Tens of thousands of chemicals are listed with the Environmental Protection Agency (EPA) for commercial use in the United States, with an average of 600 new chemicals listed each year. The EPA’s ability to effectively implement its mission of protecting public health and the environment depends on credible and timely assessments of the risks posed by toxic chemicals. In 1976, Congress passed the Toxic Substances Control Act (TSCA) to provide the EPA with the authority to obtain more information on chemicals and to regulate those chemicals that the EPA determines pose unreasonable risks to human health or the environment. The TSCA authorizes the EPA to review chemicals already in commerce and chemicals yet to enter commerce. In 2009, the EPA announced TSCA reform principles to inform ongoing efforts to manage toxic chemicals. This book assesses the increased efforts of the EPA to ensure the safety of toxic chemicals management.