EPA’s Final Standards For Ethylene Oxide Sterilizers: What To Know & What To Do Next

The Environmental Protection Agency’s (EPA’s) regulations for commercial ethylene oxide (EtO) sterilizers were finalized on April 5, 2024, as amendments to the National Emission Standards for Hazardous Air Pollutants (NESHAP) under 40 C.F.R. Part 63, Subpart O – Ethylene Oxide Emissions Standards for Sterilization Facilities. They establish highly stringent emission standards for existing EtO sources – such as sterilization chamber and aeration room vents, as well as for previously unregulated EtO leakage emissions from enclosure rooms and buildings. The regulations affect nearly 90 commercial sterilizer facilities (CSFs) nationwide.

Background & the Sterilization Process

EtO is a colorless, flammable, and reactive gas with a sweet odor that is undetectable until its concentration levels exceed those identified by EPA as having acute health effects. Exposures to excessive EtO concentrations have been determined to cause irritation of the eyes, skin, nose, throat, and lungs, and possible damage to the brain and nervous system. In addition, EPA’s “Guidelines for Carcinogen Risk Assessment” identify EtO as being potentially "carcinogenic to humans" via the inhalation route of exposure. EPA estimates that the regulations will reduce EtO emissions from CSFs by more than 90 percent, thereby substantially reducing air toxic and cancer risks in dozens of communities nationwide.

The use of ethylene oxide for sterilization is a well-established and scientifically-proven method of preventing harmful microorganisms from reproducing and causing infections – without degrading the product, unlike some other sterilization methods. EtO is one of the few methods that penetrates all packaging and will not damage delicate plastic or glass materials. According to the Food and Drug Administration (FDA), CSFs are used to sterilize approximately 50% of all medical products and devices made in the United States, including 95% of all surgical kits

Most CSFs use bulk sterilizers by which substantial volumes of product are placed or loaded within a large sterilization vacuum chamber and exposed to a sterilant gas, such as EtO, for a prescribed exposure time at predetermined temperature, humidity level and pressure. Following completion of each sterilization cycle, the sterile products are removed from the chamber and placed within an aeration room for several hours or days, depending on the product, to allow residual EtO to be completely diffused.

Regulatory Summary - Emissions Standards

The stringency of emissions standards applicable to CSFs varies in accordance with the amount of EtO used (i.e., the least restrictive standards apply to the smallest facilities that use the least EtO), whether the facility is existing or new, and the location of the sterilizer and aeration chamber. To briefly summarize the standards:

• ETO emissions from sterilization and aeration chamber vents must be continuously reduced by 99 to 99.99%, and
• ETO emissions, or fugitive emissions, from sterilization systems contained within a permanent total enclosure or building, must be continuously reduced by 80% to 98%.

Existing Sources are defined as those for which construction or reconstruction commenced on or before April 13, 2023; New Sources are those with construction/reconstruction commencing after April 13, 2023.

Initial Notifications-

Owners and operators of existing CSFs must submit an Initial Notification of Applicability to EPA no later than August 5, 2024; and New Sources must a submit Notification of Applicability within 120 days after startup.

Compliance Deadlines-

CSFs have from 2.5 to 3.5 years to comply with the regulations, depending on EtO usage. To briefly summarize:

CSFs that use 100 pounds or more of EtO per year are required to install continuous emissions monitoring systems (CEMS) for the recording of all key operational parameters, including those for emission control systems. They must also submit quarterly monitoring and performance evaluation reports via EPA's Central Data Exchange – to ensure and document that emissions are being controlled to within mandated limits during all periods of operation, including startup, shutdown and malfunctions. CSFs that use less than 100 pounds of EtO annually have the option of either conducting periodic performance tests of control devices or installing CEMS comparable to that required for larger EtO systems.

Emission Control Options

Catalytic oxidation and scrubbers are the most commonly used technologies to control emissions from the EtO sterilization processes. Both are readily capable of meeting the new EtO emission standards if properly designed and operated. Catalytic oxidation basically works by reacting EtO and other volatile organic compounds with a specially designed catalyst within a combustion chamber where they are converted to CO2 and water vapor. Scrubbers basically use a recirculating aqueous solution to absorb EtO, which is highly water soluble, from vent gases that are ducted to a scrubber column or chamber filled with random packing

The Next Step Should Begin Now

Compliance with the EtO regulation is a substantial undertaking for CSFs, and the clock is now running. As such, it’s recommended that CSFs begin evaluating their obligations and compliance options as soon as possible in order to achieve regulatory compliance within the mandated timeframe. In addition to evaluating emission control options and alternatives, substantial work may be necessary to design, permit, acquire, install and test the selected emission control equipment. In fact, EPA has estimated that the typical timeline from permit submission to project completion is approximately one year.

HETI Services

HETI’s professional staff has broad-based expertise and experience involving all aspects of environmental, health and safety compliance – including those related to EtO. We work with clients in monitoring EtO and establishing ways to best manage its emissions and exposures – along with assistance in efficiently preparing/submitting regulatory reports to avoid the risks of noncompliance. Additionally, we have extensive experience and capabilities in the engineering/design of emission control systems and technologies for meeting regulatory standards.

To find out more about HETI’s environmental and regulatory support services, please contact us.

Lawrence G. Doucet, PE, DEE Senior Professional Engineer – Eastern Regional Manager

Phone: 978.263.4044 [email protected]