Medical device sterilization is a critical piece of getting life-saving medical devices to patients all around the world.
EtO is one of the most common methods used to sterilize medical devices, and, in many cases, it is the only method approved by the FDA.² It is used on 20 billion devices annually to prevent infections, ensuring patients have safe medical procedures.² EtO is used in many other industries and is present at ambient levels all around us.
At Cook, we strive for continuous improvement in capturing and controlling EtO emissions. Our goal is to remain a leader in the usage and management of EtO, based on sound science and evaluating the latest industry technology.
Our facility in Ellettsville, Indiana, is where we do the majority of our sterilizing, just seven miles from our global headquarters. We have installed a Permanent Total Enclosure (PTE) for our sterilization operations—consistent with the 2024 NESHAP requirements. The PTE is fully enclosed, operates under negative pressure, and all emissions are routed through an abatement system before exiting the stacks, where regular air quality monitoring occurs. We monitor and report our emissions and worker safety at regular intervals, and reports are available publicly at the Indiana Department of Environmental Management (IDEM) website. To put our emissions in context, Cook emitted just 12.34 pounds of ethylene oxide in total over the course of 2025, which is orders of magnitude under our permit.
The safety and well-being of patients, employees, and communities drive our operations. We are dedicated to being a responsible neighbor by engaging with our local communities and communicating proactively about our practices, all while meeting regulatory obligations.
Learn more about our approach to environmental stewardship and being a responsible community partner: 2026 social impact and sustainability report.
Frequently asked questions
What is EtO?
- EtO is a naturally occurring, flammable, colorless gas. It is used to make chemicals and for sterilizing sensitive medical equipment, cosmetics, and spices.
- EtO is used to make antifreeze, textiles, detergents, shampoos, and lubricants, among other things.¹
- Background levels of EtO are present all around us since EtO is naturally occurring in degrading plant material, and is emitted by cars, lawn mowers, charcoal grills, and gas generators.²
Why does the medical industry use EtO?
- EtO is one of the most common methods used to sterilize medical devices.²
- It is used to prevent infections on 20 billion devices annually, ensuring patients have safe surgeries and medical treatments.²
- For many medical devices, it is the only FDA-approved option.²
- EtO was chosen as the sterilization method for Cook Medical’s devices based on material compatibility and the need to maintain device performance to ensure patient safety.
What are Cook’s emissions?
- Ellettsville, Indiana, sterilization facility:
- 2025 EtO total emissions: approximately 12.34 pounds
- Projected 2026 total emissions: 10–15 pounds
- Air Quality Division Permit allowance for total emissions: up to 20,000 pounds annually
- Sterilization chamber and aeration room emissions are abated, as required by state permit, and verified by third‑party testing.
How does Cook protect and train employees to handle EtO safely?
- Cook has a comprehensive safety program for all employees working in sterilization.
- EtO training is conducted during onboarding and completed annually for Cook employees.
- We measure to confirm that we are below the level at which handling EtO could pose risks.
- We test quarterly to ensure we achieve our safety goals, which is more frequent than is required.
- Comprehensive annual physicals are part of our worker safety monitoring program.
What is Cook doing to ensure the continued safety of employees and the community?
- We have taken a best-in-class approach to capturing and controlling EtO emissions. Our goal is to remain a leader in our use and management of EtO. This includes installing a Permanent Total Enclosure for our sterilization operation.
How is Cook responding to the NESHAP regulations?
- Our sterilization operations have installed a Permanent Total Enclosure (PTE) consistent with the new 2024 NESHAP rule, even though we received a 2-year exemption due to potential supply chain challenges for the new equipment. Our sterilization operations are fully enclosed, operate under negative pressure, and capture and abate emissions, as verified through third‑party testing.
For questions, please contact Community@CookMedical.com.
Citations
- Ethylene oxide. American Chemistry Council website. https://www.americanchemistry.com/chemistry-in-america/chemistries/ethylene-oxide. Accessed on July 14, 2026.
- Ethylene oxide & sterilization. AdvaMed (Advanced Medical Technology Association) website. https://www.advamed.org/industry-updates/hot-topics/sterilization-ethylene-oxide/. Accessed on July 14, 2026.