Beryllium particles generated in several industrial and research activities were characterized. The purpose of this investigation was to select appropriate aerosols for experiments designed to study the potential health hazards from using beryllium in fusion reactor systems. Aerosols of beryllium metal and beryllium oxide were obtained from an industrial machining operation, from laboratory studies using an electron beam and a laser beam, and from a research fusion device. Samples of stock beryllium metal and beryllium oxide powders were also examined. Respirable size particles were found in all cases. Beryllium particles from powder metallurgy and particles generated from machining beryllium metal were irregular in shape, typical of comminution processes. Particles produced at subatmospheric pressures in the electron beam and fusion devices were also irregular in shape and may have resulted from sputtering of beryllium by the plasma or the electron beam. Particles formed by laser vaporization at atmospheric pressure were branched-chain aggregates with individual particles appearing crystalline in shape.