In the United States, analytical transmission electron microscopy (TEM) often has been used for asbestos analysis because it quickly looks at crystal structure, chemistry, and morphology of the fibers. Most methods used for TEM asbestos analysis focus on qualitative energy dispersive spectroscopy (EDS) chemistry, where identification is based off of relative peak heights, because the commercial asbestos that was typically used in building material varied very little chemically. The data derived from semiquantitative EDS analysis, however, can be extremely useful in situations such as mineral powder analysis, soils, and other nonbuilding materials. Still, many commercial asbestos laboratories do not use this technique, because it is not a requirement of frequently used asbestos methods and requires extra calibration standards. Through many different naturally occurring asbestos (NOA) projects, as well as recent National Voluntary Laboratory Accreditation Program (NVLAP) Proficiency Testing (PT) rounds, the usefulness and limitations of semiquantitative EDS have been further considered. This study includes data from a network of laboratories and examines 32 different energy dispersive spectroscopy (EDS) detectors at 20 different laboratories. The results reveal the proficiency of modern EDS detectors as well as discusses real-world examples of the usefulness and limitations of this EDS technique on TEM.