In 2018, the Regional Monitoring Program for Water Quality in San Francisco Bay (RMP) launched an innovative investigation to detect contaminants that were either new to Bay sediment or had previously gone undetected. This study used nontarget analysis, a powerful tool that provides a broad, open-ended view of thousands of synthetic and naturally derived chemicals simultaneously. A leader in using novel technologies to inform decision making, the RMP has explored Bay water quality with nontarget analysis for over two decades. However, sediment had been underexplored with nontarget analysis until this study.