The EPA/NCEA Exposure Factors Handbook provides a summary of the available statistical data on various factors used in assessing human exposure. The target audience for this Handbook is exposure assessors who need to obtain data on standard factors to calculate human exposure to toxic chemicals. These factors include: drinking water consumption, soil ingestion, inhalation rates, dermal factors including skin area and soil adherence factors, consumption of fruits and vegetables, fish, meats, dairy products, homegrown foods, breast milk intake, human activity factors, consumer product use, and residential characteristics. Recommended values are given for the general population and also for various segments of the population that may have characteristics different from the general population. Soil ingestion is one of the areas where data are limited. Several studies have been conducted to estimate ingestion of soil by both children and adults. The Exposure Factors Handbook summarizes soil ingestion studies conducted up to 1997, but several new papers have been published since then, causing the need for a forum to discuss these recent findings.