Control measures and arsenic (7440382) exposures were examined at three gallium-arsenide (1303000) production facilities. The first was a gallium-arsenide crystal growing facility which produced, sliced, and polished wafers for use in gallium-arsenide optoelectronics, microwave and integrated circuit manufacturing activity. The second facility produced gallium-arsenide wafers, field effect transistors, and monolithic microwave integrated circuits. The third facility produced optoelectronic devices, specifically light emitting diodes. The Liquid Encapsulation Czochralski (LEC) and Horizontal Bridgeman (HB) crystal growing, LEC cleaning operations, ingot grinding/wafer sawing, and epitaxy processes were specifically highlighted. In all the processes at one facility except epitaxy, the average arsenic exposures were at or above the OSHA action level of 5 micrograms/cubic meter. During cleaning of the LEC crystal pullers, the average potential arsenic exposure to the cleaning operators was 1200 times the OSHA permissible exposure level of 10 micrograms/cubic meter. At the other two facilities personal exposures were well controlled.