On February 15, 2025, H.R.415, “To Prohibit the Environmental Protection Agency from using assessments generated by the Integrated Risk Information System for rulemaking and other regulatory actions, and for other purposes,” was introduced in Congress.
Similar bills have been introduced in the past, but now, with President Trump’s anti-regulatory agenda, there is an increased chance of its passage. According to Senator John Kennedy, who introduced the Senate version,
“Currently, the IRIS program is not authorized in statute. As a result, unelected bureaucrats within the EPA abuse the program to hurt chemical makers with virtually no Congressional oversight. Additionally, the EPA designed the IRIS to spot health hazards, not make policy. Unfortunately, under the Biden administration, the IRIS utilizes unscientific methods that wreak havoc on American businesses.”
The opponents of the bill, as reported In a recent article in ProPublica, consider it to be “industry-backed legislation” attacking IRIS, a program that “stands out in a world where much of the science on toxic chemicals is funded by corporations with a vested stake in them.” They claim that “IRIS’s several dozen scientists do not have a financial interest in their findings” and the “program’s calculations are the hard science that allow the agency to identify heightened disease risk due to chemicals in the air, water and land.”
History and Controversy
IRIS was first established in 1985 to provide the EPA with consensus positions on the health effects of chemicals found in the environment. This was necessary because, without it, each EPA office often used its individualized data sources to calculate different health values for the same chemical.
The purpose and role of IRIS fundamentally changed in the 1990s as the process greatly expanded to include the development of Toxicological Review documents with several internal and external reviews. IRIS became extremely powerful because EPA offices were required to use their assessments as the basis for EPA regulations. The rub is that IRIS is not statutorily mandated nor subject to the Administrative Procedure Act (APA), which requires agencies to publish proposed rules in the Federal Register and to take public comments.
Currently, IRIS contains assessments for approximately 500 chemicals out of approximately 86,000 chemicals in U.S. commerce today. The IRIS process takes decades to complete, leaving the EPA and the private sector without chemical hazard information for the vast majority of chemicals.
IRIS has been controversial since the 1990s with its assessment of formaldehyde. The first IRIS assessment of formaldehyde was released in 1990 and 1991; a draft assessment was released in 2010 and finalized in 2024. The final assessment has been criticized by the American Chemistry Council and other groups because it failed to use the best available science and did not incorporate peer review comments from respected scientific committees.
Another controversial IRIS assessment was for ethylene oxide. The draft assessment was released in 2006 and finalized in 2016, changing the EPA cancer risk descriptor from “probably carcinogenic to humans” to “carcinogenic to humans” and calculating that ethylene oxide was much more toxic than previously determined. The IRIS toxicity value was criticized because it is 19,000 times lower than naturally occurring levels of ethylene oxide found in the human body.
These IRIS assessments and others caught the attention of Congress because IRIS, a program not authorized by Congress, has a tremendous economic impact on important American industries. For example, formaldehyde is used in agriculture, food safety, medical devices, semiconductors, cars, and affordable housing. Formaldehyde technologies supported 987,000 jobs and $552.7 billion in sales in 2022.
What is the IRIS Process?
As an environmental toxicologist who spent decades as a consultant to the EPA, I worked on numerous IRIS Toxicological Review Documents.
These documents are hundreds of pages long and summarize all the relevant studies on a chemical in humans, animals, or cell systems. It begins with a systematic review involving:
- Keyword literature searches for any scientific articles written over the last 60 years on the chemical and any subjects discussed in the document.
- Sorting through these results to determine the actual relevance of the articles
- Summarizing the key information in the relevant articles and preparing tables with the relevant numeric data.
- Ranking the articles based on the quality of the study.
- Synthesizing the summaries of the relevant articles into chapters for the document.
These documents serve as the basis for determining toxicity values for cancer and other effects. The determinations and the underlying data are reviewed by all the offices within the EPA, as well as external Agencies and specialized scientific groups – often taking 6-8 years to complete!
In 2009, the General Accountability Office (GAO) added IRIS to its list of high-risk areas vulnerable to waste, fraud, abuse, and mismanagement. The GAO in 2019 reported that the EPA had addressed many process challenges in IRIS, including the length of time it takes to complete an assessment and increasing its transparency. Still, it had not made progress in producing assessments; in 2021 the GAO stated that its rating of IRIS had regressed since 2019 because it had not increased its transparency and had not increased the resources needed to complete assessments.
While Congressional criticism may center around the lack of transparency and IRIS’ impact on certain industries, the core problem is a system that only produces 500 assessments in 40 years.
Can IRIS be Reformed?
In 2019, I called for using the Six Sigma Framework to radically improve the performance of IRIS. I still believe that reform is necessary, but I am no longer convinced that IRIS can be retained in its current form because it has become too polarizing and political.
Today, IRIS, or its next iteration, should incorporate a more streamlined and transparent process. AI could accelerate data searching and summarizing. IRIS should include the methods outlined in the Administrative Procedure Act, including public comment and response, welcoming quality data, and input from all sources. EPA should derive several alternative toxicity values on IRIS and not require its offices to use them as the basis for their regulations. Each office should let its scientists decide which toxicity values are most appropriate for the proposed regulations.
In redesigning IRIS, maintaining scientific integrity while streamlining assessment must be core to any new process. Five hundred chemical assessments in 40 years are unacceptable.
