The New EPA Regulations for EtO Emissions:  
What do they mean for your hospital?

Infection Control Today Article Re: EPA 40 CFR 63, subpart WWWWW:
National Emission Standards for Hospital Ethylene Oxide
Submitted by: A.E. Ted May, Vice President

 OnDec. 28, 2007, the Environmental Protection Agency released a new Rule designed to control air emissions from hospital sterilizers using ethylene oxide (40 CFR 63, subpart WWWWW). Given the lingering confusion over this Rule (No, EtO is not going to be banned), this article aims to summarize the issues that hospital administrators must address, and to identify resources that will help make compliance easier.

First the good news. EPA decided to regulate EtO emissions from hospitals by a focus on work practices, and not new equipment requirements. Simply stated, the new rule requires that hospitals should run their EtO sterilizers fully loaded. Exceptions to the rule include medically necessary circumstances and sterilizers with air pollution control devices (APCD).

This full load requirement is consistent with existing hospital practices, since a fully loaded sterilizer is more economical to operate. From the EPA’s perspective, by minimizing EtO use, the hospital also minimizes EtO emissions.

Who is covered by the new rule?

So who is affected by the rule? If you run an inpatient hospital that performs diagnostic services or surgeries and operate an EtO sterilizer, you as an administrator should note the regulatory changes. Specifically excluded are doctor’s offices, clinics, and other facilities whose primary purpose is to provide medical services on an outpatient basis.

As noted, if your EtO sterilizers already utilize air pollution control devices (APCD) you are already in compliance with the rule requirements, as long as the APCD is operating during all sterilization cycles. However, the EPA estimates that over 600 hospitals in the United Statesdo not have add-on APCDs, making it necessary to implement specific management practices.

What Specific Management Practices?

Staff must sterilize full loads of items having a common aeration time. Partial loads may be run under medically necessary circumstances as determined by hospital CS staff, a hospital administrator or a physician, based upon generally accepted medical practices.

For each EtO sterilizer that does not use an APCD, hospital staff must maintain records of every sterilization cycle, including:

  • the date and time of the sterilization cycle,
  • whether or not the cycle contained a full load and if not,
  • a signed note from hospital staff that it was medically necessary

Deadlines for Compliance; new versus existing sources

To determine your compliance date, you first must determine if your sterilizers are “existing” or “new.”

If your ethylene oxide sterilizers were installed or rebuilt before November 6, 2006, it is considered an existing source. Existing EtO sterilization facilities have until December 29, 2008 to come into compliance with the new rule. Filing of an Initial Notification of Compliance Status (INOCS) is required 180 days after this date (May, 2009).

If your sterilizer was installed or rebuilt after November 6, 2006, but before December 28, 2007, it is considered a new source. The compliance date for sterilizers that fit this category is December 27, 2007. Hospitals with sterilizers in this new category have 180 days from December 27, 2007, to file an INOCS with the EPA.

Finally, for EtO sterilizers installed after December 28, 2007, the compliance date is start up of the sterilizer. Your INOCS will be due 180 days after start up.

Record Keeping

Once your facility has filed an INOCS with the EPA you are required to keep copies of the INOCS and sterilization Cycle Records for each sterilizer. These records should be readily available for review if necessary.


Ethylene oxide is still the most popular method of sterilizing new medical devices, and it is an essential tool for hospitals CS Departments who count on its proven reliability.

According to the EPA’s own analysis, the potential risk of EtO emissions to public health is minimal. This new rule, together with improved technology that use EtO more efficiently, will continue to reduce overall EtO emissions.

The Future of EtO Sterilization

EtO is unmatched in its ability to sterilize a wide range of delicate devices at low temperature. Combined with its compatibility with all conventional packaging materials, it is easy to understand why so many hospital CS Directors are passionate about their EtO systems.

Ultra efficient EtO sterilizers meet the spirit of the new EPA rule, and will ensure the popularity of EtO sterilization into the future.

The most gas-efficient system on the market today is the Andersen EOGas™ system. EOGas uses 100% EtO gas cartridges and plastic sterilization bags. Items to be sterilized are prepared, wrapped, and placed inside an individual sterilization bag along with a EtO cartridge. After the sterilization bag is sealed and loaded into the cabinet, the gas is released inside the sterilization bag by activating the cartridge through the bag wall.

Different bag & cartridge combinations are available, and EOGas cabinets are designed to process multiple sterilization bags simultaneously. Each sterilization cycle uses less than 11 grams of EtO.

This unique technology allows operators to match their load to the appropriate bag/cartridge combination, and to fill the sterilization cabinet with as many bags as are required. This load flexibility is unique to the EOGas system, and results in greatly reduced overall gas consumption. With EOGas, the bag is the chamber. And with this system the chamber is always full.

IMPORTANT NOTICE: This article is intended for informational purposes only, and should not be construed as legal or compliance advice. Hospitals and other healthcare facilities should consult with their Regional EPA Office for more information regarding compliance.


Resources for more research:

An EPA brochure explaining Final Rule 40 CFR 63, Subpart WWWWW, can be found at .

The EPA has also provided an example of an Initial Notification of Compliance Status (INOCS) at

More Questions? You can locate your EPA Regional Office at:

Interscan, a leading manufacturer of gas detection equipment (including EtO), has created a site with other useful links on this subject: