The Eagle Ford Shale's economic impact has been felt across the state, particularly in South Texas, but a recent study shows that it may be at a cost to the environment.

In early April 2014, the Alamo Area Council of Governments (AACOG), released data correlating rising Eagle Ford production with an increase in air pollutants.

By 2018, AACOG predicts that unhealthy levels of ozone could have an impact on South Texas as volatile organic compounds (VOCs) rise as much as 281% over 2012 levels. Nitrogen Oxide (NOx) levels are also expected to rise by 2018, but not as drastically. Ground level ozone (i.e. smog) is produced when VOCs and NOx react to sunlight, especially during the summer.

The majority of NOx emissions in 2012 were emitted by drilling rigs and well hydraulic pump engines (47%). By 2018, these sources are expected to account for only 9% of these emissions as engines are replaced with models that meet Tier 4 standards*. Compressors and mid-stream sources accounted for 39% of NOx emissions in 2012, but this number is expected to rise through 2018.

The report mentioned the San Antonio area, which is the largest city in the Eagle Ford's wake, has recorded ozone violations since August 2012 in excess of the EPA's 2008 ozone standard. That puts the region on the brink of a potential non-attainment designation, which could result in federally mandated Clean Air Act sanctions. Beyond the San Antonio area, the study looked at 25-core Eagle Ford counties, including Karnes, Webb, DeWitt and Dimmit Counties. According to the report, all 25 Eagle Ford counties are currently in attainment of all air quality regulatory standards.

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*Tier 4 is comprised of two significant stages for different engine horsepower ratings. The first stage is a significant reduction of particulate matter (PM) and NOx , and the second stage is a further but substantial reduction of NOx only emissions.