U.S. chemical risk program gets mixed review

The U.S. Environmental Protection Agency’s program for evaluating the human health risks associated with exposure to chemicals in the environment—the Integrated Risk Information System (IRIS)—is under attack by Republican lawmakers.

At a hearing on Sept. 6, Republican leaders on two subcommittees of the U.S. House of Representatives Committee on Science, Space & Technology criticized EPA for not making changes to IRIS as suggested in 2014 reports by the National Academies’ National Research Council and the Government Accountability Office (GAO).

Democrats at the hearing, however, praised EPA for significantly improving the IRIS program in a short amount of time. They questioned why no one from EPA, GAO, or the National Academies was invited to testify at the hearing to discuss changes EPA has made in recent years. Several Democrats pointed out that EPA’s Scientific Advisory Board sent a letter to EPA Administrator Scott Pruitt just days before the hearing, commending the agency for improving the IRIS program.

Earlier this year, the Trump Administration initially proposed to zero out funding for IRIS in EPA’s fiscal 2018 appropriations but later sought money for the program. Lawmakers held the hearing to assess whether the program should continue.

At the hearing, James Bus, a toxicologist with the consulting firm Exponent, raised concerns about EPA’s failure to incorporate mode of action information, or how chemicals cause toxic effects, into its IRIS assessments. Such information “is essential to establishing the human health relevance of toxicity observed in cell- or animal-based toxicity findings,” he said. Bus also chided EPA for relying on low-quality studies, particularly in its assessment of trichloroethylene. That assessment led to increased remediation costs in the hundreds of millions or possibly even billions of dollars, he claimed.

Kenneth Mundt, principal with the consulting firm Ramboll Environ, criticized EPA for not disclosing which studies the agency is relying on in its reassessment of formaldehyde. EPA is revising its formaldehyde IRIS assessment because of criticisms made in a 2011 National Academies report.

Thomas Burke, a professor of risk sciences at Johns Hopkins University, spoke in support of the IRIS program at the hearing. Burke emphasized the importance of IRIS assessments to state and local officials, as well as to first responders in disasters such as hurricanes.