EtO Micro-Dose Sterilization Benefits

Traditional Ethylene Oxide ( EtO) Gas Chamber Sterilization

Over 20,000 healthcare facilities worldwide use ethylene oxide sterilizers to process sensitive instruments which cannot be adequately sterilized by other methods. EtO, a potent, anti-microbial agent, can kill all known viruses, bacteria and fungi, annihilating even the most sterilization-resistant types of microorganisms, bacterial spores and remains the number one sterilization method by a wide margin, with over 70% of total sterilization being accomplished by this means. Tough on microbes, ethylene oxide still treats most medical materials gently, even with repeated use.

In order to benefit from economies of scale, EtO has t raditionally been delivered by flooding a large chamber with a combination of EtO and other gases used as dilutants (usually CFCs or carbon dioxide ) . This method, called "chamber sterilization" has been relied on for many decades by large institutions, but hospitals have been steering away from it because of the numerous drawbacks inherent to the use of excessive amounts of sterilant being released in a large space:

- Air contamination produced by CFCs and/or large amounts of EtO residuals.

- Flammability and storage issues that call for special handling and storage.

- Operator exposure risk and, as a consequence, high operator training costs.

- Need for a large infrastructure, logistics and installation.

Because of hese problems healthcare institutions have sought alternative sterilization methods.

Micro-Dose EtO Sterilization: All of EtO's Advantages, none of its Drawbacks.

In order to fill this void, in the late 50's Andersen Products developed the micro-dose sterilization method whereby a specially designed bag is used in order to eliminate the need to flood a chamber with EtO. This has the effect of minimizing the use of gas and tremendously reducing the economic and environmental costs associated with the traditional process. This system has been used extensively worldwide among various user groups such as hospitals, veterinarian practices, dental practices and medical device manufacturers.

The advantages of this approach quickly became evident and as a result the Andersen system became a sterilization standard since the mid 50's:

- Dramatic reduction of emissions and the resulting operator exposure associated with them by over 80%.

- Important savings in acquisition and operating costs, bringing them down to a fraction of those of a chamber sterilization system, or most existing systems.

- Elimination in operator training and re-training costs, since they are included as a free life-long sterilizer feature.

- Great simplification of the sterilization process and installation, which results in further savings.

- No CFC's are necessary

- The ability to seal items in all-plastic packaging permits indefinite sterility maintenance.>


Due to its handling ease, affordability and tremendous versatility, micro-dose gas-diffusion technology has emerged as an all-purpose, widely accepted sterilization method especilly suited for expensive medical equipment (endoscopes, electronics, fiber-optics, prosthesis, etc.), disposable items, delicate items (paper, plastics, rubber) that heat would damage, and all sorts of medical devices. For a more complete list of the items that can be sterilized using gas-diffusion sterilization, see the alphabetical product list.

Traditional EtO Chamber Sterilization vs. EtO Micro-Dose Sterilization Comparison Table

Andersen System:
EtO micro-dose sterilization
Traditional EtO chamber sterilization
50 degrees C 50-60 degrees C
Cycle time
3.5 h. + 16 h. +
EtO Gas EtO Gas + dilutant gas
Sterilization range
Most materials excluding liquids, food or drugs: plastic, paper, electronics, etc. Most materials excluding liquids, food or drugs: plastic, paper, electronics, etc.
Typical practice type
Clinical, hospital, dental, veterinarian, medical device manufacturing Hospital, medical device manufacturing
Operator skill level
Average. Free training included with machine. Over-exposure is not an issue. High. Operator exposure issues make handling cumbersome.
Environmental impact
Minimal. Emissions are reduced by 99% when scrubbed. EtO emissions
System Price range
$3,999-$50,000 $30,000-$150,000

- Full cycle in as little as 3.5 hours including aeration.
- No CFCs
-Low temperature
-The relaibility of EtO
-Sterilizes most anything but foods, drugs or liquids.
-Can sterilize and package in one step
-Relatively fast
-In larger models
sterilizer can be loaded while in operation without wait.
-Minimal gas use_

-Large loads
-Low temperature
-EtO is one of the most reliable sterilants available.
-Sterilizes most anything but foods, drugs or liquids.


- Relatively small loads
- Requires special safety handling
- Not suited for liquids, drugs nor foods.

-Long cycles
-Toxic byproduct
-Costly operation, installation and operator training.
-Long aeration
-Gas use
-Requires special safety handling


EtO-Micro Dose has all the advantages of traditional EtO sterilization and none of its drawbacks.

Cost-effective sterilization for large loads, but emissions and exposure issues limit its usability.