A National Research Council committee will evaluate human health risks and the potential for conducting a cumulative risk assessment for phthalate esters. The committee will review critical scientific data and address questions related to human relevance of experimental data, modes of action, exposure information, dose-response assessment, and the potential for cumulative effects. In its evaluation, the committee will consider the strengths and weaknesses of cumulative assessment approaches. The committee will provide recommendations to EPA on conducting a cumulative risk assessment on phthalate chemicals, including additional research needed.