DISH — Town officials have released a set of maps showing that some carcinogens and neurotoxins could be drifting a mile or more from compression facilities here — and at levels that exceed the state’s long-term screening limits.

The maps are another component of an air quality study the town commissioned from a private company last year that found 16 toxins at troubling levels near compression and metering facilities.

Researchers plugged data from air samples gathered around Dish into a computer model to see how some of those emissions might disperse throughout the countryside over the course of a year.

Dish spent about $15,000 on the report.

The model is very limited in scope, given the town’s tiny resources, but it does demonstrate problems with the state’s permitting system for oil and gas operations, according to Ramon Alvarez, a senior scientist at the nonprofit Environmental Defense Fund who has research expertise in atmospheric and combustion processes.

Similar to the town of Dish, the fund also has paid for two university studies of air quality data to determine what impact natural gas drilling and production is having on the region’s air quality.

“This [latest] study shows better state oversight of Barnett Shale operations is needed,” Alvarez said.

Because natural gas operators are granted air quality permits by a different set of rules than other big industries, the kind of data the Texas Commission on Environmental Quality, as well as the general public, would expect to get from any other company applying for an air permit simply isn’t available, Alvarez said.

For example, according to the report, the analysis assumed that toxins were coming from a single source, instead of a variety of sources at the site.

While the TCEQ has not released any raw data or infrared camera video of the compression facilities near Dish, similar data and video have been gathered by state inspectors from other compression facilities in the Barnett Shale area. They show emissions from many different kinds of equipment, including gas plants, wellheads, condensate tanks and vent stacks.

That kind of information helps make a more accurate model of the dispersion, Alvarez said. Without it, the public doesn’t have a chance of making informed decisions.

“It’s kind of shoot first and ask questions later,” Alvarez said.

Maps generated by the computer model showed benzene drifting above the state’s permitted level beyond the boundaries of the compression complex and into one Dish neighborhood. The same model showed that carbon disulfide likely goes beyond the boundaries of the study area — in other words, beyond the Dish town limits.

Environmental engineer Kevin Ware of Denton-based KJ Environmental agreed that, while the latest study followed standard protocol, there wasn’t enough data for the kind of emissions modeling that is needed to assess impact on public health.

He estimated that in his work with natural gas operators locally, more than half aren’t employing vapor recovery and other kinds of systems and controls needed to curb emissions.

As he tries to educate operators, Ware said, most are skeptical of the cost and the need to understand emissions. It’s not unexpected, he said, given the evolution of the industry over the past century.

“They tend to move down the road with horse blinders on,” Ware said.

Dish Mayor Calvin Tillman announced last week that the TCEQ will be setting up the kind of permanent ambient air quality monitor in Dish usually installed in major cities. Data from the monitor will be posted online hourly, alongside data from other monitors in the region.

The monitor comes about a month after Tillman told TCEQ managers that he had called in mid-December to report an acrid smell and was bounced around the agency. When it was clear that no state inspectors were coming, Tillman called Wolf Eagle Environmental Engineers and Consultants, which performed the air quality study, to take an emergency sample.

Dish released the report and lab results from the emergency sample last week.

Chloromethane and hydrocarbon levels were higher that December day than in August, according to the report.

Environmental engineer Greg Hawk reviewed the report and said it would help if inspectors could take handheld devices close to the suspected source of the emissions and pinpoint the problem, rather than be limited to canisters at the fence line.

Firefighters could be trained to use handheld devices and determine the level of emergency.

Tillman said he finds the continuous monitoring encouraging, even though the permanent monitors do not detect sulfur compounds in the 50-plus compounds they track.

In Texas, only Houston has extra ambient air quality monitors, because of its many refineries and chemical companies, Alvarez said.

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