Ethylene oxide has recently been in the news for increased regulations on the horizons, and companies bracing for litigation. So what is Ethylene oxide, and why has it flown under the radar for so long if it is so dangerous to human health?
Ethylene oxide is an organic compound composed of a three membered ring containing one oxygen and two carbon atoms. The compound is a colorless flammable gas at room temperature with a sweet scent. Its main use includes a chemical intermediate in the production of other products such as antifreeze, adhesives, detergents, and textiles among others. Other uses of ethylene oxide include pesticides and sterilization, though in smaller amounts. What makes it effective as a sterilizing product is its ability to damage DNA, however, this mechanism is also what makes the substance a cancer causing agent. Ethylene oxide was classified as a human carcinogen by the EPA in December of 2016, and has been linked to increased risk of cancers of white blood cells including non-Hodgkin lymphoma, myeloma, and lymphocytic leukemia. Additionally, studies have indicated long term exposure to the chemical can increase risk of breast cancer in women. This 2016 EPA Integrated Risk Information System (IRIS) assessment catapulted this overlooked molecule into the crosshairs of the federal regulators and the public.
People are exposed to ethylene oxide through inhaling or ingesting the chemical. This exposure may occur in the occupational setting, however due to the explosive nature of the gas, most equipment used to handle ethylene oxide is tightly sealed and highly automated which reduces the risk of occupational exposure. However, the general public may also be exposed through tobacco smoke or consumer products that have been sterilized with ethylene oxide. Additionally, the public can be exposed to the ambient air due to industrial emissions of ethylene oxide which disperse beyond the facility’s boundaries to local communities.
Ethylene oxide has generated public concern in the last few years. When the EPA reevaluated ethylene oxide in 2016, the agency updated its health values for the substance which came out to be “60 times more toxic to children and 30 times more toxic to adults than the previous estimate.” However, regulations that were proposed to restrict emissions of the chemical were delayed which further contributed to public concerns. According to the Trump Administration’s Spring 2020 Unified Agenda, a proposed rule was set to be issued by the EPA in September in order to have a final rule by December, although no rule was issued. Some note that one of the factors behind this delay was the need for rapid sterilization of medical equipment in order to respond to the COVID-19 pandemic. Only two weeks after the pandemic was acknowledged by the World Health Organization, the EPA reported that supply could not keep up with the demand for sterilized medical equipment. Subsequently, the EPA then announced that “environmental regulators in Georgia would temporarily allow Becton Dickinson to increase the number of devices it sterilized at plants that had previously come under fire for emissions.”
The EPA’s Toxics Release Inventory from 2016 revealed over 100 facilities in the nation were emitting ethylene oxide into the air, and many of the subsequently exposed communities were comprised of minority and low income families. In August of 2018, the EPA’s National Air Toxics Assessment (NATA) found a number of census tracts that could have higher risk from chronic exposure to ethylene oxide emissions (over 70 years). These risks were estimated using the most recently available data on ethylene oxide emissions from 2014. That same month, the U.S. Agency for Toxic Substances and Disease Registry’s (ATSDR) published an analysis that revealed an elevated cancer risk for residents of Willowbrook, Illinois, a community surrounding the Sterigenics Facility, one of the largest sources of ethylene oxide pollution in the nation. According to the ATSDR, “the residential sample location had an additional lifetime risk of 6.4 cancer cases per 1,000 people, which greatly exceeds EPA’s acceptable cancer risk threshold of 100 cases per 1 million.” Between 1993 and 2017, Sterigenics legally released over 254,000 pounds of ethylene oxide into surrounding areas. The Illinois EPA provided a new permit to Sterigenics to reduce their legal emissions of ethylene oxide from 4,6000 pounds per year to 85 pounds per year, however residents did not feel the permit was strong enough. The mayor and activists in the community “threatened to seize the company’s sterilization plant through eminent domain,” and Illinois lawmakers promised the facility would be closed for good. This achievement by the residents of Willowbrook contributed to the success of similar efforts in other towns across the state including Cobb County, Georgia and Lake County, Illinois where “blood samples from 93 people living within half a mile from a medical device sterilization facility had EtO levels 50 percent greater than those living farther away, whose results closely resembled background levels.”
However, when the pandemic began, although the Willowbrook plant remained closed, both the Lake County and Cobb County facilities reopened in order to help relieve medical supply shortages. On March 31, 2020, a management alert issued by the EPA Office of the Inspector General called upon the EPA to provide information on ethylene oxide risks to the 25 communities that were identified by NATA to be high risk for ethylene oxide emissions. Furthermore, the Center for Disease Control and Prevention warned to avoid using ethylene oxide when sterilizing masks due to the possibility of the masks emitting ethylene oxide vapors that would be inhaled by the user. Despite this, the FDA still faced pressure from the CEO of Medline Industries to approve the gas for sterilization of N95 masks. The disputes over ethylene oxide displays a common dilemma for public health issues, “should we address one public health crisis by potentially creating another?”
As the pandemic begins to wind down, environmentalists expect the Biden administration to shift back to focusing on the health risks of ethylene oxide emissions. The Office of the Inspector General has urged the EPA to develop new National Emission Standards for Hazardous Air Pollutants for ethylene oxide sources. The Office of the Inspector General has also noted that source category technology reviews are overdue, and the EPA should conduct new risk reviews for major source categories including hospital sterilizers and update risk values accordingly. Furthermore, it is also suggested the EPA should create a regular reviewing process to examine emission sources as risk information continues to be updated. According to AdvaMed, currently, over 50% of all types of medical devices are sterilized using ethylene oxide which translates to over 20 billion devices each year. As of July 2021, many European countries are conducting large recalls of some ice creams and candies that have been found to contain ethylene oxide due to an additive used in the manufacturing process containing amounts of the chemical that exceed the EU’s allowed limits.
As of June 17th of this year, the EPA has agreed to “reconsider the August 2020 National Emission Standards for Hazardous Air Pollutants: Miscellaneous Organic Chemical Manufacturing Residual Risk and Technology Review (the “MON Rule”).” This rule is the first final rule to use the 2016 IRIS value. This was in response to several petitions urging the agency to reconsider, and the EPA responded by inviting public comment on “(1) the use of EPA’s IRIS value for ethylene oxide in assessing cancer risk for the source category and (2) the use of the TCEQ risk value for ethylene oxide as an alternative.” The EPA also stated it would continue to review other concerns raised in the petitions. As of now, concerned groups await news following these reviews. Meanwhile, facilities are expecting legal toxic court cases to be brought faster than regulations. As of January 2020, 76 lawsuits have been filed against Sterigenics in Willowbrook concerning ethylene oxide emissions, and more are likely on the way.