What if one person's cancer treatment caused another person to get cancer?

That's the essence of the difficult risk-benefit calculation playing out in communities across the country, where recent changes in how carcinogens are classified at the federal level has caused alarm over the use of colorless ethylene oxide (ETO) gas to sterilize medical devices at plants in their neighborhoods.

Device makers in the Twin Cities were sent scrambling in 2019 when a major ETO plant in Willowbrook, Ill., was closed without warning amid community backlash against emissions of carcinogenic ETO in the leafy Chicago suburb.

ETO is used to sterilize more than 20 billion U.S. devices each year. The 34 ETO facilities that serve the med-tech industry run between 92% and 96% capacity, according to Washington-based med-tech trade group AdvaMed.

Four ETO plants were closed at least temporarily this year, in Illinois, Michigan and Georgia, and lawmakers in several states plan to introduce new ETO regulations in 2020. If new regulation or community opposition leads to additional closures, AdvaMed said there's a real risk of shortages affecting hundreds of millions of individual medical devices.

"2020 will be a defining year for the industry," said Greg Crist, the top lobbyist with AdvaMed.

The Food and Drug Administration requires millions of medical devices to be sterile before shipment to hospitals, including devices for serious issues like cancer and heart problems. About 80% of the millions of pre-made surgical kits for specific procedures are treated with ETO, such as heart-valve replacement kits that contain nearly 100 different preselected and presterilized devices needed for the procedure, Crist said.

The Illinois Environmental Protection Agency in February ordered the closure of the Sterigenics ETO plant in Willowbrook, one of the largest such operations in the country. The decision was prompted by a 2016 federal analysis that upgraded the cancer risk posed by ETO 30-fold, which meant the longstanding Willowbrook plant could be considered an "imminent and substantial endangerment" to public health in violation of the state constitution's guarantee of "a healthful environment" for each Illinoisan.

The February closure led to an immediate, temporary shortage of Bivona pediatric breathing tubes made by Plymouth-based Smiths Medical that had been sterilized there.

It forced another Plymouth company, Monteris Medical, to find alternate means to sterilize the specialized probes it makes to treat advanced brain cancers.

Medtronic and Boston Scientific both acknowledged having to quickly find new sterilization solutions for a range of products.

Minnesota's eight-member, bipartisan delegation in the U.S. House sent a "letter of concern" to the FDA in March urging the agency to take "any and all action" to prevent ETO-related device shortages, while not advocating that the Willowbrook facility be reopened.

The FDA issued its own statement of concern in October.

Dr. Ned Sharpless, acting commissioner of the FDA in October, said at the time that the FDA shared the public's goal of reducing "overreliance" on ETO, but suddenly closing ETO sterilization facilities could compromise patient care and cause device shortages for years to come.

Meanwhile, state officials in Georgia began scrutinizing Sterigenics' ETO plant in Smyrna, Ga., and Becton Dickinson's ETO operations in Covington, Ga., citing concerns over emissions of the gaseous carcinogen into surrounding communities. Trade publication Medical Design & Outsourcing reported this month that an ETO facility run by Viant in Grand Rapids, Mich., will stop using the chemical by Tuesday, as part of a settlement with the Michigan Department of Environment, Great Lakes, and Energy.

Despite the recent alarm in local communities over ETO's cancer-causing properties, there is some debate about how dangerous it is.

Not even AdvaMed disputes that exposure to the chemical can be harmful — "No one is saying ethylene oxide is not toxic. What we are saying is, and what we want the opportunity to share with local officials and lawmakers is, we can responsibly capture, destroy and remove these emissions. And we've done so for decades," Crist said.

But is it a carcinogen? An extensive investigation in the Intercept in February noted that ETO facilities had been emitting the chemical for decades, but community opposition arose after a division of the U.S. Environmental Protection Agency known as IRIS (for Integrated Risk Information System) upgraded the risk of ETO from a "probable" human carcinogen to just plainly "carcinogenic to humans." IRIS calculated a new risk threshold for ETO that was 30 times lower than before.

The risks of ETO exposure aren't borne by patients — the chemical doesn't "stick" to devices. The concern is centered around the communities near ETO plants, like Willowbrook.

The Illinois Environmental Protection Agency said ETO levels measured outside Willowbrook Village Hall and Police Department, across the street from the Sterigenics ETO plant, were high enough to trigger elevated cancer risks.

A study of the actual incidence of cancer in residents living near the plant from 1995 to 2015, done by the state EPA, documented a high incidence of breast cancer and lymphoma, particularly pediatric lymphomas in girls, though the study had some statistical limitations and needed confirmation in a larger study.

In litigation to try to reopen the plant, Sterigenics said its Willowbrook facility always operated within the emission limits in all applicable regulations since it opened in 1984. In 2018, the plant emitted less than one-eighth the amount of ETO allowed under its permits to operate.

Although state officials issued a new permit that would have let the plant reopen with lower emission levels, Sterigenics ultimately announced it would close it permanently, citing an "unstable legislative and regulatory landscape."

Joe Carlson • 612-673-4779