FORT WORTH -- A preliminary report that portrayed a natural-gas well just north of downtown as having elevated levels of emissions was inaccurate, city officials said Monday.
A calculation error caused the well on Mercado Drive to show levels that exceeded the threshold for pollutants.
Eastern Research Group, the company conducting the study on the effects of drilling on air quality, "has informed the city that the elevated levels they first reported at the Mercado site was inaccurate," said Jason Lamers, a city spokesman.
"The actual level of emissions at that site is under half a ton a year."
The report, which was released two weeks ago, showed levels at 103 tons a year.
It also showed that a site in west Fort Worth off Interstate 30 west of Loop 820 exceeded emissions standards. No error was found in calculations for that well.
None of the concentrations were above short-term health benchmarks and didn't necessarily reflect a long-term public health threat.
Nonetheless, the concentrations were more than 25 tons per year for "volatile organic compounds," the threshold set for the lowest level permit granted to drill.
Lamers reiterated that the results are preliminary and subject to change. The final results of the study are due in late June.
"There's still a great deal of work ahead before ERG delivers its final report," Lamers said, echoing the city's stance when the report was initially released.
The calculation error was found in the spreadsheet used to calculate the emissions, according to a city staff report.
The staff report stated that "ERG has taken measures to put in place more rigorous data control and review processes" to ensure the integrity of the findings.
Some, such as the North Central Texas Communities Alliance, have already challenged the methodology of the study.
The Texas Commission on Environmental Quality visited the sites after the initial findings were released, according to the staff report. The state agency is reviewing data and observing operating conditions at the sites and will issue a "compliance report" in April.
It is unclear whether that report will include the Mercado site in light of ERG's revelations, Lamers said.
ERG's study has been promoted as an unprecedented look at how drilling in the Barnett Shale gas field affects air quality. Never before has natural gas been explored to this degree in an urban setting.
City officials, including Mayor Mike Moncrief, said the initial findings two weeks ago showed nothing that "raised immediate concern."
Said Lamers: "It's important to understand that none of these well sites have been identified as a 'problem' per se, only that elevated levels of emissions were reportedly found at those two locations."
John Henry, 817-390-7539