The exposure assessment document provides a review and update of information related to exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (2,3,7,8-TCDD). Several scenarios are constructed to illustrate how contaminated material from contaminated soil, various land disposal situations, and municipal waste incineration can result in exposure to 2,3,7,8-TCDD. Estimates are also provided to show what the human exposure and risk would be via inhalation, dermal contact, and ingestion of contaminated soil. Part One presents an update of previous work and an analysis of key issues related to exposure assessment for chlorinated dibenzo-p-dioxins with emphasis on 2,3,7,8-TCDD, such as the behavior of 2,3,7,8-TCDD in soil and sediment, bioavailability from soil, the use of pharmacokinetics for estimating 2,3,7,8-TCDD exposures, and plant uptake. Part Two addresses the application of exposure assessment methods discussed in Part One, in evaluating 2,3,7,8-TCDD exposures from selected situations. Twenty different exposure scenarios, covering contaminated soil, landfills and incineration are presented. Human exposure and risk calculations are then computed under each pathway for the different scenarios.