Human Health Risk Assessment:

EPA Has Taken Steps to Strengthen Its Process, but Improvements Needed in Planning, Data Development, and Training

GAO-06-595: Published: May 31, 2006. Publicly Released: Jun 30, 2006.

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Over 100,000 chemicals, pollutants, and toxic substances are used in the United States and regulated by the Environmental Protection Agency (EPA). EPA uses risk assessment to determine the health risk from exposure to these substances, collectively referred to as contaminants. In the last 12 years, independent reviewers have examined this process and made recommendations for how it could be improved. GAO was asked to (1) identify the significant recommendations that have been made to improve human health risk assessment; (2) describe what EPA has done to modify its human health risk assessment process; (3) determine the effects these past modifications have had on the preparation of risk assessments; and (4) identify any additional actions experts believe EPA could take to improve its process, and the barriers it would face in doing so.

Since 1994, independent reviewers recommended that EPA better plan its risk assessments. In doing so, they said EPA should better utilize scientific data it has and identify other data it needs on the potential adverse effects from exposure to contaminants, and prioritize and support research to meet those needs. Furthermore, reviewers recommended that EPA better evaluate the analytic tools it uses and employ more powerful tools when appropriate. Reviewers also recommended that EPA better analyze and characterize the sources of uncertainty in its risk assessments. Finally, they recommended that EPA enhance its analysis of variability in exposure to contaminants and in susceptibility to harm from exposure, and improve how it considers the effects of exposure to multiple contaminants and through many sources. EPA has strengthened its risk assessment process since 1994 and improvement efforts are ongoing. For example, EPA has increased planning for assessments and has initiated actions to develop missing or incomplete scientific data. EPA has also begun to embrace new methodologies, such as ones to predict how the body will react to a contaminant. Furthermore, EPA now uses a tiered approach to conducting uncertainty analysis, employing more sophisticated analysis as warranted. Finally, EPA has made progress in characterizing variability due to differences in both exposure and susceptibility of exposed individuals and has begun to take steps to address exposure to multiple contaminants and through multiple sources. According to EPA's risk assessors, the modifications EPA has made have generally helped improve risk assessments. Many EPA risk assessors believe that agencywide guidance has helped them prepare risk assessments and have resulted in greater consistency across program offices. Furthermore, while most assessors report collaboration with internal and external entities is effective and has improved the quality of risk assessments, some said conflicting priorities and poor communication hindered collaboration among some EPA offices. Finally, while risk assessors said training has helped them gain skills and knowledge, over 70 percent said that more in-depth or relevant training would improve their risk assessment abilities. Experts identified additional actions EPA could take to further improve its risk assessment process, recognizing that it may face barriers in doing so. Experts said EPA could improve its planning process by better focusing on scientific data needs and involving stakeholders early to obtain their concurrence with EPA's approach. Experts also said EPA could more thoroughly evaluate methods and models, transparently document its analytic choices, and enhance internal review. Finally, experts said EPA could provide additional training for risk assessors, managers, and stakeholders on the risk assessment process. Experts, however, said that the scientific complexity of risk assessment, the difficulty of obtaining and applying data, and a cultural resistance to deviating from established methods could act as obstacles to successfully making such changes.

Recommendations for Executive Action

  1. Status: Closed - Implemented

    Comments: In September 2007 EPA issued a multi-year plan for human health risk assessment research that was designed to communicate EPA's activities across EPA's laboratories and programs as well as to the broader scientific community. Subsequent reviews by EPA's Board of Scientific Counselors (BOSC) note that the agency is doing a good job at reaching out to stakeholders and including them early in research planning in the fields of human health research and human health risk assessment research. The BOSC also notes that characterization of risk information and uncertainty will need continuous refinement and careful consideration, but that EPA gets high marks for its research in human health and risk assessment.

    Recommendation: To improve the overall quality, consistency, and transparency of its risk assessments, the Administrator of EPA should direct the appropriate agency entities to develop a strategy to ensure that offices engage in early planning to identify and seek the expertise needed, both within the EPA workforce and from external subject matter experts. The strategy should delineate such things as how EPA could use the available expertise to determine the needed data, the relevant default assumptions, the extent of internal and external review that needs to be included in the assessment, and the approach used to consistently involve a broad range of stakeholders--including the public, regulated industry, federal agencies, and advocacy groups--as appropriate to the risk assessment.

    Agency Affected: Environmental Protection Agency

  2. Status: Closed - Implemented

    Comments: In June 2009, GAO testified that proposed changes to EPA's Integrated Risk Information System (IRIS), which develops the first two critical elements for all risk assessments, would enhance the system's transparency, timeliness, and credibility. Specifically, EPA will, among other things, control the process of interagency reviews, make written comments from the White House and federal agencies part of the public record, and use the best available scientific information. The multi-year plans for human health and human health risk assessment that are updated periodically communicate to the scientific community and stakeholders EPA's needs and priorities for information. The agency's Board of Scientific Counselors in reviews of the human health and human health risk assessment multi year plans praised EPA's outreach to stakeholders and the scientific community.

    Recommendation: To improve the overall quality, consistency, and transparency of its risk assessments, the Administrator of EPA should direct the appropriate agency entities to more proactively identify the data most relevant to the current risk assessment needs, including the specific studies required and how those studies should be designed, and communicate those needs to the research community. Increased collaboration among program offices in identifying needed data would help ensure that the resulting data will meet the needs of multiple offices. In addition, EPA should better communicate these data needs and better coordinate research planning with the external public and private research community to help focus EPA's limited resources.

    Agency Affected: Environmental Protection Agency

  3. Status: Closed - Implemented

    Comments: In August 2010 the Acting National Program Director for Human Health Risk Assessment provided information on risk assessment training offered to risk assessors and risk managers both in EPA's Office of Research and Development (ORD) and more generally throughout EPA. Specifically he provided URLs for EPA-wide human health risk assessment training through the Risk Assessment Forum and information through the Risk Assessment Portal. In addition, he provided information and sample syllabi for ORD's Risk Assessment Training and Experience (RATE) Program 2010. These courses will be offered in the fall of 2010 with more advanced courses to follow in spring 2011. He reported that EPA recognized the need to emphasize training as senior staff are replaced by newly hired staff. He further noted that individual program offices within EPA, such as the Pesticides Program, also offered training.

    Recommendation: To improve the overall quality, consistency, and transparency of its risk assessments, the Administrator of EPA should direct the appropriate agency entities to ensure that risk assessors and risk managers have the skills needed to produce quality risk assessments by developing and implementing in-depth training. This training should address the needs of risk assessors and managers with varying levels of expertise by including basic courses, such as an overview of risk assessment, as well as more advanced courses on topics such as modeling, toxicology, and other advanced scientific techniques.

    Agency Affected: Environmental Protection Agency


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