
  • Additional exposure to chlordane may occur from digging in soil around the foundation of homes where chlordane was applied. Mean residue levels in soil around 30 homes treated with chlordane ranged from 22 to 2,540 parts per million (ppm).
  • Exposure to chlordane may also occur from eating chlordane-contaminated food. Chlordane remains in the food supply today because much of the farmland in the United States was treated with chlordane in the 1960s and 1970s, and it remains in the soil for over 20 years.
  • Chlordane has been listed as a pollutant of concern to EPA’s Great Waters Program due to its persistence in the environment, potential to bioaccumulate, and toxicity to humans and the environment

Routes of Exposure [5]

The main routes of exposure to chlordane are:

  • inhalation
  • skin absorption
  • ingestion
  • skin and/or eye contact

Health Effects [3]

Acute Effects

  • Neurological effects, such as headache, dizziness, irritability, and convulsions, and effects on the blood have been seen from acute chlordane exposure in animals and humans.
  • Chlordane is considered to have high acute toxicity based on short-term animal tests in rats.

Chronic Effects

  • Chronic exposure of humans to chlordane by inhalation results primarily in effects on the nervous system.
  • Animal studies have reported effects on the liver, kidney, blood, thyroid, and respiratory and nervous systems from chronic exposure to chlordane via inhalation.
  • The Reference Concentration (RfC) for chlordane is 0.0007 milligrams per cubic metre (mg/m3) based on liver effects in rats.
  • The Reference Dose (RfD) for chlordane is 0.0005 milligrams per kilogram body weight per day (mg/kg/d) based on liver necrosis in mice.

Reproductive/Developmental Effects

  • A study of women living in homes repeatedly treated for termites with chlordane revealed an increased incidence of ovarian and uterine disease, compared with a reference population. However, it is not possible to state whether these effects were solely due to chlordane or to other chemicals as well.
  • An animal study reported biochemical and behavioural alterations mimicking male sex steroids, while another study reported alterations in reproductive behaviour, both in male rats exposed to chlordane.

Cancer Risk

  • An occupational study investigating men with non-Hodgkin’s lymphoma found that the odds of chlordane use as an insecticide were significantly greater among cases than among controls.
  • Two other epidemiological studies did not find an association between chlordane exposure and leukaemia or multiple myeloma.
  • Animal studies have reported liver cancer in mice and male rats exposed to chlordane via ingestion.
  • EPA considers chlordane to be a probable human carcinogen and has classified it as a Group B2 carcinogen.

Safety [6]

First Aid Measure

  • Inhalation: No specific intervention is indicated as the compound is not likely to be hazardous by inhalation. Remove victim to fresh air immediately. Keep affected person warm and at rest.
  • Skin Contact: The compound is hazardous by skin contact. Remove contaminated clothing and shoes immediately. Wash affected area with mild soap or detergent for at least 15 minutes or until no evidence of chemical remains. In case of chemical burns, cover area with sterile, dry dressing. Bandage securely, but not too tightly. Get medical attention, immediately.
  • Eye Contact: In case of contact, immediately flush eyes with plenty of water for at least 15 minutes. Eyelids may be lifted occasionally, until no evidence of chemical remains. Call a physician.
  • Ingestion: The compound is toxic by ingestion. Do not use gastric lavage or emesis. Affected person must drink 100 fold of water or milk to dilute acid. Call a physician immediately.

Exposure Controls & Personal Protection

Engineering Controls

  • Ventilation – Natural ventilation.
  • Access to a safety shower and eyewash station

Personal Protective Equipment

The following personal protective equipment is recommended when handling chlordane:

  • Respiratory Protection: None required.
  • Protective Gloves: Are highly recommended.
  • Eye Protection: Safety glasses with side shields are required.
  • Other Protective Equipment: Lab coat or other long – sleeved garment is required.

Regulation [2,7]

United State

  • EPA: The Environmental Protection Agency guidelines for drinking water suggest that no more than 60 ppb chlordane should be present in drinking water that children consume for no longer than 10 days. Drinking water should contain no more than 0.5 ppb for children or 2 ppb for adults if they drink the water for longer periods. All use of chlordane were cancelled on food crops, effective March 1978. Until 1988, EPA permitted chlordane use for termite control or dipping the roots or tops of nonfood plants. On April 14, 1988, however, EPA stopped all sales and commercial use of chlordane. Federal regulations limit the amount of chlordane that factories can release into wastewater. The EPA requires industry to report releases or spills of 1 pound or more. A temporary guideline of the National Research Council indicated that 0.005 mg/m³ should be the maximum amount allowed in the air of military housing.
  • FDA: The Food and Drug Administration has established that the levels of chlordane and its breakdown products in most fruits and vegetables should not be greater than 300 ppb and in animal fat and fish should not be greater than 100 ppb.
  • OSHA: The Occupational Safety and Health Administration regulates chlordane levels in the workplace. The maximum allowable level in workplace air is 0.5 mg/m³ for a person who is exposed for 8 hours per workday and 40 hours per workweek.
  • NIOSH: The National Institute for Occupational Health and Safety also recommends an exposure limit of 5 mg/m³ for a person exposed to chlordane in the workplace for 8 hours per workday and 40 hours per workweek.


  • Safe Work Australia: Safe Work Australia has established a Time Weighted Average (TWA) concentration for chlordane of 0.5 mg/m³ for a 40-hour workweek.