On April 27, 2026, David Fotouhi, deputy administrator of EPA, directed agency staff to review any decisions the agency made based on Integrated Risk Information System (IRIS) values. Fotouhi’s memo highlighted concerns from stakeholders that EPA’s IRIS values have “historically conservatively estimated hazard[s],” resulting in “inflated” risk concerns. Moving forward, the memo directed EPA’s program offices to take a more active role in the risk assessment process – a shift from the more centralized risk assessment process provided by the IRIS program – and directed the addition of “disclaimer language” to EPA’s website that IRIS values “are not necessarily intended for use as regulatory levels.”
The agency had previously signaled distrust in IRIS values. In its proposed updates to the Ethylene Oxide NESHAP, EPA asserted that the IRIS value for EtO relied on overly cautious assumptions and EtO could be “five times safer than the 2016 EtO IRIS value provided.”
IRIS values have been crucial in understanding the public health consequences of chemicals and chemical mixtures. IRIS was developed in 1985 to organize EPA’s chemical risk analyses and make the information accessible. The IRIS risk assessment process included research review by EPA scientists, external peer review, and an opportunity for public comment. The IRIS value was then posted to the IRIS website for use by EPA and other public health agencies to inform decisions on the effect of chemicals and mixtures of chemicals on human health.
The IRIS program was housed under the Office of Research and Development within EPA until February 2026.