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The NAS IRIS review: An unnecessarily narrow review of EPA’s troubled chemical assessment program?

The National Academy of Sciences (NAS) announced in December 2017 that it will again review EPA’s Integrated Risk Information System (IRIS). Previous NAS reports, one in 2011 and another in 2014, found serious problems with IRIS and offered sweeping recommendations to overhaul the program.

NAS is not alone in identifying critical issues that need reform with the IRIS program. Since 2008, the Government Accountability Office (GAO) has regularly highlighted its concerns with regard to IRIS because of fears that the program is at risk of becoming obsolete due to an inability to produce quality chemical assessments in a timely manner. Congress has also repeatedly expressed serious concerns with regard to IRIS and has held numerous hearings in recent years—including one last September—to discuss those ongoing problems.

EPA’s mission is to protect human health and the environment. The agency originally designed the IRIS program to support this mission by using scientifically defensible methods and approaches to identify and characterize health hazards. The program has had repeated problems achieving that goal, though.

In 2016, Congress passed the Lautenberg Chemical Safety Act (LCSA), which requires EPA to use the best available science and a weight of evidence process when evaluating the risk from new and existing chemicals. Consistent application of these core scientific standards is fundamental to achieving EPA’s mission. Given the concerns that have been raised by NAS, GAO, Congress, and many in the scientific community, it is not clear that IRIS assessments qualify as the best available science, applied in a weight of the evidence approach.

Tying their own hands

Initially, it was encouraging to hear that the latest review by NAS will assess changes to IRIS that that EPA has implemented or plans to implement based on recommendations from NAS. Unfortunately, on closer review, it appears the NAS is tying its own hands in its official statement of task for the review:

“The committee primarily will base its assessment on EPA presentations and interactive sessions during a 1.5 day workshop at which multiple opportunities will be provided for stakeholder input.”

The constraints NAS is placing on itself will prevent it from fully evaluating—based on a well-informed, full, and fair scientific assessment—whether:

1. EPA made any substantive or procedural changes to the IRIS program;
2. Those changes adequately address NAS’s 2011 and 2014 recommendations;
3. EPA can demonstrate it has implemented the changes in recently completed draft or final IRIS assessments; and
4. IRIS assessments reflecting those changes constitute the best available science, applied in a weight of the evidence approach.

The committee has further constrained its ability to produce a thorough assessment by only allowing itself nine months to complete the review. Although we encourage its timely completion, NAS should ensure that it takes sufficient time to effectively evaluate the changes made to the IRIS program and to solicit additional stakeholder engagement and input.

Ensuring a robust committee review

To conduct an effective review of the IRIS program, NAS should revise its statement of task to:

1. Fully evaluate and benchmark EPA’s progress with respect to the specific recommendations set forth in the 2014 NAS Report and the 2011 NAS Report.
2. Evaluate whether EPA has developed a set of a priori data quality evaluation criteria for epidemiology, toxicology, and mechanistic data to identify and categorize the strongest and most relevant studies for any IRIS assessment.
3. Expressly evaluate whether EPA has developed a robust and scientifically defensible weight of the evidence approach to integrate scientific evidence.
4. Provide express guidance on the organization of data using mode of action to evaluate biological plausibility and to develop dose-response curves.
5. Assess whether EPA’s proposed procedural changes to IRIS have resulted in a program capable of gathering, assessing, and integrating the scientific literature with respect to chemical assessments in a way that is transparent to the public, timely, and reflective of the best current scientific methodologies.

Getting it right

The recommendations outlined above will allow NAS to fully consider recent improvements made to the IRIS process and identify the areas that EPA needs to continue working on to improve the program so that it can produce chemical assessments in a way that is transparent to the public, timely, and reflective of the best current scientific methodologies.