The Chlordane Pesticide Problem
Doctors and scientists who are knowledgeable on the chlordane problem state millions of adults and children are becoming sick by living in homes built before April, 1988 (the period when chlordane, originally developed by Monsanto, was allowed to be used). Chlordane contaminates the air of over 30 million U.S. homes by diffusion through concrete flooring – ceiling drywall – or out gassing from previously treated indoor areas. Documented health problems can include child cancers, neuroblastoma, leukemia, chronic infections, bronchitis, asthma, sinusitis, infertility, neurological disorders, aggression and depression.
Unfortunately, due to the lack of obvious odor or easily administered test, most occupants are unaware this pesticide is in the indoor air they are breathing hour after hour.
By Wayne Sinclair, M.D.
Allergy, Asthma & Immunology
Richard W. Pressinger, M.Ed.
Chlordane Research Index
Click title below for more information
Click title below for more information
The Chlordane Problem
Why scientists consider chlordane a health threat surpassing cigarettes and radon –
What is chlordane? – When was the mistake realized?
How widespread a problem? – Which homes affected?
Breast Cancer linked to chlordane exposure
Cancerous breast tissue contains 4 times higher concentrations of chlordane ingredient heptachlor epoxide, thereby suggesting causal link.
Immune problems worse in chlordane treated homes
Sinusitis, bronchitis, migraines, cough and anemia higher in chlordane homes
Immune system damage & autoimmune disorders
The body’s cancer fighting cells are paralyzed by chlordane and how chlordane can literally make the body’s immune cells attack healthy tissue by mistake (called autoimmunity)
Hidden neurological problems found
Chlordane suspected of causing chronic fatigue, depression, anger, memory and concentration problems in adults living in a chlordane treated apartment complex
Asthma and allergies higher in chlordane homes
As chlordane has shown strong immune damaging potential
Asthma and allergies are an expected consequence.
Neuroblastoma and leukemia higher
Children develop blood disorders and neuroblastoma following chlordane treatments in the home
Liver damage and chlordane
Chlordane shows the ability to cause liver damage at low exposure levels
Male and female infertility problems
Research shows chlordane can cause infertility and sperm damage
High school closes due to chlordane treatment
Teachers and students complained for 4 years before chlordane was found to be the cause of illnesses in this Virginia High School.
Overweight is a symptom of chlordane exposure
Surprising increases in body weight have been found to occur in test animals exposed to chlordane.
Researchers are not sure if this is due to the ability of chlordane to alter hormones or chlordane’s ability to damage brain centers controlling body weight.
Chlordane & Dursban Air Test Results
This table summarizes eight different indoor air testing projects by the U.S. Air Force and Governmental Agencies of over 1000 U.S. homes. Pesticides sampled include 6 chlordane test projects and 2 Dursban test projects. These test results clearly show how serious and widespread the chlordane indoor air problem is in pre-1988 homes.
75% of U.S. Homes Contaminated with Chlordane
New research shows that people living in homes built before April of 1988 are most likely breathing the pesticide chlordane each minute they are in the house. In fact, research by the U.S. Air Force and the New Jersey Department of Environmental Regulation has found in tests of over 1000 homes, that approximately 75% contain chlordane in the indoor air and 7% are over the maximum safe levels according to National Academy of Science (NAS) guidelines (1). These figures are suspected of being the same throughout the U.S.
Chlordane was the pesticide used to prevent or eliminate termites during the 1950’s, 60’s, 70’s and 80’s. However, after many reports of serious illness among both adults and children following its application and links to cancer in animals, chlordane was finally banned by the EPA in March of 1988. Unfortunately, the ban did not take place until over 30 million homes throughout the U.S. had been treated. Concerns in Florida are even greater because of the increased termite problem and the fact that research shows chlordane is higher in homes built on sandy soils.
Most homeowners are unaware that just before the concrete slab was poured for their home’s foundation, a pesticide company had come in and saturated the soil with 100 gallons of chlordane per 1000 square feet of area. People were literally building their homes on top of a toxic chemical dump. The public was reassured by the pesticide industry and entomologists that this was a safe procedure and that the chemical would not enter into the home because of the barrier provided by the cement foundation. However, this turned out not to be the case.
Homes Remain Contaminated For Decades
Chlordane is such a highly toxic and persistent chemical that homes treated 20-30 years ago are still showing unsafe levels of chlordane in the indoor air. The problem occurs because the hundreds of gallons of chlordane underneath the home are slowly evaporating, rising through cracks in the foundation or around plumbing pipes and entering the home. One of the first studies to find there was a problem came in the 1970’s when the U.S. Air Force randomly tested over 500 apartments and housing units of its airmen. Results showed approximately 75% of the units tested contained chlordane in the air and over 5% were above the National Academy of Sciences “safety guidelines” of 5 micrograms per cubic meter of air (1).
Unfortunately, this is turning out not to be an isolated case. Further studies by the New Jersey Department of Environmental Regulation and other agencies have found similar results in hundreds of homes in New Jersey and New York. Of great concern, when testing 64 homes built before 1980, researchers found more than 30% of the homes contained chlordane levels above the 5 microgram safety limit set by the National Academy of Sciences (2).
Illnesses Linked To Chlordane Home Exposure
There are now several university studies showing even so-called acceptable levels of chlordane in indoor air can cause respiratory and neurological problems. These are outlined by sections below.
Families in apartment complex treated with chlordane show increases in sinusitis, bronchitis, migraines, cough & anemia
JOURNAL: Bulletin of Environmental Contamination Toxicology, 39:903 (1987)
A study of 261 people who were either living or had lived in homes with higher air chlordane levels were found to have nearly three-times more respiratory illnesses, including sinusitis (infection of the sinuses) and bronchitis. The study, conducted at the School of Public Health, University of Illinois, also found other illnesses significantly more often in the chlordane homes. These included chronic cough, anemia, neuritis, ovarian/uterine disease and skin disorders. The migraine headaches, which was the worst acute symptom found, was occurring in 22% of people living in the higher level chlordane homes.
An important point of this study is that researchers divided the 261 people into three groups based on the level of chlordane found in their homes. These included:
- LOW EXPOSURE (under 1 microgram of chlordane per cubic meter of air in the home)
- MEDIUM EXPOSURE (1-5 micrograms of chlordane per cubic meter of air in the home)
- HIGH EXPOSURE (over 5 micrograms of chlordane per cubic meter of air in the home)
Separating people into these groups is done in order to look for what is called a “dose-response” effect, which strongly suggests that the chemical is in fact causing the illnesses. A dose-response effect means that as the amount of chlordane in the air increases, we would also see a corresponding increase in health problems. This is in fact, exactly what the researchers stated they had found. In conclusion, Dr. Clark stated,
“The finding of a dose-response relationship between the indoor air concentrations of chlordane and three self-reported chronic health conditions (migraine, sinusitis, and bronchitis) suggests that chlordane could have chronic human health impacts. The association between chlordane and migraine and bronchitis is consistent with previous reports of these symptoms in chlordane poisoning or incident cases. Aplastic and acute refractory megaloblastic anemia and effects on the female reproductive system have also been associated with chlordane and/or heptachlor exposure. In our study, half the homes judged to have had a proper termiticide application had detectable air levels of chlordane, an average of 2.7 micrograms per cubic meter, months to years following the last application… The United States Environmental Protection Agency has often considered lifetime cancer risks exceeding one in a million as unacceptable. An air level of less than 0.1 micrograms per cubic meter, which appears unachievable, may need to be required to have cancer risks within an acceptable range. On August 11, 1987, on the basis of new evaluations regarding the safety of the cyclodiene termiticides, EPA announced the cancellation of virtually all termiticide uses of chlordane, heptachlor, aldrin and dieldrin.”
This study was reported by Dr. J. Milton Clark, Ph.D.
School of Pubic Health, University of Illinois (3).
Breast Cancer Linked to Chlordane Exposure
JOURNAL: Breast Cancer Research and Treatment, 90:55-64 (2005)
One in eight women in the United States will develop breast cancer according to the latest statistics. Breast cancer rates in the U.S. are 3-7 times higher than those in Asia. This 2005 study conducted at the US Army Institute of Surgical Research and Texas Tech University Health Science Center in Lubbock Texas found that cancerous human breast tissue contained the chemical heptachlor epoxide (found in the common home pesticide chlordane) at levels 4 times higher than non-cancerous breast tissue. Chlordane was the primary termite prevention pesticide used in over 30 million U.S. homes between the mid 1950’s and 1988. An estimated 50 million U.S. residents are currently exposed to the volatization of this chemical from previously treated pre-1989 homes on a daily basis.
Dr. Richard A. Cassidy, Sridhar, George M. Vaughan
Tox Free, Inc., Tell City, IN
Texas Tech University Health Science Center, Lubbock, TX
US Army Institute of Surgical Research
Immune System Damage & Autoimmune Problems
JOURNAL: Archives of Environmental Health, 43(5):349-352 (1988)
An excellent test to determine how well a person’s immune system is functioning is called “proliferative response.” This test measures how fast a person’s immune system cells multiply in order to eliminate invading bacteria or viruses. In several different tests of proliferative response, conducted at the Southern Illinois School of Medicine, it was found that people living in chlordane treated homes had immune system cells that multiplied only about half as fast as immune system cells of people not exposed to chlordane. (This provides an explanation for the increase in infections shown in the previous study.) In another immune system test conducted by the same scientists, eleven of twelve chlordane exposed people were found to have a condition known as autoimmunity. This is where the person’s own immune system mistakenly attacks their own self, which the researchers stated can then result in a variety of other illnesses.
Immune System Macrophages Paralyzed By Chlordane
JOURNAL: Agents & Actions Journal, 37:140-146 (1992)
The pesticide chlordane is showing a strong tendency to seriously weaken the body’s ability to fight cancer cells. Macrophages are one of the most important immune system cells which organize the attack against bacteria, viruses and cancer. However, in tests conducted at the Department of Immunology at the University of Arkansas, it was found that when mice were exposed to chlordane, their macrophages were almost entirely paralyzed in the ability to destroy cancer cells for 24 hours after exposure (5).
Fatigue, Depression, Anger, Memory, Concentration Probs. All Caused by Chlordane Exposure
JOURNAL: Bulletin of Environmental Contamination Toxicology, 39:903 (1987)
In June-September 1994, 216 adult occupants or former residents of an apartment complex which had its exterior surfaces treated with chlordane were examined by researchers at the University of Southern California School of Medicine (6). The 109 women and 97 men were given a battery of neurological tests to determine if the low levels of chlordane in their apartments was causing any harmful effects. The tests given are considered sensitive indicators of neurotoxicity. To determine if chlordane was in fact causing neurological problems, the test scores of the chlordane exposed adults were compared to the test scores of 94 women and 68 men from Houston, known not to have been exposed to chlordane.
Results of the testing showed many harmful effects upon mental function from the low levels of air chlordane. Not only were their test scores significantly lower for reaction time, balance, and memory, but the testing also showed significant increases in attention deficits, tension, depression, anger and fatigue.
In conclusion, Dr. Kaye Kilburn stated,
“The exposure of our study group appears to be from indoor air, due to the outgassing of chlordane from the wooden surfaces of the apartment complex…. Chlordane is a chlorinated cyclodiene insecticide introduced in 1948 and considered to act as a toxicant with many of the signs and symptoms of poisoning like those produced by DDT… It is tragic that exposure is still occurring to a material that the National Research Council in 1982 characterized as a hazard at any dose: it could not determine a level of exposure to any of the cyclodiene termiticides below which there would be no biological effect. Every effort should be made to minimize exposure (29:p.164). Also in 1986 the EPA reported that chlordane was the most frequently misused or misapplied of the termiticides… As of 1987 under an agreement with EPA, the manufacturer Velsicol ceased to sell chlordane for consumer use in the United States, although the company was still licensed to export it. It is regrettable that chlordane was applied around and on 30 million or more homes in the United States before the ban.”
Asthma, Allergies, Bronchitis and Cough Linked to Chlordane Homes
JOURNAL: Bulletin of Environmental Contamination Toxicology, 39:903 (1987)
Along with the neurological problems found among people living in chlordane treated homes in the previous study at the University of Southern California, the researchers also found significant increases in many other health symptoms among the families living in the chlordane homes. These included significant increases in allergies, cough, bronchitis, wheezing, asthma and shortness of breath at rest and while walking and climbing stairs.
Neuroblastoma & Leukemia After Chlordane Exposure
JOURNAL: Teratogenesis, Carcinogenesis, and Mutagenesis, 7:527-540 (1987)
Chlordane has also been linked to causing neuroblastoma and leukemia in children along with other blood abnormalities. Severe anemia and leukemia developed in a baby girl following home termite treatment. The case was settled in the California Superior Court (1975). Five cases of brain cancer were also reported to develop in children following prenatal or postnatal chlordane exposure.
A 1987 study at the School of Public Health, University of Illinois Medical Center, reported 25 new cases of various blood problems with the majority occurring following chlordane termite treatment. These included more examples of leukemias and anemias (8).
In a study reported by Velsicol (the manufacturer of chlordane), it was found that when monkeys were exposed for 90 days to air chlordane levels of 100 micrograms per cubic meter of air, they were more likely to develop a condition known as leukopenia (9), which means their disease fighting white blood cells dropped to a dangerously low number. Leukopenia often predisposes an individual to increased colds, flu, and infections. Levels of 250 micrograms per cubic meter of air chlordane have been reported in some chlordane treated homes, which is two and one-half times higher than the level causing leukopenia in the animals.
Chlordane exposure has also been linked to causing an increase in leukemias among agricultural workers. 1,084 death certificates of leukemia cases among Nebraska residents during the years 1957-1974 were matched with 2,168 deaths from other causes. These farmers exhibited a considerably higher risk of acute leukemia in counties where corn was grown in large quantities (10). Similarly, death certificates from Iowa for 1,675 white males over the age of 30 years who died of leukemia were investigated for possible causes of the cancer. Iowa farmers had a higher risk for lymphatic leukemia in counties where there was extensive production of corn and soy bean. There was also an association of death from leukemia with the amount of corn produced per acre. During the period of these studies, one of the major agricultural uses of chlordane was on corn crops.
JOURNAL TITLE: Leukemias and Blood Dyscrasias Following Exposure to Chlordane and Heptachlor
Liver Damage Results from Chlordane Exposure
SOURCE: Science News, November 24, 1984.
The human liver appears to also be vulnerable to damage from exposure to chlordane. After a 48 year-old woman had her home treated for termites with chlordane, she developed symptoms of nausea, sore throat and chest discomfort. Her medical history showed no signs of previous health problems. Blood tests found low levels of chlordane in the woman’s blood. Indoor air testing of the woman’s home was then performed which found high airborne levels of heptachlor (a breakdown contaminant of chlordane).
Follow-up blood tests of the woman, conducted monthly, showed abnormal liver function indicators that “track exactly with the levels of pesticide in her blood,” stated Dr. Alexander, who as a physician had been clinically involved in the case. Even though the levels of heptachlorepoxide (the form stored in the body) never exceeded 3 parts per billion in blood, Dr. Alexander stated, “We’re now able to say that she has a mild chemical hepatitis-representing liver damage, caused by these pesticides..”
Male and Female Infertility Increasing Past 50 Years Evidence Chlordane Could Be Part of the Problem
Several biological problems affecting the male testicles have been occurring with greater frequency over the past 50 years. The summary of the problem, which appeared in the 1993 journal, Environmental Health Perspectives (13), discussed the observed rise in testicular cancer and the medical conditions hypospadias and cryptorchidism, as well as the apparent declining sperm count among the overall male population. Hypospadias is when the testicles do not descend and cryptorchidism is when the opening to the penis appears on the underside of the penis.
According to the researchers at the Statistical Research Unit, University of Copenhagen, Denmark, cancer of the male testicles has increased over 3-fold from 1940 to 1980. The frequency of hypospadias (the opening of the penis on the underside) in England has doubled from 0.15% in 1964 to 0.36% in 1983. Similar increases were also reported from Sweden and Hungary. Recent British data also detected a near doubling of cryptorchidism. This problem has risen from 1.6% of the boys born in the 1950’s to 2.9% born in the late 1970’s.
The researchers also performed a detailed survey of the international literature on sperm and semen levels published between 1930 and 1991. Compiling information from over 61 papers and 14,947 males indicated a significant decline in average sperm density form 113 million per milliliter in 1940 to 66 million per milliliter in 1990. The mean semen volume also declined from 3.40 milliliters to 2.75 milliliters (a nearly 20% drop). This means that the total sperm count decreased even more than that expressed by sperm density.
These figures show that men are producing only about half as much sperm per ejaculation today as they did in the 1940’s. This should generate concern as research has shown that as sperm count decreases, there is an increase in the risk of birth defects, miscarriages and general problems with the child. Therefore, these figures suggest that we should be observing a greater number of health and neurological problems among our children due to the connection between lower sperm count and lower sperm quality resulting from exposure of the male population to widespread environmental chemicals.
In conclusion the researchers stated,
“Recent data clearly indicate that the semen quality has markedly decreased during the period 1938-1990, and concomitantly the incidence of some genitourinary abnormalities including hypospadias, maldescent, and cancer has increased. Such a remarkable increment in the occurrence of gonadal abnormalities over a relatively short period of time is more likely to be due to environmental rather than genetic factors. Generally, it is believed that pollution, smoking, alcohol, and sexually transmitted diseases play a role.”
Because of the widespread contamination of chlordane in American homes (the chemical emits vapors for decades after treatment) and its link with causing abnormalities in blood and childhood blood and brain cancer, Dr. David Ozonoff, of the Boston School of Public Health, stated there is an “urgent need for legislation creating a national program for monitoring homes known to have been treated to detect persistent contamination with these highly dangerous pesticides.”
This persistent exposure to the U.S. population raises serious concerns regarding the effects of the chemical upon male and female fertility. Therefore, it is important to look at the research that addresses this issue.
Infertility Occurs in Male Test Animals
In the following chlordane study, researchers divided mice into three groups of ten mice each. Two groups were subjected to either a low or higher level of chlordane and the third group was used as a control group not exposed to any chlordane. After 30 days of daily exposure, the animals were sacrificed and the testicles were examined. The researchers stated that the chlordane exposed groups showed obvious changes to the part of the testicles where sperm development occurs (called the seminiferous tubules). Damaged tubules were present in 19% of the lower chlordane exposed animals- 31% of the higher chlordane exposed animals and only 3% in the animals not exposed to chlordane. There was also a reduction in the seminiferous tubule diameter in the higher chlordane exposed group.
This research was conducted by Dr. K. J. Balash and colleagues at the Biological Research Center, Scientific Research Council, Baghdad, Iraq (13).
How Chlordane Causes Infertility in Female Test Animal
JOURNAL: Toxicology and Applied Pharmacology, 19:234-246 (1971).
There are several studies showing female infertility in test animals increases after exposure to the pesticide chlordane. In the study conducted by Wellcome Research Laboratories, Research Triangle Park, North Carolina, scientists exposed over 100 mice to low levels of chlordane (25 mg/kg)once a week for three weeks before mating and compared their fertility success with over 100 mice not exposed to chlordane before mating. The experiment was performed three different times to see if the results were consistent. Each time the results were the same – that female animals exposed to chlordane conceived far less often than females who were not exposed to chlordane.
In the first experiment, the results showed 27% of mice exposed to only corn oil conceived while only 3% of mice exposed to chlordane mixed with corn oil conceived.
In the second experiment, the results showed 29% of the mice exposed to only corn oil conceived while 19% of mice exposed to chlordane mixed with corn oil conceived.
In the third experiment, the results showed 50% of the mice exposed to only corn oil conceived, while 20% of mice exposed to chlordane mixed with corn oil conceived.
To help explain why the decreases in fertilization was being observed, the scientists found that chlordane exposure was causing excessive metabolism in the liver of important estrogen compounds necessary for reproduction. In other words, the chlordane was actually causing the liver to remove estrogen at too rapid a rate, thereby decreasing its level in the female body to unusually low levels. Not only was fertility success lower, but it was found that the uterine weight of the chlordane exposed animals was also up to 34% lower. With approximately 7% of U.S. homes being tested showing unsafe levels of chlordane, it would certainly be of interest to determine the air chlordane levels of homes where couples were having trouble conceiving. For more information on infertility problems caused by common environmental chemicals click – Infertility Facts.
This study was conducted by R.M. Welch and colleagues at the Wellcome Research Laboratories, Research Triangle Park, North Carolina published in the journal Toxicology and Applied Pharmacology, 19:234-246 (1971).
Overweight – a Symptom of Chlordane Exposure
JOURNAL: Toxicology & Applied Pharmacology, 126:326-337 (1994)
One unexpected symptom of chlordane exposure is an increase in body weight. In fact, in an experiment of over 20 test animals receiving a chlordane exposure equal to that sometimes found among the U.S. population (100 ng/g – nanograms of chlordane per gram of body fat) there was an average 8% increase in body weight among the animals. Animals receiving 500 ng/g chlordane exposure were showing an average 11% increase in body weight. Chlordane exposure has been shown to reduce by-half the levels of some hormones in female test animals, however, scientists are unsure if this is the actual reason for the weight gain being observed or if it is due to another reason such as changes in the areas of the brain which control body weight. This raises the question of whether the same symptom may be occurring among residents living in chlordane homes built before March of 1988.
Richard A. Cassidy, Ph.D., Charles V. Vorhees, Daniel J. Minnema, Lloyd Hastings
U.S. Army Institute of Surgical Research, Fort Sam, Houston, Texas
Division of Basic Science Research, Children’s Hospital Research Foundation
Department of Pediatrics, University of Cincinnati, Cincinnati, Ohio
Teachers and Students Develop Illness –
High school found to contain high levels of chlordane- SOURCE: E-Magazine
Andrew Jackson High School finally closed in May 1989. However, it took 4 years of student and teacher complaints about persistent fatigue, headaches and respiratory problems to find the cause. The reason for the closing was that investigators were finally called in from NIOSH (National Institute of Occupational Safety and Health) and found air chlordane levels in the school at levels eleven times higher than the National Academy of Sciences (NAS) safety limit.
The testing of other schools for chlordane has sometimes been a little more difficult. East Fairmont High School in West Virginia was also having its own problems with sick-building syndrome. Students and teachers complained of headaches, rashes and tremors. The parents hired their own private toxicologist, Dr. Robert Simon, to perform tests. He found several pesticides including chlordane and concluded that the school needed an extensive hazardous waste clean-up.
The Marion County Board of Education followed by hiring a law firm to put together another group to retest the school. This time it found lower levels of the chemicals. The board then hired two independent consultants to analyze both test results – they concluded that there was nothing hazardous at the school. It was recommended only to clean the art room, cafeteria and kitchen as a matter of “good housekeeping and hygiene.” Although the board maintained that the school never posed a health risk, it authorized a clean-up in August 1991 that cost $15,000.
Some parents were still upset. They alleged that two other firms were hired and then fired by the school board when they found the school to be unsafe. The parents and teachers still wanted a third test to be done by a federal agency such as NIOSH. Although such testing wouldn’t cost the district anything, the school board would not agree to it. As a result, five lawsuits were filed against the board and more were expected.