A national inventory of the sources and emissions of the element magnesium was conducted. The study included the preparation of an overall material flow chart depicting the quantities of magnesium moving from sources of mining and importation through all processing and reprocessing steps to ultimate use and final deposition. All major sources of magnesium-containing emissions were identified and their magnesium emissions into the atmosphere estimated. A regional breakdown of these sources and their emissions was also provided. The physical and chemical nature of the magnesium-containing emissions was delineated to the extent that information was available, and a methodology was recommended for updating the results of the study every two years. (Author)