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Deeper Dive

Below is a discussion of the specific EPA proposals that we believe could apply to Andersen and its customers.


For the past few years there has been growing concern regarding the emissions from large ethylene oxide (EO or EtO) commercial sterilization facilities. These facilities have very large chambers that can use hundreds of pounds of gas per cycle and may use many hundreds of thousands of pounds of EO per year. These facilities are responsible for the sterilization of over 50% of the medical devices in the United States. EPA has proposed new restrictions on emissions from these plants.

By comparison, Andersen tabletop EO sterilizers use only 17.6 grams of EO per cycle (about a half ounce). If used non-stop, most of our sterilizers could process about 25 lbs. of gas in a year. Most of our customers are actually using 5 lbs. of EO or less per year.

The EPA is proposing to extend many of its new proposed restrictions to health care facilities (HCF) using EO systems. Please note: EPA’s “health care facilities” designation includes veterinary clinics and single practitioners like dentists and plastic surgeons. This is a major change, as HCFs have been exempted from these regulations in the past.

1. Reduction of EO operator exposure limits to 10 ppb (parts per billion).

  • The document is ambiguously worded. However, it seems the EPA may intend to limit HCF workplace exposure levels to 10 parts per billion (ppb) (p.12 & 79, 25). This level is so low, it is less than the exposure many individuals have in the natural world, from plant decay and made inside their own body for example.
  • The EPA’s risk assessment was based upon workers in commercial sterilization facilities, who work around EO eight hours day, forty hours week, over a 35-year career (p. 21, 22). Workers in these facilities are involved with processes that can employ hundreds of pounds of EO per cycle, and thousands of pounds of EO per day.
  • Health care workers are not in the sterilization business. A HCF may run its EO sterilizer a few times a week, or at most twice a day. Given the long combined sterilization and aeration times, these cycles are typically run overnight when the facility is empty. It is mistaken to compare the risks at a dedicated EO sterilization facility to a HCF that is occasionally running its EO system.
  • In the Andersen “all-in-one” system, the sterilizer is operated inside of a dedicated negative pressure cabinet. The only potential for EO exposure would occur when the sterilizer is unloaded. This risk is currently covered under OSHA regulations by the Short-Term Exposure Limit (STEL). There is no STEL level in the proposed EPA guidance.
  • Elsewhere in the proposed guidance, EPA states; “Our established methodology for assessing economic impacts of regulations indicates that the potential for adverse economic impacts begins when the cost to sales ratio exceeds five percent.” We have only been able to find one supplier of a Fourier Transform Infrared Spectroscopy (FTIR), a monitoring system capable of measuring down to 10 ppb, the level proposed by the EPA. Its current cost is over $200k not including installation or maintenance. This is cost prohibitive for HCFs using small, tabletop EO systems that cost $10-15K.
  • The proposed exposure levels are so low that the EO emitted from natural sources, such as plant decay and generated within the human body, would be considered hazardous to human health. In some parts of the country, it would be impossible to separate natural ambient EO from generated sources when measuring down to 10 ppb.

2. Requirement that HCF-based EO systems are installed in a dedicated negative pressure room.

  • This has been a requirement in AAMI ST41 (hospital-based EO sterilization) for over twenty years.
  • Andersen has engineered an EO sterilization process that meets this requirement. In the Andersen all-in-one system, the chamber (the sterilization bag) is operated inside of a dedicated negative pressure cabinet, obviating the need for a separate room.
  • However, if the EPA refuses to acknowledge this design safeguard and the requirement is extended to all practices under the EPA’s “health care facility” umbrella, it would create a significant burden and expense.

3. Requirement that EO exhaust ducts would be terminated away from areas where people walk or work, and the duct would be located at least 7.6 meters (25 feet) away from the building air intake source and be engineered according to existing codes.

  • Again – this has been a requirement in AAMI ST41 for over twenty years.
  • This requirement is already included in Andersen installation instructions and is part of our inspection when performing on-site service and maintenance of our systems.
  • To help ensure compliance with this requirement, Andersen provides our customers with a copy of AAMI ST41 with the purchase of a sterilizer.

4. Proposal that health care workers wear elaborate self-contained breathing apparatus (SCBA) or supplied airline respirator Personal Protective Equipment (PPE) when operating EO sterilizers.

  • This proposal is framed as a question. They ask if this would be feasible for your business, which implies they are at least considering making it a requirement.
  • Supplied airline respirators or self-contained breathing apparatus respirators are a sensible precaution in an EO factory setting when an employee must work in an environment with known unsafe EO levels.
  • This type of PPE might have made sense with older hospital EO systems that employed large 50 lb. tanks. However, these tank-based systems were phased out after 2012 and are no longer in use.
  • SCBA or supplied air PPE make no sense with “all-in-one” EO systems that employ single-use 17.6 gram cartridges.

5. Proposal that all health care facilities employ EO abators with their sterilizers. Required abatement efficiency for systems using less than 1 ton of EO/year is >99%.

  • Andersen has a proven and reliable abatement system that exceeds this requirement (99.9% efficiency). Our abators are in use in many parts of the country that already require emissions capture.
  • With an Andersen abator, emissions from an Anprolene or EOGas 4 sterilizer is reduced to a fraction of a gram per cycle.
  • Given the very small amount of annual EO emissions our systems generate, we believe emissions abatement should not be necessary in most municipalities.

bottom line

It makes no sense to apply these regulations to employees of small businesses like yours who empty one of our highly efficient and smartly designed machines at most twice a day.

We are working to ensure that they do not affect you and will keep you posted on our progress via these pages and social media.


IRIS = Bad Science

iris = bad science

The EPA’s risk assessment tool – IRIS – is deeply flawed & controversial


Our position, how this may impact you and a request for your help


Andersen is different from every other sterilization company, in many key ways


Have a look at the math and see why there’s just no comparison