The federal Centers for Disease Control and Prevention (CDC) conducts a national biomonitoring program. Under a Cooperative Agreement, Biomonitoring California uses CDC funding to help support laboratory activities, field work and sample collection, and return of results to participants. CDC provides technical assistance and consultation to Biomonitoring California in the areas of sampling strategy, data collection methods, and data management systems. CDC laboratory staff also share chemical analysis methods with state laboratories and train state laboratory staff. CDC staff help Biomonitoring California develop rigorous protocols to ensure that blood, urine, and other biological specimens are tested in the most accurate and valid manner.