CHICAGO — Ethylene oxide emitted by Sterigenics continued to pose high cancer risks after the company installed new pollution-control equipment last summer, according to a new federal study based in part on months of air quality testing in Willowbrook and nearby west suburban communities.
Top officials at the U.S. Environmental Protection Agency confirmed Wednesday that toxic pollution from the company's Willowbrook sterilization plant was responsible for long-term cancer risks up to 10 times higher than what the EPA considers acceptable.
Cancer risks remained high in the area despite improvements Sterigenics voluntarily undertook to prevent all but one-tenth of 1% of the ethylene oxide it used from escaping into surrounding neighborhoods.
"Based on current science, there are very high levels of risk," said William Wehrum, the Trump administration's top air official, who told sometimes angry residents at a public meeting in Burr Ridge that he takes their concerns "very, very seriously."
Responding to questions, EPA officials said pollution from Sterigenics increased the risk of developing cancer for people living as far as 25 miles away from Willowbrook. The biggest risks were in six suburbs -- Willowbrook, Darien, Burr Ridge, Hinsdale, Indian Head Park and Western Springs -- and declined steadily the farther away a neighborhood was from the facility, according to a map the EPA posted online and statements from agency officials during the meeting.
Wehrum and other EPA officials suggested the company could take more aggressive steps that would allow its now-shuttered facility to safely resume operations. But bipartisan state legislation sent Thursday to Gov. J.B. Pritzker would ban Sterigenics from reopening unless medical equipment suppliers -- the company's main clients -- certify their products can only be sterilized with ethylene oxide.
The new EPA report comes as the federal agency is pledging to adopt more stringent restrictions on sterilization facilities nationwide, a rare departure from attempts by Wehrum and other Trump appointees to block, delay or undermine environment and public health regulations.
Willowbrook is a focal point in the ongoing debate, largely because EPA scientists determined last year that neighborhoods near Sterigenics are among just a few dozen throughout the U.S. where breathing toxic chemicals is responsible for more than 1 case of cancer for every 10,000 people exposed during their lifetime.
Like in the Willowbrook area, ethylene oxide is the main chemical of concern in nearly all of those other areas. The volatile gas has been on the federal list of carcinogens since 1985, and in 2016 the EPA released a long-delayed reassessment linking it more conclusively to breast cancer, leukemia and lymphomas at extremely low levels of exposure.
Several residents at the Wednesday meeting said they don't trust the EPA or Sterigenics to protect them. Agency officials, they noted, acknowledged that local cancer risks likely were significantly higher in the past when the Willowbrook facility emitted up to 169,000 pounds of ethylene oxide a year.
"The only appropriate resolution ... is for Sterigenics to permanently shut down," said Margie Donnell, a member of the Stop Sterigenics community group.
More than 19,000 people live within a mile of the Willowbrook facility. Four schools and a day care center also are close by, including Hinsdale South High School in Darien and Gower Middle School in Burr Ridge.
Laws and regulations don't allow the EPA to force Sterigenics to close for good, Wehrum said, but the agency can take action to ensure cancer risks posed by the company's pollution are within federal guidelines.
Wednesday's meeting was the third public forum organized by federal and state officials since the EPA released its latest National Air Toxics Assessment in late August.
A Chicago Tribune analysis of agency data revealed that of 73,057 census tracts in the United States, seven tracts near Sterigenics are among just 109 nationwide with long-term cancer risks exceeding the agency's guidelines. The findings prompted months of intense pressure from elected officials and the public, forcing the EPA to pay closer attention to a once-obscure industry.
"It is not lost upon us, and it certainly isn't lost upon me, the depth to which this has affected you," John Kim, acting director of the Illinois EPA, told residents. "We are doing everything we can to bring you relief."
After months of meetings with Wehrum and his staff, Sterigenics is vowing to overhaul its facility again, even as the company contends that other sources of ethylene oxide were responsible for spikes of the toxic gas recorded by monitoring equipment deployed near its facility between November and March.
"With these improvements, we estimate our annual emissions will be less than 1% of the estimated annual emissions from just the mobile sources (vehicles) in DuPage County, not considering the additional contributions from the myriad other ethylene oxide sources," Philip Macnabb, president of Sterigenics, wrote in a May 10 letter to Wehrum that the company released publicly on Wednesday.
Macnabb did not provide details about the company's plans. At the meeting, federal and state officials said Sterigenics is proposing something similar to plans floated last week by Medline Industries to control ethylene oxide emissions at its facility in north suburban Waukegan.
Once Medline's project is completed, company officials told the Chicago Tribune Editorial Board, the Waukegan facility will operate under negative pressure to prevent ethylene oxide from escaping through doors and vents. Emissions from sterilization chambers and storage areas will be reduced with two types of scrubbing devices, with any leftover gas released into the air through a single stack that is constantly monitored.
At the same time, Sterigenics and Medline have joined the American Chemistry Council, the chemical industry's chief trade group, in attempts to raise doubts about decades of research showing the toxic gas is far more dangerous than previously thought.
A Sterigenics news release issued Wednesday cites two new studies financed by the industry trade group that contend ethylene oxide doesn't increase the risk of cancer for sterilization plant workers. "Establishing sound public policy to protect citizens in our community requires accurate information and reliable data," Macnabb said in the release.
So far the EPA isn't backing down from its conclusions about the dangers of ethylene oxide.
The first study detailing how the toxic gas causes genetic mutations was published in 1948. During the 1970s, animal studies confirmed that its powerful ability to scramble DNA could trigger cancers. The 2016 EPA evaluation, which underwent two rounds of independent peer review, relied on decades of additional animal research and study of more than 18,000 workers at 17 sterilization plants conducted by the National Institute of Occupational Safety and Health.
As the EPA does with any cancer-causing chemical, agency scientists adjusted their safety limit to account for people in the general population who are particularly sensitive to chemical exposures. For the first time, the EPA applied additional safety factors to protect children, who are more susceptible to cancer-causing chemicals.
Wehrum confirmed the agency will rely on the 2016 evaluation when drafting new regulations for Sterigenics and other sterilization companies. In a document recently posted online, the EPA announced it plans to release its proposed rules by July and intends to formally adopt them by the end of the year.
While Sterigenics suggests that vehicles, barbecue grills and construction work could have been responsible for high levels of ethylene oxide detected in Willowbrook in recent months, the EPA study repeatedly states that the latest estimate of cancer risks was based solely on emissions from the company's facility.
Before Sterigenics was forced to stop operating in February, the EPA found that average daily concentrations of ethylene oxide spiked as high as 26.4 micrograms per cubic meter at one of the monitors closest to the Willowbrook facility. High levels were detected when prevailing winds blew from Sterigenics toward a specific monitor, while the amounts measured upwind of the sterilization plant during the same day were significantly lower.
During March, with the facility shut down, the highest level detected at that same monitor was 0.46 micrograms per cubic meter.
"All roads are pointing to Sterigenics as the source of the EtO," said Michelle Colledge, a research officer at the Agency for Toxic Substances and Disease Registry, an arm of the Centers for Disease Control and Prevention that is updating its own study of the cancer risks posed by Sterigenics.