This paper outlines the regulatory framework behind the upcoming changes in the Commercial Sterilizer NESHAP (40 CFR 63 Subpart O). We will discuss how the US EPA decided on the continuous emissions monitoring requirements – including what those requirements are. Many in the sterilization industry have concerns about how to meet these requirements as previous technologies have struggled to demonstrate the response necessary to demonstrate compliance. This paper will go through Performance Specification 19 (PS-19), which provides the framework for a facility to certify its Continuous Emissions Monitoring System (CEMS). From there, this paper will dive into what happens after certification and how a facility maintains continual compliance. As this paper navigates the required components of CEMS compliance, it will discuss how Picarro, Inc. can make meeting federal and state/local regulations a simple feat. The results of Picarro’s CEMS system are shown for each individual test – providing commercial sterilizers with confidence in a solution that far exceeds the requirements of the US EPA.