Appalachian Basin

Data Show Public Health Impacts from Natural Gas Production Overstated

New York State Governor Andrew Cuomo received a letter on October 5, 2011 from a group of 250 advocates urging him to delay approval of the state’s draft SGEIS until a comprehensive Health Impact Assessment is completed on the process of extracting natural gas from shale .  This concern was based on an assertion that “there is a growing body of evidence on health impacts from industrial gas development.” The letter to the governor claimed that, in several states across the country, “cases have been documented of worsening health among residents living in proximity to gas wells and infrastructure.” Our research has found that more than 70 of these individuals are not medical professionals and over 60 percent reside in areas outside the Marcellus Shale region.

Qualification and geography aside, a closer look at the actual data and available health statistics found in areas where natural gas development has taken (or is taking) place on a large scale suggest the assertions put forth by those who oppose energy exploration on the basis of health concerns are largely without merit.

Our research was focused on two areas.  First, we examined the health statistics of the metropolitan Fort Worth area, home of the prolific Barnett Shale, where more than 16,000 natural gas wells have been developed over the past decade.  According to the Powell Shale Digest, there were 15,675 producing wells as of January, 2011 and about 75 wells have been drilled every month in 2011.  Certainly, if these impacts would be found anywhere on a longitudinal basis, it would be there.

While there have been a few claims of worsening health conditions among a handful of individuals in these areas, the data depict quite a different story for the broader community in these areas. In particular, we  studied the health trends and trajectory of the North Texas county of Denton —  epicenter of Barnett shale development in the state.  What did we find? Well, for starters, even as natural gas development expanded significantly in the area over the past several years, key indicators of health improved across every major category during those times.

Does Natural Gas Lead to Public Health Issues? An In-Depth Look at Health Statistics In the Barnett Shale

Barnett Shale Footprint

The Barnett Shale is a large natural gas reserve encompassing more than 5,000 square miles in North Central Texas including the Dallas-Fort Worth metropolitan area. According to reports, recent natural gas development began when Mitchell Energy developed its first well in 1981. By the late 1990s, Mitchell began using hydraulic fracturing methods to produce the gas trapped underground in shale deposits.  In 2002, fracturing and horizontal drilling were combined to extract greater quantities of natural gas which led to a significant increase in production.  The Barnett Shale is located in the 4th largest Metropolitan Statistical Area in the United States and has already produced more than ten trillion cubic feet of natural gas, according to the Powell Digest.  As one of our nation’s largest metropolitian areas, with a high concentration of gas wells being developed, north-central Texas makes for a strong case study for potential public health impacts from natural gas development.

When a public health official or researcher is attempting to understand the general health of a community, one of the first places he or she looks is the Community Health Status Indicators (CHSI) collected by the Department of Health and Human Services.  This tool provides community specific reports of action-oriented health information that reflect valid and meaningful measures of a broad range of health for the community of focus.

To understand what impacts, if any, were occurring in the Barnett Shale area, we closely examined CHSI data for this MSA from 2000 to 2008 to determine if a trend was noticeable with respect to public health. In doing so, we focused on the areas where the greatest intensity of production had occurred, specifically Denton County.

Denton County is important to highlight in seeking these answers. Not only is it home to extensive production activity, but it also  includes the Town of Dish (highlighted in the movie Gasland) as well as portions of Dallas and Fort Worth[SM1] .  Below find a chart that compiles health data obtained from the CHSI.

Denton County Texas Key Health Indicators 2000-2008

2000 2008
Population 65+ 21,703 34,762
Deaths for all causes: 857.7 814.1
Stroke 64.1 44.3
All Cancer 184.1 182.8
Chronic Lower Respiratory Disease: 77.5 67.0
Heart Disease 263.8 178.9

In examining these health statistics, it’s worth pointing out that, despite a growing elderly population, every major health indicator improved at the same time natural gas production was rapidly expanding across the Barnett.  For example, in 2009 natural gas production in the Barnett Shale had increased by 2,144 percent from 2000 levels.  In just nine years, technological advancements enabled 22 times as much natural gas to be produced from the Barnett as was produced in 2000. When all is said and done, the volume of natural gas produced during this period represents a total increase in production of over 6,000 percent. As production occurred and expanded, the health of the populations in counties experiencing development simultaneously increased.

If there were any negative health impacts as a result of natural gas development, it would be assumed that an area that underwent a historical production boom would have seen such an impact. The facts, however, tell a different story. Health records indicate that while production increased, fewer residents were diagnosed with serious illnesses such as cancer, respiratory disease, strokes, and heart disease. This improvement occurred even as the population of residents age 65 or older increased by over 13,000, a significant uptick for any population segment.

A strong example underscoring this point can be found in the Town of Dish, where former Mayor Calvin Tillman declared in the movie Gasland;

“Six months ago, nobody knew that facilities like this would be spewing benzene. Someone could come in here and look at us and say, ‘You know what? They’ve sacrificed you. You’ve been sacrificed for the good of the shale.’”

Following the release of the movie, however, the Texas Department of State Health Services (DSHS) challenged that claim, stating:

“Biological test results from a Texas Department of State Health Services investigation in Dish, Texas, indicate that residents’ exposure to certain contaminants was not greater than that of the general U.S. population.” (DSHS report, May 12, 2010).

They would go on to mention that, “DSHS paid particular attention to benzene because of its association with natural gas wells. The only residents who had higher levels of benzene in their blood were smokers. Because cigarette smoke contains benzene, finding it in smokers’ blood is not unusual.”

The findings of DSHS were only further solidified with the release of a comprehensive study by the Texas Commission on Environmental Quality (TCEQ). The Commission studied air quality in Dish and Dallas-Fort Worth to determine air impacts from natural gas development.  As part of this effort,  in the spring of 2009 TCEQ installed automated gas chromatograph (AutoGC) monitors in two locations surrounded by natural gas operations—the Town of Dish, in Denton County, and near Eagle Mountain Lake, in Tarrant County. These monitors operate around the clock, measuring levels of more than 45 VOCs, including benzene. After two years of continual monitoring there have been no chemicals measured above levels of concern for public health. The results from the monitors are posted hourly on the TCEQ website.

Key excerpts from the study’s findings include:

After several months of operation the Barnett Shale area is showing no levels of concern for any chemicals. This reinforces our conclusion that there are no immediate health concerns from air quality in the area, and that when they are properly managed and maintained, oil and gas operations do not cause harmful excess air emissions.

In addition to studying the presence of VOCs, some of the most harmful air pollutants, the study also examined ground level ozone due to many claims that natural gas production was decreasing air quality in the region as a result of this pollutant.  However, when one looks at the complete picture, as TCEQ did, they again find the opposite to be true. While total gas production in 2009 increased by 94 percent from 2000 levels, the levels of ground level ozone fell by nearly 15 percent as noticeable in the chart below.

Is the SGEIS Adequately Structured to Protect New Yorkers from Potential Contamination Pathways?

While experience in Denton County shows public health was not sacrificed during natural gas production, it is still important that a state developing natural gas put in place a regulatory structure that defines the playing field and ensures any potential contamination pathways are eliminated or mitigated to the point that impacts are extremely unlikely.  It is this point that was directly challenged in the letter sent to Governor Cuomo when the signatories declared human health impacts were “omitted” in the SGEIS and the “SGEIS does not, in fact, consider health impacts”.

Developing natural gas from shale is an engineer’s challenge; protecting public health and the environment is a regulators’ challenge. The New York State Department of Environmental Conservation’s (NYSDEC) for the past three years has sifted through public comments, professional opinions, technical comments and documents from a variety of sources. They have poured through the regulatory construct of all states producing natural gas and produced an extensive document, indeed one of the most extensive in the nation, that address the permit conditions and the regulations associated with natural gas development requiring high volume hydraulic fracturing (HVHF).

The product from this exhaustive search, the State’s Supplemental Generic Impact Statement (SGEIS), has as a primary focus a sound regulatory structure that is scientifically developed and protects human health and the environment from potential impacts associated with HVHF.  While the SGEIS does not have a specific section title that focuses on the protection of public health, the premise of the entire document is “to ensure that all environmental and public health impacts are mitigated or avoided.

That underlying premise is outlined in the SGEIS in three essential approaches:

  1. Understanding the potential impacts (cumulative included) and providing solutions on how to mitigate them. This section was completed in consultation with the NYSDOH [(iii) extensive consultations with scientists in several bureaus within the New York State Department of Health (“NYSDOH”);”SGEIS Page 3]
  2. Using Water Quality Standards and Air Quality Standards to protect human health. This requires limiting levels of contaminants to levels that are anticipated not to adversely affect public health. [Under the SDWA SGEIS] and also under the [CWA – SPDES Program SGEIS]
  3. Examining incidences in other states [SGEIS 10] and review of other state’s regulations [SGEIS 8.4] other states regulations]

Understanding potential impacts

The best way to protect human health from potential impacts from contaminants is through  proper containment of the chemicals of concern. Containment may not always be possible so risk assessors look for potential exposure pathways. These pathways include pathways that can occur as a result of routine and non-routine events. Once pathways have been identified, the mitigation or elimination of those pathways is needed to protect public health.  Below is a sample graphic that provides a basic understanding of the elements of a comprehensive pathway analysis.

Involvement of Health Professionals in Developing the SGEIS

The idea that public health was not taken into account, and public health professionals were not consulted, in the development of the SGEIS flies in the face of the document itself and its suggested regulatory structure, as well as the correspondence shared during its development.  According to the SGEIS, NYSDEC consulted at length with the New York State Department of Health (NYSDOH) to determine potential exposure pathways and the toxicity of all constituents of concern.  This is noticeable in correspondence between the then NYSDOH’s Director of the Division of Health, Dr. Edward G. Horn, and Bradley Field, the Director of the Division of Mineral Resources of the NYSDEC.

Indeed, many agencies solely focusing on the protection of public health participated in the effort, including offices in the NYSDOH Center of Environmental Health (CEH), the Bureau of Toxic Substances Assessment (BTSA), the Bureau of Water Supply Protection (BWSP) and the Bureau of Environmental Radiation Protection (BERP).

All of these agencies reviewed information that included “confidential business information identifying the chemical composition of products used or proposed for hydraulic fracturing of gas wells in New York.”   They also reviewed flowback and production fluid data from West Virginia and Pennsylvania.  Specifically, staff members at these agencies and others comprehensively reviewed toxicological data from the human health perspective.

Also noticeable in the same correspondence is a discussion on well construction requirements and setbacks. From the information exchange one can garner that setbacks proposed for use in the SGEIS are based on NYS Sanitary Code NYCRR Part 5. Section in Table 1: Required Minimum Separation Distances to Protect Public Water Supply Wells from Contamination. The separation or setback numbers are scientifically derived numbers (see EPA 625/R-94/001 September 1994 Groundwater and Well Head Protection). The correspondence discusses the scientific rationale behind the selection of the setback distances.  Again the discussion from the NYSDOH is focused on the protection of human health.

Do the Proposed Setbacks in the SGEIS Have Scientific Support in Limiting Pollutant Pathways?

Other independent consulting groups work (mentioned below) confirm that the proposed SGEIS setbacks significantly reduce or eliminate possible pathways of pollution and in turn significantly mitigate any potential health impacts natural gas production may have on water resources.

  1. Gradient Corporation, an environmental consulting firm, presented information to the USEPA at the HF study technical Workshop (Fate and Transport Workshop March 28-29). Their presentation discussed various scenarios of potential completed pathways of exposure and the resultant concentration of chemicals at the potential point of exposure. Based on the presented scenarios, the results showed that concentrations of the chemicals after transport (not including biological or chemical fate) are not significant enough to cause health impacts past the SGEIS setback of 500 feet from a private water well.
  2. Supporting the 500 foot setback is also a paper by Newell and Connor (1998). In the studies undertaken 75% of the hydrocarbon plumes studied did not travel beyond 200 feet.
  3. Quality Environmental Professional Associates (QEPA) did Pathway Analysis and Risk Assessment for the Colorado Oil and Gas Association to specifically address the data gaps and uncertainty regarding the human health impacts of activities related to oil and gas development. Their findings showed:
  4. “An evaluation of the chronic human health risk reveals that these [Oil and Gas activities] processes:
  • do not show a significant excess risk, and
  • do not pose a public health concern to the citizens of Colorado, using nationally recognized methods of review from ASTM and EPA, and ATSDR.”


Using Water Standards to Protect Human Health from Sediment and Contamination

In addition to the setback requirements included in the SGEIS, key portions of the Clean Water Act will further ensure New York’s water is safe from other sources of potential contamination like sedimentation that may have come into contact with production additives.  For example, the state administers the State Pollutant Discharge Elimination System (SPDES). This is a program that was approved, and is monitored for compliance by, the U.S. Environmental Protection Agency.  The SPDES program is broader reaching than the federal CWA which requires states to control discharges to surface water.  The SPDES permit program manages water quality standards to further help protect and restore the quality of all water.  NYSDEC isseeking to enact a new law that requires operators to obtain a HVHF SPDES permit. The proposed twenty-one part SPDES permit would cover the entire cycle of water and sedimentation management throughout the life of every natural gas well in the state.  All parts are written to ensure that ambient water quality is maintained and human health and the environment is protected.

Composition of Natural Gas in New York, and Proposed Regulations, Show New York Air Quality Not at Risk from Wellpad Operations

The composition of the natural gas in the Marcellus Shale is expected to be dry, meaning the natural gas is not expected to be paired with liquid hydrocarbons in the shale deposit.  It is expected, based on geological study, that there will be very low levels of volatile organic compounds (VOC) inherent in the shale due to this composition. Therefore BTEX compounds, an acronym that stands for benzene, toluene, ethylbenzene, and xylenes, are not expected to be in any flowback emanating from New York natural gas wells.  However, if low levels of VOCs are anticipated, and permit conditions require a closed-loop system as they currently do, then the availability of VOCs to create ozone or any other potential health impact is greatly diminished.

In conclusion,  because NYSDEC permit conditions require strict setback requirements proven to isolate contaminants from water sources, require the use closed-loop systems to limit any exposure to land, water and air, and the composition of natural gas underlying does not contain high levels of VOC’s, there are limited possibilities at worst for significant public health impacts.

While worries about public health impacts are often genuine, a fact-based review shows concerns over human health impacts from natural gas production in shale may be better placed elsewhere.  It would be helpful for NYSDOH, through community health education, to help local communities and their citizens discern the difference between real health risks and perceived health risks from natural gas production.

There is one thing that most scientists agree on, however, and this is that there is always a need for ongoing collection of data. There needs to be  monitoring to ensure that standards are met and health is not compromised in addition to ongoing research. But that should not diminish the clear fact that public health impacts from natural gas development are, and should continue to be, effectively mitigated.




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