The Environmental Monitoring and Support Laboratory at Cincinnati provides quality assurance support for EPA's water-related programs in response to the Clean Water Act, the Safe Drinking Water Act, the Marine Protection, Research and Sanctuaries Act, the Resources Conservation and Recovery Act, the Comprehensive Environmental Response Compensation and Liability Act, and the Toxic Substances Control Act. Two important segments of this support are: (1) the Quality Control (QC) Sample Program which provides samples of known concentrations for use as independent Hazardous Materials which provides calibration standards for trace organic analyses of interest to the Agency. The samples and standards are prepared as stable concentrated solutions in all-glass ampuls. Each series contains one or more related analyses, each with a true or reference value. These are provided for dilution to volume and analyses as needed by EPA, EPA contractor/grantees, and other federal, state and local agencies.