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.