Ethylene-oxide (75218) (EtO) exposure levels for workers in the sterilization areas of 12 hospitals were assessed. The hospitals surveyed were selected to represent a wide range of exposure situations resulting from various engineering controls, administrative controls, and work practices. The hospitals varied in size, location of sterilizer, and size or number of sterilizers used. EtO levels in 15 sterilization areas were evaluated by gas chromatography with electron capture detection of samples collected in sorbent tubes. Engineering controls included local exhaust ventilation (LEV) above the sterilizer door, LEV at the sterilizer drain, general room air ventilation, and vacuum purges. Work practices to reduce EtO exposure included vacating the sterilizer area during the exhaust cycle, opening the door slightly at the end of the cycle to allow EtO levels to decrease, and limiting the time and close contact with sterilized items. The 8 hour time weighted average personal EtO exposure levels ranges from less than the limit of detection (LOD) to 6.7 parts per million (ppm); short term exposures ranged from less than the LOD to 103ppm. Good engineering controls in conjunction with good work practices afforded the best reduction in exposure potential, reducing EtO exposure to less than detectable levels; good engineering controls were far more influential than good work practices. Areas with poor engineering controls and poor work practices showed unacceptable exposure levels.