Ethylene Oxide Can Be Used Safely
Ethylene oxide (EtO) has been used for sterilizing medical devices since the 1950s because it sets the gold standard for sterilization that other chemical sterilization methods such as using hydrogen peroxide can only aspire to. Ethylene oxide has its drawbacks – it is a known cancer causing agent (IARC) and can cause reproductive problems for both women and men. However, EtO can be used safely if appropriate safety measures are used.
As Paracelsus said nearly 500 years ago the dose makes the poison and modern sterilizers such as those produced by 3M and Steris have many safety feature built in to prevent exposure. These include operating under reduced pressure to ensure that any leaks are in rather than out. Single use cartridges avoid the problem of handling large EtO gas cylinders and their sometimes leaking connections. Aeration is now only performed in the same chamber as sterilization, negating the past-practice of manually transferring just-sterilized medical supplies from the sterilizer to an aerator.
Workplace standards have also been improved. OSHA and AAMI require high air exchange (10x/hr) and non-recycling of exhausted gases, again to prevent exposure. AAMI (in ST-41) also recommends the use of continuous monitors of EtO, which will alarm if the concentration of EtO exceeds OSHA’s permissible exposure limit (PEL) . The use of gas monitor in particular assures employers and employees that people are not being exposed to excessive concentrations and that all the safety measures that the sterilizer manufacturers and building architects have implemented really do work, and more importantly continue to work over time.
Sterilant chemicals are inherently hazardous (they are intended to sterilize medical equipment after all), but with proper safety measures they can be used safely. Many people are switching to hydrogen peroxide from EtO, perhaps unaware that hydrogen peroxide’s OSHA PEL is the same as for EtO, and that the ACGIH states that hydrogen peroxide is a known animal carcinogen with unknown effects in humans. EtO and hydrogen peroxide, as with other hazardous chemicals can be use safely so long as the exposure of operators is kept at safe levels. Hydrogen peroxide and EtO are both hazardous chemicals but with modern safety features and continuous monitoring to ensure that these safety features continue to work, hydrogen peroxide and EtO sterilization are both safe and essential contributors to modern healthcare.
For more information about EtO sterilization see a recent Self Study article by Jeff Wiser from 3M in the February 2019 edition of Healthcare Purchasing News: