The ASTSWMO Sediments Focus Group has produced this document that discusses causes and issues related to recontamination. Discussion topics include new contamination of sediment sites from both known sources and newly identified sources, including contamination from new chemicals or those not addressed in previous assessments, and identification of pollutants most commonly found in areas where recontamination has occurred. Also included are case studies at sediment remediation sites where inadequate source control and/or recontamination have been documented after remedy efforts have commenced.