Review of human health exposure assessment frameworks in the United States and development of a unified framework for exposure assessment practitioners.

The process of conducting a human health exposure assessment has been framed as a stepwise approach by multiple organizations and various authors. However, the recommended steps within these frameworks can vary depending on the organization or author referenced, and it is valuable to have a cohesive analysis of this important topic. The aim of this review was to systematically analyze and compile relevant exposure assessment frameworks in the United States (U.S.) and condense the differing recommended steps to create one consolidated, broadly applicable framework. A review of exposure assessment frameworks identified from U.S. governmental agencies, U.S. consensus guidance organizations, peer-reviewed scientific articles, and book chapters was performed. Inclusion and exclusion criteria were applied such that only comprehensive exposure assessment frameworks were included in the consolidation process. Five comprehensive exposure assessment frameworks from the U.S. Environmental Protection Agency, the American Industrial Hygiene Association, and the peer-reviewed scientific literature were determined to be appropriate for consolidation into the single framework. The steps identified within each existing approach were aligned to ensure all elements were incorporated into the creation of the final overarching framework, hereinafter referred to as the Unified Exposure Assessment Framework (UEAF) for human health risk assessment. The UEAF includes all essential elements of the identified published frameworks and further captures nuances within each source to allow practitioners to have one comprehensive process to reference when preparing to conduct an exposure assessment. Additional frameworks with specific nuances, or those identified as critical resources in the field, were also assessed and discussed. Through this effort, occupational and environmental health and safety (OEHS) and exposure science practitioners are provided with a consolidated crosswalk and proposed stepwise structure that may support more consistent consideration of key exposure assessment elements across U.S.-based occupational and environmental contexts.