Comment-21106-anonymous

Monitoring Ethylene Oxide Emissions

Dear OEHHA,

On behalf of our community of ethylene oxide (EtO) sterilization facilities, I write to advocate for the broader adoption of the Cavity Ring-Down Spectroscopy (CRDS) system and Other Test Method 47 (OTM-47) in place of incumbent technologies, for the continuous monitoring of EtO emissions as per the regulations of 40 CFR 63, Subpart O.

Given the recent advancements in CRDS technology, it offers significant improvements in sensitivity, precision, and reduced operational costs over the Fourier Transform Infrared Spectroscopy (FTIR) and gas chromatography (GC) systems. Our observation of various commercial sterilizers employing the Picarro CRDS systems have demonstrated a consistent efficiency in the analysis of sample matrices with profoundly improved specificity over other technologies.

The CRDS-based Continuous Emissions Monitoring Systems (CEMS) deliver a level of detection (LOD) of <1ppb for EtO. This presents a substantial enhancement in sensitivity compared to other technologies, particularly relevant considering that EtO emissions from this source category are routinely below 50ppb. The LOD, precision, specificity, and response time of CRDS technology at concentrations ranging from <1ppb to more than 100ppm provide a more accurate representation of emissions, a vital aspect for maintaining safety and compliance with state and NESHAP regulations.

An important additional advantage of CRDS over optically enhanced FTIR (starboost), regular FTIR, and GC systems is the reduction in operational and maintenance costs. Standard preventative maintenance for CRDS-based systems is much simpler and don't require chromatographic columns, optical filters, no moving mirrors, or the failing detectors commonly seen in OE-FTIR. CRDS demonstrates an exceptional mean time before failure (MTBF) of 15+ years, which companies like Picarro having build CRDS systems for nearly 30 years. Furthermore, the ability of CRDS to measure EtO in the presence of other compounds, including water vapor, methane, carbon dioxide, and VOC’s, removes the need for moisture management and sample conditioning systems, further reducing operational complexity and costs. On the other hand, OE-FTIR which is a new technology just release in 2019, require thermal oxidation modules and significant cooling systems such as liquid nitrogen in order to operate.

This improved accuracy, coupled with the reduction in operational and maintenance costs, makes the adoption of CRDS and OTM-47 an attractive, efficient, and cost-effective alternative for continuous emissions monitoring in sterilization facilities.

We request OEHHA to consider our plea for the broad application of OTM-47 and the transition to CRDS systems for continuous EtO emissions monitoring and workplace expsoure monitoring. This step will not only help the sterilization industry maintain compliance with the proposed EtO regulations more efficiently and economically but will also contribute to better protecting public health and the environment.

Thank you for considering our request. We remain committed to meeting or exceeding the regulatory standards set for EtO emissions while ensuring the safety of our employees, communities, and the environment.