Citing the risk of cancer to healthcare workers, employees of commercial sterilizers, and the neighborhoods that surround the facilities, the Environmental Protection Agency (EPA) has proposed regulations to reduce use and prevent exposures to ethylene oxide (EtO) gas sterilant.
EtO is used on approximately 50% of all sterilized medical devices annually, including an estimated 95% of all surgical kits. EtO can sterilize heat- or moisture-sensitive medical equipment without causing any damage.
“Presently, there are no viable alternatives to EtO for the sterilization of certain medical devices and equipment,” the EPA states.1,2 “Moreover, the absence of EtO for use on medical devices and equipment would cause widespread disruption to the availability of sterile medical devices.”
The EPA is seeking comment on the proposed regulation, including the feasibility of adopting some of the controls included. Unless meticulously controlled and mitigated through various stages of use and exhaustion of the gas, EtO can pose a risk of cancer over long periods of time. The gas is mutable to cells, making it an effective sterilant and a carcinogen in sufficient doses.
“EPA is moving urgently to advance new protections based on the agency’s latest assessment of cancer risks from EtO exposure in occupational settings, which are more significant than previously understood,” the EPA stated. “EPA’s new analysis estimates the additional lifetime cancer risk associated with continuous workplace exposure to EtO for eight hours per day, for 240 days per year, over a period of 35 years in an occupational setting is between 1 in 36 and 1 in 10 for workers who apply EtO in sterilization facilities. [The cancer risk over the same period] is between 1 in 25 and 1 in 12 for workers who apply EtO in healthcare facilities.”
EtO is carcinogenic to humans by the inhalation route of exposure. The Centers for Disease Control and Prevention is unequivocal about the dangers of EtO, saying “occupational exposure in healthcare facilities has been linked to an increased risk of spontaneous abortions and various cancers.”3
Healthcare Provisions
Although aimed primarily at freestanding sterilization facilities — particularly after it was discovered that EtO could leak from these sites into surrounding communities — the EPA also is seeking comment on several provisions aimed at protecting hospital workers.
Healthcare facilities use much smaller volumes of EtO than the freestanding sterilization facilities, but “given the low concentration at which EtO may present inhalation cancer risks of concern, EPA now believes additional risk mitigation measures are needed,” the EPA states.
As of 2010, hospital sterilization is required to be performed in a so-called “all-in-one” chamber where the various stages of EtO application are followed by aeration in the same unit to remove residue and absorption.
“Most modern EtO sterilizers combine sterilization and aeration in the same chamber as a continuous process,” the EPA notes. “These facilities sterilize material in oven-sized chambers using 4.5 [grams] to 170 grams of EtO per load. The exhaust from the chambers is typically routed to an air pollution control device, and the room air is typically ventilated through an exhaust stack.”
These measures — which some hospitals already may be doing — would be required two years after the EPA regulations are finalized. The provisions for hospitals include the use of respirators not typically used in healthcare. The EPA wants to know the feasibility of using “supplied airline respirators or self-contained breathing apparatus (SCBA) respirators in healthcare facilities for employees who are unloading EtO sterilization equipment from the sterilization chamber.”
Although designs vary, the air supply model provides air from another source beyond the work area and could be plugged into a wall or stationary equipment. The SCBA is a breathing system worn by the employee, with a positive pressure inhalation device on the face supplied by a tank of compressed air worn on the back.
In addition, the EPA proposes to require that all-in-one sterilization devices be located in a containment area that is physically separate from all other work areas of the healthcare facility. The room should be under negative pressure in comparison to the rest of the healthcare facility to prevent dispersion of the gas.
The EPA proposes that additional abatement devices be required to be used along with all-in-one sterilization devices in healthcare settings. Accessory abatement devices can reduce EtO emissions by more than 99%, the EPA states. After that, the EtO would be vented through exterior ventilation stacks that serve the sterilization area only. The use of these abatement devices and the other interventions should reduce the risk of exposure to EtO in areas around a hospital to close to zero.
The EPA was conscious of the burden these requirements may put on healthcare facilities, even conceding that the new masks and air hoses may be awkward to use at first.
“The agency acknowledges that there would be impacts to healthcare facilities from implementation of engineering controls,” the EPA stated. “Through discussions with industry leaders, the agency determined that some engineering control measures described in this section may already be common practice while others would impose costs from retrofitting existing facilities to meet the new standards proposed. The agency seeks public comment on the cost and time necessary for registrants to implement label amendments requiring the implementation of the proposed engineering controls.”
Commercial Sites Primary Target
The requirements for freestanding EtO sterilization sites were appropriately more prescriptive, with the EPA saying “people who go to school near [commercial] places where EtO is used are also potentially at an elevated risk of cancer due to EtO levels in the air. Actual risks will vary based upon a facility’s control measures for workers and community members and the distance and amount of time people live, work, or go to school near a facility.”
The issue blew up in 2018 when a federal study by the EPA’s National Air Toxics Assessment warned of potentially high risks of cancer in 109 census tracts nationally that were near plants that use EtO sterilization.4 Lawsuits are still being filed, including one by the nonprofit Earthjustice, against the EPA for its “failure to take legally required action to protect the public from harmful carcinogenic air emissions from ethylene oxide sterilization facilities.”
The EPA certainly is acting now, saying that “there are 85 commercial sterilization facilities in this source category, many of which are located near residences, schools, and other public facilities. Many of these facilities also are located in communities with environmental justice concerns. [It has been] determined that approximately 23 of these facilities pose elevated lifetime cancer risks to the surrounding communities.”
Saying that most freestanding sites are using more EtO than is needed, the EPA recommends the majority of devices be sterilized at concentrations no higher than 500 mg/L.
The EPA also would require engineering controls that reduce worker exposures to EtO, such as automation or emissions capture technology. Personal protective equipment (PPE) would be mandated in sterilization facilities when EtO is detected using state-of-the-art monitoring technology. This PPE would include supplied airline respirators or SCBA respirators.
At a May 1, 2023, EPA hearing on the proposed regulation, Darya Minovi, MPH, a senior analyst at the Union of Concerned Scientists, cited a report by the group that found many commercial sterilizers are near communities of color and people with low income.5 “We found that in 12 Metro areas across the U.S there are sterilizer ‘hot spots’ with two or more sterilizers less than 10 miles apart,” she said.
Latino communities are particularly affected, since there are five sterilizers in United States-Mexico border communities and seven in Puerto Rico, Minovi said.
“While I absolutely recognize the importance of medical supply sterilization, I ask that you consider the cruel irony of harming a community’s health for the health of others,” she said.
Maya Nye, PhD, director of federal policy, at Coming Clean, a nonprofit collaborative of environmental health groups, also spoke at the hearing.
She said a chemical facility has released massive amounts of EtO, far exceeding the accepted EPA cancer risk “into my community, where my friends, my family, and other loved ones still live, work, play, and pray.”
“I [also] have a family member whose life-altering health conditions are likely resulting from their career as a cleaner at a medical facility where they used ethylene oxide to sterilize the equipment,” Nye said.
Editor’s note: To submit a comment on the EPA action go to https://www.regulations.gov/ and enter Docket ID number EPA-HQ-OAR-2019-0178. Comments must be received on or before June 12, 2023.
REFERENCES
- Pease A, Reaves ME. Ethylene oxide: Proposed interim registration review decision, case number 2275. Environmental Protection Agency. Published March 2023. https://www.epa.gov/system/files/documents/2023-04/eto-pid.pdf
- Environmental Protection Agency. EPA proposes new standards to protect public health, reduce exposure to ethylene oxide pollution. Published April 11, 2023. https://www.epa.gov/newsreleases/epa-proposes-new-standards-protect-public-health-reduce-exposure-ethylene-oxide#:~:text=WASHINGTON%20%E2%80%93%20Today%2C%20the%20U.S.%20Environmental,medical%20devices%20and%20certain%20spices
- Centers for Disease Control and Prevention. Ethylene oxide “gas” sterilization (2008). Reviewed Sept. 16, 2016. https://www.cdc.gov/infectioncontrol/guidelines/disinfection/sterilization/ethylene-oxide.html
- Environmental Protection Agency. National Air Toxics Assessment. Updated Feb. 8, 2023. https://www.epa.gov/national-air-toxics-assessment
- Minovi D. Invisible threat, inequitable impact: Communities impacted by cancer-causing ethylene oxide pollution. Union of Concerned Scientists. Published Feb. 7, 2023. https://www.ucsusa.org/resources/invisible-threat-inequitable-impact#:~:text=Ethylene%20oxide%2C%20a%20colorless%20gas,unrecognized%20threat%20to%20nearby%20communities
Citing the risk of cancer to healthcare workers, employees of commercial sterilizers, and the neighborhoods that surround the facilities, the Environmental Protection Agency has proposed regulations to reduce use and prevent exposures to ethylene oxide gas sterilant.
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