Panelists at thyroid cancer/coal ash community meeting seek to educate, reassure public

Posted at 11:36 AM on May 11, 2019


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State Reps. John Fraley and Rena Turner, State Sen. Vickie Sawyer, and Iredell County Board of Commissioners Chairman James Mallory listen as experts detail thyroid cancer research and data.


Iredell County Board of Commissioners Chairman James Mallory welcomed about 100 people to a community meeting on thyroid cancer and structural coal ash landfills on Thursday night, noting that state and county officials are using a scientific process and data collection in a fact-finding mission.

Mallory added, however, that answers often lead to more questions. “We don’t know what we don’t know,” he said.

Mallory also thanked tenacious “mama bear” Susan Wind for her effort to draw attention to the elevated thyroid cancer occurrences in the area. “We would not be here without her. She is an example of one person really making a difference,” he said.

Wind saw a problem, used her investigative experience, and shined a light on the issue, which helped invigorate ongoing research and examination of the issue.

Mallory also thanked State Reps. John Fraley and Rena Turner and Sen. Vickie Sawyer for being “effective, tireless advocates” who stayed in frequent contact with state agencies and other legislators to foster a sense of urgency and find answers to the thyroid cancer issue in southern Iredell County.

Fraley, who served as moderator for much of the event, also thanked Iredell Health Department Director Jane Hinson, Environmental Health Director Brady Freeman, and Deputy County Manager Susan Robertson for their commitment to find answers.

The speakers featured an array of state experts, including Dr. Elizabeth Tilson, state health director; Dr. Zack Moore, state epidemiologist with the N.C. Department of Health and Human Services (DHHS); and Shelia Holman, assistant secretary for the environment with the N.C. Department of Environmental Quality (DEQ).

Other panelists were Duke University professors Dr. Heather Stapleton, Dr. Avner Vengosh and Dr. Kate Hoffman and Dr. Andy Olshan, a Univeristy of North Carolina cancer epidemiologist from the Lineberger Cancer Center.

Local physician Michelle Stowe Ong, a healthy integrative aging specialist, was also on the panel.

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Dr. Elizabeth Tilson, state health director, talks during Thursday night's community meeting.


Tilson explained that a collaboration between state agencies, academic research partners, and local health departments is working to discover as much information as possible about the thyroid cancer issue.

She explained that the state relies on its academic partners when the answer is not clear. They serve as the research arm to help agencies find answers.

The N.C. Central Cancer Registry (CCR) is the sole repository of complete cancer incidence data for the state. The registry collects data from hospitals, doctors, labs, and death certificates, explained Tilson. CCR staff then perform statewide analysis on 27 major cancer types and a county-level analysis of the five most common types (lung, breast, prostate, colorectal, and melanoma).

The registry shares this information with research partners to further medical inquiry.

DHHS is also working with doctors to ensure complete thyroid cancer data is sent to the state cancer registry.


There are several other limitations to consider when interpreting this DHHS information. Most importantly, people should realize this is not a research study.

Since the CCR does not collect detailed information about potential environmental exposures, community members can draw no conclusions about the association between any environmental contaminant and thyroid cancer.

Additionally, ionizing radiation is the only confirmed environmental exposure that has been clearly linked to thyroid cancer.

Also, CCR data are based on the patient’s address at the time of diagnosis; the registry does not collect or track patients’ residence history or occupations.

Also, many years can pass between exposure to a cancer-causing substance and diagnosis with cancer, making it difficult to determine whether residence in the area is associated with an excess of PTC diagnoses. In an interview after the meeting, Fraley said researchers believe five to eight years pass between exposure and cancer development.

Most importantly for community members to note is that few investigations of increased cancer rates in a local area result in identifying a specific environmental cause.

In a recent review of over 400 U.S. cancer cluster investigations, only three investigations found a link to an environmental risk factor and only one of those was considered a cause of the cancer cluster.

Similarly, the U.S. Centers for Disease Control reports that, even after thorough investigation of a potential cancer cluster, typically no cause is identified.


In February 2018, the DHHS, utilizing the CCR data, began analysis of thyroid cancer rates in the 28115 and 28117 ZIP codes following requests from Iredell County residents and the county health department.

In March, DHHS, under the direction of Dr. Moore and CCR Director Chandrika Rao, began further analysis of CCR data, started compiling and summarizing the scientific literature about trends in thyroid cancer diagnoses and known possible contaminants associated with thyroid cancer, and began working with partner agencies to identify potential sources of these contaminants in Iredell County.

DHHS included only one type (papillary thyroid cancer) in its investigation since this type is not hereditary and accounts for 85 percent of diagnoses in North Carolina and 88 percent of diagnoses in Iredell County during the period of 1995-2016. This type accounted for most of the recent increase in thyroid cancer diagnoses.

The age-adjusted rate for all new thyroid cancer cases in North Carolina during this 2011-2015 period was 12.6 cases per 100,000. PTC rates were higher than North Carolina's in 38 states and lower in 11.

Nationwide, 94 counties (3 percent of 3,142 total counties) had age-adjusted PTC rates greater than or equal to 23.0 cases per 100,000 persons during this period, with the highest reported rate at 36.5 cases per 100,000 persons.

The average Iredell County age at thyroid cancer diagnosis was similar to the average statewide and nationally except in southwestern Iredell, where the average age at diagnosis was slightly higher. Southwestern Iredell also had a higher percentage of male thyroid cancer cases than the state rate.

White women who are age 50 are the most commonly diagnosed with PTC.

Thyroid cancer rates have been increasing statewide, nationally, and globally in the past ten years. During 2011-2015, thyroid cancer was the 13th most commonly diagnosed cancer in the United States and the 14th most comen in North Carolina.

The CCR reported that the new thyroid cancer diagnosis rate in Iredell County was higher than the state rate during 2005-2016, especially in the southern part of the county.

Between 1995-2016, the rate of age-adjusted thyroid cancer diagnoses in Iredell County increased. Until 2004, the rates were the same as the state average, but during the 2005-2009 period, southwestern Iredell had a higher age-adjusted rates (34.6 cases per 100,000 persons).

In the most recent five-year period (2012-2016) for which data are available, the rate of papillary thyroid cancer (PTC) diagnoses in North Carolina was 11.6 percent (with a a 95 percent confidence interval (CI) of 11.3 to 11.9 cases per 100,000 persons). However, the rate in Iredell County was 21.8 (with a 95 percent Cl of 18.7 to 25.2 cases per 100,000 persons).

However, Tilson noted that thyroid cancer rates seem to be declining in the area more recently.

Eleven other counties in North Carolina also had significantly higher PTC diagnosis rates during this time period: Brunswick, Cabarrus, Carteret, Catawba, Durham, New Hanover, Onslow, Pender, Randolph, Rowan and Watauga.

In an interview after the meeting, Fraley said the collaboratory of researchers and DHHS are “drilling down the data in these 11 counties” to look for any commonalities. Any links would trigger a deeper dive into that data in this ongoing research effort.

DHHS wants to reassure the community that having a higher than expected rate of thyroid cancer diagnoses does not necessarily mean that people living in the community now are at a higher risk of developing cancer.

This investigation also does not mean that there will be a common cause identified, such as something in the environment, since PTC can be attributed to many recognized and unrecognized risk factors (family history of thyroid cancer, some genetic diseases, a low iodine diet, history of benign breast disease, obesity, exposure to ionizing radiation from medical tests or treatment, and older age at first menstruation).

These factors were not accounted for in this investigation and can contribute to geographic variation PTC occurrence.

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Dr. Heather Stapleton discusses thryroid cancer research at the community meeting.


DHHS has shared CCR data for all cancer types with Duke University researchers, whose results they hope will generate hypotheses about environmental exposures of interest and precipitate further research studies.

Duke’s Dr. Stapleton noted that unknown latency periods, variables in different populations, and multiple environmental exposures make cancer study complicated. Changes in doctors’ diagnostic procedures and frequency of screenings also affect PTC discovery rates.

She noted that the Wilmington area also has high PTC rates, though each area’s increase may be from different variables.

Duke researchers found in a survey of 43 Iredell County PTC patients who responded that 80 percent were diagnosed since 2014 and lived in the county for an average of eight years. They do not share the same drinking water source. Some had prior thyroid conditions but no other major health problems.

Water does not seem to be a factor for the study group since no contaminants were found in their water sources other than zinc, lead, and copper related to home plumbing pipes, not water sources.

Researchers are also looking at soil samples to see if coal ash is present and possibly mixing with soil, resulting in potentially increased radium nuclide levels.

Stapleton concluded by saying that “we need more time and research to understand if environmental exposures are playing a role in thyroid cancer rates in Mooresville.”


Dr. Moore said the reasons for higher PTC rates in southern Iredell County are not known. Many factors can contribute to local and regional rate differences, including population, medical care, and screening changes or differences in environmental exposures.

Ionizing radiation is the only confirmed environmental exposure that has been clearly linked to thyroid cancer. The community can be somewhat reassured since DHHS review found no evidence of increased exposure to radiation, based on routine monitoring, around the McGuire Nuclear Station during the past for decades.

No community-level exposures to radiation were identified.

During 1998-2017, no radionuclide samples (radioactive iodine in surface water and cow’s milk and tritium in surface waters) were measured greater than the investigative action level at McGuire.

Furthermore, the DHHS Radiation Protection Section reported that no radionuclides have been detected in surface waters, air, or cow's milk beyond investigational limits around McGuire Nuclear Site in the past 40 years.

During this investigation, DHHS has also heard concerns from the community about the possible contribution of other chemicals to increased PTC incidence, particularly related to coal ash.

In response, DHHS examined the research to locate possible links between coal ash and thyroid cancer. Although coal ash can contain radionuclides, no published studies support an association between coal ash exposure and thyroid cancer.

No specific chemicals are known to cause thyroid cancer.

Although scientific research identifies several chemicals (flame retardants, bezene, nitrates, malathion, atrazine, solvents used in shoe manufacturing, formaldehyde, polybrominated ethers, tris phosphate, biocides, and 2,3,7,8-tetrachlorodibenzo-p-dioxin) that may have an association with thyroid cancer, only a comprehensive research study can determine whether exposure to any of these factors actually directly links to PTC rates in a specific area.

The word “association” means that a link between exposure to the environmental contaminant and thyroid cancer occurred in at least one study. However, an association does not confirm exposure contributed to cancer development.

DEQ’s Division of Water Quality conducted a review of historical monitoring data from 38 community and non-transient non-community (NTNC) public water systems in southern Iredell (28115 and 28117) to determine whether long-term exposure to any of these chemicals occurred at concentrations above existing regulator/levels. Thirty-one of the 38 systems are community water systems monitored for radionuclides.

They found that in 2010, one facility had a water sample with radionuclide exceedances, one had nine exceedances between 2003-2005, and one had 21 samples from 2000-2013 with exceedances.

The Division of Air Quality also reviewed air emissions of 19 facilities with records in those ZIP codes and found 10 of 19 emit two chemicals (benzene and formaldehyde) that have potential to increase thyroid cancer risk. Both are common environmental contaminants emitted from many sources.

The Division of Waste Management’s examination of records revealed that benzene was detected at one inactive hazardous site and at one pre-regulatory landfill. The Underground Storage Tank Program detected 145 incidents since 1990; 24 incidents had benzene levels above the regulatory groundwater level and remain open cleanups.


Dr. Tilson noted that the signs and symptoms of thyroid cancer include a lump or swelling in the neck, trouble breathing or swallowing, pain when swallowing, hoarseness or other voice changes that do not go away, and a constant cough that is not due to a cold. If you experience these signs and symptoms, see your doctor.

The United States Preventive Services Task Force and the American Cancer Society do not recommend thyroid cancer screening for people who do not have any signs and symptoms.

Though DHHS does not have enough information to recommend any specific actions to lower thyroid cancer risk, the agency does recommend that private well water owners routinely test their water according to DHHS recommendations to protect themselves and their families from other health effects.

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DEQ Assistant Secretary Holman discusses efforts to regulate coal ash.


DEQ Assistant Secretary Holman noted that coal ash in the state exists in impoundments (which are no longer allowed in North Carolina), lined landfills (with a soil cover and groundwater monitoring), and in compacted structural fill on construction sites (parking lots, roads, sidewalks, etc.)

Holman noted regulations have recently tightened with passage of the N.C. Coal Ash Management Act (CAMA) in 2014.

Duke Energy’s Marshall Steam Station has one 394-acre coal ash impoundment holding almost 17 million tons of ash.

Under CAMA rules, Duke Energy must excavate and dispose of the Marshall coal ash site in a lined landfill, close it with a cap-in-place system, or close it under the federal coal combustion residuals rules.

DEQ chose the excavation and disposal option for Marshall, the more protective option to guard against groundwater contamination. Duke is currently appealing this decision in court for Marshall and five other coal ash sites.

The agency also continues to monitor a construction area near Lake Norman High School where a lined site containing coal ash was accidentally disturbed. The problem is currently being remediated.

In response to a question about the emissions from the Marshall smokestacks, Holman said all coal plants in N.C. “generally have state-of-the-art quality controls on them, controlling for sulfur dioxide, nitrogen dioxide, and many of the heavy metals.”

“The EPA has issued several regulations in recent years that require controls of air toxins in addition.”

“I would also say that those constituents are monitored continuously by equipment in the stacks. The emissions coming out of those facilities today are much cleaner than 10 years ago when the controls were put on," she said. “We can point to the data of the actual emissions.”


In answer to an audience question, Dr. Stapleton revealed that Duke’s test results so far have indicated high levels of radon in the homes tested in this area. Radon exposure is associated with development of lung cancer, particularly in smokers.

Any association with PTC is another area Duke researchers are looking at.

N.C. Radon Program Coordinator Phillip Gibson said that any home, whether with a crawl space or concrete foundation, is susceptible to radon gas. He urges all residents to get a radon test kit. This includes mobile home owners and those in multi-floor apartment buildings.

Remediation includes properly installed plastic lining (sealed with 12 inch overlap) in crawl spaces or the installation of relatively inexpensive fans to circulate the air.

Free test kits are available at the Government Center South (610 Center Avenue) in Mooresville (2nd floor), Building Standards Department (349 N Center Street, Statesville), or the Iredell County Cooperative Extension (444 Bristol Road, Statesville).

Visit for more information.


Fraley, Sawyer and Turner, as well as state officials at DHHS and other departments, are all committed to continued thorough investigation and research into these area health concerns. DHHS tracks cancers to the county and sub-county level to monitor citizens’ health and possible areas of concern.

Fraley believes the next steps should involve taking a look at any possible soil and air problems that might exist since studies conducted so far seem to rule out groundwater or well water issues.

He also supports the continuation of research by Duke University, Virginia Tech, and UNC in cooperation with DHHS and the monitoring of scientific journals on thyroid cancer trends and research worldwide.

Fraley is particularly interested in the N.C. Thyroid Cancer Research Advisory Panel meeting on Monday, May 14, at UNC. This group of national experts will review past research and make recommendations for additional research areas to seek new evidence that might explain the increased thyroid cancer rates in North Carolina.

The panel includes Dr. Olshan, Dr. Stapleton, Dr. Cari Kitahara of the National Cancer Institute, and Dr. Louise Davies of the Geisel School of Medicine at Dartmouth College.

This panel will accept public comments through May 31 at For more information on the panel, visit online

The health and well-being of all North Carolinians is the highest priority of the N.C. Department Health and Human Services, and the concerns raised by the citizens and leaders of Iredell County have been heard by state and local officials.

DHHS, along with other organizations, is working hard to better understand the higher-than-expected rate of thyroid cancer diagnoses in parts of Iredell County and will continue to partner and collaborate with citizens, the Iredell County Health Department, and other local officials and researchers to provide accurate, useful health information.

Dr. Moore said that DHHS will continue to monitor geographic anomalies in the PTC occurrence and is developing plans to specifically examine its occurrence in other N.C. areas with incidence rates above the state average.

The department will also will continue working with hospitals and physicians to confirm that all cases of thyroid cancer are reported to the cancer registry. It will also continue to provide data to researchers and agencies working to investigate potential causes for PTC in Iredell and across the state.

The department is also looking at CDC's county-level data and consulting with academic and federal partners to explore possible collaborations in future investigations and research.


For more information about the North Carolina Central Cancer Registry, visit https://schs.dph.ncdhhs.sov/units/ccr/. For more information on thyroid cancer visit

For frequently asked questions on thyroid cancer in Iredell County, visit https;//

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