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Medical Device Sterilization

Bioburden reduction of consumer goods:

  • cosmetics
  • spices
  • herbs
  • toiletries
  • pharmaceutical raw materials
  • food packaging
  • dyes and colorants

Industrial products processing



Background radiation measured on the exterior wall of Scandinavian Clinics Estonia OÜ´s plant (μSv/h):

(Natural background radiation in Estonia may reach up to 0,3 μSv/h)



Survey area: 0,12 µSv/h;
Control area: 0,10 µSv/h;
Pool: 0,08 µSv/h


Ethylene Oxide (EtO) is an industrial chemical used in sterilizing medical items, fumigating spices, and manufacturing other chemicals. Pure EtO is a colorless gas at room temperature and a mobile, colorless liquid at -47oC. Sold as a mixture with either carbon dioxide or fluorocarbon 12, EtO has been licensed by the Environmental Protection Agency (EPA) in the US for use as an anti-microbial pesticide since the 1940s.

Ethylene oxide kills microorganisms by denaturing their proteins and subsequently modifying their molecular structure. This activity allows ethylene oxide to be effective as a sterilizing agent.

There are some hazards associated with EtO use. Acute inhalation of high levels of EtO has resulted in nausea, vomiting, neurological disorders, bronchitis, pulmonary edema, and emphysema. Skin and eye contact with solutions of EtO has caused irritation of the eyes and skin in humans. Tests involving acute exposure of animals have shown EtO to have relatively high toxicity from oral and inhalation exposures.

A short-term effect of EtO in humans is mainly central nervous system depression and irritation of the eyes and mucous membranes. Chronic (long-term) exposure to ethylene oxide in humans can cause irritation of the eyes, skin, and mucous membranes, and problems in the functioning of the brain and nerves. Some human data show an increase in the incidence of leukemia, stomach cancer, cancer of the pancreas, and Hodgkin's disease in workers exposed to EtO. EPA has classified EtO as a Group B1 hazard (probable human carcinogen).

EtO is not only present in sterilizers but also (in small concentrations) in the environment. Sources of environmental EtO include automobile exhaust and tobacco smoke.

Despite these drawbacks EtO is widely used for sterilization today because it is such an effective agent. There are however some practical limitations since EtO have difficulties penetrating different types of packaging material. In addition, the design of the product must allow the gas to enter into all cavities.

During the last 10 years EtO has become available as a steam under pressure mimicking the action of conventional steam sterilization. The future role of this modality remains to be seen.



An expert from the dialysis industry has currently ( 2003) claimed that EtO as a sterilizing agent is dead in the Western dialysis world due to hyper sensitation against EtO residuals. EtO is however still used for non-developed markets like Africa. The same person said that one way to express the danger of EtO is: The same exposition for an EtO worker as for a dialysis patient.