Barbara D. Beck is an expert in toxicology and in health risk assessment for environmental chemicals, especially metals and air pollutants, and is the author of over 100 book chapters and journal articles on these topics. While at Gradient, she has performed site-specific and chemical-specific risk assessments, developed exposure and risk assessment methodologies, and has presented the results to different audiences including regulatory agencies, the US Congress, and the public. Before joining Gradient, she was Chief of Air Toxics Staff for US EPA Region I. Prior to that she was a Fellow in the Interdisciplinary Programs in Health at the Harvard School of Public Health. She is at present a Visiting Scientist in the Molecular and Integrative Physiological Sciences Program in the Department of Environmental Health at the Harvard School of Public Health.