Time to shut down IRIS—for good

The Environmental Protection Agency (EPA) is reportedly preparing to eliminate its Office of Research and Development, which houses the controversial Integrated Risk Information System (IRIS). According to a recent New York Times report, this action could lead to more than a thousand layoffs and a fundamental reshaping of how EPA conducts scientific assessments. While critics warn the reorganization would diminish EPA’s scientific capacity, more likely it presents a long-overdue opportunity to end a deeply flawed program that has consistently undermined sound regulatory policy.

CEI has documented many problems with the IRIS program over the years. IRIS evaluations often rely on worst-case hazard assumptions that fail to consider real-world exposure scenarios. Its assessments are frequently disconnected from the practical concerns of the program offices who are charged with regulatory implementation. And its methods are out of step with the risk-based framework mandated by laws like the Toxic Substances Control Act (TSCA).

The core issue at hand is the distinction between hazard and risk. A hazard is a potential for harm, whereas risk accounts for both the severity of harm and the likelihood of exposure. Tigers are undoubtedly hazardous animals. But when confined behind the bars of a zoo enclosure, the risk to visitors is vanishingly small. Similarly, sharks are hazardous predators, but that doesn’t mean swimming is unsafe everywhere. The actual risk depends on whether people are swimming in shark-infested waters.

IRIS, by contrast, tends to treat hazard alone as sufficient grounds for ringing the regulatory alarm, producing assessments without quantifying human exposure levels or weighing the tradeoffs of alternatives—for instance, issuing alarmist assessments of microplastics without accounting for the environmental costs or health consequences of replacement plastics.

This matters because IRIS assessments can carry sweeping regulatory consequences. IRIS values have been used to justify costly new restrictions on everything from formaldehyde to ethylene oxide to pesticides—chemicals vital to agriculture, manufacturing, medical device sterilization, and other industry sectors. When these assessments are based on worst-case assumptions untethered from scientific best practices, the result is unnecessary harm to farmers, manufacturers, and consumers.

EPA may have legal authority to abolish IRIS through administrative action, particularly if the Office of Research and Development is dissolved. However, congressional action is still helpful to make this change durable. That’s where two bills introduced this year come into play.

First, the Improving Science in Chemical Assessments Act (H.R. 123) introduced by Rep. Andy Biggs (R-AZ) would transfer responsibility for chemical toxicity assessments from IRIS to EPA’s program offices—those directly tasked with implementing statutes like TSCA, the Clean Water Act, and the Clean Air Act. These offices have stronger incentives to get risk assessments right. They operate under specific statutory mandates and are accountable for implementing regulations.

Second, the No IRIS Act (H.R. 1415) introduced by Rep. Glenn Grothman (R-WI) would bar the EPA from using IRIS-generated assessments in rulemaking or enforcement altogether. This would prevent the agency from relying on legacy IRIS values that were developed under its flawed hazard-only framework.

These bills could easily be combined to offer a comprehensive solution. By moving personnel and responsibilities to the appropriate program offices while also prohibiting future regulatory reliance on IRIS values, Congress can ensure the program’s retirement is not just a reshuffling of acronyms, but is a meaningful realignment of EPA’s scientific processes toward real risk evaluation.

Congress should also consider reviving elements of the HONEST Act. That legislation would require EPA to rely only on scientific studies that are publicly available and reproducible, providing safeguards against the kind of opaque “trust me” science that has typified IRIS assessments.

The goal here is not to weaken environmental protection, but to modernize it. Americans deserve clean air and water, but they also deserve a regulatory system that is grounded in real risks, not hypothetical hazards. Programs like IRIS that exaggerate harms without accounting for actual exposure or trade-offs do not protect the public—they mislead it.

EPA’s potential move to dismantle the Office of Research and Development offers a once-in-a-generation opportunity to address decades of problems associated with IRIS and thereby realign environmental policy with principles of sound science. Congress should act decisively to make this realignment permanent, bringing both risk and responsibility back to the heart of EPA’s regulatory mission.