The Biochemical and Exposure Science Group (BESG) provides the measurement science, standards, technology, and data required to support environmental and human health science. The BESG applies the analytical techniques of Nuclear Magnetic Resonance (NMR), organic mass spectrometry (MS), and optical spectroscopy for the measurement of trace organic compounds in environmental samples. These capabilities are also used for characterizing plastic pollution, profiling and measuring biomolecules (including proteins, lipids, hormones, and metabolites), and assessing environmental contaminants. The group develops reference materials, certifies standard reference materials, and disseminates reference data to improve quality assurance and harmonization of measurements, enabling the development of new technologies by NIST and its stakeholders. The BESG provides guidance, measurement services, and technology transfer to government agencies (federal, state, and local), scientific organizations, academia, and industry, and works closely with international standards organizations and National Metrology Institutes to establish comparability of measurement capabilities. The Biochemical and Exposure Science Group maintains analytical facilities at the Hollings Marine Laboratory in Charleston, South Carolina, and at the Hawaii Pacific University Center for Marine Debris Research in Waimanalo, Hawaii.