An evaluation of the accuracy and reliability of ethylene oxide diffusion badge monitors

Ethylene oxide (EO) gas is widely used in hospitals to sterilize certain moisture- and heat-sensitive materials. Based on scientific studies indicating its potential as a human carcinogen and mutagen, and the possible genotoxic, reproductive, neurologic, and sensitization hazards associated with EO exposure, the Occupational Safety and Health Administration (OSHA) has recently lowered the permissible exposure limit (PEL) from 50 ppm to 1 ppm as an 8-hour time-weighted average (TWA). This standard also established an 'action level' of 0. 5 ppm for an 8-hour TWA, below which employers are exempted from such requirements as periodic employee exposure monitoring or medical surveillance. The capabilities of five EO diffusion monitors were examined in the TWA concentration range of 0. 25-3. 7 ppm. Both accuracy and precision were tested by exposing these devices simultaneously to measured concentrations of EO in a stainless steel exposure chamber. Temperature and humidity conditions were controlled, as was the flow rate of the gases across the sampling areas of the diffusion monitors.