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Endocrine Disruptors

The term "endocrine disruption" was first coined in 1991when a University of Wisconsin scientist, Dr. Colborn presented her findings which convened 21 international scientists from 15 different disciplines to share their research relevant to trans-generational health impacts. Specific participant and specialty information is provided in the Wingspread Consensus Statement at

In 1992 a book titled; Chemically Induced Alterations in Sexual and Functional Development: The Wildlife/Human Connection, a collection of manuscripts provided by those who attended the 1991 session. The information from this volume and subsequent scientific publications on exposure effects of endocrine disruptors was popularized in a1996 book, Our Stolen Future co-authored with Dianne Dumanoski and J. Peterson Myers now published in eighteen languages’. Colborn’s work has prompted new laws of protection around the world and directed the research of scientists, government, and other public health sectors.

An endocrine disrupter is a chemical that can disrupt or interfere with the proper functioning of the endocrine system. The endocrine system consists primarily of glands that produce hormones that help to guide the development, growth, reproduction, and behavior of human beings and animals. Hormones work by attaching to specialized receptors on cell surfaces. A problem can occur if a chemical (instead of a natural hormone) binds to the receptor and blocks the action of the hormone. Consequently, normal biological function can be blocked by the presence of endocrine disrupting chemicals.

Many pesticides and industrial chemicals are capable of interfering with the proper functioning of estrogen, androgen and thyroid hormones in humans and animals.
Exposures can cause sterility or decreased fertility, impaired development, birth defects of the reproductive tract, and metabolic disorders.

Relevent link from Endocrine Society, Statement on Endocrine Disruptors

Endocrine Disrupters Findings

In the last 10-15 years, many widely used chemicals have been linked to the disruption of hormone function in humans and/or wildlife. These chemicals have been shown to alter levels of male and female hormones, as well as certain thyroid hormones. Changes in these hormone levels affect developing organisms more than adults and can result in abnormalities in reproduction, growth, and development, as well as cancer and immune system disorders, even at very low levels of exposure.

While it is clear that some pesticides are capable of having endocrine-disrupting effects, no "official" list of these chemicals has yet been compiled in the United States. Testing to identify endocrine-disrupting pesticides was mandated by the federal Food Quality Protection Act of 1996; however, delays and lack of funding have set back the schedule for implementation. Updates on the status of the U.S. EPA Endocrine Disruptors program can be found at the U.S. EPA web site.

The European Union has done extensive work towards official designation of endocrine-disrupting substances, collecting literature studies on many chemicals. They now have a list of 564 chemicals under evaluation for endocrine disruption effects. This data is not yet publicly available but will be incorporated in the near future.


  •  1. U.S. EPA Endocrine Disruptor Screening Program Web Site. Viewed on October 31, 2002.

  • 2. Endocrine Disruption: An Overview and Resource List, Natural Resources Defense Council. Viewed on October 31, 2002.

  • 3. Introduction to Endocrine Disrupting Chemicals, Dr. A Michael Warhurst. Viewed on October 31, 2002.

  • 4. Endocrine Disrupting Substances in the Environment, Environment Canada. Viewed on October 31, 2002.

  • 5. Environmental Estrogens and Other Hormones , Tulane and Xavier Universities. Viewed on October 31, 2002.

  • 6. Endocrine Disruptors: Links to Other Sites, Physicians for Social Responsibility. Viewed on October 31, 2002.

Pesticide Action Network (PAN) Summary Endocrine Disruptor Rating

The PAN suspected endocrine disruptor (ED) designation is based on several different sources of information. Because ratings from different sources sometimes conflict with each other and because there is not yet an "official" list of EDs, PAN created a summary ED designation that designates any chemical that is listed as a potentially endocrine disrupting by any of the sources is ranked as a Suspected endocrine disruptor.

PAN staff last updated this list in December 2002, adding the Danish EPA list and EU prioritization list at that time. Most of the lists are static lists in published works and do not change, with the exception of the Our Stolen Future web site which is updated several times per year.

Illinois EPA List

In 1997, the Illinois state EPA published a list of endocrine disrupting compounds. The list contains three categories of endocrine disrupting chemicals corresponding to the overall evidence available that the chemical is capable of disrupting the endocrine system:
  • Known: Chemicals for which strong evidence exists that endocrine-disrupting effects occur in intact animals.

  • Probable: Chemicals for which the preponderance of the evidence (in both intact animals and in bioassays) suggests that the chemical can cause disruption of the endocrine system.

  • Suspected: Chemicals lacking good evidence in intact animals or for which only assay evidence of endocrine disruption exists.
This data was taken from the Report on Endocrine Disrupting Chemicals, Illinois EPA (February, 1997). To our knowledge, this list has not been updated. At the time the list was published, U.S. EPA Headquarters was just beginning to evaluate endocrine disruptors under the mandate of the Food Quality Protection Act.

Danish EPA List of Endocrine Disrupting Auxiliaries

In 2000, the Danish EPA published a list of compounds used as "inerts" or adjuvants in pesticide products which-based on available information-the Danish EPA considers to have estrogenic effects or to be capable of decomposing into estrogenic compounds.

In the autumn of 1995 the Danish EPA published the report "Environmental Project no. 292: Male Reproductive Health and Environmental Chemicals with Estrogenic Effects". Following up the report the Danish Government announced the goal of phasing out by the year 2000 all pesticides containing estrogenic auxiliary matters. The chemicals are added to the products for various reasons-e.g. to enhance the effect of the active ingredients in the pesticide.

This data was taken from the document entitled Auxiliary Matters with Estrogenic Effects, Danish EPA, April, 2000. PAN last checked the currency of this data set on December 28, 2002.

European Union (EU) Prioritization List

In December 1999, the European Commission adopted a strategy for addressing the problem of endocrine-disrupting chemicals. Part of this stratgey was to establish a priority list of substances for further evaluation of their role in endocrine disruption. The list is to be used to identify substances for priority testing, once test methods become available, and to identify gaps in knowledge of the toxicity and exposure pathways.

Prioritization was based on evidence of endocrine disruption in humans or animals and on the exposure potential for the chemical based on persistence in the environment and the amount of the substance produced. The starting pint of the study was a working list, complied from the lists of suspected endocrine disrupting chemicals drawn up by various organizations as well as from an up-to-date literature search. The list contains three categories of endocrine disrupting chemicals:
  • Group I: At least one study providing evidence of endocrine disruption in an intact organism. Not a formal weight of evidence approach.

  • Group II: Potential for endocrine disruption. In vitro data indicating potential for endocrine disruption in intact organisms. Also includes effects in-vivo that may, or may not, be ED-mediated. May include structural analyses and metabolic considerations.

  • Group III: Substances which meet the criteria of High Production Volume and/or persistence in the environment for which: a) no or insufficient data are available, or b) sufficient data are available for evaluation, but the compounds to be endocrine disrupters.

The lists of chemicals were distributed among groups of experts for classification using the following guidelines and criteria:

  • If reliable in-vivo evidence for endocrine disruption was available, the substance was placed in Group I;

  • If less reliable in-vivo evidence for endocrine disruption was available (for example in case of contradictory test results), the substance was placed in Group II;

  • If only in-vitro evidence for endocrine disruption was available with positive test results, the substance was placed in Group II;

  • Substances with no data but closely related to substances categorized as category 1 were placed in Group II;

  • Substances with no data but closely related to substances categorized as category 2 were placed in Group II;

  • Substances with no evidence for endocrine disruption or no data and not related to Group I or II substances were placed in Group III.

This data was taken from the report Towards the Establishment of a Priority List of Substances for Further Evaluation of Their Role in Endocrine Disruption, Appendix 1, BKH Consulting Engineers and TNO Nutrition and Food Research(June 21, 2000).

  • 1. Communication from the Commission to the Council and European Parliament, Community Strategy for Endocrine Disrupters, COM (99)706. Viewed on December 26, 2002.

  • 2.Towards the Establishment of a Priority List of Substances for Further Evaluation of Their Role in Endocrine Disruption,Appendix 1, BKH Consulting Engineers and TNO Nutrition and Food Research(June 21, 2000). Viewed on December 26, 2002.

  • 3. Opinion on BKH Consulting Engineers Report "Towards the Establishment of a Priority List of Substances...," Opimion adopted at the 17th CSTEE plenary meeting, Brussels, September 5, 2000, Scientific Committee for Toxicity, Ecotoxicity and the Environment. Viewed on December 26, 2002.
Colborn List

A list of suspected endocrine disrupting chemicals was published in the scientific literature in 1993 by Theo Colborn(1), followed by the popular book for the layperson Our Stolen Future(2). The book highlighted the effects of endocrine disrupting chemicals on humans and the environment and was instrumental in raising public awareness of the need to find out more.

In this reference, chemicals are not ranked according to their endocrine-disrupting effects, thus the rating simply describes whether the chemicals is contained in the reference or not.

The chemicals listed in the PAN database are taken from reference 1. Colborn's current list can be found at the web site in reference 3. The PAN Pesticide Database was last updated from this site in February 2002.


  • 1. T. Colborn, F.S. Vom Saal and A.M. Soto, "Developmental effects of endocrine-disrupting chemicals in wildlife and humans,"Environmental Health Perspectives, 1993, v. 101, pp. 378-384.

  • 2. T. Colborn, D. Dumanoski, and J.P. Myers, Our Stolen Future, Penguin Books(New York, 1996).

  • 3. Widespread pollutants with reproductive and endocrine-disrupting effects. Our Stolen Future web site. Viewed on October 31, 2002.

Keith List

Lawrence Keith is the author of a book on environmental endocrine disruptors. Published in 1997, this book summarizes the endocrine disrupting effects of approximately 50 pesticides and industrial chemicals. In this reference, chemicals are not ranked according to their endocrine-disrupting effects, thus the rating simply describes whether the chemical is contained in the reference or not.

This data was taken from Lawrence H. Keith's Environmental Endocrine Disruptors: A Handbook of Property Data, Wiley Interscience(New York, 1997). This is a published book, so no updates are possible until a second edition is published.

Benbrook List

Charles Benbrook is the author of a report on endocrine disruptors written for the National Campaign for Pesticide Policy Reform. This report lists a number of compounds as suspected endocrine disruptors. In this reference, chemicals are not ranked according to their endocrine-disrupting effects, thus the rating simply describes whether the chemical is contained in the reference or not.

This data was taken from Charles M. Benbrook's, Growing Doubt: A Primer on Pesticides Identified as Endocrine Disruptors and/or Reproductive Toxicants, National Campaign for Pesticide Policy Reform(Washington, D.C., September 1996). This is a published report and will only be updated if a second edition is published.

Although the human harm from endocrine disrupters is not as clear as the animal harm, there's reason to worry. In terms of biochemistry, we're not that different from other mammals, where endocrine disrupters effects are clear, particularly in the reproductive apparatus.

But there was one giant "experiment" with endocrine disrupters on humans. Between the 1940s and 1970s, doctors prescribed an artificial estrogen named diethylstilbestrol, or DES, to prevent miscarriages in millions of pregnant women. Only long after the fact did doctors find that DES had caused a rare form of cervical cancer in some of their daughters.

Other evidence is more ambiguous. Several studies -- but not all -- have found a worldwide lowering of sperm counts, and blamed it on the rising concentrations of estrogen mimics in the environment. Some scientists say estrogen mimics could also explain the growing incidence of breast cancer.

The putative endocrine disrupters have structures akin to real hormones, and seem to include:
  • Breakdown products of several pesticides that are now banned, such as DDT.

  • PCBs, a persistent group of chemicals still found in electrical equipment that pollutes lake and stream sediments in many industrial regions.

  • Dioxins, a group of toxic chemical byproducts from paper production and incineration.

  • Chemicals found in the epoxy lining of "tin" cans, plastics used for storing food, dental sealants, and Vinclozolin, a fungicide used on fruit.

Although some of these chemicals, like the PCBs, are off the market, they break down very slowly. Tests of people living as far from factories as the Arctic have found PCBs at levels that could be dangerous. In animal tests, remember, endocrine disrupters and hormones can act at tiny concentrations -- parts per trillion.(What kind of fraction is one-trillionth? It's about the width of a magazine page -- compared to the distance to the sun.)

The congressional edict

The growing alarm over endocrine disrupters reached Congress. In September 1996, Sen. Alphonse D'Amato urged funding for a new screening program, citing "a growing concern over the effect of pesticides and other substances on human endocrine systems and their ability to increase the likelihood of disease, such as breast cancer."

The Congressional edict requires EPA to devise a strategy to screen chemicals for endocrine disrupters effects by August 1998. The EPA formed the Endocrine Disrupters Screening and Testing Advisory Committee (EDSTAC) to devise a rational process for assessing the hazards of environmental endocrine disrupters.

While much of the research to date has focused on estrogen disrupters, EDSTAC has chosen to include androgens (so-called "male" hormones) and thyroid hormones, which direct body growth and metabolism.

The screening job is a big order, since there are so many possible effects in so many animals -- from alligators to people wearing alligator shoes.

What You Can Do About Hormone Disruptors

  • Educate yourself about endocrine disruptors, and educate your family and friends.

  • Buy organic food whenever possible.

  • Avoid using pesticides in your home or yard, or on your pet -- use baits or traps instead, keepin your home especially clean to prevent ant or roach infestations.

  • Find out if pesticides are used in your child's school or day care center and campaign for non-toxic alternatives.

  • Avoid fatty foods such as cheese and meat whenever possible.

  • If you eat fish from lakes, rivers, or bays, check with your state to see if they are contaminated.

  • Avoid heating food in plastic containers, or storing fatty foods in plastic containers or plastic wrap.

  • Do not give young children soft plastic teethers or toys, since these leach potential endocrine disrupting chemicals.

  • Support efforts to get strong government regulation of and increased research on endocrine disrupting chemicals.

Natural Alternatives To Reduce Risk of Endocrine Disrupters

Estrogen dominance is a term that describes a condition where a woman can have deficient, normal or excessive estrogen, but has little or no progesterone to balance its effects in the body. Even a woman with low estrogen levels can have estrogen dominance symptoms if she doesn't have any progesterone.

Estrogen is also received transdermally from all sorts of external sources. These are called Xenoestrogens. These are fat-soluble and non-biodegradable in nature. The major sources of these Xenoestrogens are pesticides, detergents, petroleum products, plastic products, cosmetics, even spermicides used for birth control in diaphragm jellies, condoms and in vaginal gels. So think twice when you drink your hot coffee or tea in that plastic or styrofoam cup from the convenient store on your way to work. What ever you do, DO NOT heat your food in plastic cookware. All of these contribute to the estrogen dominance and have been linked to birth defects in both humans and animals.

Recommended Herbs:

Liver Health-Milk Thistle

Milk Thistle yields three main active compounds known collectively as Silymarin, which work in a number of ways to restore liver health. Silymarin inhibits the factors responsible for causing liver damage. As well, it increases the liver's content of a substance called glutathione which is responsible for detoxifying many chemicals, drugs and hormones. Silymarin also stimulates the growth of new liver cells so that damaged areas of the liver may be regenerated.

With continued use of any drug you should support your liver by adding Milk Thistle it will help your liver to detoxify any medications that you take so your liver works better and the medication will do what it is intended to do.
PANNA (Pesticide Action Network North America) works to replace pesticide use with ecologically sound and socially just alternatives.
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