Blood Tests Show Exposure to Ethylene Oxide

Brenda Goodman, MA, and Andy Miller

December 11, 2019

Illinois residents living about a half mile away from a medical sterilization facility have levels of the cancer-causing gas ethylene oxide in their blood that are about 50% higher than those who live farther away, according to newly released test results.

The testing was limited, involving blood samples from just 93 people who responded to fliers and social media posts about the project. Participants were not randomly selected, which may have introduced bias. The results have not been published in a peer-reviewed medical journal.

Even so, the testing offers the first biological evidence that living near a facility that emits ethylene oxide increases a person's body burden of the chemical, which has been linked to breast and blood cancers.

Researchers say their results suggest that the government should fund a second round of more carefully controlled sampling to better define the threat to residents living near the plants.

The CDC paid for the screening, which was done by environmental health researchers at the University of Illinois at Chicago. The CDC also analyzed the blood samples.

The results will be used to inform health reports for area residents that are being compiled by the Agency for Toxic Substances and Disease Registry, a specialized division of the CDC that analyzes risks to communities from environmental exposures. The division is investigating health risks from ethylene oxide exposure in other communities, including Covington, GA.

Susan Buchanan, MD, associate director of the Occupational and Environmental Medicine Residency Program at the University of Illinois at Chicago, says the results surprised her. Buchanan, who led the project, says the test results have strengthened her belief that facilities that emit ethylene oxide are health hazards to the communities that surround them.

"This is a class 1, known carcinogen. It should not be emitted anywhere near where people are living," she says.

Chris Nidel, a Washington D.C.-based attorney who practices environmental health law, says the testing is significant.

"This is what public health should be doing. It's great that they're doing it," he says.

"These studies are kind of few and far between, especially with respect to a live source like this."

"This is interesting in the sense that it points a finger at an industry and that it raises an alarm about cancer risk in the surrounding community, both of which rarely happen," says Nidel, who is not currently representing any clients who believe they've been exposed to ethylene oxide.

"This shows that people are being poisoned in Illinois by these facilities," he says.

This is a class 1, known carcinogen. It should not be emitted anywhere near where people are living. Susan Buchanan, MD, University of Illinois at Chicago

In August 2018, the Environmental Protection Agency released a report that projected increased cancer risks to people in roughly two dozen communities around the U.S. Most of that risk was driven by exposure to the chemical ethylene oxide, which is used to sterilize medical equipment but is also a building block of products like antifreeze and detergent.

The EPA findings have led to community outrage in Illinois, Georgia and Michigan, with sterilizing plants closing and government action aiming to curb emissions.

People who took part in the blood testing pilot project live in Lake County, IL, in the northern suburbs of Chicago. Lake County has four census tracts where EPA modeling suggests that cancer risks rise above 100 for every million people exposed over the course of their lifetimes.

The area has two facilities that release ethylene oxide: Vantage Specialty Chemicals and Medline Industries. Vantage uses the chemical to make household and industrial products. Medline packages surgical kits, then uses ethylene oxide gas to sterilize them. A cluster of people who had their blood drawn came from a neighborhood that about .56 miles away from Medline. Others were scattered throughout the area, and some lived farther away.

In August, when researchers first advertised the project, they looked for residents who had lived within three-quarters of a mile of either facility for at least 4 months.

But researchers soon realized they weren't going to get enough participants with such restrictive limits — the CDC had asked them to try to recruit 100 participants — so they expanded the project to people who lived farther away.

Because wind disperses and dilutes the gas, air testing and air modeling have shown that ethylene oxide levels drop the farther the distance from a known source. At the time, air testing results for the area had been uneven, with sporadic spikes and many samples showing that the chemical couldn't be detected in outdoor air.

Researchers thought the all-comers approach would limit their ability to see any meaningful patterns.

"I'm just afraid there may not be dramatic differences between these folks, we'll see," Buchanan said in an August interview with WebMD.

When the results came back a few weeks ago, she was surprised to see clear differences. The results showed statistically significant differences between residents who lived closer to Medline — within .56 miles of the facility — and those who lived farther away. There were no similar correlations with proximity to the Vantage facility.

Medline spokesman Jesse Greenberg said the company was not able to comment since a full report was not available for review, but supported additional testing around the facility.

"It should be noted that recent ambient air tests released by the Lake County Health Department show EtO levels at sites closest to Medline in Waukegan are below background levels the EPA measured in 34 different cities," Greenberg said. "Also, Medline regularly administers blood tests for Waukegan employees and has never found elevated EtO levels in 25 years."

The tests measured something called a hemoglobin adduct. Hemoglobin is the oxygen-carrying protein in blood cells. Ethylene oxide glues itself to an amino acid that's a building block of this protein, and it will stay there for the life of the blood cell — about 126 days. So tests for hemoglobin adducts measure about the last 4 months of a person's exposure to the chemical.

Peter Boogaard, an industrial toxicologist and professor of environmental health in The Hague, Netherlands, has studied hemoglobin adducts in workers exposed to ethylene oxide. He says they are an important biomarker for exposure. His studies have shown that hemoglobin adduct levels are linked to changes to DNA.

But when told that researchers were trying to measure them in communities exposed to industrial emissions, he was skeptical they would be able to see meaningful differences.

"Unless it's sky-high, meaning you would have had very significant exposure, it would be very difficult to determine if you've been exposed," says Boogaard, who was interviewed before the study results were released. He says that's because scientists think that our bodies make some ethylene oxide when we digest food, and there appears to be a measurable background level of the chemical in the air, even in locations away from known sources.

It should be noted that recent ambient air tests released by the Lake County Health Department show EtO levels at sites closest to Medline in Waukegan are below background levels the EPA measured in 34 different cities. Jesse Greenberg, Medline spokesman

Boogaard, like some other scientists who have studied the chemical, says he also believes the emissions from these facilities aren't large enough to cause harm. He says ethylene oxide can damage DNA, but our bodies have repair mechanisms in place to fix that damage before it causes troubles like cancer.

Buchanan acknowledged that measuring hemoglobin adducts in people exposed to the relatively lower levels of the gas that had escaped into outdoor air was an open question.

"We don't know because it's never been done before. That's exactly why CDC paid for this to be done. Nobody has measured levels from residents from living near a facility," she says.

For participants who lived in a neighborhood about a mile from Medline, the average level of blood for ethylene oxide hemoglobin adducts was 50.1 pmol/gmHb, which stands for picomoles per gram of hemoglobin.

For participants who lived farther away, the average ethylene oxide hemoglobin adduct level was 29.8 pmol/gmHb. Those study participants were considered to have background levels for comparison.

Buchanan says she feels confident calling that number a background level, because previous studies have shown background levels at around 26 pmol/gmHb.

The lowest level in the study was 15 pmol/gmHb. The highest was 333 pmol/gmHb, in a smoker. Results from smokers were excluded from the study because their levels were 5 to 6 times higher because of their exposure to tobacco. Researchers didn't just take people's word for their smoking history. They excluded anyone who tested positive for the nicotine metabolite cotinine.

Buchanan mailed the test results to participants last week. The results caused a stir on social media as people compared their levels and posed questions about what they might mean. For now, researchers aren't sure what level of exposure is considered harmful. The University of Illinois at Chicago research team is planning to take questions at a community meeting on Jan. 12 at 2 p.m.

Tea Tanaka, one of the founders of the grassroots community group Stop EtO in Lake County, says her own level came back on the high end of the spectrum: 58.2. She lives about 4 miles from both facilities, but she works 2 miles south of Medline, an area which is often downwind of the plant. She thinks most of her exposure happens at work. Her husband, who works from home, had an average level: 26.

She says the results made her "feel ill with worry."

She says she and her husband have discussed moving. They're worried they will lose thousands of dollars on their house, since property values have crashed in the area. Now she's worried she may have to change jobs to get away from ethylene oxide, too.

"It's sickening," she says.

Brenda Goodman is a senior news writer for WebMD. Andy Miller is editor and CEO of Georgia Health News.

Sources: University of Illinois at Chicago, Summary of Blood Testing Results, Dec. 9, 2019; Journal of Occupational Health, Sept. 2006; Susan Buchanan, MD, Clinical Associate Professor and Associate Director of the Occupational and Environmental Medicine Residency Program, The University of Illinois–Chicago, Chicago, IL; Peter Boogaard, PhD, PharmD, Toxicologist, Researcher, The Hague, Netherlands; Tea Tanaka, resident of Lake County, Ill.; Chris Nidel, Attorney, Environmental Health Law, Washington, D.C.; and Jesse Greenberg, spokesman, Medline.