Fracking & Health

Who we are: 

Physicians for Social Responsibility (PSR) is a scientific and educational organization representing medical and health professionals and concerned citizens, with nearly 40,000 members and supporters. PSR has been working for more than 50 years to create a healthy, just and peaceful world for present and future generations. 

PSR Colorado works to elevate the voice of health professionals in regard to protecting the public from the health impacts of hydraulic fracturing, the climate crisis, and exposures to radionuclides and other toxic substances on current and future generations. PSR Colorado advocates for solutions to reliance on fossil fuels and nuclear energy.



A 2016 meta study of peer-reviewed scientific literature looked at more than 700 studies on the impacts of fracking published between 2009-2015. Of the studies looking specifically at health impacts, more than 80 percent document risks or actual harms. More specifically: 

  • 84% of public health studies contain findings that indicate public health hazards, elevated risks, or adverse health outcomes; 
  • 69% of water quality studies contain findings that indicate potential, positive association, or actual incidence of water contamination; and
  • 87% of air quality studies contain findings that indicate elevated air pollutant emissions and/or atmospheric concentrations (Hays et al. 2016).


Physicians for Social Responsibility, in alliance with Concerned Citizens for a Healthy NY, publishes a periodic “Compendium of Scientific, Medical, and Media Findings Demonstrating Risks and Harms of Fracking” (1,000+ studies). Here are some conclusions from its 6th edition:

  • Growing evidence shows that regulations are simply not capable of preventing harm.
  • Fracking and the disposal of fracking waste threaten drinking water.
  • Drilling and fracking contribute to toxic air pollution and smog (ground-level ozone) at levels known to have health impacts.
  • Public health problems associated with drilling and fracking include poor birth outcomes, reproductive and respiratory impacts, cancer risks, and occupational health and safety problems. 
  • Natural gas is a threat to the climate.
  • Earthquakes are a proven consequence of drilling and fracking-related activities in many locations.
  • Fracking infrastructure poses serious potential exposure risks to those living nearby.
  • Drilling and fracking activities can bring naturally occurring radioactive materials to the surface.
  • Fracking raises issues of environmental justice 
  • Health professionals are increasingly calling for bans or moratoria on fracking, based on a range of potential health hazards and as reviews of the data confirm evidence for harm.


The Compendium concludes that findings to date from scientific, medical, and journalistic investigations combine to demonstrate that fracking poses significant threats to air, water, health, public safety, climate stability, seismic stability, community cohesion, and long-term economic vitality. Emerging data from a rapidly expanding body of evidence continue to reveal a plethora of recurring problems and harms that cannot be sufficiently averted through regulatory frameworks. There is no evidence that fracking can operate without threatening public health directly or without imperiling climate stability upon which public health depends.


Air emissions:

Fracking operations release toxic gases, the most dangerous of which are volatile organic compounds (VOCs) including the BTEX complex (benzene, toluene, ethylbenzene and xylene). Benzene is a potent carcinogen and, according to the EPA, cancer risk can occur at any exposure level. All BTEX compounds are known to cause birth defects, impact the reproductive system, and affect the kidneys, liver and lungs (Colborn et al., 2011).

Benzene has also been found to have short term effects on the nervous, gastrointestinal, cardiovascular, and dermatological systems, with symptoms including dizziness, headaches, nausea, vomiting, tachycardia (rapid heart rate), blisters, and rashes. In the long term benzene suppresses bone marrow function and affects reproduction. 

“Benzene is known to cause cancer, based on evidence from studies in both people and lab animals. The link between benzene and cancer has largely focused on leukemia and other cancers of blood cells” (American Cancer Society).

“Rates of leukemia, particularly acute myeloid leukemia (AML), have been found to be higher in studies of workers exposed to high levels of benzene, such as those in the chemical, shoemaking, and oil refining industries” (American Cancer Society).


Negative birth outcomes:

Negative birth outcomes include neural tube defects, congenital heart defects (Mckenzie et al 2014), low birth weight (Currie et al., (2017), premature birth and greater probability of high risk pregnancy (Casey et al. 2016).

  • A retrospective study of births that occurred between 1996 and 2009 found that mothers in rural Colorado who had babies born with neural tube defects were twice as likely, and mothers who had babies born with congenital heart defects (CHD) were 30% more likely to live in the highest density wells as compared to those with no wells within a 10 mile radius (Mckenzie et al 2014).  
  • A 2015 retrospective study in Pennsylvania looked at the records of almost eleven thousand babies born between 2009 and 2013 and found that living in the most active quartile of drilling and production activity was associated with a 40 percent increase in the likelihood of pre-term birth, and a 30 percent increase in the likelihood that they had been labeled by an obstetrician as “high risk” (Casey et al 2016).
  • A Princeton University study looked at birth certificates for all 1.1 million infants born in Pennsylvania between 2004 and 2013—a period that spanned the drilling of thousands of fracking wells in the state. For mothers living within one kilometer (.6 miles) of wells they found a 25 percent increase in the probability of low birth weight as compared to infants more than three kilometers away (Currie et al., 2017). 
  • A 2019 study conducted by the Colorado School of Public Health looked at 3324 infants born between 2005 and 2011 to mothers living in counties with drilling activity (20+ well/10,000 births). Maternal exposure was estimated from three months prior to conception to the second gestational month. Births of infants born with one of four congenital heart defects were identified from the CRCSN birth defects registry (536 cases) and matched 1:5 with children born without birth defects. Based on residence of mother relative to geocoded proximity/density of wells, CHD mother/infant pairs were overall 1.4 and 1.7 times more likely than controls (no CHD) to  live in the medium and high density exposure groups as compared to the low density groups. In rural areas the likelihood of CHD mother/infant pairs living in the medium and high density groups was even higher (McKenzie et al, 2019).


Respiratory/cancer/mental health/other:

A 2016 study analyzed medical records of more than 35,000 Pennsylvania asthma patients, ages five to ninety and found a significant association between living close to active fracking operations and progressively worsening asthma symptoms (Rasmussen, et al., 2016).

A retrospective study conducted in 2017 found that children and young adults in Colorado diagnosed with acute lymphocytic leukemia were up to four and a half times more likely to live in areas with the highest density of wells as compared to those with no wells within a 10 mile radius (McKenzie et al., 2017). 

A 2015 study found that residing near active gas and oil fracking sites in Pennsylvania was associated with increased cardiac, neurological, urological, cancer-related, and skin-related problems. In communities with the most wells, the rate of cardiac hospitalizations was 27 percent higher than in a neighboring county where such operations were banned (Jemielita et al. 2015).

In a pilot study of 97 people in Fort Collins, Greeley and Windsor, Colorado, researchers from the Colorado School of Public Health found that those who lived in areas of more intense oil and gas development showed early signs of cardiovascular disease, including higher blood pressure, changes in stiffness of blood vessels, and markers of inflammation (Crooks et al. 2018).

Research has shown significant psychological distress among people who live near wells including anxiety, depression, helplessness and fears for safety; a general deterioration of lifestyle and social world; a loss or diminishment of well-being; serious sleep disturbances from lights and noise; uncertainty about the health and safety of their futures. Overall, authors suggested that there are long-lasting and widespread negative mental health effects to those living in close proximity to fracking operations (Hirsch et al 2017). 


Ozone and Health:

In Colorado, while the CDPHE (Colorado Department of Public Health and Environment) has done risk assessments of the health impact of VOC’s from oil and gas, the health risks from particulate matter and ozone precursor emissions from oil and gas operations have been largely ignored.  

The study estimated that in 2025 the human health burden would be about 1000 respiratory and cardiovascular hospital admissions, 3600 emergency department visits, tens of thousands of upper and lower respiratory symptoms, approximately 100,000 of lost work days and over a million cases of exacerbated asthma and acute respiratory symptoms. Premature deaths alone would result in losses of 13 to 28 billion dollars (Fann et al. 2018). 

The Clean Air Task Force publication Gasping for Breath estimates:  


  • More than 750,000 summertime asthma attacks in children under the age of 18 due to ozone smog resulting from oil and gas pollution.
  • Each summer, there will be more than 2,000 asthma-related emergency room visits and over 600 respiratory related hospital admissions nationally due to ozone smog resulting from oil and gas pollution.
  • Children will miss 500,000 days of school nationally each year due to ozone smog resulting from oil and gas pollution.
  • Each year, adults must deal with 1.5 million days when they are forced to rest or reduce activity due to ozone smog resulting from oil and gas pollution

And in Colorado: 

  • According to our baseline case, over 250,000 tons of volatile organic compounds will be emitted by oil and gas facilities in Colorado in 2025. This is the anticipated level of emissions even after taking into account the significant expected reductions from Colorado’s 2014 oil and gas air emissions standard.
  • There will be more than 32,000 summertime asthma attacks in children under the age of 18 due to ozone smog resulting from oil and gas pollution.
  • Children will miss nearly 24,000 days of school each year due to ozone smog resulting from oil and gas pollution.
  • Each year, adults will have to deal with nearly 70,000 person-days when they are forced to rest or reduce activity due to ozone smog resulting from oil and gas pollution.
  • The vast majority of the health impacts in Colorado will occur in three metropolitan areas: Denver, Fort Collins, and Colorado Springs (Clean Air Task Force 2014).


Fires and explosions: 

Between 2006 and 2015 Colorado experienced at least 116 reported oil and gas fires and/or explosions (Colorado Public Health News 2017). The actual number is thought to be larger, as many incidents are unreported because the COGCC (Colorado Oil & Gas Conservation Commission) requires reporting only in cases that “require medical treatment” or cause “significant damage” (Colorado Public radio 2017). 


Leaks and spills:

COGCC data analyzed by the University of Colorado-Boulder shows that some spills didn’t report amounts, less than half occurring in 2014 were cleaned up or closed by 2016 and sixteen percent of spills from 2008-2011 have not been closed (Armstrong et al. 2017).

There are about two industry self-reported spills per day in Colorado. The COGCC requires documentation of all spills but does not aggregate the data or evaluate ways to reduce spills. Of the 509 spills reported in 2016, 82% were on private land and flowback fracking fluid was the source of over half of the spills. Thirty-two percent were within 1500 feet of an occupied building, but no distance was reported for 52% of spills (Prentice-Dunn, J., 2016).

Companies reported 619 spills in 2017, state data show. Altogether, companies spilled more than 93,000 gallons of oil into soil, groundwater and streams. They also spilled more than 506,000 gallons of “produced water,” waste from drilling and hydraulic fracturing that emerges from deep underground and contains chemicals. That number of spills reflects a 17 percent increase above the 529 spills reported in 2016, state data show. Total annual spills remained lower than the 792 spills in 2014 and 624 in 2015 (Finley 2018).

In a five year period between 2008-2012, more than 2,000 Colorado leaks were reported, just by the industry. Of these, 17% resulted in verified groundwater contamination. As a result of the flooding in 2013, the COGCC reported spills totaling more than 90,000 gallons from oil/gas operations. The spill rate since 2013 has increased to approximately two per day.(Denver Post / Colorado Oil and Gas Conservation Committee)


Environmental Justice Issues:

In Greeley, Colorado, a massive well pad housing 24 wells was sited near Bella Romero Academy, an elementary school in a low-income community where 82 percent of students are Latino, after earlier plans were scrapped for a site near a charter school where students are majority white and middle-class (Turkewitz 2018).


Climate Change:

Climate change “generates more frequent and intense heat waves, extreme weather events, shoreline loss, flooding and drought, air and water pollution, and agricultural losses. These in turn have health consequences: heat-related illness and death; storm-driven mortality and injuries; allergies, asthma, and other conditions exacerbated by pollution; insect and water borne diseases; poorer nutrition and lessened food security, and greater mental and emotional stress” (Physicians for Social Responsibility Compendium).

Atmospheric methane (CH4) levels in the US have increased exponentially in the last 20 years, an increase directly tied to fracking. With methane being 86 times more potent than CO2 at trapping atmospheric heat over a 20-year period, and CO2 levels stabilizing, US fracking for natural gas is now the single most significant contributor to global methane increases. And while methane has less impact on climate than CO2, it has far greater impacts on human health and food crops through its roles in ozone formation and photosynthesis interference. Each additional Mt of methane causes 220-490 premature deaths per year due to ozone (Howarth 2019) (Drew Shindell, NASA/GISS/Duke U).


American Cancer Society

Armstrong, K., Rogers, J.D., Burke, T.L., Ryan, J.N. & Sherwood, O.A., (2017). Characterization of accidental spills and releases affecting groundwater in the Greater Wattenberg Area of the Denver-Julesburg Basin in northeastern Colorado. Presentation at Society of Petroleium engineers. April 18-20, 2017

Casey, J.A., Savitz, D.A., Rasmussen, S.G., Ogburn, E.L., Pollak, J., Mercer, D.G., & Swartz, B.S. (2016). Unconventional natural gas development and birth outcomes in Pennsylvania, USA. Epidemiology 26(2), 163-172. doi: 10.1097/EDE.0000000000000387

Clean Air Task Force (2016). Gasping for Breath.

Colborn, T., Kwiatkowski, C., Schultz, K., & Bachran, M. (2011) Natural gas operations from a public health perspective. International Journal of Human and Ecological Risk Assessment, 17:1039-1056

Colorado Health Institute (2017) Colorado’s Climate and Colorado’s Health: Examining the Connection

Colorado Public Health News, Colorado study finds 116 documented oil and gas fires and/or explosions over 10 years. May 10, 2017.

Colorado Public Radio, June 2017. Operator's discretion in reporting may account for lower rate of oil and gas fires in Colorado,

Crooks, J., McKenzie, L.M., Peel, J.L., Brindley, S., Blair, B.,  Allshouse, W.B., Adgate, J.L., & Malin, S. (2018). Relationships between Indicators of cardiovascular disease and intensity of oil and natural gas activity in Northeastern Colorado,” Environmental Research, Mar;170:56-646  doi: 10.1016/j.envres.2018.12.004

Currie,J., Greenstone, M., & Meckel, K.I. (2017) Hydraulic fracturing and infant health: New evidence from Pennsylvania, Science Advances, 3(12), el603021. Doi:10.1126/sciadv.1603021

Fann N., Baker, K.R., Chan, E.A.W., Eyth, A., MacPherson, A., Miller, E., & Snyder, J., (2018). Assessing human health PM2.5 and ozone impacts from U.S. oil and natural gas sector emissions in 2025. Environmental Science and Technology, 52:8095-8103. doi:10.1021/acs.est.8b02050

Finley, B., (2018). Oil and gas industry spills increased by 17 percent around Colorado last year.

Hays, J., Shonkoff, S.B.C., (2016) Toward an understanding of the environmental and public health impacts of unconventional natural gas development: a categorical assessment of the peer-reviewed scientific literature, 2009-2015. PLoS ONE, 11(4)

Hirsch J.K., Smalley, B.K., Selby-Nelson, E.M., Hamel-Lambert, J.M., Rosmann M.R., Barnes, T.A.,  Abrahamson, D., Meit, S.S., GreyWolf, I., Sarah Beckmann, S., LaFromboise, T., (2017). Psychosocial Impact of Fracking: A Review of Literature on the Mental Health Consequences of Hydraulic Fracturing. International Journal of Mental Health and Addiction, 16(1):1-15. DOI 10.1007/s11469-017-9792-5   

Howarth, R., (2019). Is Shale Gas a Major Driver of Recent Increase in Global Atmospheric Methane? Biogeosciences. Accepted for review

Jemielita, T., Gerton G.L., Neidell, M., Chillrus S., Yan B., Stute, M., & Panettieri, Jr., R.A.,  (2015). Unconventional gas and oil drilling is associated with increased hospital utilization rates, PLoS ONE,

McKenzie, L.M., Guo, R., Witter, R.Z., Savitz, D.A., Newman, L.S., & Adgate, J.L., (2014). Birth outcomes and maternal residential proximity to natural gas development in rural Colorado. Environmental Health Perspectives,122:412-417. doi:10.1289/ehp.1306722.

McKenzie, L.M., Allshouse, W.B., Byers, T.E., Bedricik, E.J., Serdar, B., & Adgate, J.L. (2017). Childhood hematologic cancer and residential proximity to oil and gas development. PLoS ONE, 12(2), e0170423.doi:10.1371/journal.pone.0170423,

McKenzie, L.M., Allshouse, W.B., & Daniels, S. (2019).  Congenital heart defects and intensity of oil and gas well site activities in early pregnancy. Environment International, 2019; 104949 DOI: 10.1016/j.envint.2019.104949

McMullen, T., Bamber, A., Bon, D., Vigil, D., & VanDyke, M., (2018) Exposures and health risks form volatile organic compounds in communities located near oil and gas exploration and production activities in Colorado. International Journal of Environmental Research and Public Health, 15(7), doi:10.3390/ijerph15071500

Prentice-Dunn J., (2016). Colorado Oil and Gas Toxic Release Tracker. Center for Western Priorities. Data from COGCC accessed on January  25, 2017.

Rasmussen, S.G., Ogburn, E.L., McCormack, M., Casey, J.A., Bandeen-Roche, K., Mercer, D.G., & Swartz, B.S. (2016) Association between unconventional natural gas development in the Marcellus Shale and asthma exacerbations. Journal of the American Medical Association. 176(9):1334-1343. doi:10.1001/jamainternmed.2016.2436. 

Turkewitz, J. (2018, May 31). In Colorado a fracking boom and a population explosion collide. New York Times. Retrieved from

US House of Representatives Committee on Energy and Commerce 2011. Chemicals used in hydraulic fracturing.

Cover photo of Bald Eagle at fracking site: credit, Dana Bove/Front Range Nesting Bald Eagle Studies - used with permission.



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