Neighborhoods unaware of airborne cancer-causing toxin

This story is jointly reported by Brenda Goodman of WebMD and Andy Miller of Georgia Health News.

Ann Singley was trying to muscle her lawnmower out of a ditch in front of her home in Covington when she felt a tug in her breast. It was a hard lump, and in the days after she discovered it, it didn’t go away.

It was stage 3 breast cancer. Singley, 33 at the time, was beginning what would be a long and desperate fight to survive. Her youngest child, Gene, was only 3.

“She told me, all he’s going to remember about her is her being sick,” said Singley’s mother, Velma Slaton.

The year Singley was diagnosed with breast cancer, 2007, a company now called BD Bard, which sterilizes medical devices, reported releasing more than 9,000 pounds of a gas called ethylene oxide into the air about a half-mile from her home.

Ann Singley

Ethylene oxide is used on about half the medical products in the U.S. that require sterilization, according to industry estimates. It’s also used to make other chemicals, like antifreeze.

As Singley began her treatment, scientists at the EPA had just begun a 10-year study to better understand the risks of ethylene oxide to human health.

By 2016, the agency had rendered its decision — ethylene oxide was far more dangerous than the scientists had previously understood. The agency moved it from a list of chemicals that probably could cause cancer to a list of those that definitely caused cancer. The EPA also updated a key risk number for the chemical to reflect that it was 30 times more likely to cause certain cancers than scientists had once known.

Two years later, in 2018, the agency used that new risk value for a periodic report that assessed health risks from releases of airborne toxins in the U.S. That report, called the National Air Toxics Assessment, or NATA, flagged 109 census tracts across the country where cancer risks were elevated because of exposure to airborne toxins. Most of the risks were driven by just one chemical: ethylene oxide.

The highest risks were in 12 census tracts in so-called “Cancer Alley” in Louisiana, near facilities that make ethylene oxide or use it to manufacture other chemicals. Other states with affected areas included Pennsylvania, Colorado, Texas, New Mexico, Delaware, New Jersey and Illinois, according to an analysis of the NATA data by the investigative reporting site The Intercept.

Georgia has three affected census tracts, all in metro Atlanta — two in the Smyrna area, and one in Covington where Ann Singley lived. The report estimated that around Smyrna, ethylene oxide causes about 70 of the 114 extra cases of cancer for every million people exposed over their lifetimes. In Covington, it estimated the gas causes about 170 of 214 cases for every million people exposed. The EPA considers the cancer risk from pollution to be unacceptable when it tops 100 cases for every million people who are exposed to a chemical over the course of their lifetime.

In the neighborhoods that have been impacted in Georgia, people are just hearing about the hazard — from Georgia Health News and WebMD — nearly a year after the federal government released its official list of the hotspots. The EPA made a decision not to put out a press release, and state regulators did not issue one either.

“EPA is not issuing a press release,” wrote Larry Lincoln, director of EPA’s office of external affairs for Region 4, which covers the southeastern U.S., in an email message to state officials.

As a result, few people who live in the impacted census tracts in Georgia and elsewhere are aware of the threat, which goes back decades.

Companies that release ethylene oxide have largely continued to conduct business as usual. Many are legally allowed to release thousands of pounds of ethylene oxide each year because they received state permits before the EPA lowered the risk threshold for the chemical. Though the EPA can rule that chemicals carry a high level of risk to people, there’s nothing in the law that compels environmental regulators or companies to act on that risk.

“No one wants to believe something irresponsible is going on,” said Tony Adams, a former board member of the homeowners association at a townhomes development in the Smyrna area.

News that ethylene oxide might be a problem touched off heated debate on the neighborhood’s Facebook page.

Maps made in June by the Georgia Environmental Protection Division (EPD), which did its own modeling to examine risks from the toxin, show that releases in both the Covington and Smyrna areas exceed the state’s determined level of a chemical at which health risks begin to rise. That level is known as the Acceptable Area Concentration, or AAC.

The AAC for ethylene oxide represents one additional case of cancer for every 1 million people exposed.

In Smyrna, the state estimates ethylene oxide emissions are 27 to 61 times higher than the AAC. In Covington, concentrations of ethylene oxide in neighborhoods around the plant range from 17 to 97 times the AAC.

“Oh, my,” said Stephanie Cargile as she looked at the state’s maps.

“So what do I need to do? Move? I’m not going to jeopardize my children,” said Cargile, 59, who lives in Covington with her two grandsons.

EPD’s modeling map of the Sterigenics plant. The colored rings indicate cancer risk calculations from ethylene oxide.

The state maps offer only educated guesses about the pollution in the affected areas. That’s because they are based on estimated emissions that are self-reported by the companies. No air testing for ethylene oxide has been done in the neighborhoods around the plants. In an interview, the Georgia EPD said it currently has no plans to do air testing. It also said it has no immediate plans to require the companies to reduce their emissions.

“It’s far too early for that,” said Karen Hays, chief of Georgia EPD’s Air Protection Branch, in an interview with Georgia Health News and WebMD. “We’re trying to figure out what is actually going on, on the ground. This is modeling. We’re looking at this. This is what we have come up with so far.”

When asked whether the EPD had any plans to talk to people about the pollution near their residences, Hays said, “We have not so far.”

Proving that cancers have been caused by environmental pollution is difficult, and there has been no specific health investigation of the Georgia census tracts that are at risk.

However, data compiled by the Georgia Comprehensive Cancer Registry show at least one of the cancers tied to ethylene oxide, non-Hodgkin lymphoma, has risen significantly over the last decade, especially among men, in the 30014 ZIP code around the sterilizing plant in Covington. That’s the same pattern seen in studies of exposed workers. The EPA’s risk review noted that men who worked with ethylene oxide in sterilizing plants were more vulnerable to “lymphoid” cancers — including non-Hodgkin lymphoma — than their female co-workers.


A lawmaker says he is troubled by the state’s response.

“I’d like to see independent air quality testing in the area around Covington that the EPD study says is impacted,” said U.S. Rep. Hank Johnson, a Democrat who represents Georgia’s 4th District, which includes Covington and the BD Bard Plant. “The fact that state and federal agencies have known the dangers of ethylene oxide and have not informed residents is unacceptable. Federal, state and local officials should work together to assess the dangers these emissions pose to our communities and determine next steps to protect the health and well-being of our citizens.”

State Sen. Brian Strickland, a Republican who represents the Covington area, declined comment.

An airborne menace

Ethylene oxide is a stealthy poison. It’s an invisible gas with no noticeable odor in outdoor air.

It’s used to sterilize medical equipment because it penetrates cardboard, paper and plastic, laying waste to microbes like bacteria and fungi that can cause infections or spoil foods.

The chemical can snip and scramble DNA, the instructions for how living cells work. Errors in DNA can cause cells to grow uncontrollably, leading to cancer.

Workers exposed to the gas on the job developed breast, leukemia and lymphoma cancers at higher than expected rates, according to a 2004 study of more than 18,000 employees at sterilization plants.

BD plant in Covington

Besides breast and blood cancers, rats and mice experimentally dosed with ethylene oxide for toxicology studies developed lung and brain tumors, uterine cancers, and cancers of their connective tissue. They also had more miscarriages and breathing problems than unexposed mice.

Ethylene oxide molecules disperse in outdoor air, but they don’t disappear for a long time. The chemical has a half-life of about 200 days in air, or almost 7 months. That means it takes that long for just half of the chemical to break down.

“It’s enough time that an ethylene oxide molecule that’s released will probably go around the world two or three times before it’s destroyed,” says Richard Peltier, PhD, an associate professor of environmental health sciences at the University of Massachusetts at Amherst.

In communities where ethylene oxide is steadily released, “you’re being exposed to this continuously 24 hours a day,” he says.

Documents obtained through lawsuits against chemical companies show that the industry had heard about the cancer risks related to ethylene oxide as early as the 1980s.

At a toxicology conference in Galveston, Texas, in 1981, Marvin Legator, PhD, briefed the audience on emerging cancer risks from chemicals. “The biggest problem chemical we have right now is ethylene oxide,” he said.

It would be 35 more years before EPA policy caught up to Legator’s warning.

Outrage in Illinois

There was one place where the news about ethylene oxide exploded — the Village of Willowbrook, IL, an affluent suburb of Chicago.

The EPA has a regional office in Willowbrook. There, EPA staff had been working for months behind the scenes, prior to the air toxics report’s public release, to learn whether the cancer risks predicted by that  upcoming assessment existed in the real world.

The EPA’s air toxics assessment is a cancer risk screening tool. Its conclusions are based on data modeling, not a measurement of chemicals in air. The regional EPA staff wanted to know how much ethylene oxide they were actually breathing. For them, the threat was personal.

They ordered air testing in 39 locations in the neighborhood that surrounds a medical sterilizing plant run by a company called Sterigenics, which reported releases of hundreds of thousands of pounds of ethylene oxide to the outside air there over more than two decades. The results of that sampling confirmed elevated levels of ethylene oxide in the air around Willowbrook.

The regional EPA staff then asked the Agency for Toxic Substances and Disease Registry (ATSDR), a specialized division of the CDC, for help. ATSDR reviews the latest science and likely exposures to understand specific health risks to communities from toxic pollution.

Based on the levels of ethylene oxide detected in the air around Willowbrook, ATSDR’s calculations showed the extra cancer risk for residents was roughly 6,400 cases of cancer for every million people. The EPA considers the cancer risk in a community to be too high when it tops 100 cases for every 1 million people exposed to a pollutant.

The ATSDR report came out August 21, 2018. EPA released its National Air Toxics Assessment the next day.

News of the cancer risks around Willowbrook spread rapidly.

“We found out about the ATSDR report the day after it was published,” says Margie Donnell, a real estate attorney who lives in Willowbrook. “We were told it was never supposed to be made public,” she says. “The village freaked out.”

Residents in Willowbrook quickly mobilized, forming a nonprofit called Citizens 4 Clean Air. They raised money and started a Facebook group called Stop Sterigenics to spread the word about the pollution.

Three days after the report came out, the group was protesting in front of the Sterigenics plant. They enlisted the help of Illinois lawmakers, including Democratic U.S. Senators Dick Durbin and Tammy Duckworth.

By October, the Illinois attorney general had sued Sterigenics in state court. In February 2019, after more air testing, the Illinois Department of Environmental Protection issued an order that shut the plant down.

Just this week, though, state and company officials announced that Sterigenics will be cleared to resume operations at its Willowbrook facility after installing new equipment intended to dramatically reduce emissions of ethylene oxide.

Sterigenics says that the amounts of ethylene oxide it released were tightly controlled and always within legal limits.

“Sterigenics has a proven track record of complying with and going above and beyond what the regulations require in the safe use of EO [ethylene oxide] to sterilize critical medical products and devices,” said the company in a statement posted on the Sterigenics Willowbrook website.

Margie Donnell says the EPA’s air testing suggests that the emissions the company was reporting to the EPA were wrong.

“Self-reporting [by a company] is a guess. It’s abundantly clear that the numbers are just a guesstimate or whatever the company wants to submit,” she says.

In other public responses, Sterigenics has questioned whether its operations were the sole source of emissions measured near the plant. They say the EPA failed to account for ethylene oxide from background sources like traffic and construction around the canisters that took air samples.

Scientists don’t dispute that ethylene oxide can come from sources other than sterilization plants. But they note that EPA air testing showed that levels of ethylene oxide fell by an average of 50 percent after the company ceased operations, according to the Chicago Tribune. The emissions plunged by more than 90 percent in air monitors that were placed closest to the plant.

Sterigenics and other medical sterilizers also take issue with the EPA’s new risk value for ethylene oxide, which finds that the chemical can cause cancer in minuscule amounts. They say the threshold set by the EPA is unreasonable, because it’s a level of ethylene oxide that is lower than the amount found in healthy human bodies.

Independent experts acknowledge that human bodies make some ethylene oxide. But they say that even if it comes from normal body processes, that doesn’t mean there’s no harm when a person’s levels are elevated.

Environmental health scientist Peltier says ethylene oxide from industrial pollution adds to what people already have in their bodies. And he says that airborne ethylene oxide is a cancer source we should be able to protect people from.

“We can control the outside environment exposures. We can’t control the ones on the inside,” he says.

Sterigenics in Georgia

In Smyrna, another Sterigenics plant sits tucked into a low-slung industrial area next to The Light Bulb Depot and a doggie day care. The Garden, a shelter for homeless women and children, is across the street.

Smyrna is one of Atlanta’s closest suburbs. New townhomes in the area, which has become a hot location thanks to its proximity to Atlanta highways, are selling for $500,000 and up.

The Sterigenics plant in Smyrna

There, residents are just learning from reporters that a toxic gas is drifting through their neighborhood.

Cassandra Saffold started shaking when a reporter from WebMD showed her a map made by the Georgia Environmental Protection Division. The map estimates concentrations of ethylene oxide near a townhomes development, where she lives, at 27 times the annual safe level determined by the state.

“This is my major investment,” she said, speaking of her home’s resale value. “What if we can’t get it shut down?”

Saffold alerted her homeowners association, and within three days, members were posting on the Stop Sterigenics Facebook page, looking for more information.

Adams, a massage therapist who also lives in the townhomes, said he is worried about his home’s value, but “I’m more concerned about my health than money. And I like money.’’  Adams says he and his neighbors “want to have peace of mind that the air we’re breathing is not toxic.’’

To come up with its maps, the state worked for months with BD Bard and Sterigenics, using numbers reported by the companies for the modeling. Unlike in Willowbrook, no follow-up air testing has been performed.

Emails obtained through the Georgia Open Records Act show that as the companies worked with state regulators, they dramatically lowered their own emissions estimates, dropping them from thousands to hundreds of pounds.

Sterigenics says it was able to lower its emissions, in part, by better controlling “back vent” emissions that escaped when plant workers opened the door of the sterilizing chamber after a cleaning cycle.

Bard says its numbers dropped because testing showed its pollution control equipment removes more ethylene oxide than the company had first estimated.

Keller and his wife, Jo Ann

Even using the companies’ lower figures, data modelers at the state EPD found that the estimated ethylene oxide emissions from the Sterigenics and BD Bard plants exceeded the state’s yearly acceptable levels.

Smyrna resident John Keller says he is troubled that the state has relied solely on the company for information about their releases.

“That’s a mistake,” says Keller, 83, a retired dentist. “They need to do their own testing. Depending on the company to admit to their own pollution is like depending on Philip Morris to tell you about cigarettes.”

The state’s response

The state of Georgia consistently ranks high on lists of the best states for businesses. One reason, according to surveys, is a friendly regulatory environment.

According to state guidelines, a company seeking a permit to operate in Georgia has to demonstrate that its releases will not exceed acceptable concentrations of certain toxins. And even though the models EPD made followed the same process the state uses to set limits on releases of toxic air pollutants, the EPD said these models won’t be used for that purpose.

Emails obtained under the Georgia Open Records Act show how the state has been reluctant to provide information to assist federal investigations into Georgia’s ethylene oxide pollution. EPD air branch chief Karen Hays pushed back at EPA staff who requested more information on medical sterilizers in Georgia, including how companies were making their estimates for ethylene oxide emissions. Hays said the work was unnecessary and burdensome, emails show. EPA backed off the request.

In April, ATSDR, a division of the CDC, reached out to see if the state had modeled any health impacts from ethylene oxide sterilizers. Emails show that Hays suggested that ATSDR file an open records request to get more data, though her staff had, in fact, been working on those models for months.

An EPD manager who works on determining health risks to people from environmental pollution questioned that federal agency’s report on Willowbrook. “My concern with ATSDR’s recommendations is the assumption that a causal relationship can be easily drawn between chronic exposure to [ethylene oxide] air emissions and elevated cancers in the population surrounding a facility under routine monitoring,” the manager wrote.

It’s unclear whether the state of Georgia will require either company to take any corrective measures.

Sterigenics says it is installing new pollution control equipment, which will make its operations even safer.

Hays says she has asked a different department of EPD to study what their maps mean for the health of residents around the plants. She has given them a deadline of August 1 to report back.

State regulators say they are waiting before they take further action, because the EPA may roll back the new, stricter risk value for ethylene oxide at the request of the American Chemistry Council.

When Hays read the news that the EPA might be reconsidering its new risk value for ethylene oxide, she responded to a colleague with just one word: “Yeah!”


Though the state doesn’t plan to test air in the impacted neighborhoods, EPD is testing a single sample of air for ethylene oxide at its monitoring site in south DeKalb County. The site is not near any plants that release ethylene oxide. Instead, Georgia wants to see if ethylene oxide may be present in the air from sources like traffic.

Jen Jordan, the state senator who represents part of the impacted Smyrna area, questions whether enough is being done.

“This is bad,” says Jordan, a Democrat who represents the 6th District.

“I’m incredibly troubled that it sounds like they were trying to manage the situation instead of being transparent,” she says. “When we have modeling and a memo that shows elevated cancer risk, why that would not somehow have some kind of regulatory or legal impact on a company, especially when we know what they’re doing is hurting the people that live around them.”

Cancer risks around medical sterilizers

At the request of WebMD and Georgia Health News, the Georgia Department of Public Health looked up cancer rates in the ZIP codes around the plants in Smyrna and Covington.

The 30339 ZIP code sits next to the Sterigenics plant in Smyrna. The ZIP code encompasses a slightly different area from the one the pollution was projected to impact, so there’s no way to make a direct comparison.

EPD’s modeling map of the BD plant. The colored rings indicate cancer risk calculations from ethylene oxide.

Cancer rates in this ZIP code appeared to be on par with those in the rest of the state. In 30339, the latest data show 474 cases of cancer were diagnosed for every 100,000 people, the same as the statewide rate.

While rates of breast cancer were slightly higher in 30339 than in the rest of the state, the difference is not statistically significant, meaning it could be due to chance alone.

While increased levels of cancer haven’t shown up in state data in the Smyrna area, the numbers tell a different story in Covington.

People who live in the 30014 ZIP code are diagnosed with more cancers than residents in Newton County overall and in the state as a whole. In 30014, there were 527 cases of cancer diagnosed for every 100,000 people, compared to an average of 474 cases of cancer diagnosed for every 100,000 people statewide. The difference between the cancer rate in 30014 and the state is statistically significant, meaning that the increase is not likely due to chance alone.

Rates of non-Hodgkin lymphoma, a type of cancer linked to ethylene oxide exposure, have recently been higher in the 30014 ZIP code compared to the Georgia average.

Non-Hodgkin lymphoma rates have been rising an average of nearly 7% each year from 2007-2016 in this ZIP code. The increases are statistically significant, according to public health officials.

Rates of breast cancer, another type of cancer linked to the toxin, have varied. The latest data show rates in the ZIP code are close to the state average of 127 cases diagnosed for every 100,000 people. But historical data indicate that they peaked in this ZIP code between 2010 and 2014, when 139 cases were diagnosed for every 100,000 people. Over the same time frame, Georgia’s breast cancer rate was 127 cases per 100,000.

In a written statement, the state’s Department of Public Health cautions that it is extremely difficult to determine whether an environmental exposure has caused cancer. The department says its data shouldn’t be construed as link between any particular environmental exposure and a specific type of cancer. That’s particularly true in some of the impacted neighborhoods in Covington, which have had documented exposures to other types of toxic chemicals in addition to ethylene oxide.

Cancer and the environment

Ann Singley lived in the same neighborhood of neat wooden row houses for much of her life. The homes were built to house workers at the old Covington Mill.

Singley grew up, for a time, in a house on Wheat Street, where she lived with her mother and four brothers. She moved back in 1991 when she married her husband, Kelly, a deputy for the Newton County Sheriff’s department.

Bard has a longstanding presence here, too.  The company has been using ethylene oxide to sterilize medical equipment in the area for decades.

Federal records show the plant, which sits about half a mile as the crow flies from the yellow house where the Singleys lived, has been emitting ethylene oxide into the outdoor air since at least 1987, the first year companies were required to report releases of toxic chemicals to the federal government. That year, the plant reported releasing more than 76,000 pounds of ethylene oxide. By 1991, when the Singleys moved in, that number was down to 35,700 pounds.

Those numbers are much higher than current reported releases, but experts say that when the releases were made years ago, less was known about the risk, which means communities impacted by ethylene oxide may have been exposed for decades.

The state’s model shows the risks from the ethylene oxide emissions span a wide area in the Covington area — more than 15 miles from the facility. Data mapping company ESRI estimates more than 18,000 people are impacted there.

In the Covington Mill neighborhood, ethylene oxide emissions exceed the state’s annual safe level by an average of 23 to 34 times. In 2015, the average concentration of ethylene oxide in a neighborhood on the other side of Bard, called Settlers Grove, was 97 times higher than the state’s safe level. That means ethylene oxide in the air could be expected to cause 97 cases of cancer for every 1 million people exposed over the course of their lifetimes.

According to the American Cancer Society, 1 in 3 people will develop cancer over the course of their lifetime and most people will never know exactly what caused it. Some of the risk for cancer can be inherited, through genes. Cancer can also develop because of exposure to something in the environment.

Experts who have studied the issue believe that environmental cancer triggers have been underappreciated.

In 2010, a federal report from the President’s Cancer Panel concluded that “the true burden of environmental induced cancer has been grossly underestimated” and that human exposure to cancer-causing chemicals is widespread in the U.S., where chemicals are untested and “largely unregulated.”

In response to questions from WebMD and Georgia Health News, BD Bard issued a written statement:

“BD cares deeply for our employees and the communities in which we operate. We are an important part of the Covington community and take our responsibility to be a good corporate citizen very seriously. We continue to take all steps necessary to ensure the safe operation of our facilities.”

The company further says that the EPD’s maps are based on computer modeling and not actual air testing.

“Neither Georgia EPD nor U.S. Environmental Protection Agency has asked BD to take any actions as a result of this report, as our ethylene oxide levels . . . are well below all required levels.”

On the other side of the BD plant, in apartments maintained by the Newton County Housing Authority, state regulators predict concentrations of ethylene oxide are 42 times higher than the acceptable limit. Resident Cynthia Newsome was not surprised to learn her air quality could be compromised.

“You just walk outside and your lungs say, ‘Nope!’ ” Newsome says.

Newsome with her and her family’s medicines

Newsome, who is 49, has developed asthma since moving to the unit she rents here. Her daughter and her two grandsons, who live with her, have it also. They require an arsenal of pills and inhalers to manage their breathing problems.  She runs an air purifier  as well as a cheap dehumidifier inside the house, and she has stopped sitting on her front porch because of her health problems.

“I stay sick all the time,” she says. In addition to her breathing problems she says she has symptoms like skin rashes that she attributes to “weird allergies.”

She’d like to move, but three bouts of breast cancer have wiped her out financially. She was first diagnosed at age 29, when she lived 12 miles away from the BD Bard plant at the Salem Glen apartments. That neighborhood is just outside the state’s impact zone for ethylene oxide. She said she has no history of breast cancer in her family and no known risk genes for it.

Many different factors can contribute to the development of cancer and asthma. It would be almost impossible for doctors to pinpoint what led to Cynthia Newsome’s health problems.

Still, it’s rare for a woman to be diagnosed with breast cancer in her 20s or 30s. According to the National Cancer Institute, the chances of a woman being diagnosed with breast cancer between the ages of 30 and 40 are just .4 percent. That translates to about 1 case for every 227 women. (Ann Singley was also diagnosed in her 30s).

Velma Slaton says her daughter always wondered how she got breast cancer. Tests failed to find any genes that would have increased her risk.

Ann Singley (left) and Velma Slaton

“I would have traded my life so she could be here with her family and her kids because my kids were grown. Hers weren’t,” Slaton said.

The year after doctors found Ann’s breast cancer, Velma and her twin sister, both of Covington, were diagnosed with it, too. They survived, but Ann was not so fortunate.

After surgery, chemotherapy, and radiation put the cancer into remission, it returned in 2010. Her bones were riddled with it. Her doctor hoped she would make it to Christmas of 2012, but she didn’t. She passed away on Dec. 10 at home. Her youngest son, Gene, was 8.

“It was a horrible experience. I’ve been alone ever since. I guess I’m afraid to start over because something like that could happen again,” says her husband, Kelly. Ann died the day before the couple’s 21st wedding anniversary.

When told by reporters about the ethylene oxide near his home, he said the information was troubling. He recalled that his birth mother worked at the Bard plant in the 1970s. She died of a brain tumor when he was 3.

“If that’s something that’s going on, if something is causing a problem, they need to stop that particular part of the operation and move it out to unincorporated areas where people won’t be affected by it,” he said.

“If they knew about it, if they knew there was a possibility that it could cause cancer and they allowed it to continue anyway, those people should be punished,” he added.

Correction: An earlier version of this story did not include other factors besides ethylene oxide that contributed to increased risk of cancer in affected census tracts in Georgia. 


Velma Slaton, Breast Cancer Survivor and mother of Ann Singley, Covington.

Kelly Singley, Widower, Covington.

Tony Adams, resident, townhomes in Cobb County.

Karen Hays, Chief, Air Protection Branch, Georgia Department of Natural Resources, Environmental Protection Division, Atlanta.

Richard Peltier, PhD, an associate professor of environmental health sciences, The University of Massachusetts at Amherst, Amherst, Mass.

Margie Donnell, Co-founder, Stop Sterigenics, Willowbrook, Ill.

Cassandra Saffold, resident, townhomes in Cobb County.

John Keller, lives near Sterigenics, Smyrna.

Jen Jordan, Georgia State Senator, District 6, Smyrna.

Rene McLeroy, resident of Covington Mill, Covington.

Cynthia Newsome, resident of Newton County Housing Authority, Covington.

Environmental Protection Agency, Toxics Release Inventory, accessed July 15, 2019

Ethylene Oxide Sterilization Association, Position Statement, September 2018

EPA, Integrated Risk Information System, Ethylene Oxide, July 15, 2019

EPA, National Air Toxics Assessment, Aug. 22, 2018

The Intercept, “A Tale of Two Toxic Cities” by Sharon Lerner, Feb. 24, 2019

Georgia Open Records Act Request to the Georgia Department of Natural Resources, Environmental Protection Division, April 2, 2019

International Agency for Research on Cancer, ethylene oxide monograph, June 2018

University of California at San Francisco, Industry Documents Library, “Toxicology Conference in Galveston,” July 16-18, 1981

Chicago Tribune, “State Finds More Cancer Than Expected Near the Sterigenics Plant,” by Michael Hawthorne, March 29, 2019

ATSDR, “Letter Health Consultation: Sterigenics International, Willowbrook, Illinois,” Aug. 21, 2018

Area Development Magazine, “2018 Top States for Doing Business”

Georgia EPD, “Toxic Impact Assessment Guideline,” accessed July 15, 2019

Sterigenics, “Responses to Georgia Health News”, June 28, 2019

BD, Company Statement, June 2019

American Chemistry Council, Request for Correction, Sept. 25, 2018

Georgia Department of Public Health, Georgia Comprehensive Cancer Registry 2019

ESRI, location intelligence company, 2019 Updated Demographics

National Cancer Institute, SEER breast cancer data, accessed July 2019