Q: What is the Ethylene Oxide Sterilization Association, Inc. (EOSA)?

A: EOSA is a non-profit organization whose members include medical device manufacturers, sterilization consultants, laboratories, contract sterilizers, and equipment manufacturers with a common interest in promoting the responsible use of ethylene oxide(EO). See ‘Who is EOSA’ page for more information.

Q: What types of activities does EOSA pursue?

A: EOSA monitors and comments on regulatory issues, such as the U.S. Environmental Protection Agency’s (EPA) reregistration of EO, EPA’s draft assessment of the on the carcinogenicity of EO, and the Department of Homeland Security’s draft list of chemicals of interest. EOSA strives to ensure that agencies are aware of EO’s critical use as a sterilizer for medical and health care purposes. EOSA also works with its members to address specific issues of concern within the industry, such as development of best practices for certain devices or accessibility of personal protection equipment. Perhaps most important, through its annual meetings and conference calls, EOSA provides excellent networking and information sharing opportunities for entities engaged in sterilization processes.

Q: Why is EO important as a sterilizer?

A: EO plays a critical role in antimicrobial sterilization to protect public health. Medical science professionals agree that EO is a critical sterilization technology for medical and health care purposes, and that there do not appear to be any feasible replacements for its use in sterilizing medical devices. EO’s uses include sterilizing certain heat-sensitive and irradiation-sensitive materials, as well as some instruments and devices on-site in hospitals.

Are there hazards associated with EO?

A: From a flammability viewpoint, it is important to note that EO is flammable as a liquid and explosive as a vapor. EO has a wide flammability range from 3 percent to 100 percent. Industrial users of EO are required to comply with many various regulatory requirements from several regulatory agencies and local municipalities.

From a human health aspect, there is a large and impressive body of information on EO, including epidemiology data concerning actual health outcomes for workers exposed to EO. This body of human data includes a retrospective cohort study by the National Institute of Occupational Safety and Health (NIOSH) of more than 18,000 workers from 13 sterilizing facilities, an earlier assessment of the NIOSH cohort and another cohort of workers exposed to EO, and a statistical evaluation of cancer potency estimates based on data from both of these cohorts.

More information on ethylene oxide safety and health effects can be obtained from the various resource links provided on the “Links” page.

It is important to note that any potential harmful effect from EO during the sterilization procedure or afterwards will be contingent on the EO exposure potential.  For this reason, it is critically important to control EO exposure adequately. 

Q: How do sterilization facilities control EO exposures?

A: Although approaches to control EO exposure differ from facility to facility, there are some common elements. The emphasis at EOSA member facilities is on integrated “cycle design,” and stresses careful air-handling at each potential EO source. The resultant control strategies consist of multi-layered EO containment measures for both the sterilization and aeration chambers, precise air-handling including maintenance of air pressure differentials that direct any EO emissions away from occupied areas, continuous monitoring designed to detect EO concentrations well below the level permitted by the Occupational Safety and Health Administration (OSHA), and use of supplementary respiratory protection during certain operations even when EO levels are otherwise in compliance with OSHA requirements. In general, the systems that flush the chambers after a sterilization or aeration cycle has been completed are totally automated and do not permit worker entry until after the flushing process is complete. At some facilities, there are also automated conveyance systems that move sterilized goods directly to aeration chambers without human intervention. Optimized “cycle design” may include the use of “all-in-one” technology, but also can include conventional cycles, which have been modified to incorporate increased gas washes and aeration times.

Q: What is the status of EPA’s review of EO under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA)?

A: On May 30, 2007, EPA’s Office of Pesticide Programs (OPP) announced the availability of a revised risk assessment for EO. On July 30, 2007, EOSA submitted comments that described a number of the technical deficiencies in the EPA risk assessment and exposure assessment for EO. EOSA asked EPA to reconsider its decision to issue a final Reregistration Eligibility Decision (RED) for the non-food uses of EO, and to consider several issues before publishing a final RED. EPA has stated its intent to issue a final RED in 2008.

Q: What is the status of EPA’s Integrated Risk Information System (IRIS) assessment of EO?

A: On September 22, 2006, EPA released a document entitled Evaluation of the Carcinogenicity of Ethylene Oxide -- External Review Draft for public comment. EPA’s Office of Research and Development then asked the Science Advisory Board (SAB) to review the draft document and specifically requested comment on three issues: (1) carcinogenic hazard; (2) derivation of a cancer unit risk value for inhalation exposure to EO; and (3) uncertainties associated with the carcinogenicity assessment. SAB convened an EO Review Panel to review the draft document. SAB reviewed the EO Review Panel’s draft report at its October 2-5, 2007, meeting. Once EPA has received and resolved the conclusions of the SAB review, a final document will be completed and posted on the IRIS database.