Human health risk assessment, or HHRA, is a scientific and technical process to investigate and characterize the nature and magnitude of [[risk]] to human health for various populations (residents or recreational visitors, both children and adults, and adult workers) exposed to chemical stressors in the environment, for example, chemicals such as arsenic or mixtures of many organic chemicals such as in oil spills that have contaminated soil or groundwater¹. HHRA involves a multi-step process related to the collection of data and information, including the magnitude of the levels of chemicals in the environment, assessing how chemicals are distributed and move through the environment, how receptors are exposed, using available information on chemical toxicity to estimating risks from potential exposure, and discussion of the uncertainties related to the risk assessment process. HHRA conducted as part efforts by number of governmental agencies, for example, federal- or state-led cleanup cleanup efforts in the United States, that are used to assess how threatening a site where hazardous waste has been released is to human health and the environment². ¹See [About Risk Assessment | US EPA](https://www.epa.gov/risk/about-risk-assessment#whatisrisk) ²See [[HHRA following CERCLA Guidance]]