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Recent developments of the 

Endocrine Disruptor Screening and Testing Advisory Committee (EDSTAC)

including a summary of EDSTAC's final report 

Davis Baltz /  Commonweal 28aug98

This document reports on recent developments of the Endocrine Disruptor Screening and Testing Advisory Committee (EDSTAC), including a summary of EDSTAC's final report. EDSTAC was chartered by the U.S. Environmental Protection Agency (EPA) in October 1996 to develop recommendations for EPA about how to screen and test chemicals for their potential to disrupt hormone function in humans and wildlife, based on provisions of the 1996 Food Quality Protection Act and the reauthorization of the Safe Drinking Water Act. EDSTAC was established under the provisions of the Federal Committee Advisory Act (FACA), and has been chaired by Dr. Lynn Goldman, EPA Assistant Administrator in the Office of Prevention, Pesticides and Toxic Substances.

EDSTAC met publicly nine times in different U.S. cities, beginning with San Francisco in December 1996. EDSTAC's final plenary was June 17-18 1998 in Washington D.C. The committee also visited Houston, Baltimore, Chicago, New York, and Orlando.

The EDSTAC is composed of approximately forty stakeholders drawn from industry, academia, government agencies, and public interest and environmental organizations. A full list of members, as well as other documents, including the draft report, is available from this EPA website:

http://www.epa.gov/opptintr/opptendo/index.htm  (no longer available) The new URL http://www.epa.gov/endocrine/  12jul01


EDSTAC met for the final time face-to-face on June 17-18, 1998 in Washington D.C. The original deadline for completing the report has slipped. Now it appears the first of September 1998 will see the final report released to EPA.


It is expected that EPA will formally issue its proposed program in detail in early fall, 1998 in a detailed Federal Register announcement. EPA's proposal will be largely based on EDSTAC's recommendations, and its announcement will initiate a formal 60 or 90 day nationwide public comment period and scientific peer review by a first-ever combined panel of the EPA's Science Advisory Board (SAB), and the EPA's Scientific Advisory Panel (SAP). The formal peer review is now expected to take place in March 1999 instead of December 1998 as earlier scheduled.

EPA may also decide to "roll out" its proposal with a press conference and briefing. This is the first time in over 20 years that Congress has spoken with regard to actually testing chemicals, and in the Agency's view, the announcement of the proposed Endocrine Disruptor Screening and Testing Program will be a significant step forward.


No matter what the details of the EPA's proposal are, locating the funds to carry the screening and testing program forward is an extremely important task. Initial key activities will revolve around the standardization and validation of proposed assays; a recommended research project to address low dose issues; and the implementation of High Throughput Pre-Screening. The costs will not be inexpensive, and public funds will need to be resourced to carry the program ahead. Once the assays are standardized and validated, the screening and testing program will formally begin and presumably industry money will be used for its operation.


After the EPA presents its proposed Endocrine Disruptor Screening and Testing Advisory Program to Congress in the fall of 1998, there will be a formal, nationwide public comment period of sixty or ninety days. This comment period will be particularly important because comments will be directly to EPA on their proposed program. The first six EDSTAC plenaries included public comment periods, which were well-attended. A wide range of citizen interests appeared before the committee to provide comment. With EDSTAC completing its work, the opportunity to comment on the EDSTAC's work and report is over.


Barring a last minute, unexpected disagreement, the full EDSTAC will submit a consensus document to EPA. EPA is pleased that EDSTAC has achieved consensus. It had been the hope of the Agency from the beginning to have an agreed-upon set of recommendations. The rationale has been: if all EDSTAC stakeholders across the spectrum concur, then it will be much more feasible to have a screening and testing program that gets on with the important business of assessing chemicals for endocrine disrupting properties, as opposed to a system that becomes bogged down by administrative challenges and litigation by various interest groups at every step.

EDSTAC's consensus is a significant accomplishment that attests to the broad concern across society about endocrine disruption. However, the EDSTAC has in some cases left key decisions to EPA, meaning that important decision-making will be made by EPA without the consensus backing of the EDSTAC panel.


EDSTAC has long known a tiered approach would be recommended to EPA, and this conceptual framework is not controversial. After an initial SORTING step, chemicals will undergo PRIORITY SETTING which will determine, in essence, in what order the chemicals will be screened and tested. The next step is TIER ONE SCREENING, a first "rough cut" battery of assays, followed by TIER TWO TESTING if necessary, which would provide much more comprehensive and specific information. Chemicals which ultimately test negative, or are not prioritized because of low concern, would be deferred until such time as new evidence indicates they should be re-examined. Chemicals which ultimately test positive as endocrine disruptors after Tier Two Testing would then undergo Hazard Assessment at EPA.

A total of 87,000 chemicals will be available for the first Sorting step. This includes the TSCA inventory, pesticides (active ingredients and inerts), and ingredients in cosmetics and food additives in collaboration with U.S. FDA.


At its final plenary, EDSTAC agreed on language to describe an "endocrine disruptor." This had been a contentious issue from the beginning. The language reads: "The EDSTAC describes an endocrine disruptor as an exogenous chemical substance or mixture that alters the structure or function(s) of the endocrine system and causes adverse effects at the level of the organism, its progeny, and populations or subpopulations of organisms - based on scientific principles, data, weight-of-evidence, and the precautionary principle." It should be noted that EDSTAC chose to label this as a "description" and not a "definition." Nearly everyone agrees that it is too long, and rather klunky.

While industry is pleased that the final document includes "adverse effects" language, the trade-off for public interest advocates is gaining explicit mention of the precautionary principle. In addition, the document states that the current level of knowledge and experience in endocrine disruptor toxicology "do not permit the simple categorization of all endocrine effects into adverse and non-adverse," reflecting some EDSTAC members' concern that it can be very difficult to recognize adverse effects, particularly at the population level.

The difficulty agreeing on a definition stemmed primarily from the question of whether or not the phrase "adverse effects" should be included. Industry consistently pushed the position that an "endocrine disruptor" must not only alter the structure or function of the endocrine system, but also cause adverse health effects. In other words, evidence of a synthetic chemical binding to receptors would not be "disruption" unless it was shown that this binding then led to adverse health effects.

Public interest representatives have said that the interference in the functioning of the hormone system caused by receptor binding (or another mechanism) is evidence enough to cause concern. Waiting for adverse effects, which may not become manifest for a generation, irresponsibly allows chemical exposure to continue that might be harmful. There is enough evidence now to warrant the exercise of more precaution to protect the public from exposure to potential endocrine disrupting chemicals.

Because the EDSTAC description of an endocrine disruptor contains the "adverse effects" language, industry has insisted that the final document be mostly cleansed of the word "disruptor." Industry does not want anything to be labeled as a "disruptor" unless and until adverse health effects have been demonstrated at the conclusion of Tier Two Testing. Until that time, industry prefers to refer to chemicals in the program that test positive as "endocrine active" or "endocrine-mediated." Industry's concern is that any "tag" of endocrine disruptor will put great pressure on a chemical for product de-selection, voluntary or otherwise.


EDSTAC recognized that the statutory requirements of the Food Quality Protection Act and the Safe Drinking Water Act would drive some chemicals towards early screening and testing regardless of EDSTAC recommendations. For Priority Setting, EDSTAC concentrated on putting forth its best suggestions based on public and environmental health concerns rather than on existing regulatory requirements.

EDSTAC recommendations in Priority Setting exceed what would be required solely by statute in some significant ways:

* EDSTAC recommends EPA consider a much larger universe of chemicals as potential candidates for screening and testing (87,000).

* EDSTAC recommends EPA screen and test for androgen and thyroid effects, not limiting itself solely to estrogen-related effects.

* EDSTAC recommends EPA's screening and testing program should address environmental impacts, and focus on both human and ecological health.

* EDSTAC recommends that mixtures be considered.


EDSTAC has recommended several criteria for EPA to use in the Priority Setting process by which chemicals will enter the screening and testing program. Five of these pertain to "exposure," three pertain to "effects," and "exposure and effects" together comprise another criterion to consider. Together with special cases such as mixtures or nominations, each of these "compartments" would contribute some unspecified number of chemicals for each phase of the screening and testing program. This approach came to be known as the "compartment-based" method of Priority Setting.

The EDSTAC began work building a powerful database tool which incorporates the Priority Setting criteria. Due to time and resource constraints, however, EDSTAC was not able to complete the database, but recommends that EPA carry it through to completion with multi-stakeholder involvement.

This database will be a crucial tool to ask "what if" questions for determining which chemicals should receive a high priority for early screening and testing. EDSTAC recognized that Priority Setting is a value-laden process no matter who is doing it, and therefore attempted to construct a prioritization system in which the values of those setting priorities would be evident.

It is left to EPA to generate a list of named chemicals to enter the program first, as well as a minimum number to enter each phase of the program. No matter what the Agency decides, it will almost certainly anger some stakeholders.

The database will be an immensely useful source of information for the public, and public interest representatives on EDSTAC want to ensure that it is available to everyone. The fact that a multi-stakeholder process is envisioned for the database's future development is evidence of the sensitive nature of how the database could be used.


How will screening and testing results be interpreted? What level of proof should be required to send a chemical to the next tier of scrutiny? In most cases, interpreting the results from a series of assays, which could likely include both positive and negative results, will require professional judgment.

EDSTAC is recommending that a "weight of evidence" approach be utilized on what will mostly be a case-by-case basis. Many decisions may prove to be straightforward - the weight of evidence will clearly indicate a consensus path of action. But there will also be cases where equivocal evidence is in the record, and EPA decisionmaking may be controversial.


Because so many chemicals have no information whatsoever, EDSTAC will recommend that High Throughout Pre-Screening (HTPS) be implemented. In HTPS, chemicals are screened with a limited number of simple assays that can be conducted by robotics technology. The technology exists to conduct this kind of automated assay on thousands of chemicals per year. This relatively inexpensive and fast process is a way to get more information quickly so that Priority Setting can proceed more fully informed.

The assays recommended for HTPS are designed to show whether or not a chemical binds to an estrogen, androgen, or thyroid receptor and causes transcriptional activation of genes. The EDSTAC recommends that all chemicals produced in excess of 10,000 pounds per year would be subjected to HTPS. Currently, there are 15,000 chemicals which are produced at this level or greater. The cut-off figure of 10,000 pounds was arrived at as a way to limit the size of the task. EDSTAC also recommends that HTPS be performed on all pesticides (active and inert ingredients), and on all chemicals proposed to bypass a tier in the program (see below), regardless of production volume.

A demonstration project to assess HTPS's feasibility is underway, and a contract lab has begun work assembling samples and running the HTPS assays on 78 substances selected to undergo HTPS. No results are available yet. Most EDSTAC members are assuming that the demonstration project will be successful, in which case the formal HTPS program could begin with some or all results available in 1999. If the HTPS system does not prove to be viable, the same information will be gathered in Tier One Screening using already developed assays - but it will be more expensive.

It is important the HTPS demonstration project be completed in a timely way so the formal HTPS program can begin. HTPS results will enable Priority Setting to proceed with more information to consider.


EDSTAC is recommending a nominations track in the program whereby individuals or organizations can recommend chemicals for inclusion in the screening and testing program. The primary objective is to capture chemicals that are not identified by other means in Priority Setting, but are of concern to communities or populations that might have disproportionately high exposure.

Nominating organizations will be made public. Nominating individuals will be able to request anonymity if they do so in writing. For each phase of the program when a new group of chemicals is poised to enter Tier One Screening, EDSTAC recommends that no less than five percent be drawn from nominated substances which were not selected by another prioritization criterion.


The recommended Tier One Screening battery does not contain an assay that looks at early developmental exposure. Since irreversible effects from endocrine disruption may occur during these developmental life stages, the lack of an assay that examines prenatal or pre-hatch exposure is a shortcoming of the recommended EDSTAC battery and a compelling concern. Some SAB/SAP peer reviewers specifically mentioned to EDSTAC that it would be useful to know how embryonic tissue could be looked at in more detail in Tier One Screening.

EDSTAC recommends that EPA take "affirmative steps" in collaboration with stakeholders to develop a protocol for a full life cycle developmental exposure screening assay which would address embryonic exposure and the evaluation of adult offspring. If developed, EDSTAC recommends the assay should undergo validation and if validated, EPA should integrate it into the existing Tier One Screening battery.

In its final report, EDSTAC suggests one in utero developmental screening assay for further research. Industry believes this particular assay is too expensive, and is in fact a Test rather than a Screen that doesn't belong in a Tier One Screening battery.


The document contains recommendations for bypassing Tier One Screening in two ways. The first is for chemicals that have previously been subjected to two-generation reproductive toxicity tests, although not necessarily for all endpoints of concern in endocrine disruption. The second way to bypass Tier One Screening is for the owner of the chemical to voluntarily move directly to Tier Two Testing without Tier One Screening results (or potentially any other prior toxicology testing).

In both cases, all chemicals bypassing Tier One Screening would undergo High Throughput Pre-Screening, and the "default" plan for Tier Two Testing would be that all T2T assays would be run. In the first case, a bypass mechanism means that "functionally equivalent" information can be substituted for results that the endocrine disruptor screening and testing program itself would generate.

What exactly does "functional equivalence" mean? EPA may likely have to initiate a formal rulemaking to clarify this, even though EDSTAC offers guidance by defining a screen or test as functionally equivalent to a Tier One Screening or Tier Two Testing assay when it "provides equivalent information for each endpoint being studied."

In both bypass options, skipping Tier One Screening could be problematic because the chemical will enter Tier Two Testing with less information to tailor its particular mix of Tests, including dose selection. The risk of false negatives in Tier Two Screening could be elevated without the data provided by Tier One Screening. (end of part one)


The recommended Tier One Screening battery is comprised of three in vitro and five in vivo assays. In addition, EDSTAC is recommending alternative assays for validation which could replace parts of the recommended battery in some circumstances. These alternatives would be proposed for use when they yielded information which was "functionally equivalent" to the first choice battery, thus precluding the need to run full complement of assays in the first choice battery. Whether the alternative assays will be capable of providing equivalent information will be determined during the validation phase.

As is the case with bypassing Tier One Screening, the issue of "functionally equivalent" information raises concerns because it would usually mean that less information is used for decision-making. But if less information is available, can it really be "equivalent?"


The final document recommends a full two-generation reproduction study for Tier Two Testing, which is essential for some of the most important endpoints of concern. At the same time, however, industry has successfully added a mechanism whereby the full two-generation study can be replaced by either a less comprehensive study call the Alternative Mammalian Reproduction Test (AMRT), or a one-generation test. Both of these will begin the validation process, along with other EDSTAC-recommended assays and tests.

The AMRT or one-generation test would be proposed for use when "functionally equivalent" information could be generated using these alternative assays, with or without existing information, thereby precluding the need for a full two-generation reproduction study.

Industry wants to limit the multi-generational studies both because they cost more, and because this is where they have the most to fear because of heightened sensitivity during developmental life stages. While the AMRT and one-generation test look at developmental life stages, they are considerably more limited than a two-generation reproduction study in looking at both the timing and life stages when exposure occurs.


Industry has always wanted an assurance that a negative Tier Two Testing result would be definitive; i.e., if a chemical tested negative in Tier Two Testing, then it would be fully exonerated and shown NOT to be an endocrine disruptor (at least unless or until new information is presented). While EDSTAC acknowledges that there may be cases where the evidence is mixed about a chemical's endocrine disrupting properties, it recommends that a negative result in Tier Two Testing should be definitive because Tier Two Testing results carry more weight than other information.

Industry wants to avoid any label of "endocrine disruptor" for a chemical substance until all screens and tests have been completed and the final result is positive. Industry's attraction to the bypass idea for Tier One Screening is based in part on avoiding the ambiguous status of a positive Tier One Screening result. Even though everyone is in agreement that a positive Tier One Screening result will not count as sufficient evidence to arrive at a final conclusion about a chemical's endocrine disrupting potential, much less trigger regulatory action, industry feels strongly that the stigma of a positive Tier One Screening result will unfairly prejudice the public against the chemical substance with detrimental effects in the marketplace.


During EDSTAC's life, there were concerns that proposals to detect thyroid effects in Tier One Screening were inadequate. It was acknowledged that in general, the dataset for thyroid is not as complete as for estrogen or androgen.

A frog metamorphosis assay was added to the Tier One Screening battery to help address this. From what is known, thyroid disrupting chemicals usually act through non-receptor-mediated mechanisms, and the frog metamorphosis assay was added because it is believed to be relatively sensitive to thyroid disruption. Public interest organizations on EDSTAC pushed to include as much language as possible emphasizing that neuro-developmental endpoints always need to be considered if there is any question of thyroid effects, and also if the chemical skips Tier One Screening.


Of the more than 87,000 synthetic chemicals now in existence, some 25,000 are polymers. Because the monomers and oligomers which comprise the polymer are more biologically active than the larger, intact polymers, the EDSTAC is recommending that the focus should be on screening and testing the monomers and oligomers. Another reason to focus on them is because of the daunting complexities of studying whole polymers.

EDSTAC recommends that all polymer components should be prioritized within the context of the "compartment" approach, along with additives and degradates. In addition, EDSTAC recommends that all "small" polymers be prioritized for screening.

EDSTAC is recommending that "large" polymers with a number average molecular weight (NAMV) of more than 1,000 daltons be deferred because their size would prevent their penetration through a cell membrane, based on studies of aquatic organisms and the intestinal systems of mammals. There is some controversy about the cut-off of 1,000 daltons. Although this figure is already used as a regulatory threshold, research was cited during EDSTAC deliberations suggesting neonates are able to absorb much larger molecules than adults because they do not undergo "intestinal closure" until the age of 4-5 months. The young of animal species could be vulnerable in the same way. These citations are included in the report even though the 1,000 daltons threshold remains. Presumably, these particular chemicals of concern would enter the screening and testing program by receiving a high priority in another "compartment."

EDSTAC is also recommending that all "old" polymers (those that were included in the first published TSCA inventory of 1979) be deferred as "existing chemicals" for which little information exists. Public interest representatives have said that just because a polymer is "old" does not mean it should be grandfathered with a deferment. There is very little known about these chemicals - EPA does not even know the NAMV for polymers that were in existence before 1979, although all the monomers have a CAS number.

If any of these component monomers or oligomers, from any polymer, tested positive as an endocrine disruptor, EDSTAC is recommending that the component proceed to hazard assessment. In addition, EDSTAC is recommending that an exposure assessment be performed at this time to gauge the potential for exposure from the intact polymer.

There is a concern because polymers can degrade over time, and EDSTAC is not recommending that EPA create degradation conditions in the screening and testing program. While degradates can enter the screening testing program via another "compartment" (assuming there is existing information), the report states that "EDSTAC does not consider it necessary to give special consideration to the potential degradates of polymers."

From a public interest perspective, if a monomer or degradation product tests positive, it would be prudent to classify the polymer itself as positive. The point should be "to test the yogurt container after it has been through the dishwasher, not before yogurt is put into it in the first place."


The EDSTAC recommends six specific mixtures for initial scrutiny in the screening and testing program. They are:

1. contaminants in human breast milk;

2. phytoestrogens in soy-based infant formulas;

3. mixtures of chemicals most commonly found at hazardous waste sites;

4. pesticide/ fertilizer mixtures;

5. disinfection byproducts;

6. gasoline.

EDSTAC acknowledges that screening and testing mixtures is a vastly complicated undertaking. For example, can standardized presumptive mixtures even be developed? That is, will a mixture to be tested change significantly from sample to sample? This in itself will be a large hurdle to overcome. It was also noted during EDSTAC deliberations that a positive result on a single mixture would create a large and possibly unwieldy follow-up program by itself.


Naturally occurring non-steroidal estrogens (NONEs) are derived from plants and fungi. They are ubiquitous in food. EDSTAC is recommending that six representative groups of NONEs enter the screening and testing program to compare them with hormones and synthetic chemicals. In addition, one mixture of NONEs is recommended (phytoestrogens in soy-based infant formulas). There is evidence that some NONEs are safe and beneficial to humans, and humans metabolize them relatively rapidly. However, their effects, particularly from exposure in large amounts during developmental life stages, are not well studied.


Low dose testing issues have been among the most controversial EDSTAC has addressed. The concern is that some chemicals seem to have effects at low doses which are not seen at higher doses, including neuro-developmental effects which are emerging quickly in this regard. If developmental effects are not adequately addressed at all relevant doses, including current environmental "background" levels, a vital piece of the screening and testing program's mission will be missed.

Industry has downplayed the significance of existing low dose research because of the profound market implications it has for specific chemical products and for the concept of risk assessment in general. During EDSTAC deliberations, industry representatives said that in terms of hurdles to their ultimate sign-on to the EDSTAC document, the low dose issue was their "Mt. Everest" and they would not allow their products to be "held hostage to ten mice."

Over the course of the 20 months since EDSTAC first met, there has been broader public acceptance of low dose effects in the scientific community. A workshop entitled "Characterizing the Effects of Endocrine Disruptors on Human Health At Environmental Exposure Levels" was conducted May 11-13, 1998 in North Carolina by National Institute of Environmental Health Sciences (NIEHS). The research findings presented at this workshop helped convince some who had claimed that low dose research already conducted had not been replicated. In addition, some of the SAB/SAP peer reviewers for EDSTAC, who met in Washington D.C. on May 5-6, 1998, provided initial feedback to EDSTAC expressing support for a more detailed examination of low dose issues.

The EDSTAC did not agree on a specific protocol to recommend dose levels. However, the committee recommends the following features for low dose issues in the screening and testing program:

* For in vitro assays in High Throughput Pre-Screening (HTPS) and Tier One Screening, several dose levels are recommended (five plus a control) to develop a dose response curve and an assessment of relative potencies. The goal is to establish a 50 percent response rate for receptor activation relative to a positive control which is known to bind to receptors. Presumably, this would require some relatively low doses.

* For in vivo assays in Tier One Screening, EDSTAC recommends that the decision to use one or more dose levels be determined subject to the validation process. Information to assist decisionmaking would include existing data, HTPS results, and range finding studies. Public interest representatives have been very uncomfortable with a recommendation of a single high dose for in vivo Tier One Screening. The reason is that it creates the potential for a chemical to test negative at one high dose and then be deferred from further scrutiny without ever undergoing low dosing levels in a whole-animal (in vivo) screen.

* In Tier Two Testing, EDSTAC agrees that special attention should be paid to setting the low dose. Deciding dose levels in Tier Two Testing will rely on existing information (including HTPS and Tier One Screening results), environmental exposure where appropriate, and range-finding studies that include low-dose sensitive endpoints.

* EDSTAC believes that a "recommended project to address low dose issues" is required to resolve the underlying uncertainties and controversy about dose selection and the identification of a no-observed-adverse-effect-level (NOAEL). EDSTAC provides a suggested time frame for the project of 4-6 months. It will be important for EPA to quickly take steps to carry this out. In a similar way, EPA must build a mechanism into its overall screening and testing program to quickly consider and incorporate new scientific evidence.

* The low dose project would focus on substances with estrogenic activity only. Existing evidence of low dose effects is strongest with estrogenic substances, and the Food Quality Protection Act specifically mentions estrogenic effects.

* If the results of the low dose project demonstrate the need to include any additional hormonal endpoints (i.e., androgen and thyroid which EDSTAC have agreed should be addressed), re-testing of chemicals which have already passed through the screening and testing program would be required for these additional endpoints.

* If the results of the low dose project demonstrate the need to include additional low doses, re-testing of chemicals would be required of chemicals which had already tested positive at a high dose. However, re-testing of chemicals which had already tested negative at a high dose would not be required (unless other new information on the chemical would warrant it).


Industry argued that the costs of implementing the screening and testing program should be considered in deciding which screens and tests to run. Their concern is to hold down the costs of the program which they will largely pay for.

Public interest groups wanted to see all mention of costs expunged from the document. They argued that the screening and testing program should focus on the protection of public and environmental health, utilizing the most effective and appropriate tools without regard to how much they cost.

Some references to cost will appear in the document. For example, in High Throughput Pre-Screening, the document says that "the cost of performing an assay needs to be taken into account...as high cost may limit the number of chemicals that can be evaluated."

On the other hand, the report notes elsewhere that cost estimates (for validation in this case) are "both preliminary and uncertain given the inherent uncertainties regarding the outcome of the validation...process." Public interest language was also inserted saying, "The EDSTAC notes that these cost estimates should be viewed in the context of the near- and long-term public health and environmental protection benefits to society."


EDSTAC recognizes that an effective EPA communications system is crucial for the success of the new Endocrine Disruptor Screening and Testing Program, both for the public's right-to-know, and to prevent the misuse of information.

EPA will need to develop explanatory materials about the screening and testing program, including the Nominations mechanism, to respond to expected public interest and requests for information. Some constituencies which may have particular concerns, such as environmental justice advocates, disease-impacted groups, farm workers, or downstream industries, may need tailored information about the program, and EDSTAC recommends that EPA be prepared to deliver this as necessary.

EDSTAC is recommending that a tracking system be developed that allows the public to quickly ascertain the status of any chemical in the program. This would be available through an interactive website and other means. In addition, regular program updates would be generated by EPA and communicated to stakeholders who expressed an interest in receiving them.


The EDSTAC recognizes that the screens and tests it is recommending will need varying levels of standardization and validation before the program can formally begin. It is important that standardization and validation occur quickly, so the actual screening and testing program can begin as soon as possible. EDSTAC recommends that standardization and validation be pursued on an "accelerated schedule" because it is of the "highest priority."

There is ample potential for foot-dragging delays if industry does not make good faith efforts to move forward on the validation process. It is important to note that the bar is being set very high for validation of assays in the context of the endocrine disruptor screening and testing program.

From a public interest perspective, putting a time limit on the validation process could be one way to drive it forward.

There is agreement that once an assay is validated, it can begin to be used. It will not be necessary to wait for the entire Tier One Screening or Tier Two Testing batteries to be validated before individual screens and tests can begin to be run. On the other hand, industry may try to insist that all endpoints being looked at in a particular screen or test be validated before the screen or test can be used.

To carry the validation work forward with EPA, a post-EDSTAC non-FACA "operational" committee of government, industry, academic and public interest representatives is envisioned and in fact has already begun to meet. This committee will likely also take on the further development of the prioritization database, the evaluation of High Throughput Pre-Screening, and other Priority Setting issues.

Standardization and validation costs will not be inexpensive. Some combination of public and private funds need to be resourced to pay for this next key step.


* End of August, 1998: EDSTAC formally submits its report to EPA.

* Fall, 1998: EPA presents proposed Endocrine Disruptor Screening and Testing Program (EDSTP) to Congress. Formal public comment period begins. Formal peer review period begins. * Fall, 1998: High Throughput Pre-Screening (HTPS) demonstration project complete.

* Winter, 1998-89: HTPS program formally begins (if demo was successful).

* Winter, 1998-89: estimated release date for National Research Council report on endocrine disruption.

* March 1999: SAP/SAB peer reviewers provide guidance to EPA in public meeting.

* Aug. 1999: EPA's statutory deadline to implement the EDSTP.

* Fall, 1999: HTPS complete.

* Aug. 2000: EPA reports to Congress on the EDSTP.

This summary prepared by:

Davis Baltz
PO Box 316
Bolinas CA 94924
415 868-0970 or 510 845-9023 telephone
415 868-2230 fax

I am a member of the public who has tracked EDSTAC's work from a public interest perspective, and am reporting on the committee's work in my own capacity. During the life of the EDSTAC committee, I encouraged the public to: attend remaining plenaries; provide pertinent public comments; and educate their colleagues about endocrine disruption. Early in the EDSTAC process, I was recruited to join EDSTAC's Communication & Outreach Work Group as a member representing the public.

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