REVIEW OF EPA’S INTEGRATED RISK INFORMATION SYSTEM (IRIS) PROCESS
David C. Dorman, DVM, PhD, DABT, DABVT
Professor of Toxicology
North Carolina State University
Member, Committee to Review the IRIS Process
Board on Environmental Studies and Toxicology
Division on Earth and Life Studies
National Research Council
The National Academies
Subcommittees on Oversight and Environment
Committee on Science, Space, and Technology
U.S. House of Representatives
July 16, 2014
Good morning, Chairmen Broun and Schweikert and members of the subcommittees. My name is David Dorman. I am a professor of toxicology at North Carolina State University. I served as a member of the National Research Council (NRC) Committee to Review the IRIS Process and the NRC Committee to Review EPA’s Draft IRIS Assessment of Formaldehyde. The NRC is the operating arm of the National Academy of Sciences, National Academy of Engineering, and the Institute of Medicine of the National Academies, chartered by Congress in 1863 to advise the government on matters of science and technology.
I am pleased to appear before you today to discuss aspects of the report, Review of EPA’s Integrated Risk Information System (IRIS) Process, which was released on May 6, 2014. Our review of the IRIS process was written by a 15-member committee with a wide array of scientific expertise, appropriate to the task. The committee was asked to assess the scientific, technical, and process changes being implemented or planned by EPA and recommend modifications or additional changes as appropriate to improve the scientific and technical performance of the IRIS program. It was also asked to review current methods for evidence-based reviews and recommend approaches for weighing scientific evidence for chemical hazard and dose-response assessments. We have provided a copy of the report for the subcommittees, and the summary is attached.
The IRIS program is responsible for developing toxicologic assessments of environmental contaminants. Over the last decade, the NRC has reviewed some of the more complex and challenging IRIS assessments, including those of formaldehyde, dioxin, and tetrachloroethylene. In 2011, an NRC committee released its review of the IRIS formaldehyde assessment. Like other NRC committees that had reviewed IRIS assessments, the formaldehyde committee identified deficiencies in the specific assessment and more broadly in some of EPA’s general approaches and specific methods. Although that committee focused on evaluating the IRIS formaldehyde assessment, it provided general suggestions for improving the IRIS process and a roadmap for its revision (in Chapter 7 of that report) in case EPA decided to move forward with changes to the process. After release of the NRC formaldehyde report, Congress instructed EPA to incorporate as appropriate the NRC recommendations. The report of the IRIS committee reviews the resulting changes that have been made to the IRIS assessment process.
Overall, the IRIS committee found that the changes that EPA has proposed and implemented to various degrees constitute substantial improvements in the IRIS process. If current trajectories are maintained, inconsistencies identified in the committee’s report are addressed, and planned revisions still to be implemented are successfully completed, the IRIS process will become much more effective and efficient in achieving the program’s basic goal of developing assessments that provide an evidence-based foundation for ensuring that chemical hazards are optimally assessed through a transparent and replicable approach.
Specifically, the IRIS committee found that EPA has implemented a new document structure that streamlines the assessments, drafted a preamble and a handbook that provide descriptions of the IRIS process, formed chemical assessment support teams to oversee the assessment-development process and ensure consistency among assessments, and implemented several initiatives to increase stakeholder input into the IRIS process. Those changes should substantially strengthen the IRIS process. The committee noted, however, that EPA still needs to indicate how the general principles described in the preamble are applied in a given assessment, it might also require outside experts to fill gaps in expertise in specific areas, and it might consider ways to provide technical assistance to under-resourced stakeholders to help them develop and provide input into the IRIS process.
The IRIS committee reviewed each step of the IRIS process and the changes that EPA has made or is planning to make, evaluated progress, and offered recommendations. For evidence identification, EPA has substantially improved its approach and is well on its way to adopting a more rigorous approach that when fully implemented should meet the recent Institute of Medicine standards for systematic review. For evidence evaluation, EPA correctly identifies important study attributes but does not describe how it will assess risk of bias in the identified studies. Risk of bias is related to internal validity of a study and reflects study-design characteristics that can introduce a systematic error that might affect the magnitude and even the direction of the apparent effect. The IRIS committee recommended that EPA conduct risk-of-bias assessments on studies that are used as primary data sources, and that the results of the evaluations be fully described and reported in IRIS assessments. For evidence integration, EPA is moving toward a more structured approach. The IRIS committee described several qualitative and quantitative options in its report and suggested that EPA adopt the approach that best fits its plan for the IRIS program. However, the committee emphasized that quantitative approaches to integrating evidence will be increasingly needed and useful to EPA, and the agency should seriously consider expanding its ability to perform quantitative modeling for evidence integration. Regardless of the approach, EPA should develop templates for informative narrative justifications of the evidence-integration process and the conclusions reached. Finally, for dose-response assessment and calculation of toxicity values, the IRIS committee was encouraged by the improvements, particularly the shift away from choosing one study as the “best” one for deriving a toxicity value and toward deriving and graphically presenting multiple candidate toxicity values. However, the IRIS committee recommended that EPA develop formal methods for combining the results of multiple studies and selecting the final IRIS toxicity values and that EPA develop guidelines for uncertainty analysis and communication in the context of IRIS.
To ensure that the IRIS program provides the best assessments possible, the IRIS committee identified three broad areas on which EPA should focus attention. First, the assessment methods will need to be updated in a continuing, strategic fashion, and EPA should develop a plan for doing so. Second, the sources of inefficiencies in the IRIS process need to be identified and addressed systematically. Third, EPA management needs to evaluate the human and technologic resources that are needed to conduct IRIS assessments and support methodologic research and the implementation of new approaches. The IRIS committee emphasized that if sufficient financial and staff resources are not available to EPA, it will not be able to continue to improve the IRIS program and keep pace with scientific advancements.
As noted, the IRIS committee found that substantial improvements in the IRIS process have been made, and it is clear that EPA has embraced and is acting on the recommendations in the NRC formaldehyde report. The NRC formaldehyde committee recognized that its suggested changes would take several years and an extensive effort by EPA staff to implement. Substantial progress, however, has been made in a short time, and the IRIS committee’s recommendations should be seen as building on the progress that EPA has already made. The IRIS committee recommended further peer review as the EPA completes the revisions.
Thank you for the opportunity to testify. I would be happy to answer any questions the subcommittees might have.
An archived webcast of the hearing can be found on the House Science, Space, and Technology Committee's Web site.