DISH — For a mid-August day that Mayor Calvin Tillman said, smell-wise, “was not that bad,” a city-commissioned air quality study detected a host of volatile organic chemicals, several in concentrations greater than allowable limits.

Residents have complained for years about foul-smelling air around the natural gas production facilities on Tim Donald and Strader roads, both to the industry and to regulators. The gas-gathering pipelines for many Barnett Shale production companies converge in that area, with Atmos, Crosstex, Chesapeake, Enbridge and Energy Transfer Partners operating either compression or metering facilities there, or both.

Atmos Energy moved and altered its facilities that add mercaptan — the compound that makes gas leaks readily detectable — in the past year to address those complaints, spokesman Ray Granado said in a prepared statement. In addition, the company’s other equipment, including a compressor that has a catalytic converter and a condensate tank, is small enough that Atmos does not believe it is creating an emissions problem.

The other energy companies with compression facilities near Dish, as well as the Texas Pipeline Association, did not return calls for comment.

But among the sulfur-smelling compounds, the study found carbon disulfide and carbonyl sulfide, potentially dangerous compounds associated with oil and gas production, among those exceeding state limits.

“They can overtake you and make people very sick,” said Wilma Subra, a Louisiana-based chemist who received a MacArthur Fellowship “genius grant” in 1999 for her environmental work.

According to documents obtained through an open records request, Wolf Eagle Environmental Engineers and Consultants also found the neurotoxins methyl pyridine and dimethyl pyridine above state limits.

The Flower Mound-based company placed seven canisters in areas around town, measuring the ambient air quality for a 24-hour period. They also detected three of the “BTEX” carcinogens — benzene, toluene and xylene — at all seven locations, with at least one of the compounds above state limits at three locations.

The cumulative effect of those airborne compounds on people and other living things in and around Dish is not known, according to Alisa Rich of Wolf Eagle.

An Environmental Protection Agency risk assessment could answer that question, she said.

“That’s a numerical evaluation that identifies whether, in combination all together, the compounds exceed the risk for this area,” Rich said.

Her company is mapping the readings from the seven sample sites as a final step in its analysis, Rich said.

Energy companies have built metering stations and multiple compression engines, varying from 1,231 to 3,500 horsepower. In addition to possible emissions from that equipment, other support equipment there, including condensate tanks, can contribute to emissions, according to Rich’s report.

During the study, Rich interviewed residents and learned that some experienced farmers were having trouble with their animals, including young ones that fall asleep and never wake up, with no external signs of trauma.

“You hear about more things like that in rural areas,” Rich said. “In urban areas, you don’t have the larger animals. You’re not breeding animals and seeing the changes in healthy animals versus those that are sick all the time.”

One collection site was near a horse farm, she said. The breeder had a reliable breeding mare that birthed a sickly foal that eventually died. After 2 1/2 years, the breeder also gave up on a gelding that had health and behavior problems. He gave it away, only to learn later that the animal is now healthy.

Town leaders will discuss the study’s results Monday, during the Town Council’s regular meeting, and decide what needs to be done next. The town has asked for help for years, from both the industry and state regulators, Tillman said.

In response to the town’s complaints, industry officials commissioned a study of the area. Colorado-based Apogee Scientific conducted a leak survey in a 3.5-square-mile area in and around Dish in May. The survey found no concentrations of methane that would indicate a leak, according to the report.

After that study, Dish town leaders voted in May to spend $10,000 — about one-sixth of this tiny town’s annual budget — for an independent study of local facilities.

After reviewing the results, members of the Oil and Gas Accountability Project encouraged town leaders to post a health survey on the town’s Web site, www.townofdish.com, to gather information from current and former residents, Tillman said.

Subra, who is a member of the Oil and Gas Accountability Project’s board of directors, said that once natural gas is collected from a well, sour distillates and other impurities are removed a little farther down the pipeline. The gas also must be dried and prepared for consumer use.

Emissions can occur where the impurities are removed, at compressor sites, metering stations and anywhere along a pipeline.

Pipeline companies can do two things to lower toxic emissions, but both cost money, Subra said.

“They can install scrubbers to eliminate contaminants before they are released,” Subra said. “They can also put in vapor recovery systems for carbon absorption.”

Both operations would keep most toxic releases out of the air, but once collected, the material requires proper disposal. Neither would take care of fugitive emissions — those little leaks that occur along pipeline joints and seams, Subra said.

PEGGY HEINKEL-WOLFE can be reached at 940-566-6881. Her e-mail address is pheinkel-wolfe@dentonrc.com.

If You Go

What: Dish town hall meeting

Topic: Ambient air quality study

When: 7 p.m. Monday

Where: Dish Town Hall, 5413 Tim Donald Road