Box 14. Case Study: A Solution in Water Sourcing

Box 14. Case Study: A Solution in Water Sourcing

Box 14. Case Study: A Solution in Water Sourcing

At its sites in the Fayetteville Shale play in Arkansas, Chesapeake Energy had been purchasing most of its water for drilling and hydraulic fracturing from private sources and trucking it to the well pads. While this process was working for the company, the truck traffic was causing damage to local roads. In 2008, therefore, Chesapeake decided to look into new water supply sources. The company found that by creating what is essentially a holding lake for the overflow from the Little Red River, it could cut down on some of its trucking needs.

Under the system the company developed, water is pumped from the river to the holding lake and transferred into a gravity-fed pipeline that traverses over 40,000 feet, with fourteen hydrants positioned at crossroads where the water can be pumped into trucks. The piping system reduces the air quality impact and safety concerns of trucking, and serves a dual purpose as a source of water for local fire departments. The project was approved to extract a limit of 1,550 acre-feet of water annually. 1

Although water is only diverted from the river during periods of high flow, as mandated by the Arkansas Natural Resources Commission (ANRC), there were local concerns about how this project would affect the Little Red River’s ecosystem. The river is home to a trout population prized by anglers, so Chesapeake turned to the local chapter of Trout Unlimited for input on the project.

As a result of this collaborative effort, various methods were identified to protect the wildlife in the river—for example, the intake pipe is oriented to face upstream and is covered with a metal mesh to prevent harm to the fish. 2 The company has also instituted monitoring of water quality and both game and nongame fish species in the reach of river surrounding the intake. Working with the community, Chesapeake was able to identify and implement measures to protect the river’s wildlife and its recreational and scenic values to the community.


  1. National Energy Technology Laboratory, “Modern Shale Gas Development in the United States: A Primer,” prepared for U.S. Department of Energy, Office of Fossil Energy, April 2009, 65.
  2. Chesapeake Energy, “A River Runs Through It: Environmentally Sensitive Operations in the Natural State,” Spring 2008, 2.

Box 4. Case Study from the Mining Industry: The Good Neighbor Agreement

Box 4. Case Study from the Mining Industry: The Good Neighbor Agreement

Box 4. Case Study from the Mining Industry: The Good Neighbor Agreement

In 2000, when Stillwater Mining Company began making plans to expand their mining operations in two Montana counties, several environmental NGOs saw an opportunity to engage with the company about protecting the area’s natural resources. During the hearing on the initial draft of the expansion permit, NGO representatives raised questions about its environmental implications. The groups subsequently entered into negotiations with the mining company on how to resolve these issues before the permit was finalized. The result of their negotiations was the creation of the 2000 Good Neighbor Agreement, 1 a legally binding document. The purpose of the agreement is to protect the area’s quality of life while providing for responsible economic development.

Designed to avoid triggering state government regulatory action on water quality, the Good Neighbor Agreement (GNA) establishes water quality requirements that exceed those required by the state. Three citizens’ committees and a set of projects were established to implement the objectives outlined in the agreement. As part of the agreement, an independent third-party consultant provides the citizen councils with technical assistance. The consultant costs, as well as other expenses of implementing the agreement, are covered by Stillwater.

One citizen committee focuses on engaging local residents in water quality monitoring for the agreement in the Stillwater, Boulder, and East Boulder Rivers. 2 Other initiatives of the GNA have increased public safety and decreased air pollution by establishing traffic restrictions and providing for carpooling, as well as a busing program for miners. On an annual basis, the technology committee considers any emerging best practices in the mining industry that could be applied to either of the mines.

The company’s transparency about its operations, along with citizen participation in monitoring activities, has fostered an environment of trust. 3 Maintaining an ongoing relationship has been important for stakeholders in the GNA because it has allowed for open dialogue and development of amendments to the agreement as needed. For example, the busing agreement originally stated that Stillwater was permitted only 35 private vehicles on the road per day. Nine years later, stakeholders renegotiated the traffic provisions to accommodate the changing operational needs of the mine while keeping traffic to a minimum.

In its newsletter commemorating the tenth anniversary of the GNA, the Northern Plains Resource Council, one of the original NGO parties to the agreement, stated that the GNA “has become a template for resolving disputes and promoting positive interaction in the permitting and development of natural resources.” 4

For more information, contact the Northern Plains Resource Council, (406) 248 1154,


  1. Good Neighbor Agreement Between Stillwater Mining Company and Northern Plains Resource Council, Cottonwood Resource Council, and Stillwater Protective Association (originally signed May 8, 2000; amended November 11, 2009).
  2. Northern Plains Resource Council, “Good Neighbor Agreement: A Unique Solution for Local Protection,” accessed December 9, 2014.
  3. Northern Plains Resource Council, “10th Anniversary Good Neighbor Agreement Newsletter,” 1, accessed December 9, 2014.
  4. Northern Plains Resource Council, “10th Anniversary,” 1.

Box 3. Case Study: Health Impact Assessment

Box 3. Case Study: Health Impact Assessment

Box 3. Case Study:  Health Impact Assessment

Oil drilling has taken place in Alaska since 1967. With the expansion of the industry in recent decades, some development activities began to occur near rural Alaskan native communities in the North Slope region, where some residents began expressing health concerns. In 2006, local tribal leaders and the borough government responded with a decision to jointly conduct the region’s first HIA. The project’s goals were to address community concerns and bring a more systematic, evidence-based approach to integrating public health data into the oil and gas planning and regulatory process. The Bureau of Land Management (BLM) agreed to integrate the HIA into an existing environmental impact statement (EIS) process for proposed oil and gas leasing near several local villages.

The study produced some significant findings. The HIA highlighted potential impacts on regional fish and wildlife populations, which would have consequences for local diet and nutrition. It also recognized potential social changes that the anticipated large increase in population would bring to the region. Finally, the HIA acknowledged the potential benefits for local communities, such as increased revenues to support police and emergency services, education, and public health programming.

As a result of the HIA’s identification of specific risks to the community, preventative measures were taken to prepare the community for the expected changes, including:

  • new BLM requirements for monitoring contaminants in locally-harvested fish and game
  • air quality modelling for large industry facilities located near villages
  • water quality monitoring
  • worker education programs on drug and alcohol use and sexually transmitted diseases

The HIA process also led to a new level of collaboration between state and tribal public health authorities; state and federal regulators; and industry. The state subsequently established an HIA program and now conducts HIAs for large projects throughout Alaska.

Sources:  Aaron Wernham, “Inupiat Health and Proposed Alaskan Oil Development:  Results of the First Integrated Health Impact Assessment/ Environmental Impact Statement for Proposed Oil Development on Alaska’s North Slope,” EcoHealth 4 (2007), 500513; The Pew Charitable Trusts, “Case Study: Oil Development, North Slope of Alaska” (December 30, 2006)

Appendix E: Pipelines—Transporting Shale Gas to Markets

Appendix C: Overview of the U.S. Legal and Regulatory Framework for Shale Gas Development

Appendix C: Overview of the U.S. Legal and Regulatory Framework for Shale Gas Development

U.S. Federal Legislation & Regulation


In 2012, the EPA issued enhanced regulations under the CAA, requiring that natural gas emissions from new hydraulically fractured and re-stimulated shale gas wells be flared (burned), as opposed to vented, thus reducing the level of toxic emissions when the well is prepared for production. Beginning in January 2015, 95 percent of all volatile organic compounds (VOCs) emitted during the well completion stage must be captured through a process known as green completion, whereby commercially useful gas and liquid hydrocarbons are separated from flowback in a closed-system technology. 1

In August 2015, the EPA issued proposed rules to reduce methane emissions under the CAA, with the goal of reducing emissions by 40 to 45 percent below 2012 levels by 2025. 2 Building on the 2012 standards for natural gas wells, the proposed  rules will require reductions of  methane emissions from shale oil wells and more downstream (associated with natural gas transmission) equipment and infrastructure. The proposed rules require operators to locate and plug leaks from equipment and infrastructure, including pneumatic pumps, pneumatic controllers, and compressor stations, which can be a significant source of emissions. 3 Operators of shale oil wells will be required to implement green completions, which capture both VOCs and methane. These rules will apply only to sources newly constructed or modified after the date of proposed rule publication in the Federal Register (September 18, 2015). In addition, the agency offers guidelines for states to reduce VOC emissions from existing oil and gas sources in areas with smog problems. The proposed rules have been issued with a 60-day comment period, and the agency intends to have the final rules in place in 2016.


  1. U.S. Environmental Protection Agency (EPA), “EPA’s Air Rules for the Oil and Natural Gas Industry: Summary of Key Changes to the New Source Performance Standards,” accessed November 21, 2014,
  2. U.S. EPA, “Proposed Climate, Air Quality and Permitting Rules for the Oil and Natural Gas Industry: Fact Sheet,” 1,
  3. U.S. EPA, “Proposed Climate, Air Quality and Permitting Rules for the Oil and Natural Gas Industry: Fact Sheet,” 1.

What can be done to address health concerns? What have others done?

What can be done to address health concerns? What have others done?


In addition to making an effort to restore the land as close as possible to its original state per the API guidelines, the company can maintain a dialogue with local officials and community members to get their input during the decommissioning process. It can anticipate safety and environmental risks that could arise from the site and strive to reduce or eliminate those risks. The API guidelines recommend adopting a “consistent and forward-looking focus on safety and the environment.” 1


State officials have a role in ensuring that wells are properly plugged and abandoned. At this stage, any surface use agreements that were signed prior to site development can help to guide the site restoration.


Property owners can work with the operator to make sure that the site is properly restored to the specifications in the surface use agreement.


  1. API, “Community Engagement Guidelines,” 9.

What health considerations are there?

What health considerations are there?

Air & Water Quality and Safety

If wells are not properly sealed when they are abandoned, they can pose a safety risk to residents and livestock, as well as air and water quality risks, given that contaminants could be released into the air or migrate to ground and surface waters. When this has been suspected of occurring, it has been linked to old, historically abandoned sites (orphaned wells). A 2013 study conducted in New York found that three-fourths of the abandoned oil and gas wells had never been plugged. 1 The National Petroleum Council also acknowledged the problem nationwide in a 2011 working paper. 2 Furthermore, a 2014 study of 19 abandoned wells in Pennsylvania – some dating back to the 19th century – found that not only were most of them unplugged, but both plugged and unplugged wells were also leaking methane. Extrapolating the amount released from the wells under study, the researchers estimated that such abandoned wells could be responsible for 4%-7% of the state’s methane emissions in 2010. 3   

The Interstate Oil and Gas Compact Commission (IOGCC), in collaboration with the U.S. Department of Energy, has been studying the problem of orphaned wells and making recommendations to the states, which are ultimately responsible for locating and plugging the wells. As of 2007, the states had identified about 60,000 such wells, with potentially 90,000 more yet to be located. 4 The IOGCC concluded that while the states have improved their response to the problem, funding remains an issue. 5 The IOGCC therefore recommended that wells presenting the greatest safety risks be prioritized and urged states and industry to collaborate in finding creative solutions. 6  


  1. R. E. Bishop, “Historical Analysis of Oil and Gas Well Plugging in New York: Is the Regulatory System Working?New Solutions 23, no. 1 (2013), 113- 114.
  2. National Petroleum Council, Plugging and Abandoning Oil and Gas Wells (2011).
  3. Mary Kang, Cynthia M. Kanno, Matthew C. Reid, Xin Zhang, Denise L. Mauzerall, Michael A. Celia, Yuheng Chen, and Tullis C. Onstott, “Direct Measurements of Methane Emissions from Abandoned Oil and Gas Wells in Pennsylvania,” Proceedings of the National Academy of Sciences 111,  no. 51 (December 23, 2014), 18173-18174.
  4. Interstate Oil and Gas Compact Commission (IOGCC), Protecting Our Country’s Resources: The StatesCase (2007), 3.
  5. IOGCC, Protecting Our Country’s Resources, 16-17.
  6. IOGCC, Protecting Our Country’s Resources, 17.

What can be done to address health concerns? What have others done?

What can be done to address health concerns? What have others done?

Industry Representatives

Air Quality & Safety

In 2011, the Shale Gas Roundtable, a multi-stakeholder group of leaders in Pennsylvania, convened to consider ways to promote effective and responsible oil and gas development in the state. One of the roundtable’s recommendations is to consider building pipelines to transport water to and from the well site (see Box 14. Case Study:  A Solution in Water Sourcing). 1 It is also important to consider, however, the issues raised by pipeline construction (for more on pipelines, see Appendix E). Furthermore, operators could also work with other companies in the region, as well as state and local authorities, to identify locations for centralized processing facilities and infrastructure that would optimize transport routes while reducing surface disturbance and traffic. 2


  1. University of Pittsburgh Institute of Politics, “Shale Gas Roundtable:  Deliberations, Findings, and Recommendations” (August 2013): 10.
  2. University of Pittsburgh, 12.

What health considerations are there?

What health considerations are there?

Air Quality

In addition to the air quality impacts discussed in Stage 3, new activities and infrastructure come online in the production phase that may contribute to air emissions. In the production stage for oil operations, the associated natural gas that emerges from the well is separated from the crude oil. While saleable gas is sometimes captured and transported to market, it is often flared or vented due to the lack of natural gas pipelines in the area. As discussed in Stage 3, however, new EPA regulations effective in 2015 and 2016 will significantly limit both practices.

In natural gas operations, the produced gas generally undergoes processing to remove water and other constituents to meet sales quality requirements prior to transport. The dehydration units that remove water from the gas can also release VOCs and other hazardous air pollutants (HAPs) into the air. If the gas contains sulfur, it goes through a sweetening process to remove it. Once extracted, the sulfur may be flared, incinerated, or possibly captured for market. 

After the gas has been conditioned, it is piped to compressor stations where it is pressurized for transport over longer distances. If the compressor engines are diesel-powered, they can emit nitrogen oxides, carbon monoxides, and VOCs.

There are also fugitive emissions of methane from pipelines and other equipment, as well as releases from the pneumatic instruments controlling the operation of valves. Researchers have identified these pneumatic devices, which release gas as part of their regular operation, as a major source of methane emissions from natural gas infrastructure. 1 These sources too will be affected by the EPA’s proposed regulations under the Clean Air Act, which require operators to locate and plug leaks from equipment and infrastructure, including pneumatic pumps, pneumatic controllers, and compressor stations. 2 The agency anticipates the rule will be final in 2016.   

Three Brothers Compressor Station, PA. By Bob Donnan, 2014


  1. David T. Allen, Adam P. Pacsi, David W. Sullivan, Daniel Zavala-Araiza, Matthew Harrison, Kindal Keen, Matthew P. Fraser, A. Daniel Hill, Robert F. Sawyer, and John H. Seinfeld, “Methane Emissions from Process Equipment at Natural Gas Production Sites in the United States: Pneumatic Controllers” Environmental Science and Technology 49 (2015), 633-4,
  2.  U.S. EPA, “Proposed Climate, Air Quality and Permitting Rules for the Oil and Natural Gas Industry: Fact Sheet”

What resources can provide further information?

What resources can provide further information?

Air Quality

  • The Center for Dirt & Gravel Road Studies is a non-profit organization that operates under the Larson Transportation Institute at Penn State University. The organization has several research, education, and outreach programs related to environmentally sensitive maintenance of unpaved roads and trails. Their mission is to create more environmentally friendly maintenance techniques and implement them in Pennsylvania. Their website provides:
  • Department of Health and Human Services, CDC, NIOSH, and IMA-NA, “Dust Control Handbook for Industrial Minerals Mining and Processing (January 2012). This handbook was produced for industrial minerals producers to provide guidance on use of state-of-the-art dust control techniques for all stages of mineral processing, in effort to eliminate or reduce hazardous dust exposures and create safer, healthier conditions for mine workers.
  • National Industrial Sand Association (NISA), “Occupational Health Program for Exposure to Crystalline Silica in the Industrial Sand Industry” (2011). NISA offers guidelines for industry to monitor and manage workers’ exposure to silica dust, which can occur during sand mining operations, during transport, and at the well pad.
  • Southwest Pennsylvania Environmental Health Project (SWPA-EHP), “Air.” SWPA-EHP, a nonprofit environmental health organization that provides assistance to local residents concerned about the health impacts of shale gas development, offers information and resources to residents for home air monitoring.
  • U.S. EPA, “Natural Gas STAR Program,” last updated October 23, 2014. The Natural Gas STAR Program is a voluntary program for oil and gas companies that aims to help companies employ new techniques to increase efficiency and reduce emissions. Through the Natural Gas STAR program, industry participants share information on cost-effective emission reduction technologies and practices. There is also a “Recommended Technologies and Practices“ page (last updated May 30, 2014). 

What can be done to address health concerns? What have others done?

What can be done to address health concerns? What have others done?

Industry Representatives

Air Quality

There are a range of measures that can be taken to reduce air pollution from shale development. The EPA’s Natural Gas STAR program, a voluntary program that partners with industry, offers an extensive list of recommended technologies and practices for reducing methane and VOC emissions.

Options for reducing air emissions include:

  • transitioning from diesel-powered equipment to natural gas- or solar-powered or reduced-emission engines and motors (some companies are using gas produced at the site to fuel equipment engines, thus reducing the use of diesel fuel)
  • constructing pads and roads of gravel, or applying water or other dust suppressants to them
  • instituting carpooling and busing programs to transport workers, thereby reducing the number of vehicles accessing the site (see Box 4. Case Study from the Mining Industry:  The Good Neighbor Agreement)
  • establishing driver training and incentive programs to ensure local speed limits are obeyed (also relevant to safety; see Box 9. Case Study: Driver Safety)
  • establishing a community-based participatory monitoring program, in which trained and experienced volunteers conduct air sampling in the surrounding area to monitor for chemical constituents that could pose a health risk

In order to ascertain the amount of air emissions that might be coming from the site, it is important to conduct monitoring activities before, during, and after drilling takes place. 

What health considerations are there?

What health considerations are there?


As silica sand is commonly used as a proppant during the hydraulic fracturing of shale deposits – requiring up to 10,000 tons of sand for the fracturing and re-fracturing of a single well 1  – the mining of silica sand for shale development operations has increased dramatically in recent years. Much of this silica is mined and processed in western Wisconsin, where the number of active silica sand facilities increased from 7 in 2010 to 85 in 2015. Illinois, Texas, and Minnesota also have significant silica sand facilities. 2, 3 This boom in the production of silica sand has led to concerns about increased exposures for workers and residents near sand mining and shale development operations.

What are the health concerns with silica dust?

Silica dust, officially known as respirable crystalline silica, is composed of microscopic particles about 100 times smaller than ordinary beach or playground sand. It has long been known that silica dust creates health risks for employees working in certain industries, including during the mining of this naturally occurring mineral. Health risks from exposure include respiratory problems like bronchitis and asthma; chronic obstructive pulmonary disease (COPD); silicosis, which is a permanent scarring and chronic inflammation of lung tissue; lung cancer; and kidney disease. Exposure has also been associated with some autoimmune disorders like rheumatoid arthritis and lupus, as well as with heart disease. 4  

What is workers’ exposure to silica?

In June 2012, the Occupational Safety and Health Administration (OSHA) disseminated a hazard alert for workers in the oil and gas industry, based on air samples taken at shale development sites. 5, 6 Many samples showed potential exposure levels above those considered safe, and some sites had levels ten times or more above the current permissible exposure limit (PEL). In September 2013, based on new research and analysis, the OSHA proposed more stringent standards for silica exposure. 7 If adopted, the new regulations would limit worker exposure to a PEL of 50 micrograms of respirable crystalline silica per cubic meter of air, averaged over an 8-hour workday. In addition, OSHA suggested provisions for measuring exposures and for reducing or mitigating risk. The National Industrial Sand Association (NISA), an industry group, has also developed a program for eliminating the adverse health effects of inhaled respirable silica through a program of careful monitoring and management of exposures. 8

What is the community’s exposure to silica?

The risks to communities in proximity to sand mining and shale development operations are currently not well understood. Community members near sand mining sites have voiced concerns about the local air quality and potential water contamination due to both the silica dust around the sites and the chemicals used in processing the sand. Silica dust could also affect residents living near rail lines transporting silica sand. In addition, some have pointed out that agricultural soils around mining sites may be compromised as the dust blows across farmland. 9 

To better understand the risks to communities near silica sand mines, in September 2013 the National Institutes of Health (NIH) approved a grant to the University of Iowa to study the impact of mines on respirable crystalline silica levels in nearby communities. 10 The researchers plan to take air samples from nearby homes, as well as to assess silica sand migration during rail transport.

What can be done to address health concerns?

Operators:  The OSHA-NIOSH hazard alert and the NISA program contain the following recommendations that companies should undertake to protect workers:

  • exploring the safety and effectiveness of alternative proppants

  • monitoring the air at well pads for respirable silica using the new proposed standards

  • controlling dust exposure through wetting down the sand and using air filters in both vehicles and buildings at the site

  • providing respiratory protection, training, and hazard information to workers

  • establishing medical monitoring of exposed workers 11

Groups concerned about the effects on communities have also made suggestions for improving public safety, such as installing air monitors every 1,000 feet around the perimeter of sand mining facilities and using closed-car rail transport when possible. 12

Drilling truck convoy. Courtesy of WV Host Farms Program.


  1. Zahra Hirji, “’Frac Sand’ Mining Boom: Health Hazard Feared,” Inside Climate News, November 5, 2013. 
  2. Zahra Hirji, “‘Frac Sand’ Mining Boom.”
  3. Wisconsin Department of Natural Resources, “Locations of Industrial Sand Mines and Processing Plants in Wisconsin,” last revised September 8, 2015 
  4. Centers for Disease Control and Prevention, “Workplace Safety and Health Tips: Silica” (July 2013). 
  5. Occupational Safety & Health Administration (OSHA), “OSHA-NIOSH Hazard Alert: Worker Exposure to Silica during Hydraulic Fracturing,” accessed December 6, 2014.
  6. Eric Esswein, Max Kiefer, John Snawder, and Michael Breitenstein, “Worker Exposure to Crystalline Silica During Hydraulic Fracturing,” NIOSH Science Blog (May 23, 2012).
  7. OSHA, “OSHA’s Proposed Crystalline Silica Rule: Overview” (September 2013).
  8. National Industrial Sand Association, “Occupational Health Program for Exposure to Crystalline Silica in the Industrial Sand Industry” (2011).
  9. Wisconsin League of Conservation Voters, “Frac Sand Mining,” accessed December 6, 2014.
  10. University of Iowa, Environmental Health Sciences Research Center, “Exposure Assessment and Outreach to Engage the Public on Health Issues from Frac Sand Mining,” accessed December 6, 2014 
  11. OSHA, “OSHA-NIOSH Hazard Alert: Worker Exposure to Silica.”
  12. Wayne Feyereisn, “Potential-Public-Health-Risks-of-Silica-Sand-Mining-and-Processing,” slide show, available as a PowerPoint presentation through The Sand Point Times, accessed December 7, 2014. 

What health considerations are there?

What health considerations are there?

Table 3: Examples of Fracturing Fluid Additives and Main Compounds 1

Note: It is important to take level of exposure into account when considering health effects of pollutants.


What is it?

Health Effect


A colorless, odorless, tasteless, and flammable gas that is the primary component of natural gas.

Toxicological data suggests that pure methane is nontoxic. 2 High concentrations can cause oxygen-deficient air spaces, fire hazards, or explosions. 3 Water contaminated with methane poses risk of explosion if ignited. 4 

Hydrogen Sulfide

Chemical air hazard produced during petroleum/natural gas drilling and refining. 5 It is a colorless, flammable, and extremely hazardous gas with a strong odor of rotten eggs at low concentrations. Regulations require onsite monitoring for hydrogen sulfide. 

Lower levels and long-term exposure can cause eye irritation, headache, and fatigue. 6 Inhalation of very high concentrations can result in respiratory distress, respiratory arrest, or death. 7


A volatile organic compound (VOC) found in crude petroleum, natural gas, and diesel exhaust. May be released during well unloadings or other maintenance. 8 It is a colorless to light yellow liquid with an aromatic odor.

Low levels of exposure can result in irritation to skin, eyes, and respiratory systems, dizziness, tremors, and fatigue, among other symptoms; it has also been linked to reproductive effects. 9 Exposure to very high concentrations has been linked to leukemia and can result in death. 10


A VOC found in natural gas and hydrocarbons issuing from the well during the fracturing process. It is a colorless liquid with a sweet-smelling odor and is flammable.

Low levels of exposure are not associated with health risks. 11 However, short-term exposure at high levels can cause dizziness, confusion, irritation of skin, eyes, and throat, difficulty breathing, and possible changes in the liver or kidneys. Very high levels can result in unconsciousness or death. 12


A VOC found naturally in hydrocarbon deposits, and might be present in chemicals used during the drilling and fracking process. 13 It is a colorless liquid with distinct sweet odor.

Symptoms of low to moderate levels of toluene exposure include fatigue, confusion, memory loss, nausea, loss of appetite, and hearing and vision loss. 14, 15 Inhalation of high levels can cause light-headedness, dizziness, fatigue, unconsciousness, and death; it has also been linked to birth defects and kidney damage. 16


A VOC that is highly flammable; vapors can be explosive. 17 It is a colorless liquid with a gasoline-like odor.

Inhalation is most common route of exposure, but it can be found in contaminated private wells. 18 Inhalation of low levels is not associated with health effects. 19 High levels can result in nausea, eye and nose irritation, nerve damage, and paralysis. 20

Particulate matter (PM2.5 and PM10)

PM2.5 and PM10 are microscopic particles that can be found in diesel or smoke, near roads, or in dusty areas.

Due to their small size, these particles can be inhaled deeply into the lungs and some can enter the bloodstream, affecting the lungs and heart. 21 Individuals with heart or lung diseases, older adults, and children are particularly at risk. Short-term exposure can worsen existing lung or heart conditions. 22 Long-term exposure is linked to chronic bronchitis and premature death in some cases. 23

Ground-level ozone (smog)

Under certain conditions, ozone can be formed when VOCs react with nitrogen oxide, which is found where combustion occurs, such as in diesel engines.

Short-term exposure can cause cough, reduced lung capacity, throat irritation, and other temporary respiratory effects. 24 Evidence about the effects of long-term exposure is inconclusive, although some studies link daily exposure to elevated levels of ozone with asthma, cardiovascular effects, increased hospital admissions, and increased daily mortality. 25 Children, older adults, and people with lung disease are at greatest risk. 26



  1. Modeled on Alliance of Nurses for Healthy Environments, “Facts on Fracking: What Healthcare Providers Need to Know,accessed November 21, 2014 
  2. Seth Shonkoff, Jake Hays, and Madelon L. Finkel,  “Environmental Public Health Dimensions of Shale and Tight Gas DevelopmentEnvironmental Health Perspectives 122, Issue 8 (August 2014).
  3. Indiana Department of Natural Resources, Division of Oil and Gas, Division of Reclamation, and Indiana State Department of Health, “Methane Gas & Your Water Well: A Fact Sheet for Indiana Water Well Owners” (no date).
  4. New York State Department of Health, “A Public Health Review of High Volume Hydraulic Fracturing for Shale Gas Development” (December 2014).
  5. Occupational Safety and Health Administration (OSHA), “OSHA Fact Sheet: Hydrogen Sulfide” (2005).
  6. Agency for Toxic Substances and Disease Registry (ATSDR), Division of Toxicology and Human Health Sciences, “Hydrogen Sulfide- ToxFAQs” CAS # 7783-06-4 (October 2014).
  7. ATSDR, “Hydrogen Sulfide.”
  8. Centers for Disease Control and Prevention (CDC), “Facts about Benzene” (updated February 2013).
  9. CDC, “NIOSH Pocket Guide to Chemical Hazards” (updated February 13, 2015).
  10. CDC. “NIOSH Pocket Guide to Chemical Hazards.”
  11. ATSDR, “Xylene: Division of Toxicology and Environmental Medicine ToxFAQs” (August, 2007).
  12. ATSDR, “Xylene.”
  13. Valerie J. Brown, “Industry Issues: Putting Heat on Gas,” National Center for Biotechnology Information (February 2007).
  14. ATSDR, “Toluene: Division of Toxicology and Environmental Medicine ToxFAQs,” CAS # 108-88-3 (February 2001).
  15. Valerie J. Brown, “Industry Issues.”
  16. ATSDR, “Toulene.”
  17. ATSDR, “n-Hexane,” CAS ID # 110-54-3 (updated March 3, 2011).
  18. ATSDR, “Toxicological Profile for n-Hexane” (July 1999).
  19. ATSDR, “Toxicological Profile for n-Hexane.”
  20. ATSDR, “Toxicological Profile for n-Hexane.”
  21. U.S. EPA Office of Air and Radiation, “Particle Pollution and Your Health” (September 2003).
  22. U.S. EPA Office of Air and Radiation, “Particle Pollution and Your Health.”
  23. U.S. EPA Office of Air and Radiation, “Particle Pollution and Your Health.”
  24. U.S. EPA, “Health Effects of Ozone in the General Population” (updated January 30, 2015).
  25. U.S. EPA, “Health Effects of Ozone in the General Population.”
  26. U.S. EPA, “Ground-level Ozone:  Health Effects” last updated October 1, 2015.

What health considerations are there?

What health considerations are there?

Air Quality

Shale development can introduce a broad range of local air quality concerns, some of which appear later in the development and production phases. Many of them begin with the drilling of exploratory wells and carry on through the later phases of development and production.  The major sources of potential air quality impacts include venting and flaring of natural gas from wells and fugitive emissions from oil and natural gas processing equipment; diesel-powered trucks and machinery; road dust; evaporation from storage pits; and dust from silica sand (see Box 6 on silica dust). Depending on the people affected and the exposure levels and pathways, these emissions can potentially provoke a variety of health effects, ranging from a nuisance, to acute to chronic respiratory problems, to psychological stress caused by the perception of worsened air quality. For a summary of the potential health effects of air pollutants from shale development, see Table 3.

While there are few studies of air quality in the vicinity of shale development sites, there are numerous documented community complaints of odors and other symptoms consistent with exposure to contaminants from oil and gas operations, such as upper respiratory ailments and skin irritation. 1 One Colorado study measured air samples near well pads during the well completion phase and found that volatile organic compounds (VOCs), an ozone precursor, were present more frequently and at higher concentrations than in regional ambient air samples. 2 Residents nearest to the well pads were found to be at higher risk of acute and sub-chronic respiratory, neurological, and reproductive effects. 3

In another study in the Barnett Shale region of Texas, researchers established a regional air monitoring network to monitor for VOCs near Dallas-Fort Worth, an area of high-density shale development. 4 They compared the monitoring data to a variety of regulatory health-based air comparison values (HBACVs) and found that none of the VOCs measured exceeded the HBACVs, concluding that the community was not being exposed to VOCs at a level that would cause a health concern. 5 Given that this was a community-scale study, the authors noted that individual property owners could potentially be exposed at higher or lower levels than those measured. 6

In addition to monitoring location, the variability of air emissions at shale development sites (due to the intermittent use of equipment; the varying composition of shale formations and fracturing fluids; and the influence of weather patterns and terrain, among other factors) could be responsible for differing outcomes between the Texas and Colorado studies. 7 Some researchers have concluded that further study – including community-based research – is needed in order to account for the potential cumulative impacts of the various sources of air pollution over time at shale development sites. 8, 9

Venting and flaring

Prior to the installation of equipment for collecting natural gas at an oil or gas well site, operators historically vented or flared the natural gas produced by the exploratory well. Venting has the effect of releasing methane, the primary component of natural gas – along with VOCs like benzene, toluene, ethyl benzene, and xylene (the BTEX chemicals) – directly into the atmosphere. Methane itself is principally a safety hazard if it accumulates in closed spaces; it can cause asphyxiation or explosions at high concentrations. VOCs can cause health issues such as respiratory problems and eye and skin irritation and, under certain conditions, can combine with other hydrocarbons to produce ground-level ozone, which might cause lung damage at high exposure levels. Chronic and prolonged exposure to ozone can result in asthma, lung disease, and cardiovascular effects.

As an alternative, flaring can take place in a closed incinerator box or, more commonly, at the top of a tall flare stack. The operator may also flare the gas when testing well flow or in emergency situations to prevent explosions or fires. Flares have a destruction efficiency of at least 98%, 10 thus significantly reducing methane and VOC emissions. Natural gas flaring principally forms carbon dioxide and water, but also results in some residual emissions of combustion byproducts, such as carbon monoxide and nitrogen oxides. 11 Flaring typically lasts between three and ten days and can create loud noise and heat, often requiring companies to notify local communities and fire departments before the burn takes place.

To avoid the environmental and health issues associated with venting, incinerating, or flaring the gaseous materials during a well completion, many companies now capture the marketable gas in a process referred to as a green completion. Effective January 2015, new EPA regulations under the Clean Air Act (Amendment of New Source Performance Standards 12) require 95% of VOCs from natural gas wells to be captured by green completions 13 as the well is prepared for production. Under the EPA rules, venting, incinerating, or flaring may still occur under certain circumstances; for example, during periodic maintenance and emergencies.

In August 2015, the EPA issued additional proposed rules that apply green completion requirements to shale oil wells. 14 The rules will apply only to sources newly constructed or modified after the date of proposed rule publication in the Federal Register (September 18, 2015). The agency intends to have the final rules in place in 2016. (For more information on laws and regulations, see Appendix C.)

Fugitive emissions

Local air quality might not only be impacted through operational releases of gases, but also through fugitive emissions of methane and VOCs due to leakage at wellheads, pipelines, storage tanks, compressors, and other equipment. There is uncertainty about how much leakage occurs and studies have drawn varying conclusions, depending on the method used to calculate emissions. In light of the new EPA requirements for green completions and the reduction of fugitive emissions from equipment and infrastructure, fugitive emissions from shale development should be significantly reduced. 15, 16 EPA’s August 2015 proposed rules require operators to locate and plug leaks from pneumatic pumps, pneumatic controllers, and compressor stations, among other sources.

Diesel-powered trucks and machinery

The estimated 1,148 one-way heavy truck trips during the early phase of well development 17 can result in significant emissions from diesel fuel combustion. The preparation of drilling sites and construction of rigs and other industrial infrastructure require operation of heavy machinery, which is often diesel-powered. Once well drilling operations begin, diesel-powered generators usually power the drills and power the pumps and compressors that force hydraulic fracturing fluid down wells and funnel natural gas through pipelines.

Diesel fuel contains PM2.5, or very fine particulate matter, that can penetrate deep into the lungs if inhaled. Exposure to diesel fuel exhaust and its components (such as arsenic, benzene, formaldehyde, and nickel) can cause immediate health effects such as cough, headaches, lightheadedness, and irritation of the eyes, nose, and throat. It can exacerbate respiratory illnesses, and studies have indicated that long-term exposure can lead to the increased risk of lung cancer. 18 For vulnerable populations, such as the elderly or those with respiratory conditions, exposure to high levels of fine-particle pollution is linked to increases in hospital admissions, emergency room visits, asthma attacks, and even premature deaths. 19

The many diesel-powered engines used in shale development also result in emissions of carbon monoxide (CO), nitrogen oxides (NOX), sulfur dioxide (SO2), and volatile organic compounds (VOCs). Under certain conditions, NOX and VOCs can combine to form ground-level ozone, which brings its own health concerns (see Table 3).

In 2007, EPA issued the “Highway Diesel Rule,” which set new emissions standards for heavy-duty vehicles. This new ruling is expected to reduce harmful emissions from diesel fuel by 90%. The NIEHS Working Group on Unconventional Natural Gas Drilling Operations indicated that the impact of this rule on diesel fuel emissions from shale development operations is unknown and an important subject for further study. 20

Road dust

The construction and maintenance of oil and gas operations entails the transport of heavy equipment and truck traffic on local roads. New access roads may also be constructed to accommodate this traffic. The particulate matter (PM2.5 and PM10) generated can cause respiratory effects, particularly in vulnerable individuals. Dust can also worsen visibility conditions on roads, which can lead to traffic accidents.

Evaporation pits

Large surface pits that store produced water and other wastewater from the shale development process can be a source of emissions when VOCs and other hazardous air pollutants (HAPs) volatilize from the stored water. These pits were mostly used in Western states, and their use is declining as the industry transitions to the use of storage tanks for wastewater, either on the well pad or in a central location. 


  1. Adgate, Goldstein, and McKenzie, “Potential Public Health Hazards, Exposures and Health Effects from Unconventional Natural Gas Development,” Environmental Science and Technology (2014), 8310-11.
  2. Adgate, Goldstein, and McKenzie, “Potential Public Health Hazards,” 8310.
  3. Adgate, Goldstein, and McKenzie, “Potential Public Health Hazards,” 8314.
  4. Several previous air quality studies in the Dallas-Fort Worth area indicated that VOC emissions did not exceed air quality standards and that shale development is not the largest source of emissions (motor vehicles are). See B. Zielinska, D. Campbell, V. Samburova, “Impact of Emissions from Natural Gas Production Facilities on Ambient Air Quality in the Barnett Shale Area: A Pilot Study,” Journal of the Air Waste Management Association 64 (December 2014), 1369-1383;  Rachel Rawlins, “Planning for Fracking on the Barnett Shale: Urban Air Pollution, Improving Health Based Regulation, and the Role of Local Governments,” Virginia Environmental Law Journal 31 (2013), 226-306; Charles G. Groat and Thomas W. Grimshaw, Fact-Based Regulation for Environmental Protection in Shale Development, report by the Energy Institute (University of Texas-Austin:  February 2012).The 2014 Bunch et al. study aimed to build on previous shorter-term studies.
  5. A.G. Bunch, C.S. Perry,  L. Abraham, D.S. Wikoff, J.A. Tachovsky, J.G. Hixon, J.D. Urban, M.A. Harris, L.C. Haws, “Evaluation of Impact of Shale Gas Operations in the Barnett Shale Region on Volatile Organic Compounds in Air and Potential Human Health Risks,” Science of the Total Environment 468-469 (2014), 832-833.
  6. Bunch et al., “Evaluation of Impact of Shale Gas Operations,” 841.
  7. Gregg P Macey, Ruth Breech, Mark Chernaik, Caroline Cox, Denny Larson, Deb Thomas, and David O Carpenter, “Air Concentrations of Volatile Compounds near Oil and Gas Production: A Community-Based Exploratory Study,” Environmental Health 13  (2014), 3.
  8. Charles W. Schmidt, “Blind Rush? Shale Gas Boom Proceeds Amid Human Health Questions,” Environmental Health Perspectives 119, no.8 (August 2011) 
  9. Macey et al., “Air Concentrations of Volatile Compounds,” 1.
  10. Dana R. Caulton et al., “Methane Destruction Efficiency of Natural Gas Flares Associated with Shale Formation Wells,” Environmental Science and Technology 48, no. 16 (July 30, 2014), 9548-9554.
  11. U.S. Environmental Protection Agency, “Compilation of Air Pollutant Emission Factors,” AP-42, Fifth Edition (1995), 13.5-1 -13.5-3.
  12. U.S. Environmental Protection Agency, “EPA’s Air Rules for the Oil and Natural Gas Industry: Summary of Key Changes to the New Source Performance Standards,” accessed November 21, 2014 
  13. Green completion technologies vary by basin type.
  14.  U.S. EPA, “Proposed Climate, Air Quality and Permitting Rules for the Oil and Natural Gas Industry:  Fact Sheet,” 1
  15. U.S. EPA, “Proposed Climate, Air Quality and Permitting Rules for the Oil and Natural Gas Industry: Fact Sheet,” 1.
  16. U.S. Environmental Protection Agency, EPA’s AirRules for the Oil and Natural Gas Industry: Summary of Key Changes to the New Source Performance Standards, accessed November 21, 2014
  17. New York State Department of Environmental Conservation, High-Volume Hydraulic Fracturing in NYS: 2015 Final Supplemental Generic Environmental Impact Statement (SGEIS) (April 2015), 6-305.
  18. California Office of Environmental Health Hazard Assessment, “Health Effects of Diesel Exhaust,” accessed December 6, 2014.
  19. California Office of Environmental Health Hazard Assessment, “Health Effects of Diesel Exhaust.”
  20. Penning et al., “Environmental Health Research Recommendations from the Inter-Environmental Health Sciences Core Center Working Group on Unconventional Natural Gas Drilling Operations,” Environmental Health Perspectives 122.14 (November 2009), 10.