During the last century, chromate and dichromate chemical production facilities processed considerable amounts of chromite ore for industrial manufacturing purposes. The waste material from these operations called chromite ore processing residue (COPR) was disposed of in waste sites across the United States, and also used as fill material for building foundations, road construction, and other civil engineering applications such as filling of wetlands. The material has been found in residential, commercial, industrial, and recreational areas. In New Jersey alone, over two million tons of waste was discarded, and 160 waste sites have now been identified that were contaminated with COPR. This waste material consists of a mixture of chromite (CrIII) and chromate (CrVI), otherwise known as hexavalent chromium, which is now widely recognized as a human carcinogen. Based on its relatively high solubility in aqueous systems, hexavalent chromium is fairly mobile and therefore the potential environmental and human impact is of great concern. For effective site remediation and waste management activities, there is a need to make analytical measurements of known quality. There is an critical need for a high-quality reference material to provide quality assurance for such measurements.