AMDR is receiving notices of increased interest and questions about the use of the gas Ethylene Oxide (EtO), which may be used as a sterilant for reprocessed single-use devices (SUDs).

Summary

• Federal safety standards with regard to sterility often necessitate use of EtO. Both original equipment manufacturers (OEMs) and reprocessors engage in the same protocols and meet the same standards when using the sterilant (namely AAMI/ANSI/ISO 11135).[1]
• Historically, about half of all medical devices (original or reprocessed) can only be successfully sterilized with EtO.
• For those quantifying emissions or impact related to EtO, in general, a cycle of EtO is the same whether the devices sterilized are original or reprocessed.
• In January 2024, FDA recognized vaporized hydrogen peroxide (VHP) as an alternative to EtO. Some OEMs and AMDR members are exploring which products may be candidates for VHP and conducting sterilization validations.
• Some reprocessors use a half cycle of EtO on non-invasive reprocessed SUDs, so in these instances more EtO may be used than in the original production of that device. However, a number of published life cycle assessments comparing the overall environmental impact of reprocessed to original devices consistently show that on nearly all other environmental measures, reprocessing is less adversely impactful on the environment than is the original device construction.
• Some commercial reprocessors of non-critical, external devices, such as pulse oximeter cables, use a water-based disinfection process to further reduce environmental impact.

Background

EtO is a common disinfectant and sterilant used for many medical devices, including both OEM and reprocessed (referred to as remanufactured in Europe) medical devices sold by AMDR members. Due to the construction of many medical devices, including those that incorporate plastics, the use of EtO is the preferred method of sterilization because the gas allows all elements, including intricate or difficult to reach places, to be disinfected and/or sterilized without subjecting the device to extreme moisture or heat. Use of EtO must adhere to nationally and internationally recognized standards, including AAMI/ANSI/ISO 11135 and AAMI/ANSI ST 41, which cover the safe and effective use of EtO as a sterilant in healthcare facilities, sterility assurance, occupational exposure, and proper use of processing equipment. [2]

The American Hospital Association reports that about 50% of medical devices used in the U.S. cannot be effectively or efficiently sterilized using any other method than EtO.

According to the Center for Disease Control and Prevention, EtO is a colorless, flammable and explosive gas. The four parameters essential for use of EtO as a disinfectant or sterilant are the gas concentration, temperature used in the sterilization chapter, relative humidity and  exposure time. CDC also notes that EtO became favorable when few alternatives existed for heat and moisture sensitive devices.

In January 2024, FDA recognized vaporized hydrogen peroxide (VPH) as an alternative to EtO. Like the larger medical device industry, some AMDR members are exploring which products may be candidates for VHP and conducting sterilization validations.

Reprocessor Use of EtO

For invasive medical devices, such as laparoscopic instruments or cardiac catheters, reprocessors use EtO in the same way as the OEM with the same standardized cycle to assure the device is sterile. Thus, from an environmental or life cycle perspective, whether an invasive or semi-invasive device is “new” or reprocessed, the same amount of EtO sterilant is used. As demonstrated in numerous Life Cycle Assessments, use of reprocessed devices result in numerous additional environmental benefits over use of original devices. If an OEM uses EtO in the manufacture of the device, then the reprocessor also must use EtO in the reprocessing of the device to help ensure substantial equivalency.

Authors of studies comparing EtO use in virgin and reprocessed devices should be careful to make clear that standards for original and reprocessed versions of the same device are identical. Thus, the use of EtO when necessary is the same for each device. A second use of EtO by reprocessors is as a disinfectant for some non-critical devices. This disinfection process uses less EtO than would be used in a full sterilization cycle, and the reprocessor often uses EtO when the OEM did not. While this use of EtO may result in increased environmental considerations, numerous life cycle assessments have shown that even in these circumstances, reprocessing is preferable to using virgin devices. Some AMDR members have found ways to avoid the use of EtO in these situations, using water-based disinfection instead.

EPA Proposal

The U.S. Environmental Protection Agency (EPA) has proposed implementing tougher standards on the use of EtO. According to its proposal, companies “would need to slash EtO concentrations used to sterilize medical devices down to 500 milligrams per liter for each cycle and ensure pollution controls are in place and working.” Nationally, these measures would cut EtO emissions by about two-thirds from 2020 levels according to EPA, bringing them down by 80% per year, which would fall below the Clean Air Act’s benchmark for elevated cancer risk.

Moody’s Investors Service estimated that commercial medical device sterilizers may need to spend more than $220 million to meet the agency’s proposed limits. A report assessing the impact of the proposal on the medical device industry, from Medical Device and Diagnostic Industry states:

“The proposal estimated that the 86 United States sterilization facilities, which are owned by 46 different companies, would cumulatively need to spend $220 million in one-time capital investments as well as an additional $86 million a year in recurring operating and maintenance costs on upgraded equipment. However, Moody analysts wrote in their report that the total cost could exceed those estimates.”

Conclusion

AMDR will continue to monitor the discussion surrounding the use of EtO and any changes that may be made to regulatory requirements or recognized standards. Whatever changes may or may not happen, however, it is important to note that both OEM and reprocessed devices will be subjected to the same strictures. In the end, therefore, the use of reprocessed devices remains the prudent environmental and economic choice.

Additional Resources:

1. House Energy and Commerce Committee Warns EPA: Don’t Make Medical Surgeries and Equipment Unsafe and Non-Sterile, 28 Sept. 2023: https://energycommerce.house.gov/posts/e-and-c-warns-epa-don-t-make-medical-surgeries-and-equipment-less-safe-and-sterile
2. Medical Device and Diagnostic Industry, EtO Proposal Could Cost Companies More than the 220 Million Estimated, 12 June 2023: https://www.mddionline.com/sterilization/eto-proposal-could-cost-companies-more-than-the-220-million-estimated
3. AAMI ANSI/ISO 11135: Sterilization of Health-Care Products, Ethylene Oxide, Requirements for the development, validation and routine control of a sterilization process for medical devices. https://www.iso.org/standard/70821.html
4. AAMI ANSI ST 41; Ethylene Oxide Sterilization In Health Care Facilities: Safety And Effectiveness, 2008: https://webstore.ansi.org/standards/aami/ansiaamist412008r2018
5. ANSI/AAMI 67 Sterilization of health care products – Requirements and guidance for selecting a sterility assurance level (SAL) for product labeled sterile.  https://webstore.ansi.org/standards/aami/ansiaamist672019