While ethylene oxide does dissolve in water, it can also evaporate from water back to the air.

How long does ethylene oxide sterilization last?

ETO should be considered a known human carcinogen. The basic ETO sterilization cycle consists of five stages (i.e., preconditioning and humidification, gas introduction, exposure, evacuation, and air washes) and takes approximately 2 1/2 hrs excluding aeration time.

At what temperature does ethylene oxide evaporate?

Pure ethylene oxide vapour decomposes explosively if ignited even in the absence of air. Ethylene oxide decomposition is initiated if the chemical is heated to about 560°C, the auto-decomposition temperature (ADT).