Chapter 2. Approach and Methodology

2.1 Approach

2.2 Stakeholder Involvement

2.3 Phase I: Chemical Impacts and Uses

• 2.3.1 Potential Impacts of Chemicals (Phase Ia)
• 2.3.2 Identify Uses (Phase Ib)
• 2.3.3 Prioritize Uses (Phase I.c)

2.4 Phase II: Alternatives

• 2.4.1 Identify Alternatives (Phase II.a)
• 2.4.2 Screen Alternatives
• 2.4.3 Prioritize Alternatives for Study

2.5 Phase III: Alternatives Assessment

• 2.5.1 Technical Feasibility
• 2.5.2 Financial Feasibility
• 2.5.3 Environmental and Human Health Assessment
• 2.5.4 Procedures Followed for Evaluating Mixtures, Material Alternatives, and Process Alternatives

2.6 Economic Impact Study

2.7 Quality Assurance/Quality Control (QA/QC)

2.1 Approach

This chapter presents the approach taken by the Institute to perform the study and describes the methodology used to assess alternatives. The Institute's approach was designed to achieve the goals stated in Section 1.2, while recognizing the constraints of time and resources. As a "pilot project" the approach had to be flexible, allowing for changes in the methodology as it was implemented. As a result the project outcomes are both a more robust assessment methodology and a series of informative alternatives assessments for the five chemicals.

A consistent process for setting priorities and evaluating the alternatives for the five chemicals was first established. The methodology for this study is outlined in a companion document entitled "Five Chemicals Study Methodology - Alternatives Assessment Process Guidance" (see Appendix A). That document reflects the original methodology developed, and provides guidance to those conducting assessments. The guidance document was especially important because, due to the short timeline and broad scope of the project, different Institute staff members and their technical experts conducted the alternatives assessments simultaneously.

It is important to note that this study was not conducted in a manner designed to assess the relative safety of one alternative over the other. Rather, alternatives were compared to the study chemical as a baseline. The following graphic illustrates the phased approach that was used in this study.

Figure 2.1 Project Approach

Phase I focused on characterizing the potential environmental health and safety impacts of each chemical and identifying the priority uses in Massachusetts. In Phase II the Institute identified alternative chemicals and/or technologies for those priority uses and utilized a set of environmental, health and safety screening criteria to determine those alternatives that warranted assessment. In addition, where there were more potentially feasible alternatives than could be assessed in this study, additional criteria were used to determine those alternatives that were a high priority for assessment.

Each of these two initial phases was performed under an aggressive schedule so as to allow as much time as possible for completion of the assessments. Phase III represented the bulk of the assessment work, involving evaluation of the technical financial, and environmental and human health and safety parameters of the identified alternatives.

2.2 Stakeholder Involvement

To produce useful results in the time available it was necessary to narrow the scope of the project to areas that would have the greatest positive impact on Massachusetts. The Institute evaluated existing alternatives assessments would provide the most valuable and useful information for them. Representatives of Massachusetts companies, government, non-government environmental, health and labor organizations, and industry associations participated in a series of stakeholder meetings to assist the Institute in identifying significant uses, both in manufacturing and in products, and in prioritizing the uses and alternatives to be assessed.

Organizations participating at stakeholder meetings represented a wide range of Massachusetts interests, including but not limited to:

• Alliance for a Healthy Tomorrow
• Associated Industries of Massachusetts
• Astro Chemical
• Boston Scientific Corporation, Inc.
• Children's Hospital of Boston
• Clean Water Action
• Greater Boston Physicians for Social Responsibility
• Haemonetics Inc.
• Korean Dry Cleaners Association
• M/A-COM, a subsidiary of Tyco Electronics
• Massachusetts Public Interest Research Group
• Massachusetts Chemistry and Technology Alliance
• Massachusetts Coalition for Occupational Safety and Health
• Massachusetts Department of Environmental Protection
• Massachusetts Office of Technical Assistance
• Massachusetts State Legislature
• New England Fabric Care Association
• New England Korean Dry Cleaners Association
• North Shore Labor Council
• Rohm and Haas Electronic Materials
• Saint-Gobain
• Solutia
• Teknor Apex
• We Care Cleaners
• Western Massachusetts Coalition of Occupational Safety and Health

Stakeholder participants provided valuable contributions in three areas. First, they helped to refine the methodology and project plan. Second, they helped to narrow the scope of the project to areas that would have the greatest positive impact on Massachusetts. Third, stakeholders provided their own experience, expertise, and contacts to supplement the Institute's science and technical research. Comments were solicited at meetings, through email and telephone conversations, and through a draft report review process.

Four structured process meetings were held, as well as several less formal topic-specific meetings that addressed a specific method, chemical, or economic topic. The structured process meetings were held in Lowell and each were attended by close to forty participants:

1. September 26, 2005 - Methodology and Project Plan
2. October 21, 2005 - Use Prioritization
3. November 9, 2005 - Alternatives Prioritization
4. April 11, 2006 - General Project Update

While, in general, the input from stakeholders varied depending on their perspective, concerns and interests, during the use prioritization phase there were some common themes that emerged, including:

• A high priority should be placed on uses that are associated with higher potential exposure to the public and/or workers in small businesses.
• A low priority should be placed on uses where alternatives are already being readily adopted, or where significant research on alternatives is being carried out by others.

Stakeholders assisted in the identification of experts in academia, industry, national trade associations, labor, and environmental and health groups. Institute staff conducted on-site visits with specific industries to identify pertinent manufacturing and product performance criteria, as well as to obtain industry-specific financial information. For example, project staff visited several drycleaners using perchloroethylene and alternatives, and a resilient flooring manufacturer using DEHP and alternative plasticizers and materials. Certain industry experts met with Institute staff to address such topics as formaldehyde chemistry in adhesives, technical criteria for shooting range ammunition, and the toxicology of certain plasticizers. The stakeholder meetings and follow-up communications were very helpful in identifying highpriority uses and alternatives for assessment, as well as in ensuring the technical accuracy of Institute findings. Broad and detailed information collected at each stage was shared and posted on the project website at www.turi.org. At meetings focused on prioritization, each chemical was discussed separately, reviewing its hazards, uses and potential alternatives. Specific input from stakeholders on each chemical and use is included in the chemical chapters of this document.

2.3 Phase I: Chemical Impacts and Uses

2.3.1 Potential Impacts of Chemicals (Phase Ia)

Potential human health and environmental impacts associated with the use of the five chemicals were summarized as part of the prioritization process. This information was obtained primarily from public databases and published reference sources. In addition, peer-reviewed scientific journals, other published reference materials, industry trade group resources (publications and web sites) and advocacy group resources (publications and web sites) were used to provide more depth or to identify newer, emerging information. The Institute did not conduct a comprehensive review of toxicological studies.

The objective of this summary was to provide background information on the chemical, highlight environmental, health and safety issues, and provide a baseline against which the alternatives could be compared.

2.3.2 Identify Uses (Phase Ib)

Uses of chemicals in Massachusetts range from manufacturing processes to services to consumer products. For each of the five chemicals considered in this study, the majority of the major uses of the chemical were identified. This information is included in Appendix B. The range of uses identified for each chemical was so wide and varied that the Institute was not be able to evaluate all of them in the short time span allowed for this project. It was therefore necessary to narrow the scope to evaluate uses that were considered a high priority for Massachusetts (Phase I.c). In order to prioritize uses for further study, information was gathered from the literature and experts to determine the following:

• Major suppliers of the chemical
• Major derivatives, components and/or end products that incorporate the chemical or use the chemical as a feedstock, and their manufacturers - this considered the Massachusetts, domestic, and international markets
• Major distributors, retailers, or customers of end product, focused on Massachusetts customers
• Functionality requirements of chemical or component or end-product - for example, why is the chemical used and what is it used for?
• Relevant stakeholders, including businesses, industry associations, environmental, public health, and labor organizations.

2.3.3 Prioritize Uses (Phase I.c)

Meetings with Massachusetts stakeholders, as described in Section 2.2, were organized to provide information to stakeholders on the chemical use prioritization criteria, review the list of uses researched by the Institute, and solicit input from stakeholders on priority uses for further investigation. The Institute's final selections of high priority uses for study are listed in Table 2.3 A. The final selections were made based on the following criteria:

• Importance to the Commonwealth of Massachusetts:
  • Use in manufacturing: Total quantity of chemical used in manufacturing operations in Massachusetts
  • Use in consumer products: Total quantity of chemical used in products sold in Massachusetts.
  • Potential availability of alternatives.
• Exposure potential (environmental, occupational, and public health).
• Potential value to Massachusetts businesses and citizens of the alternatives assessment results. Specifically, the preferences of the pertinent stakeholders for each chemical were given priority.

In addition, for each chemical the Institute attempted to select at least one use that was applicable to each of three end users, i.e., Massachusetts manufacturers, small businesses and consumers, when making the final selection of priority uses to study. A detailed discussion of the prioritization process for each chemical is included in the relevant chemical chapter.

Table 2.3.3 : High Priority Uses

2.4 Phase II: Alternatives

2.4.1 Identify Alternatives (Phase II.a)

Alternatives to toxic chemicals may include drop-in chemical substitutes, material substitutes, changes to manufacturing operations, changes to component/product design, and other technological solutions. Existing and emerging alternatives were identified for each of the high priority uses of the chemicals. In addition, industry specific performance requirements were identified.

Sources of information on available and emergent alternatives included trade associations, manufacturers, U.S. Environmental Protection Agency (EPA) documents and programs, municipal, state and federal pollution prevention research centers, literature and internet searches, and other technical experts. In addition to experts at the Institute, experts from the University of Massachusetts Lowell, other universities, industry, medicine and many other organizations were consulted. As a result, more than 200 potential alternatives were identified for the 16 different use categories of the 5 chemicals. Each alternative typically consisted of several different chemical constituents.

2.4.2 Screen Alternatives

To eliminate from further study any chemical alternatives that would pose a high risk to the environment or human health, alternatives were subjected to an initial environmental, health and safety (EH&S) screen. If a specific alternative was determined to be persistent, bioaccumulative and toxic ("PBT"), a known or probable human carcinogen, or on the TURA Science Advisory Board's (SAB) 1999 More Hazardous Chemicals list, it was eliminated from further consideration. In order to be screened out as a "PBT" a substance needed to exceed the EPA criteria for two of the three PBT indicators (very persistent, very bioaccumulative, and high concern for toxicity). The PBT screening process utilized the EPA's PBT Profiler, a predictive modeling tool. Chemicals that are listed in either the EPA Group A or B, or the International Agency on Research of Cancer (IARC) Group 1 or 2A (carcinogenic or probably carcinogenic to humans) were also eliminated from further study. In the SAB list, "hazard" includes inherent toxicity, potential for exposure through dispersal in the work place (based on the physico-chemical properties of the chemicals such as vapor pressure) and indicators of safety of use (e.g., flammability).

The initial EH&S screen was only applied to the substances present in the alternative formulation or product, not to feedstock materials upstream, or breakdown products downstream. For example, if an alternative material is a polymer made from a carcinogenic monomer, it would not be screened out during this initial phase. A detailed discussion of the screening criteria is included in Appendix A.

2.4.3 Prioritize Alternatives for Study

At this stage, all available alternatives that had passed the EH&S screening were evaluated to determine which alternatives would be assessed fully. The objective of this step was to select for full assessment a small number of alternatives (typically 6 or fewer) that appeared most likely to be feasible and safer. The following criteria were considered in prioritizing the alternatives to be assessed:

1. Performance: Known performance of the alternative, which could include maintenance and durability as well as specific performance requirements and potential for future performance enhancements.
2. Availability: Number of suppliers or manufacturers and volume produced.
3. Manufacturing Location: Products or materials manufactured in Massachusetts were considered a higher priority.
4. Environmental and human health and safety issues: Concerns identified during the initial EH&S screening.
5. Global Market Effect: Pending or existing global restrictions
6. Classes of Similar Alternatives: Where several similar alternatives were identified, one representative of that type was chosen for further study.
7. Cost: Compared to the existing chemical and considering the potential for future cost reductions associated with increased production volume. Includes consideration of raw material costs, storage and handling costs, disposal costs, etc.
8. Value to Massachusetts Stakeholders: If an alternative was of particular interest to one or more stakeholder, or there appeared to be a high value to Massachusetts for the alternative to be included in the assessment, it was given a higher priority.

Meetings with stakeholders, as described in Section 2.2, were organized to provide information on the alternatives prioritization criteria, review the list of alternatives researched by the Institute, and solicit input from stakeholders on alternatives for the assessment phase of this study. The final list of alternatives for full assessment is listed in Table 2.4.3.

Table 2.4.3 : High Priority Alternatives

Some alternatives, particularly those comprised of single chemicals, were assessed as generic alternatives (e.g., TOTM plasticizer or steel fishing sinkers). Other alternatives vary considerably depending on the precise formulation or manufacturer. In these cases a representative product was assessed (e.g., products for aerosol brake cleaning and educational specimens for dissection). The choice of a particular manufacturer's product as representative does not constitute an endorsement of that product, or indicate that other similar products are not worthy of further consideration by users.

2.5 Phase III: Alternatives Assessment

Information for each aspect of the assessment - technical, environmental, human health and safety, and financial - was collected and reviewed. The specific types of information and procedures for evaluating them are described in the following sections. When all available data had been collected for each alternative, the information was reviewed and summarized in a qualitative summary table for that particular use.

For each critical parameter in the summary table, a qualitative assessment of "better than" (+), "similar/equivalent" (=), or "worse than" (-) the chemical being studied was indicated. Where insufficient information was available to make a determination, a "?" was indicated. It should be noted that these are approximate indicators only, and that all parameters should not be considered equal (for example, most users would not consider "carcinogen" with equal weight as "irritant." For these reasons, it is not appropriate to simply add up the total number of +, - , and = in order to determine the "best" alternative. Users should look to the summary tables, and the supporting assessment text and tables, for guidance in conducting their own assessment of feasibility and preferred alternatives. Their own assessments will include personal or corporate values, priorities, levels of concern/acceptability and situation-specific modifications and additions to the assessments included in this report.

2.5.1 Technical Feasibility

The study identified application-specific performance requirements that were required for each use - including longevity, key performance requirements, key physical characteristics and key quality parameters. One primary source of this information was industry/user experience with the chemicals and their substitutes. User comments and review were sought from manufacturers, trade associations and customers who use the chemical or its derivatives.

The quality of performance information that the Institute was able to obtain on the alternatives varied considerably among uses. For some uses information was obtained from published robust studies or directly from several users of the alternatives or technical experts. For other uses assessments relied on information provided by product manufacturers. This directly impacts the degree and nature of follow-up that would be required for a user to make a determination of technical feasibility for their unique application. Where appropriate, the study also included readily available information on life cycle considerations, such as maintenance requirements, although it is important to note that this study did not include a comprehensive life cycle assessment.

The summary tables include a relative assessment of key performance parameters as appropriate for each use, compared with the reference chemical or product, using the symbols discussed above.

2.5.2 Financial Feasibility

Financial information was sought for each alternative (see Appendix A for table of financial assessment parameters). Data sources included manufacturers, stakeholders, the Chemical Economics Handbook and other publicly available reference sources. The amount of financial information available for each use and alternative varied widely. In many cases, particularly for emerging alternatives with few or no current instances of actual use, no hard cost information was available; if so, this is indicated in the discussion of those particular alternatives. In other cases, sufficient cost information exists to conclude that the alternative is either more or less costly than the current chemical use; again, this is noted in the discussion where appropriate.

Other significant barriers to determining financial feasibility of alternatives include: manufacturers' reluctance to share cost information, facility or application-specific nature of many costs, and the fact that cost comparisons today may not be the final answer tomorrow for technologies not yet widely adopted, since economy of scale and market size will often reduce costs. This issue is discussed more thoroughly in Chapter 8.

For these reasons, the financial assessments should be viewed as a preliminary look at potential impacts as a result of adopting an alternative. Those wishing to conduct a more thorough financial analysis will need to include application- and facility-specific impacts, including the cost of raw material, capital improvements and new equipment, processing changes, waste disposal, energy, worker health and safety protection, permitting, and other life cycle costs, such as end-of-life product management. Tools and information for "total cost assessment" and other financial assessment approaches may be found in many existing publications (contact the Institute for more information).

2.5.3 Environmental and Human Health Assessment

The Institute assessed each alternative for its impact on human and environmental health relative to the chemical of concern. A set of pertinent environment, health and safety (EH&S) parameters was evaluated. The list of the parameters and their associated metrics, concern levels and primary data sources is presented in Appendix A. The Institute did not perform a detailed toxicological review for each alternative. Rather, the study relied on information obtained from authoritative bodies1, with the most recent validated data presented first or data that has been referenced by a US governmental agency such as the Environmental Protection Agency (EPA), the Centers for Disease Control (CDC) and the Occupational Safety and Health Administration (OSHA). The primary sources were those available from the National Library of Medicine's Toxicology Data Network (ToxNet)2. Where this type of information was not available, or where more recent studies called into question the results previously published by authoritative bodies, supplementary information was noted.

Differences of opinion among experts and variations in test results were also noted where applicable. Table 2.5.3 lists the environmental, health and safety parameters that were researched and evaluated. Specific sources of information for individual parameters are provided in the complete EH&S assessment tables in Appendix D. These sources also contain detailed background information about the parameters. Unless otherwise noted in the tables in Appendix D, the assessments used the US EPA PBT Profiler3 software to determine environmental persistence, bioaccumulation potential and toxicity for organic chemicals. The summary table for each use found within the individual chemical sections of this report includes the EH&S parameters judged to be most critical to the particular use and set of alternatives.

In many instances key parameter data were not available for all alternatives. In this case a "?" was inserted into the summary table. It is important for users of this report to consider the implication of data gaps for their particular situation. In some cases users may have access to data that the Institute did not, thereby allowing them to make a fuller comparison of the alternative to the reference chemical. In others, users can assume that a question mark is indicative of a need for additional research or testing.

Where appropriate the study also included readily available information on key life cycle considerations, such as waste disposal limitations, energy usage required during manufacture, impact on product recyclability or reuse potential, etc. This was typically included where complex materials or products were being assessed, rather than individual chemicals or formulations because the life cycle issues become more important in those types of comparisons. It is important to note that this study did not include comprehensive life cycle assessments of each alternative, but rather provides qualitative discussions of life cycle considerations where appropriate.

Table 2.5.3: EH&S Parameters Considered in Assessing Alternatives

2.5.4 Procedures Followed for Evaluating Mixtures, Material

Alternatives, and Process Alternatives

For the purposes of this study, a chemical is considered to be any element, chemical compound or mixture of elements and/or compounds. Chemicals are the constituents of materials. A chemical "mixture," also known as a chemical "preparation," includes multiple chemicals. A one-for-one chemical substitution represents the simplest type of alternative, where the chemical being evaluated can be directly substituted with another chemical that satisfies the functional requirements for the particular use. In this instance, the alternatives assessment was relatively straightforward; information associated with the parameters in Appendix A were obtained, verified and presented in a way that allows a direct comparison of the two chemicals.

Evaluating Mixtures

Often the chemicals being evaluated are used in formulations of multiple chemicals. In this case, each of the chemical constituents of the mixture was considered in the assessment in a manner similar to that used for individual chemicals (as above). The Institute obtained environmental and human health information about each of the chemical constituents of a mixture, and performance and cost information for the overall formulation when doing the assessment. The primary source of information on the constituents of a mixture was the product Material Safety Data Sheet (MSDS). For the purposes of this study, the Institute focused on the primary constituents of each formulation being evaluated. Specifically, constituents present in amounts exceeding 1% by mass were included in the assessment. Although no quantitative indicators were calculated for mixtures during the evaluation process, the general approach was to consider the weight percents of constituent chemicals in determining overall EH&S impacts. When formulation breakdowns were presented on associated MSDSs as a range, the Institute assumed the average weight percentage of the range presented.

As the EH&S factors associated with the constituents of a mixture were determined, their relative significance to the overall EH&S characteristic of the mixture was evaluated based on the weight percent within the mixture. The actual approach to evaluating the EH&S impact of a mixture differed depending on whether the chemicals in the mixture cause similar or different health effects. If the health effects are similar (e.g., two constituents are central nervous system (CNS) depressants), their weight percentages were added and the overall impacts of the combined chemicals assessed. If the health effects are different (e.g., one chemical is a CNS depressant, while another is a respiratory irritant), the effects were evaluated separately based on the weight percentages of each constituent.4 When alternative mixtures were evaluated in summary tables, an attempt was made to apply the weighting criteria described above, although the resulting indicator typically reflected the most problematic constituent for that mixture. Evaluating Material AlternativesA material is defined as the basic matter (e.g., metal, wood, plastic, fiber) from which the whole or the greater part of something physical (e.g., a machine, tool, building, fabric) is made. In some cases the chemical being studied is used to impart particular qualities in a material. For instance, DEHP is used in poly vinyl chloride (PVC) to make this otherwise rigid plastic flexible. Rather than find other ways to make the material (PVC) less rigid, there may be opportunities to find alternative materials (e.g., other plastics) that are inherently more flexible, therefore bypassing the need for this particular chemical additive.

When evaluating material alternatives, performance and cost considerations may be readily compared. However the impact of a material on environmental or human health may not be as readily assessed as it can be for chemical substitutes. For materials, life cycle considerations may become more important. For this study the Institute looked both at EH&S impacts when appropriate and at life cycle issues that, based on the research, appear to be of most significance relative to the material being replaced. The inclusion of life cycle considerations only occurred when a preponderance of literature indicated that life cycle issues exist that should be accounted for. It is important to note that comprehensive life cycle assessments were not performed as part of this study. Rather, when the research indicated that at a particular point in a material's life cycle there are important positive or negative impacts, these were noted qualitatively relative to the material being substituted.

Evaluating Process Alternatives

For the purposes of this study, process alternatives are those that employ a different technology, process or approach to achieve the objective or function of the original product or process associated with the chemical. For example, when considering alternatives to perchloroethylene in vapor degreasing, one approach might be to change the upstream process to use lubricants that either do not require cleaning, or are easier to remove using water-based surfactants. The feasibility of this type of alternative can be assessed, but it is very difficult to compare the EH&S impacts quantitatively. These types of alternatives are included in the study where appropriate, and their feasibility assessed qualitatively. Where our research indicates that there are important positive or negative attributes or impacts relative to the substance being substituted, these are mentioned.

2.6 Economic Impact Study

As part of the study, the Commonwealth requested an analysis of potential impacts on employment level and economic competitiveness of the Commonwealth from adopting any alternative chemical or technology. Dependable economic and employment predictions are lengthy and expensive to prepare, and require a great deal of information about both broad economic conditions and material and industry-specific costs. In addition, the impacts cannot be generalized across products and industry sectors. Rather, the impacts depend on the many different situations that exist for the five chemicals, their uses and alternatives.

Therefore, the approach taken in this study was to develop guidance to those seeking to quantify economic impacts from substitution by identifying the principal factors that influence the result for a given situation. Case material was used to create a useful list of economic factors present in particular situations. Further development by experts of the influences, duration, dynamics, interactions, sector specificity or other characteristic of these economic factors led to useful guidance regarding economic impacts for specific alternatives. This evaluation was completed using the following process:

1. The Institute briefly reviewed existing literature on the economic impact of environmental regulations, alternatives assessment and the TURA program.
2. Case materials were created for the following sectors: formaldehyde in building materials, lead in electronics, and perchloroethylene in dry cleaning. This material was used to focus the discussion by experts. (See Appendix E)
3. Ten experts in the economics of technology change and innovation were gathered for a facilitated discussion. They included representatives from Associated Industries of Massachusetts, the Small Business Association, the Massachusetts Manufacturing Partnership, Tufts University, Northeastern University, the University of Massachusetts, the Economic Development Research Group, Tellus Institute, and the Environmental Management Accounting Research and Information Center. Using the case materials, a list of economic factors and their influences was developed.

Chapter 8 presents a summary of this analysis and a framework outlining the factors that may influence the economic impact of adopting an alternative chemical or technology. Due to the limitations discussed above, this chapter does not present specific quantitative information.

2.7 Quality Assurance/Quality Control (QA/QC)

All EH&S data were initially collected by one Institute staff member and independently verified by a second staff member. The initial data were entered into a spreadsheet; this included the chemical name and CAS number, the actual data, and the sources of the data. The second staff member independently checked the accuracy of the CAS number and consulted the original data source and, where available, a secondary source. If data sources were inconsistent, the information was further evaluated and either a determination was reached or the differences noted. Each Institute researcher leading the individual chemical assessment section also reviewed the data provided, and augmented the EH&S data using current peer-reviewed scientific research obtained during the course of the assessment.

In addition to general input on the methodology for this study that was received from stakeholders and experts, the Massachusetts Toxics Use Reduction Act Science Advisory Board (SAB) was asked to review the screening criteria and environmental, health and safety parameter list. The SAB was created by the Toxics Use Reduction Act (TURA) of 1989 specifically to advise the Institute on scientific matters, and consists of experts in health and environmental issues, as well as technical chemical experts. They commented on the draft methodology and concurred with the final methodology.

Each assessment was sent out to the appropriate stakeholders and experts for general technical review. Reviewers provided a great deal of valuable technical feedback that improved the accuracy of the study, but were not asked to verify all information and data in the report.