A new cancer study in Flower Mound re-affirmed earlier statistics showing a slightly higher rate of breast cancer among women but no other cancer-related anomalies — the same information released in previous studies of the area by the Texas State Department of Health Services.
The report, which studied a broader range of cancer statistics than in previous reviews in 2010 and 2011, indicated no other cancers were significantly elevated beyond expected norms.
The latest report released Wednesday from the state follows concerns among residents that they are being exposed to carcinogens from gas wells and compressor stations within the town limits.
“I understand people are concerned about gas drilling,” said Flower Mound Mayor Tom Hayden. “What are we going to do? We’ve already done it. We have been more proactive in testing than any other community in Texas.”
New natural gas drilling first began within town limits in 1997 with the town creating its first gas drilling-related ordinance in 2003.
In 2011, the town enacted a 92-page ordinance which established a 1,500-foot setback from homes, schools, businesses, parks and other properties for any gas wells drilled within the town limits. And, since then, no new permits have been submitted, Hayden said.
The 2014 study employed updated population numbers from 2002 to 2011, a 95 percent confidence rating as well as broadened the types of cancers reviewed. Flower Mound’s population currently sits just under 70,000.
The study is the third by the state agency after residents reported concerns that possible exposure to benzene and other contaminants related to natural gas drilling and hydraulic fracturing in the Barnett Shale was causing higher rates of cancer among children and adults in Flower Mound.
The first study in March 2010 investigated cancer incidence in zip codes 75022 and 75028 with a second review following in March 2011.
An article published earlier this year in the Virginia Environmental Law Journal and written by Rachael Rawlins, a faculty fellow with the Center for Sustainable Development with the University of Texas, renewed public concern in Flower Mound, prompting officials to conduct a new study using updated information and an industry-accepted confidence rating of 95 percent instead of the former 99 percent used in the previous studies.
Female breast cancer was the only type higher than expected and considered statistically significant, which was consistent with earlier findings, according to the report.
Given residents’ concerns, the Texas State Department of Health Services indicated it plans to continue monitoring cancer incidences in Flower Mound.
In the report, officials cited better access to medical care and changing cancer rates over a period of time as one reason for the increase. In addition, the differences could be due to common lifestyle factors, environmental or occupational exposures, random chance, zip code boundary changes or changes in diagnostic methods and case reporting.
In Texas, cancer is the second leading cause of death, accounting for 22.1 percent of all deaths. The leading cause of death is heart disease.
“Relative to other risk factors, the chance of a person developing cancer as a result of exposure to an environmental contaminant is small. The Harvard Center for Cancer Prevention estimates 5 percent of cancer deaths are due to occupational factors, 2 percent to environmental pollution, and 2 percent to ionizing/ultraviolet radiation,” according to the study.
Exposure to a carcinogen and the development of cancer can span a period of 10 to 40 years, making investigations into cancer clusters challenging, according to the report. The changing population, as people move in and out of an area under review, also adds complexity to the study, state officials reported.
“It becomes more difficult to tell whether living in the area is associated with an excess of cancers because residential history is not tracked,” officials noted in the study.
From 2002 to 2011 in zip code 75022, a total of 131 breast cancer incidents were reported, above the 101 expected for the region — an estimated 30 percent difference. In zip code 75028, a total of 238 breast cancer reports were noted, about 18 percent above the estimated 202.3 expected for the population.
For men in zip code 75022, a total of five acute lymphocytic leukemia cases were reported, above the expected 1.8; in women, three cases of the same cancer were noted, slightly above the 1.5 expected. Other slight anomalies for women included five cases of acute myeloid leukemia, up from 2.2 expected and 15 reports of non-hodgkin lymphoma, up from the 11.3 expected cases. In zip code 75028, cancer reports were at or lower than expected norms for men.
For women, there were slight elevations in acute lymphocytic leukemia and acute myeloid leukemia. All other cancer reports were at or below expected levels.
For children, observed cases of lymphoid leukemia were slightly higher for both boys and girls in zip code 75022. Four cases for boys were observed, up from the expected 1.3; three cases for girls were reported, up from the 1.1 expected.
In zip code 75028, two cases of acute myeloid leukemia in boys were reported, up from the expected 0.6 norm. For girls, four cases of lymphoid leukemia were reported, up from the expected two cases.
In her report published earlier this year, Rawlins took state officials to task for selecting a 99 confidence rating instead of a 95 rating, which she called an industry norm used by the agency when studying emission for an El Paso metal smelter.
“A study based on this level of certainty would not conclude that elevated cancer rates were significant unless it was 99 percent sure that the findings were not due to chance, allowing only a one in hundred chance that the conclusion could be in error,” she wrote.
Rawlins also stated that from her review of information in Flower Mound, the breast cancer rate more than tripled from 1998 to 2008 from 13 cases per year to 45 cases per year at a time when the town’s population rose 41 percent.
Adam Briggle, assistant professor of philosophy at the University of North Texas, has served on a Denton committee to review fracking concerns in the northern Denton County community and has studied the issue extensively.
“It highlights to me the difficulty in pinpointing cause and effect,” he said, adding that unlike the state of New York, which is doing studies before allowing drilling, Texas is drilling and then studying possible effects.
As more time passes and people are exposed, the outcomes could change, he said.
“We chose our strategy,” he said. “That’s the reality in Texas.”
Hayden said while the report shows Flower Mound does not have cancer clusters, officials are committed to monitoring air quality and working with the state to continue studying future cancer rates.
Flower Mound began quarterly air monitoring in 2010 to assess ambient air conditions adjacent to gas wells and other areas around town, according to a news release. The following year, town officials began monthly air monitoring. In 2014, the town council approved additional monitoring efforts including upwind and downwind pad site monitoring as well as monitoring near equipment and pad sites to access potential issues with production equipment. Air quality reports are available on the town’s website at www.flower-mound.com/airquality.
“In Flower Mound, you know what is in your air,” Hayden said.