In the town of Willowbrook, Illinois, just 30 minutes from Chicago, one might notice the stretches of trees lining the neighborhood streets; the tan stucco strip malls and grocery stores; the expanses of grassy fields and ponds home to ducks lazing around on sunny days. But hidden in plain sight, something more nefarious was putting lives at risk. 

From the outside of the modest-looking office building, one wouldn’t think it housed a sort of danger that would toxify the surrounding air for years, with its multi-colored brick, bright interiors from floor-to-ceiling windows and friendly green shrubbery dotting the entrance. But it was in the name — those simple black letters stamped on a white sign on the side of the wall: Sterigenics.

Sterigenics, a medical device sterilization company, was toxifying the air surrounding its Willowbrook plant location with dangerous levels of ethylene oxide (EtO) — a flammable, colorless gas used to sterilize equipment and plastic devices that cannot be sterilized by steam. EtO is a known carcinogen, and Sterigenics, which describes itself as “a global leader in comprehensive sterilization solutions meeting industrial sterilization needs in the medical device, pharmaceutical, advanced applications, commercial and food industries,” had been emitting the toxin since 1985.

Sterigenics states on their website that “EtO sterilization effectiveness depends on its ability to freely diffuse through a product and packaging. All products must be placed in breathable packaging that allows gas to penetrate the sterile barrier and reach all surfaces of the device or product.” Without medical sterilization, hospital patients would have a higher risk of developing infections, but those who work with EtO must also be protected against dangers, as the CDC stresses it should be considered a known human carcinogen.

The reason EtO is used in medical sterilization is because it can react with and destroy microbial DNA, but if the poisonous gas is exposed to humans, it may result in “respiratory irritation and lung injury, headache, nausea, vomiting, diarrhea, shortness of breath and cyanosis,” according to the U.S. Department of Labor’s Occupational Safety and Health Administration. EtO exposure has also been associated with cancer occurrence, reproductive issues, cell mutations and neurotoxicity.

In September 2022, a jury ordered Sterigenics to pay Willowbrook resident Susan Kamuda $363 million for exposing her to the carcinogen. Sterigenics plans to appeal the verdict, reiterating that it has always safely complied with environmental regulatory requirements.

Kamuda developed breast cancer after moving to Willowbrook with her family in 1985. That same year, Sterigenics moved only a third of a mile from her home and was emitting dangerous levels of EtO until February 2019, when the plant shut down following testing from the U.S. Environmental Protection Agency (EPA). More recently, Kamuda’s son was diagnosed with lymphoma, another type of cancer.

According to a September 2022 Bloomberg Law article, Willowbrook’s Sterigenics plant has had over 760 lawsuits filed due to the toxic emissions, with claims the company knew of the dangers of these chemicals in the surrounding air without warning nearby residents.

“Ethylene oxide is a powerful sterilizer but also has cancer-causing properties due to its capacity to damage DNA,” says Jacques Ferlay, informatics officer at the International Agency for Research on Cancer, an intergovernmental agency forming part of the World Health Organization. “Humans are primarily exposed to ethylene oxide by inhalation and ingestion, which can happen as a result of occupational, consumer or environmental exposure.”

According to the CDC, the basic EtO sterilization cycle takes approximately two and a half hours, excluding aeration time. “Most modern EtO sterilizers combine sterilization and aeration in the same chamber as a continuous process,” says the CDC. “These EtO models minimize potential EtO exposure during door opening and load transfer to the aerator.” Aeration is required because EtO is absorbed by many materials, and aeration will remove residual EtO.

In 2019, CBS News Chicago uncovered concerning information about how Sterigenics completes these processes, reporting that Willowbrook Sterigenics workers were allegedly told to dump toxic chemicals into the public sewer system on the company’s orders. Higher ups were also allegedly covering up how much was actually released into the air. CBS says that former workers (who did not want to be identified) explained how “plant supervisors would dump ethylene oxide’s byproduct — ethylene glycol — down the public sewer drains to avoid the cost of shutting down operations.” Former workers also said the company manipulated alarm systems that were in place to warn workers when they were overexposed to dangerous chemicals.

Even when the alarms did go off, workers were told to ignore them. The article includes testimony from a forklift operator describing the frequent warnings, but “he was repeatedly told to ignore it, not talk about it and just deal with it or find work elsewhere.” This worker was also told to “just open the doors and let the gas out,” and to leave the doors to the ventilation rooms open despite dangerous vapors off-gassing from the sterilized products in those rooms, which would leak throughout the plant. The workers were then told to open all overhead doors to get rid of the gas. This eventually resulted in Willowbrook Sterigenics workers and community residents being exposed to the toxins without their knowledge, leading to untold numbers of cancer diagnoses and, in some cases, death.

Distressingly enough, the EPA knew about Sterigenics and the risks it posed to the people of Willowbrook long before the initial 2019 report. “The U.S. EPA has amassed an abundant body of data about ethylene oxide, its health risks and Sterigenics’ emissions of the chemical to decide a course of action,” a 2019 Chicago Tribune article states. EPA officials said that despite having sufficient data revealing Sterigenics’ toxic emissions, including finding that “the cancer risk in one census tract near the facility was nine times higher than the national average,” it wasn’t able to take immediate action.

Finally, in September 2019, after being temporarily shut down since the prior February, Sterigenics announced in a statement that it would be permanently closing its Willowbrook location due to the “inaccurate and unfounded claims regarding Sterigenics and the unstable legislative and regulatory landscape in Illinois [that] created an environment in which it [was] not prudent to maintain critical sterilization operations in Willowbrook.”

And while the news was a sigh of relief to Willowbrook residents, multiple Sterigenics plants throughout the U.S. must be monitored to ensure this is not happening in any of their other locations. The EPA also published revised regulations in 2020 for Miscellaneous Organic Chemical Manufacturing facilities that require additional controls on certain equipment and processes that emit EtO to reduce risk to surrounding communities. The EPA is continuing to gather information on EtO emissions, and in January 2022 sent requests for information to eight chemical manufacturing entities subject to air emission standards. The EPA announced it is also aiming to revise regulations for commercial sterilizers.