This handbook, Risk Assessment Handbook: Volume I - Human Health Evaluation, provides technical guidance to the U.S. Army Corps of Engineers (USACE) risk assessors and risk assessment support personnel for planning, evaluating, and conducting Human Health Risk Assessments (HHRAs) in a phased hazardous, toxic, and radioactive waste (HTRW) response action. The handbook, a compendium to the Risk Assessment Handbook: Volume II - Environmental Evaluation (Engineer Manual (EM) 200-1-4), encourages the use of "good science" within the framework of existing U.S. Environmental Protection Agency (USEPA) risk assessment guidelines.