Effects of 100% ethylene oxide test gas on the resistance of ethylene oxide biological indicators

Biological indicators (BI) are used during cycle development, validation, requalification, and routine monitoring of sterilization processes. As of Dec 31, 2014, the US Environmental Protection Agency Clean Air Act will prohibit the sale and use of HCFC-based (hydrochlorofluorocarbon) products in the US, and that will include Oxyfume ethylene oxide (EtO) sterilant blends such as Oxyfume 2000, which consists of 8.6% EtO and 91.4% HCFC-124.This requirement means that all BI manufacturers will have to move to 100% EtO as the test gas for determining the resistance performance of EtO BIs by the end of 2014. In anticipation of this mandatory switch from Oxyfume 2000 to 100% EtO for BI testing, additional comparison studies were performed to determine if the switch from Oxyfume 2000 to 100% EtO would have any impact on BI resistance label claims. The test results for this change were markedly different than the change between mixed gasses.