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Chemical Assessments
How to Prepare Assessments:
- Hazard Assessment
- Exposure Assessment
- Risk Assessment
- Data Needs Assessment
- Exposure Workshop
- Guidance Documents
In the Voluntary Children's Chemical Evaluation Program (VCCEP), the sponsor of a chemical prepares a chemical assessment for each chemical and each tier for which he has committed to provide information. In the Federal Register notice announcing VCCEP (65 FR 81701, December 26, 2000), the Chemical Assessment is referred to as the "Peer Consultation Document" because it is the information collected by a chemical's sponsor and submitted to a third party organization organizing the peer consultation meeting where the document is discussed by a panel of experts. The Chemical Assessment consists of a hazard assessment, an exposure assessment, a risk assessment, and a data needs assessment. The information provided by each of these components of a chemical assessment is described below.
How to Prepare Assessments
The hazard assessment should consist of summaries of studies which address the testing endpoints in the particular Tier to which the sponsor has made a commitment. Sponsors need to determine whether available information already adequately describes a given endpoint and submit summaries of this information instead of initiating new testing. EPA guidance for determining whether available data are adequate is provided in the HPV Challenge Program. The summaries should follow the guidance for robust summaries also provided by the HPV Challenge Program on the same Web site. A robust summary must include an objective, discussion of methods, results, and conclusions. The guidance also explains what technical information is necessary, on an endpoint-by-endpoint basis, to adequately describe an experiment or study. Robust summaries should provide sufficient information to allow a technically qualified person to make an independent assessment of a given study report without having to go back to the full study report. If there are existing studies which are equivalent or relevant to any of the upper tier tests, robust summaries of these studies should also be submitted with the Tier I hazard assessment. Any additional information, such as mechanistic information or structure activity relationships (SAR), that may influence decisions on further testing needs should also be included.
An exposure assessment should contain information to answer the following questions for a particular chemical:
- Who and how many people are exposed?
- What are the sources of exposure, i.e., environmental releases, consumer products, etc.?
- Does the exposure occur through breathing air, drinking water, eating food, contact with skin, or any other routes?
- How intense is the exposure, i.e., what is the potential dose level?
- How often and for how long does exposure occur, that is, what is its frequency and duration?
Populations of concern to VCCEP are children and, in certain situations, prospective parents. Exposures that can affect children are those which occur prior to conception (to either parent), during prenatal development, and postnatally to the age of sexual maturation which is completed around 18-21 years of age. Although adult exposures are not intended to be a major focus of this program, certain risks to children cannot be assessed without evaluating parental exposures. Specifically, prospective parents' exposure is relevant to an evaluation of risks due to fertility and reproductive effects, as well as developmental effects from in utero exposures. Children can be exposed to chemicals through food and drinking water, through indoor and outdoor air, through ingestion of dust and soil, and through direct contact with products they use and products used in their immediate vicinity. Prospective parents can be exposed to chemicals through these pathways as well as through occupational activities.
Exposure assessments should be developed using EPA's Exposure Assessment Guidelines, as well as other existing exposure assessment procedures and guidance.
EPA's National Center for Environmental Assessment (NCEA) has prepared a document entitled "Child-Specific Exposure Factors Handbook" which consolidates all child exposure factors and related data in one document. The exposure information that is provided for the VCCEP must be transparent and must address the completeness of the assessment, i.e., how complete the assessment is in terms of addressing sources, populations, pathways and routes of exposure to children.
C. Risk AssessmentThe risk assessment integrates the hazard and exposure assessments, and characterize the risks to children and, where relevant, prospective parents by indicating the adequacy, limitations, and/or deficiencies of the existing data for this purpose. The risk assessment should follow the guidance provided in EPA's risk assessment and exposure assessment guidelines. Guidance for characterizing risk is provided in EPA's "Risk Characterization Handbook" (PDF) (189 pages, 8.9MB, About PDF). The risk characterization should summarize key aspects of the following components of the risk assessment:
- Qualitative conclusions about the likelihood that the chemicals may pose a specific hazard to children or, where relevant, prospective parents, the nature of the observed effects, under what conditions (route, dose levels, time and duration) of exposure these effects may occur, and whether the health effects-related data are sufficient and relevant to use in a risk assessment.
- Discussion of the dose-response patterns of the effects, the relationship among various endpoints and toxicities, the rationale behind the determination of the No Observed Adverse Effect Level (NOAEL), Lowest Observed Adverse Effect Level (LOAEL), and/or benchmark dose, the underlying assumptions, and the implications of using alternative assumptions.
- Descriptions of the sources and pathways of exposure, estimates of the range of human exposure (e.g., central tendency, high end), the route, duration, and pattern of exposure, relevant pharmacokinetics aspects, and the size and characteristics of the population exposed. The strengths and weaknesses of the risk assessment.
- Areas of uncertainty and the potential impact on the assessment.
- Potential impact of missing or inadequate hazard or exposure information.
A data needs assessment identifies the additional hazard and/or exposure information needed to adequately assess the potential risks to children and, where relevant, prospective parents. When assessing what additional hazard data may be needed, the sponsor should:
- Be familiar with current requirements of test guidelines for the endpoints in each tier of VCCEP and consider to what degree the available hazard information adequately meets current data needs.
- Consider what impact the lack of adequate data for a particular hazard endpoint may have on the ability to adequately evaluate potential hazards.
When assessing what additional exposure data may be needed, the sponsor should:
- Consider to what degree the potential exposures to children from environmental releases and uses of the chemical have been accounted for and addressed.
- Consider what impact the gaps in the evaluation of exposure, along with limitations in the hazard data, may impose on the ability to evaluate the risks to children.
When considering what needed hazard and exposure information could be provided by the next tier (e.g., Tier 2), the sponsor should:
- Consider and use a weight-of-the-evidence evaluation of Tier 1 hazard and exposure information to develop recommendations regarding needed work. The sponsor should provide a scientific rationale for any work he recommends be done in the next tier.
- Provide a scientific rationale for any hazard studies that are not recommended within that tier.
On December 11 through 13, 2001, EPA and the American Chemistry Council co-sponsored a technical workshop on how to report exposure assessment results to VCCEP. The workshop focused on the development of formats and basic principles that should be used to characterize exposure assessment results. Details on the presentations, technical documents, and a summary report of the workshop are included in the following documents:
Meeting Agenda for the EPA/ACC Technical Workshop with links to Presentations and Technical Documents.
Summary Report of the EPA/ACC Technical Workshop for the Voluntary Children's Chemical Evaluation Program (VCCEP) (PDF) (123 pp., 779K, about PDF)
A June 22, 2001 letter clarifying the scope of Tier 1 exposure assessments (PDF) (1 pp., 83K, about PDF), signed by EPA's Acting Assistant Administrator for OPPTS, was sent to the American Chemistry Council.
Guidance Documents used in the HPV Challenge Program may be relevant to VCCEP. Some of the more important documents are:
- Guidance on Developing Robust Summaries
- Guidance on Searching for Chemical Information and Data
- Guidance for Assessing Adequancy of Existing Data
Additional guidance can be found in the following documents:
- Guidelines for Exposure Assessment. USEPA.
- Exposure Factors Handbook. USEPA.
- Child-Specific Exposure Factors Handbook. USEPA.
- Risk Characterization Handbook (PDF) (189 pp., 8.5MB, About PDF). USEPA.
How to Submit Assessments
A. By mail to EPA: As noted in the Dec 26, 2000, Federal Register Notice, VCCEP sponsors should submit three hard copies and one electronic copy of their submission consisting of hazard, exposure, risk and data needs assessments to EPA. The submission must reference Docket Number OPPTS-00274D. The mailing address is:
Document Control Office (7407M)
Office of Pollution Prevention and Toxics
Environmental Protection Agency
1200 Pennsylvania Avenue, NW
Washington, DC 20460
B. By hand deliver/courier to EPA: If the sponsor chooses to deliver his submission in person or send his submission by courier, it should be delivered to:
OPPT Document Control Office (DCO)
EPA East Building, Rm. 6428
1201 Constitution Avenue, NW
Washington, DC 20004
C. To Toxicology Excellence for Risk Assessment (TERA):
Sponsors participating in the Peer Consultation process managed by TERA should send one hard copy and one electronic copy of their Peer Consultation submission consisting of hazard, exposure, risk and data needs assessments to TERA at:
Toxicology Excellence for Risk Assessment
Attn: Peer Consultation Program
1757 Chase Avenue
Cincinnati, Ohio 45223
TERA would prefer the electronic copy be sent as an e-mail file to vccep@tera.org unless the size of the submission dictates that another format be used (e.g. diskette, CD). The December 26, 2000, Federal Register Notice did not note this separate submission step to TERA.