When Risk Groups Do Not Fit: A Consequence-Based Framework for Plant and Agricultural Biorisk Assessment

Background: U.S. biosafety practice depends heavily on risk group and biosafety level concepts developed for biomedical and clinical laboratory work. These concepts are essential for agents that threaten laboratory workers, patients, and the public. But they are less adequate for plant pests and some agriculturally significant veterinary pathogens where the principal concerns are escape, establishment, spread, agricultural disruption, ecological harm, regulatory consequences, international trade consequences, or intentional misuse, rather than human disease. Approach: This conceptual framework article examines the fit and limits of existing U.S. risk group logic for agricultural biological agents. It draws on the National Institutes of Health (NIH) Guidelines, Biosafety in Microbiological and Biomedical Laboratories (BMBL) 6th Edition, USDA Animal and Plant Health Inspection Service (APHIS) plant pest authorities and containment guidance, phytosanitary risk concepts, Federal Select Agent Program scope, arthropod and animal containment literature, international biorisk frameworks, and practitioner experience with institutional review of agricultural agents. Analysis: Existing mechanisms partly address agricultural biorisks. However, they do not provide a professional vocabulary comparable with NIH risk groups for widely prevalent, nonpermitted agricultural agents that may still require consequence-based containment decisions. Extending biomedical risk group terminology to agricultural consequence can support local decision-making. But doing so also risks conceptual confusion, because NIH risk groups are defined by human disease risk. Conclusions: Biosafety programs would benefit from a consequence-based agricultural biorisk framework that supplements existing biomedical systems without redefining them. Agricultural Biorisk Categories and a dual-axis model, separating direct biosafety risk from agricultural, environmental, regulatory, trade, and biosecurity consequence, offers a starting point for professional discussion, institutional documentation, and containment decisions.