This report documents results from the first phase of a study co-sponsored by the American Society of Mechanical Engineers (ASME) to assess the accuracy and precision of manual test methods adopted by the US Environmental Protection Agency (EPA) for determining the stack concentration of selected air pollutants. The program is entitled Reference Method Accuracy and Precision and is referred to by the acronym ReMAP. The Phase 1 effort addresses the precision of the selected measurement methods. The formal Purpose Statement for the program is: "To determine the precision of pollutant emission measurements based on analysis of available simultaneous - sample test data which were generated using EPA Manual Reference Test Methods 5 and 5i (Particulate Matter), 23 (Dioxin and Fur an), 26 (HCl), 29 (multi-metals), 101a and 101b (mercury) and 108 (arsenic) at a number of stationary air sources. "