Evolution of the Use of Toxicological Data for Evaluating Chemical Safety and Occupational Exposure Limits

Abstract

Abstract Conventional approaches to setting occupational exposure limits (OELs) by regulatory agencies are reviewed. Example OEL derivations show how guidance values are developed in practice. OEL values from various agencies may differ. We present a framework to help select the most appropriate OELs in practice. Use of the framework is demonstrated by OELs for n ‐hexane, a data‐rich chemical and methamphetamine, a data‐poor chemical. Looking forward, “New Approach Methodologies” (NAMs) continue to develop generating chemical toxicological data via high‐throughput in vitro screening assays, computational toxicology, and other methods. NAMs for chemical risk assessment have received support from organizations such as the Organization for Economic Cooperation and Development (OECD), which has validated a number of alternative test methods. Seven NAMs case studies for chemical screening and priority‐setting are presented. Future applications of NAMs in toxicological risk assessment and occupational environments are reviewed using a four‐level tiered testing framework previously proposed by Andersen and colleagues. The use of NAMs provides increased throughput, improved mechanistic understanding in toxicological testing and reduced costs compared to traditional mammalian toxicity testing. The formal application of NAMs in setting OELs is an area of ongoing development, and more widespread application of NAMs in deriving OELs is expected in the future.