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Hydraulic Fracturing (Fracking) and the Clean Air ActFracking and Air Quality FREE TO VIEW

Richard B. Evans, MD, MPH, FCCP; David Prezant, MD, FCCP; Yuh Chin T. Huang, MD, MHS, FCCP; on behalf of the Occupational and Environmental Health Network of CHEST
Author and Funding Information

From the Department of Medicine (Dr Prezant), Albert Einstein College of Medicine, Montefiore Medical Center; and the Department of Medicine (Dr Huang), Duke University Medical Center. Dr Evans is retired.

CORRESPONDENCE TO: Richard B. Evans, MD, MPH, FCCP, Ste b, #302, 27 Fennel Str, Skaneateles, NY 13152; e-mail: richardbevansmd@hotmail.com


FINANCIAL/NONFINANCIAL DISCLOSURES: The authors have reported to CHEST that no potential conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details.


Chest. 2015;148(2):298-300. doi:10.1378/chest.14-2582
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Published online

Hydraulic fracturing, or fracking, involves injecting large amounts of sand, water, and chemicals deep underground at high pressures to extract natural gas from rock formations. At the same time, fracking also generates by-products, such as dust, silica, and other gases. While some groups consider fracking to represent a health risk,1 others suggest that fracking poses little risk to the public.2 To date, most studies have measured emissions from the wells and estimated exposure and its health impact based on the distance from the wells,3,4 but none have addressed potential health effects associated with specific elements impacted by fracking.

In high-volume fracking, bore holes are drilled vertically 1,500 to 2,200 m and then “zones” or “stages” are drilled horizontally an additional 1,500 m into shale. A typical well will have 12 to 20 stages. Once the horizontal holes are drilled, water, sand, and chemicals are forced down the bore holes, fracturing the shale adjacent to the horizontal holes and releasing natural gas and/or oil into the bore holes. The average hydraulic fracturing operation uses 11 million to 26 million L of water, 567,000 to 1,134,000 L of chemicals, and approximately 1.22 million to 2.86 million kg of sand. In addition to natural gas returned from the fractured shale, other gases trapped underground or from added chemicals are released either at the well head or from temporary impoundment ponds at the job site. These released gases include radon (in high-radon-containing brine), hydrogen sulfide, and volatile organic compounds (VOCs), including benzene, toluene, ethyl benzene, and xylene.5

An increasing percentage of US natural gas production is being obtained from fracking. It has been estimated that > 52,000 shale gas wells have been drilled in the United States.1 More than 200,000 workers are employed in the United States by well-servicing companies. Workers are exposed to silica, diesel exhaust, and VOCs, and, at some sites, hydrogen sulfide and radon, raising concerns about occupational lung diseases, including silicosis, asthma, and lung cancer. In a study of 11 drill sites in five states, 90% of sand-mover operators and 83% of workers were exposed to crystalline silica exceeding the threshold-limit value of the American Conference of Industrial Hygienists of 0.025 mg/m3.6 Fracking in a coal-seam gas field in Australia was associated with peak outdoor radon-222 levels of nearly 0.81 pCi/L, related to the number of gas wells within 3 km and wind speed.7 The levels of radium-226, which decays to radon-222, in the brine of Marcellus Shale can exceed 10,000 pCi/L. This brine is part of the flowback liquid and radon gas is released at the wellhead.

In addition to occupational exposures, workers and nearby residents are also exposed to air pollutants emitted from various stages of fracking, including nitrogen oxides (NOx), VOCs, ozone, hazardous air pollutants, methane, and fine particulate matter.8,9 In six counties near the Barnett Shale Fort Worth Basin in Texas, increased concentrations of ambient methane, a greenhouse gas, were found from 2008 to 2010.10 In Pennsylvania, significant emissions of NOx, a precursor of ozone, were attributable to various stages of fracking.11 An ozone level of 124 ppb was recorded in early March 2011 in rural Wyoming, higher than the worst day recorded in Los Angeles, California, that same year. During the winter of 2013, ozone concentrations in the Uintah basin, Wyoming, reached 165 parts per billion.9 A high ozone concentration was also found during the winter in Utah.9 Several daily spikes in fine particulate matter were recorded in 14 homes near fracking sites in Pennsylvania.12

The Clean Air Act is the law that empowers the US Environmental Protection Agency (EPA) to regulate air pollutants considered harmful to public health and the environment. Since its enactment in 1970, air quality has steadily improved in the United States; however, recently this trend appeared to be reversing for NOx in some areas of Pennsylvania near fracking, despite a decrease in statewide emissions of NOx.9 High levels of ozone, typically observed during the summer, were recorded in the winter in areas near fracking and buck this declining trend. With increasing fracking operations in the United States, the EPA and state governments have increased their efforts to address air quality. In April 2012, the EPA issued performance standards for VOCs for new wells to reduce harmful air pollution at fracking sites.13 If fully implemented, VOC emissions from newly fractured wells should be reduced by 95%. The EPA also has adopted multiple tiers of emission standards for on-road and off-road diesel engines14,15 to regulate diesel exhaust, which impact on criteria air pollutants, such as ozone, particulate matter, or NOx, known to cause cardiopulmonary health effects. The air pollution burden from fracking has been estimated by some states largely from national emission inventories. Without direct measurements, however, the impact on ambient air quality and the health of workers and nearby residents will be difficult to assess.

Fracking has fueled an economic boom and job growth. In North Dakota, fracking contributed to a lower unemployment rate and increased median household income. In Texas, fracking provided more than $1 billion in revenue to local governments and $1.2 billion in state tax revenue for 2012. Workers and residents near the development, however, have to bear the potential environmental and health consequences. Measuring air pollutants at central monitoring stations, typically distant from the fracking site, is inadequate; rather assessing ambient air quality at each fracking site and in its vicinity is preferred. This information is critical, since fracking is now encroaching highly urbanized areas across the United States. With more funding, the EPA, state governments, and industry should expand their efforts to assess regional air quality and address environmental controls and the health of workers and nearby residents. We can have both economic prosperity and a healthy workforce and communities if public policy is guided by results from case-control or prospective cohort health and environmental studies designed to determine if a significant causal relationship exists between health (measured by surveys and examinations) and exposure (measured by air or personal monitors). In the meantime, clinicians should be aware of the potential impact of fracking when evaluating their patients.

Acknowledgments

Collaborators: The members of the steering committee for the Occupational and Environmental Health Network are Amy Ahasic, MD, FCCP; Anthony M. Szema, MD, FCCP; Arnold Schwartz, MD, PhD, FCCP; David Prezant, MD, FCCP; Lisa Zacher, MD, FCCP; Mashael al-Hegelan, MBBS, FCCP; Raghu Sundaram, MBBS; Richard Evans, MD, FCCP; Sai P. Haranath, MBBS, FCCP; Thomas Kennedy, MD, FCCP; Tony Huang, MD, FCCP.

Kovats S, Depledge M, Haines A, et al. The health implications of fracking. Lancet. 2014;383(9919):757-758. [CrossRef] [PubMed]
 
Torjesen I. Fracking poses little risk to public health, but evidence is limited. BMJ. 2013;347:f6626. [CrossRef] [PubMed]
 
Rabinowitz PM, Slizovskiy IB, Lamers V, et al. Proximity to natural gas wells and reported health status: results of a household survey in Washington County, Pennsylvania. Environ Health Perspect. 2015;123(1):21-26. [CrossRef] [PubMed]
 
McKenzie LM, Guo R, Witter RZ, Savitz DA, Newman LS, Adgate JL. Birth outcomes and maternal residential proximity to natural gas development in rural Colorado. Environ Health Perspect. 2014;122(4):412-417. [PubMed]
 
Adgate JL, Goldstein BD, McKenzie LM. Potential public health hazards, exposures and health effects from unconventional natural gas development. Environ Sci Technol. 2014;48(15):8307-8320. [CrossRef] [PubMed]
 
Esswein EJ, Breitenstein M, Snawder J, Kiefer M, Sieber WK. Occupational exposures to respirable crystalline silica during hydraulic fracturing. J Occup Environ Hyg. 2013;10(7):347-356. [CrossRef] [PubMed]
 
Tait DR, Santos IR, Maher DT, Cyronak TJ, Davis RJ. Enrichment of radon and carbon dioxide in the open atmosphere of an Australian coal seam gas field. Environ Sci Technol. 2013;47(7):3099-3104. [CrossRef] [PubMed]
 
Moore CW, Zielinska B, Pétron G, Jackson RB. Air impacts of increased natural gas acquisition, processing, and use: a critical review. Environ Sci Technol. 2014;48(15):8349-8359. [CrossRef] [PubMed]
 
Field RA, Soltis J, Murphy S. Air quality concerns of unconventional oil and natural gas production. Environ Sci Process Impacts. 2014;16(5):954-969. [CrossRef] [PubMed]
 
Rich A, Grover JP, Sattler ML. An exploratory study of air emissions associated with shale gas development and production in the Barnett Shale. J Air Waste Manag Assoc. 2014;64(1):61-72. [CrossRef] [PubMed]
 
Litovitz A, Curtright A, Abramzon S, et al. Estimation of regional air-quality damages from Marcellus Shale natural gas extraction in Pennsylvania. Environ Res Lett. 2013;8(1):1-8. [CrossRef]
 
Brown D, Weinberger B, Lewis C, Bonaparte H. Understanding exposure from natural gas drilling puts current air standards to the test. Rev Environ Health. 2014;29(4):277-292. [CrossRef] [PubMed]
 
Oil and natural gas air pollution standards. US Environmental Protection Agency website. http://www.epa.gov/airquality/oilandgas/actions.html. Accessed September 10, 2014.
 
Heavy trucks, buses, and engines. US Environmental Protection Agency website. http://www.epa.gov/otaq/hd-hwy.htm. Accessed September 10, 2014.
 
Nonroad engines, equipment, and vehicles. US Environmental Protection Agency website. http://www.epa.gov/otaq/nonroad-diesel.htm. Accessed September 10, 2014.
 

Figures

Tables

References

Kovats S, Depledge M, Haines A, et al. The health implications of fracking. Lancet. 2014;383(9919):757-758. [CrossRef] [PubMed]
 
Torjesen I. Fracking poses little risk to public health, but evidence is limited. BMJ. 2013;347:f6626. [CrossRef] [PubMed]
 
Rabinowitz PM, Slizovskiy IB, Lamers V, et al. Proximity to natural gas wells and reported health status: results of a household survey in Washington County, Pennsylvania. Environ Health Perspect. 2015;123(1):21-26. [CrossRef] [PubMed]
 
McKenzie LM, Guo R, Witter RZ, Savitz DA, Newman LS, Adgate JL. Birth outcomes and maternal residential proximity to natural gas development in rural Colorado. Environ Health Perspect. 2014;122(4):412-417. [PubMed]
 
Adgate JL, Goldstein BD, McKenzie LM. Potential public health hazards, exposures and health effects from unconventional natural gas development. Environ Sci Technol. 2014;48(15):8307-8320. [CrossRef] [PubMed]
 
Esswein EJ, Breitenstein M, Snawder J, Kiefer M, Sieber WK. Occupational exposures to respirable crystalline silica during hydraulic fracturing. J Occup Environ Hyg. 2013;10(7):347-356. [CrossRef] [PubMed]
 
Tait DR, Santos IR, Maher DT, Cyronak TJ, Davis RJ. Enrichment of radon and carbon dioxide in the open atmosphere of an Australian coal seam gas field. Environ Sci Technol. 2013;47(7):3099-3104. [CrossRef] [PubMed]
 
Moore CW, Zielinska B, Pétron G, Jackson RB. Air impacts of increased natural gas acquisition, processing, and use: a critical review. Environ Sci Technol. 2014;48(15):8349-8359. [CrossRef] [PubMed]
 
Field RA, Soltis J, Murphy S. Air quality concerns of unconventional oil and natural gas production. Environ Sci Process Impacts. 2014;16(5):954-969. [CrossRef] [PubMed]
 
Rich A, Grover JP, Sattler ML. An exploratory study of air emissions associated with shale gas development and production in the Barnett Shale. J Air Waste Manag Assoc. 2014;64(1):61-72. [CrossRef] [PubMed]
 
Litovitz A, Curtright A, Abramzon S, et al. Estimation of regional air-quality damages from Marcellus Shale natural gas extraction in Pennsylvania. Environ Res Lett. 2013;8(1):1-8. [CrossRef]
 
Brown D, Weinberger B, Lewis C, Bonaparte H. Understanding exposure from natural gas drilling puts current air standards to the test. Rev Environ Health. 2014;29(4):277-292. [CrossRef] [PubMed]
 
Oil and natural gas air pollution standards. US Environmental Protection Agency website. http://www.epa.gov/airquality/oilandgas/actions.html. Accessed September 10, 2014.
 
Heavy trucks, buses, and engines. US Environmental Protection Agency website. http://www.epa.gov/otaq/hd-hwy.htm. Accessed September 10, 2014.
 
Nonroad engines, equipment, and vehicles. US Environmental Protection Agency website. http://www.epa.gov/otaq/nonroad-diesel.htm. Accessed September 10, 2014.
 
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