Fracking and your health

By Anna E. Mazzucco, Ph.D.



Fracking is in the news, but what is it exactly?  Hydraulic fracturing or “fracking” has boomed in the last few years and is now producing most of the natural gas in the U.S.  It is praised as helping the U.S. be more “energy independent” and has lowered the cost of natural gas.  But, the controversy is whether it can harm our health, especially for people who live near the drilling sites, which are most common in Colorado, Texas, North Dakota, and Pennsylvania.

Fracking uses more than 750 chemicals, some of which are known to harm human health.1,2,3   But since fracking is a relatively new technology in the U.S., scientists are still trying to understand how fracking chemicals get into the air and drinking water in nearby areas.

Of the more than 750 chemicals used in fracking, more than 100 can affect our hormones.  These chemicals are called endocrine-disrupting chemicals, and research published in 2011 shows that these chemicals can get into the water near fracking sites, where they could potentially cause infertility, diabetes, and cancer.4 This study in Colorado found higher levels of endocrine disrupting chemicals in water samples from areas with more drilling sites compared to areas with fewer sites.  Many of the water samples were found to contain chemicals that either mimicked or blocked estrogen (a hormone that is high in females) or androgen (a hormone that is high in males).   In fact, 89% of the samples taken near fracking sites had chemicals which increased estrogen, 41% had chemicals that blocked estrogen, 12% had chemicals that increased androgen, and 46% had chemicals that blocked androgens.  In contrast, water from areas far from fracking rarely had chemicals that affect hormones.  The researchers also found small increases in these chemicals in the Colorado River, probably from the fracking sites.  This could spread the chemicals into a larger area.

What kind of impact could these chemicals have on human health?  When children are exposed to high levels of hormones, this could cause early puberty in children, or abnormal sexual development in a fetus.  Chemicals that block hormones could also affect sexual development or fertility.  In adults, this exposure could increase the risk of infertility, obesity, diabetes, or certain types of cancer, such as breast cancer, testicular cancer, and vaginal cancer.   Serious diseases, and especially cancer, can take years to develop, so it is important to study families in fracking areas carefully for many years to see what happens.  Of course, meanwhile the families could be harmed if they are not protected from these chemicals in their water.

Two other reports have raised concern about fracking and the health of newborn babies.  These reports provide evidence that mothers living near fracking sites are more likely to give birth to newborns who are underweight.  One study found that babies were 25% more likely to have low birth weight if they were born to mothers living near fracking sites compared to babies born of mothers who didn’t live near one.5 A second study found that the chance of a low birth weight baby was more than 50% higher for babies born near fracking sites, compared to babies born to the same mothers in a location far from fracking.6   This study was presented at the annual meeting of the American Economic Association in January 2014.  Neither of these two studies has been published yet.

To be more conclusive about the health risks of living near fracking sites, we need large public health studies that include information from medical records and residence history.  Currently, most of the information we have is based on evidence of surface and ground water contamination from fracking sites.7,8

Meanwhile, several families and communities have already sued because of their concerns about health problems related to fracking, and the Environmental Protection Agency (EPA) and state agencies have investigated drinking water contamination in West Virginia, Pennsylvania, Wyoming and Texas.  The EPA is currently working on a report on the potential impact of fracking on the U.S. water supply, with a draft expected late in 2014.  Legislation to lower health risks due to fracking has been proposed in many states, including California and Illinois.  In 2012, Vermont became the first and only state to ban fracking.


  1. Kassotis CD, et al. Estrogen and Androgen Receptor Activities of Hydraulic Fracturing Chemicals and Surface and Ground Water in a Drilling-Dense Region. Endocrinology (2013).  
  2. Environmental Protection Agency. Study of the Potential Impacts of Hydraulic Fracturing on Drinking Water Resources: Progress Report, (2012).  
  3. US House of Representatives. Chemicals Used in Hydraulic Fracturing, (2011).  
  4. Schug TT, et al. Endocrine disrupting chemicals and disease susceptibility. Journal of Steroid Biochemistry & Molecular Biology, 127 (2011) 204– 215.  
  5. Hill EL. Unconventional Natural Gas Development and Infant Health: Evidence from Pennsylvania. (2012).  
  6. Currie JM, Deutch J, Greenstone M, Meckel KH. The Impact of the Fracking Boom on Infant Health: Evidence from Detailed Location Data on Wells and Infants. American Economic Association Annual Meeting, (2014).  
  7. Osborn SG, et al. Methane contamination of drinking water accompanying gas-well drilling and hydraulic fracturing. Proceedings of the National Academy of Sciences, (2011).  
  8. Jackson RB, et al. 2013. Increased stray gas abundance in a subset of drinking water wells near Marcellus shale gas extraction. Proceedings of the National Academy of Sciences, (2013).