Integrated Risk Information System

IRIS values represent the first two steps of the four-step risk assessment process described by the National Research Council and are not necessarily intended for use as regulatory levels. Before relying on IRIS values, users should ensure that the IRIS assessments and information are fit for their intended purpose and that the values are consistent with the most current scientific literature.

As indicated in an April 27, 2026, memorandum from EPA Deputy Administrator: 

Program offices should consider whether the IRIS information is fit-for-purpose, represents best available science, was developed in a manner consistent with statutory and regulatory obligations, and meets current standards for transparency, impartiality, reliability, and credibility, in keeping with Gold Standard Science.

External entities that may have utilized previous assessments or information developed through the IRIS program, should consider undertaking a review similar to the reviews that will be taken by EPA program offices. Review action is encouraged to ensure any decision or reliance was accurately and properly implemented.