Statutory mandates to establish minimum thresholds for hazards that pose an unquantifiable risk of harm put regulators in a bind. And the Supreme Court’s administrative law decisions this term have exacerbated the problem. 

Consider, for example, the FDA’s current struggle to regulate agricultural water quality. 

Fresh produce, once considered the healthiest of foods, has become a major source of foodborne illness. Tainted fruits and vegetables are responsible for more outbreaks and cause more illnesses than any other food category. One source of the problem is the escape of manure from cattle feeding operations, which contaminates agricultural water sources with harmful microbial pathogens such as  E. coli O157, Salmonella, and Listeria.

To address this problem, the Food Safety Modernization Act, signed by President Obama in 2011, charged the FDA establishing “science-based minimum standards” for agricultural water quality within two and a half years. However, state-of-the-art science was, and still is, insufficient to justify specific thresholds for safe agricultural water quality. Scientists have not yet developed reliable methods for measuring the microbial quality of agricultural water, for estimating the transfer rates of pathogens from water to crops, for modelling consumers’ exposure to pathogens, or for calculating dose-response curves. In short, there is no reliable way to figure out how contaminated our fresh fruits and vegetables are or how clean they need to be.

At first, the FDA delayed publishing an agricultural water quality rule because it lacked scientific evidence to justify a minimum standard. When the statutory deadline passed, consumer groups sued and obtained an injunction ordering the agency to publish a final rule by the end of 2015. To comply with the injunction, the agency published a rule containing specific quantitative agricultural water quality standards unsupported by scientific evidence. This elicited widespread complaints from industry stakeholders and exposed the agency to a potential legal challenge alleging that the agency’s action was arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law. 

In the face of growing criticism, the agency delayed implementation of the rule and eventually relented by publishing a revised final rule this year. The new rule replaces minimum quantitative standards for agricultural water quality with a reasonable care standard. The rule requires farmers to conduct annual self-assessments to identify any conditions that are potential sources of contamination and take reasonable measures to ensure that water is “safe and of adequate quality for its intended use.” Coming full circle, the revised final rule’s lack of specificity leaves the agency vulnerable to potential lawsuits asserting that it has failed to comply with FSMA’s mandate to establish “science-based minimum standards” for agricultural water quality.

The Supreme Court’s recent decisions in Loper Bright Enterprises v. Raimondo and Ohio v. EPA are likely to exacerbate such dilemmas by narrowing the scope of agency discretion and emboldening courts to second-guess the scientific judgment of agency officials. By revising the agricultural water quality rule, it appears that agency officials have interpreted FSMA’s statutory mandate to publish “science-based minimum standards” for agricultural water quality to include qualitative standards based on unspecified criteria of reasonable care and adequate quality. Arguably, that is not the best interpretation of the statutory text or what Congress had in mind. However, given the current limits of the relevant science, the FDA’s expertise and experience in food safety, and the clear desire of Congress that the agency publish agricultural water quality standards without further delay, it would seem advisable for the courts to defer to the agency’s current approach. However, in the post-Chevron era, it is not clear that this avenue remains open. 

Moreover, should the agency attempt again to establish science-based minimum standards for agricultural water quality by filling gaps in existing science with provisional assumptions and estimates, as its initial final rule did, it may well run afoul of the more muscular approach to hard look review on display this term in the Supreme Court’s scrutiny of EPA air quality standards.

There are sensible ways that agencies can work towards compliance with mandates for science-based minimum standards while the necessary science evolves. They can pursue verifiable hazard reduction that generates new policy-relevant information. In the case of food safety, this might mean investing more resources in outbreak investigations. Outbreak investigations prompt the removal of contaminated food from store shelves, which reduces the number of people who get sick. At the same time, outbreak investigations also contribute to a growing body of data that experts can use to model the risk of human illness from specific food safety failures on farms and in production facilities.

Another strategy is to reduce the pressure on water standards as the primary means of regulating fresh produce food safety by addressing the problem of contamination earlier or later in the causal chain. Vaccinating cattle in feeding operations would reduce the presence of pathogens in manure and thereby decrease the risk of contamination in the first place. Post-harvest treatments to kill pathogens using chlorinated water, radiation, ozone gas, ultraviolet light, and cold plasma during processing are additional forms of hazard reduction that show various levels of promise.

Whether the FDA still has room to pursue these interim measures remains to be seen. It may well be that the Supreme Court’s recent decisions will crush the agency’s efforts between the rock of Loper Bright and the hard (look) place of Ohio v. EPA.

For those who are interested in further details regarding the challenges of regulating agricultural water quality and more general thoughts about regulating identifiable hazards that pose an unquantifiable risk of harm, I examine these matters in a recently published article, Known Unknowns: Unmeasurable Hazards and the Limits to Risk Regulation, 76 Okla. L. Rev. 857 (2024).

Timothy D. Lytton is a Regents’ Professor and Professor of Law at Georgia State University College of Law.