The proposed amendments to Rule 1405 reduce emissions of ethylene oxide to the lowest level of any regulations for commercial sterilizers and related operations. For example, for large sources, ethylene oxide must be reduced by 99.99% compared to the EPA’s NESHAP requirements ranging from 99% to 99.94%, depending on the source of the emission (e.g. sterilization chamber vent or aeration). Alternatively, a large source can comply with an absolute limit of 10 parts per billion, the lowest concentration limit of ethylene oxide ever proposed.
The proposed amendments require stack Continuous Emission Monitoring (CEMS) for large sources. Fenceline monitoring is also required in the proposed amendments for large sources. The fenceline monitoring requirement however is terminated once the stack CEMS is operational. Large sources must conduct fenceline monitoring using either canister collection and analysis by TO-15 / TO-15A or conduct continuous fenceline monitoring using real time monitoring. TO15 or TO-15A sampling would be conducted on a once every six-day schedule. If a facility uses a real-time monitor and measures an ethylene oxide 3-hour average concentration that exceeds the certain thresholds, the facility must initiate the collection of canister samples at the monitoring location.
Prior to initiating the fenceline program the proposed amendments require the creation of a fenceline monitoring plan. Until the plan is approved the facility must conduct mobile monitoring at the fenceline of the facility at least once per month. The facility has the option to hire SCAQMD or a third party contractor (such as Montrose) to conduct the mobile monitoring.