A scientific review of more than two dozen studies aimed at linking oil and natural gas development to poor health found no direct association between fracking and illnesses, dealing another blow to activists trying to link the two together.

The new report by the Health Effects Institute’s (HEI) Energy Research Committee examined 25 studies published from 2000 to 2018 that sought to establish an association with cases of cancer and poor perinatal, respiratory, and cardiovascular outcomes and other issues with unconventional oil and natural gas development (UOGD).

The groups’ energy committee – made up of experts from a half dozen universities – found that “data and study limitations prevented the committee from determining whether exposures originating directly from UOGD contributed to the assessed health outcomes, either within individual studies or across the body of literature.”

Furthermore, their report stated in concluding statements in each area of research that limitations in the reviewed studies made it impossible to determine whether a certain health outcome was “originating directly from UOGD did or did not contribute to” that particular health outcome.

The report adds to a growing body of science showing no clear pathway from fracking to negative public health impacts – or questioning activist “research” that attempts to portray such a link – including a recent study by a team of Shell researchers, and a joint study between the Colorado and Pennsylvania public health departments.

Lack of Data is Common Theme in Various Areas of Research

The HEI report reviewed six different health issues that activists have tried to connect to fracking through epidemiological research: perinatal outcomes, cancer, respiratory outcomes, cardiovascular outcomes, self-reported symptoms, and other outcomes based on hospitalization records.

Each time, the report showed that the existing research did not have the data to support claims that oil and natural gas development is harming local populations.

In assessing evidence for poor perinatal (directly before and after birth) effects, the researchers reviewed studies covering birth weight, pre-term birth, birth defects, and infant and fetal mortality. The committee was unable to reach a definitive conclusion:

“Results of studies with the same exposure-outcome pairs were inconsistent and the studies employed limited control of potential confounders, in particular strong measures of [socioeconomic status] and lifestyle factors. The limitations of these studies prevent the committee from concluding whether environmental exposures originating directly from UOGD did or did not contribute to the assessed perinatal outcomes.” (emphasis added)

The concluding statement for cancer showed no or weak associations:

“The cancer studies lacked strong study designs, notably insufficient allowance for latency periods, and control for potential confounding. Investigators reported no or weak associations between the UOGD exposure surrogates and cancer, and there were at most two studies for any one cancer outcome.” (emphasis added)

For respiratory outcomes, the report lacked “sufficient” data:

“Peng et al. (2018) is notable with its exceptional control for county- and ZIP-code-level temporal trends, but assessments from one study at the ecologic level are not sufficient to reach conclusions about the impact of UOGD exposure on morbidity related to COPD, pneumonia, and upper respiratory infections. The committee is therefore unable to conclude whether environmental exposures originating directly from UOGD did or did not contribute to the assessed respiratory outcomes.” (emphasis added)

In assessing cardiovascular health, the report couldn’t find comparable data:

“The two studies that sought to assess associations between UOGD and cardiovascular outcomes used different exposure surrogates, evaluated different health outcomes, and were subject to important limitations.”

The report examined studies on self-reported symptoms for physiological and mental health problems, but again they lacked data:

“Given the lack of multiple studies for the majority of self-reported symptoms in these studies, the lack of reported dose–response relationships, and several other important sources of uncertainty, the committee is unable to conclude whether environmental exposures originating directly from UOGD did or did not contribute to the assessed symptoms.” (emphasis added)

Finally, the report reviewed hospitalization records but couldn’t draw any conclusions linking oil and natural gas development to poor health outcomes.

Report Examined Work From Commonly Debunked Researcher

Among the activist-driven studies that the HEI committee reviewed were reports issued by Lisa McKenzie, a researcher at the University of Colorado whose work is commonly debunked by Colorado state health regulators for making claims that lack sufficient evidence.

One study, “Childhood hematologic cancer and residential proximity to oil and gas development” was firmly rebuked by the Colorado Department of Public Health And Environment when it was released in 2017, after it attempted to link higher cancer rates to those living near oil and gas operations.

Larry Wolk, then the executive director of CDPHE, said:

“Based on this study and other studies/data/information we have to date, we find no increased risk for childhood leukemia, especially when considering the current setbacks [of a minimum 500-foot buffer between oil and gas wells and homes].”

Wolk also said the study’s “conclusions are misleading.”

Additional HEI Study Also Has Inconclusive Results

HEI released another report in the draft stage that reviewed other studies examining oil and gas development, and like the first study, it too failed to find conclusive results.

The draft report analyzed studies over the past two decades examining potential exposure pathways for air, water, soil and sediment, noise, and sensory issues.

In each section’s concluding remarks, the report acknowledges shortcomings such as this statement for air exposure:

“Despite the size, breadth, and, in many cases, quality of the literature, it collectively falls short of providing an understanding of the extent of temporal and spatial variability of potential exposures across major U.S. oil and gas regions.”

Similarly, for water, the report said, “few studies to date have demonstrated a complete exposure pathway,” and the soil and sediment conclusion said that studies, “were not broadly generalizable to other locations and operational conditions. In addition, studies did not include information about potentially exposed populations.”


HEI’s companion reports and the previous analyses conducted by state health agencies and other organizations show that despite the headlines that research claiming to link fracking to health impacts may generate, actual findings are far from conclusive. Realistically, monitoring of air and water near well sites continue to find that the U.S. oil and natural gas industry is operating in a way that is protective of public health, while powering the American economy.