Industrial facilities such as commercial sterilizers and chemical manufacturers frequently use ethylene oxide (EtO) in their processes. Due to the toxic nature of EtO, such users need to monitor for very low levels in and around their facilities. That can be particularly challenging with EtO which can present difficulties due to interfering species, high reactivity, a low boiling point, and other challenges. In this note, we examine how a familiar analytical technology is optimized for real-time, direct measurement of EtO. The Thermo Scientific™ EMS-10 System utilizes optically enhanced FTIR (OE-FTIR) technology to successfully address the many challenges of analyzing EtO quickly and with the required sensitivity.