Overview of Gas Diffusion Sterilization

100% EtO Gas Diffusion: The most effective sterilant, the most efficient system

Unlike traditional Ethylene oxide sterilizers which involve rigid metal chambers and large external tanks of gas, the Andersen EOGas® system uses plastic sterilization bags and unit dose 100% EtO cartridges. By eliminating chamber dead space, EOGas employs only a tiny fraction of the EtO used in other systems.

Multi-load Capability

Andersen's EOGas system links our unique gas diffusion technology with advanced micro-processor control. The micro-processor keeps track of the bags in the sterilizer, and the operator may load new bags or unload finished bags while others are in process. For tracking purposes, when a bag is loaded, two labels are printed: one is placed in the log book, one is placed in the bag. Unique multi-load capabilities eliminates batch load restrictions.


Items to be sterilized are prepared and placed inside a sterilization bag along with an EtO cartridge and a Humidichip®. The bag is heat sealed and loaded into the sterilization cabinet. For each load the sterilizer prints two tracking labels, one for the bag and one for a sterilization log book. Once inside the cabinet the EtO cartridge is manually activated through the wall of the sealed sterilization bag.

Bag Sizes

EOGas sterilization bags and cartridges are available in two sizes; a 35-Liter with a 10.5 gram cartridge, or a 7 liter bag with a 4 gram cartridge. This unique technology allows operators to match each sterilization load to the appropriate bag/cartridge combination, and to fill the sterilization cabinet with only as many bags as are required. This load flexibility is unique to the Andersen EOGas system, and results in greatly reduced overall gas consumption.

Sterilization Cabinet

The sterilization cabinet acts as a heated aeration chamber, maintaining a constant temperature (50oC) and drawing off the EtO as it diffuses through the plastic of the sterilization bag over the course of the 16 hour sterilization/aeration cycle. EOGas sterilization cabinets vary in capacity from six to thirty three cubic feet, and are designed to process from three to twenty individual sterilization bags.

For more information about Gas Diffusion read : "An Introduction to Gas Diffusion Sterilization" , with permission of MD&DI Magazine. (PDF)