Neighbors in the Argyle-Bartonville area want a federal investigation after a chemical traditionally used as a pesticide and gasoline additive started turning up in air samples near natural gas drilling and production sites.
State air tests found levels of 1,2-dibromoethane, or EDB, at least six times since December near three natural gas facilities south of Argyle, according to Texas Commission on Environmental Quality records. The chemical, considered a likely carcinogen, has been banned for many uses in the U.S. since the 1980s and isn't usually associated with oil and gas development.
Members of the Argyle-Bartonville Communities Alliance, a neighborhood activist group, say they have reason to think gas drilling may be to blame in this case. They want a full investigation, regardless of who's at fault.
"TCEQ has told us they're not going to do anything because it's historical contamination," said Susan Knoll, a Bartonville resident and alliance member. "I am hoping that they clean up the EDB wherever the source is coming from so that we can breathe clean air."
State environmental regulators say they've studied the data and determined there's no threat to public health. In fact, they say they can't even be sure EDB was detected, despite the test results.
The results "may be due to the sampling and analytical procedure itself instead of actually being present in the ambient air," said Terry Clawson, a TCEQ spokesman, in an e-mail.
EDB is a colorless liquid known by several names, including ethylene dibromide. It was commonly used to kill pests and fungus on crops and soil and as an additive in leaded gasoline, but federal regulations have limited its applications.
Today, it's used mostly to treat logs for termites and beetles, to control moths in beehives and as a preparation for dyes and waxes, according to the Agency for Toxic Substances and Disease Registry, a federal public health agency.
People can be exposed to EDB by drinking contaminated water, breathing polluted air or touching tainted soil. Exposure can affect the brain, damage skin and sperm and cause death at high enough levels.
The readings in the Argyle-Bartonville area were all below the state's short-term exposure level of 0.5 parts per billion. But four of the six readings exceeded the state's long-term exposure level of 0.05 ppb, records show.
Three of those readings occurred at the Frenchtown pad site in Bartonville owned by Dallas-based Gulftex Operating Inc. in April and May, when neighbors say the company was hydraulic fracturing and flaring a well. The other reading occurred in May near a gas compressor facility run by Williams Production Co. at Frenchtown and Jeter roads near Argyle.
The findings alarmed Knoll and other members of the neighborhood alliance, a group of about 10 active members who have fought the placement of gas infrastructure near homes and schools. Knoll and her husband, Michael Knoll, are also one of several area families suing a group of energy companies, including Gulftex and Williams, over claims that their operations polluted the environment and lowered their property values, according to court records.
Denton Record-Chronicle reporter Peggy Heinkel-Wolfe lives in the area and is a plaintiff in a separate lawsuit against the companies.
Neighbors asked the state to do something about the EDB readings, but a TCEQ investigator blamed the problem on historical contamination and said there was nothing he could do, Susan Knoll said.
The alliance challenged that finding, saying privately funded testing of air, water and soil at nearby properties last year showed no traces of the chemical.
Further, a Gulftex representative told the Bartonville Town Council in December that the company was using a biocide in its hydraulic fracturing operations that was on the Environmental Protection Agency's docket to be banned in commercial uses, according to an audio recording of the meeting provided by the neighborhood group.
The representative, Jerah Hutchins, said the company would find an alternative to the biocide for the Frenchtown site.
Gulftex officials did not respond to written questions from the Record-Chronicle.
The person who answered the phone at the company's Dallas office referred questions to Dick O'Donnell of Frontier Asset Management, who said he wasn't authorized to speak for Gulftex.
Hutchins was no longer with the company.
Williams spokesman Kelly Swan said he could not explain why EDB would be present in air samples near his company's compressor facility.
"It's not something we use," Swan said. "It's not something we handle. It's not something that's associated with oil and gas production."
Swan pointed to TCEQ's finding that no chemicals were detected at levels that exceeded the state's short-term exposure limits.
Theoretically, possible sources of EDB at an oil and gas production facility could include vehicular traffic and compressor engines, said Clawson, the TCEQ spokesman.
"However, because of the reduced usage of leaded gasoline in vehicles and the fact that testing for EDB emissions from compressor engines has only measured trace amounts in some instances, it is unlikely that oil and gas facilities are sources of the EDB observed in air in the Barnett Shale region," Clawson said.
TCEQ officials were unaware of discussions between Gulftex and Bartonville about a banned biocide, Clawson said.
So what accounts for the readings?
Clawson couldn't say for sure. He said state officials aren't even sure EDB was present in the samples.
The levels recorded in the Argyle-Bartonville area are too low for laboratory instruments to accurately measure, Clawson said. In this case, no readings of EDB below 0.4 ppb can be viewed with certainty, he said.
The chemical turns up in air tests across Texas, but usually below levels that allow accurate measurement, he said. EDB was reported in about 2 percent of the 5,101 samples collected in the Barnett Shale region since 2003, and none of the concentrations were high enough to cause health problems, Clawson said.
"Based on monitoring data and what we know about the levels that actually cause health effects, we do not believe EDB poses a short-term or a long-term health concern [for the region]," he said.
Susan Knoll, the alliance member, expressed disbelief over Clawson's explanation of the test results.
"So their scientific testing is not very scientific?" Knoll said. "If what they're doing is not accurate, then who the hell is supposed to protect us from what's happening in our community?"
The alliance has called for an EPA investigation.
EPA spokesman Joe Hubbard said the agency is working with TCEQ to address the issue.
"EPA will continue to work with our state partner to protect public health which may include … data reviews and audits to ensure accuracy and compliance," Hubbard said in an e-mail.
The agency is currently unaware of any link between EDB and oil and gas production, Hubbard said.
LOWELL BROWN can be reached at 940-566-6882. His e-mail address is email@example.com.