The focus of an Imminent Hazard Evaluation is to determine actual or likely exposures within the ground surface, drinking water, or indoor air to human and environmental receptors under current site conditions and the surrounding environment based upon the potential for carcinogenic health effects. Risk Characterizations for Imminent Hazard Evaluations are conducted separately for safety, human health, and the environment, depending on the type of condition that triggered the need for the evaluation. The toxicity information used to characterize risk includes reference doses and reference concentrations, and carcinogenic slope factors and unit risk values.