Another round of attention-grabbing headlines has swept the media, this time blaming fracking for childhood leukemia, yet they fail to highlight obvious limitations and past contradictions by the very same researchers.

A new study by Yale University researchers, published by the Environmental Health Perspectives, claims to link children who live near unconventional oil and natural gas (UOG) sites to an increased risk of acute lymphoblastic leukemia (ALL). While there are several inconsistencies and various leaps to conclusion throughout this study, the first and foremost is that these researchers claim water as an exposure pathway for leukemia, yet ignore their own past research which has established no such exposure pathway.

Here’s what to keep in mind when reading this study:

#1: Actual sampling disproves water as an exposure pathway

This is an epidemiology study which relies on statistical models instead of actual measurement and analysis of data. To underscore this point, Yale researchers calculated a flow-direction metric based on a conceptual model of groundwater flow to theorize that water is an important route of exposure to leukemogenic compounds:

“This exposure metric assumes that UOG wells that are located upgradient of a residence contribute more to exposure than downgradient wells, presuming that consumption or contact with groundwater from domestic wells is a major exposure source.” (emphasis added)

However, in previous studies where the very same researchers took actual groundwater samples, rather than relying on statistical modeling, they found no change in water near oil and gas production.

Take this study from 2017 to2021:

“Our analysis of water samples collected from more than 300 households within the Appalachian Basin is one of the most comprehensive executed to date. We found that chemical concentrations in water samples were generally below federal and state standards and guidelines. Instances in which concentrations of one or more chemicals exceeded available health-based or aesthetic standards were rare, and most of these exceedances were associated with analytes that have natural sources (e.g., arsenic, barium).” (emphasis added)

Or this study from 2021, once again authored by many of the same researchers:

“…the elevated methane levels were not attributable to UOG development…” (emphasis added)

Or this 2022 study, again authored by Yale researchers on groundwater:

“Limited associations between metrics and chemicals may indicate that UOG-related water contamination occurs rarely/episodically.” (emphasis added)

How can groundwater from oil and gas production suddenly be a link to childhood cancer when no such exposure pathway has previously existed? Study after study – from these very researchers – has shown that unconventional oil and gas development does not impact groundwater or drinking water resources.

What’s more, even when putting these previous studies aside, researchers admit their study had low exposure and precision regarding this supposed water pathway:

“Low exposure prevalence limited our statistical power, and confidence intervals at the 2km2km buffer size and for the water pathway-specific metric in particular were wide…Low exposure prevalence (between 1% and 5%) when using the water pathway-specific metric (particularly at the smaller buffer sizes) may have reduced model stability and reduced the overall precision of risk estimates.” (emphasis added)

Diving deeper…

#2: Registry based case potentially leaves out key details, health patterns

This was a registry-based case study of 405 children ages 2 to7 years old diagnosed with ALL in Pennsylvania between 2009 to2017. Researchers used publicly available data from birth records and other sources including sex, mode of delivery, birth weight, race, ethnicity, maternal education, and estimates on air pollution exposure and pesticide exposure.

However, many of these data sets were again estimates – not actual measurements – posing severe restraints. The researchers even admit their values were not statistically significant:

“We were constrained by individual-level information available in the birth records, which limited our ability to investigate potential confounders such as parental occupation… Although the ORs were not statistically significant after adjusting for race, socioeconomic status, and other environmental exposures in comparison with ORs from models accounting for year of birth alone, the odds remained consistently elevated across different time periods and metrics.” (emphasis added)

Key details such as family cancer history, pattern of paternal or maternal drug or smoking use, and other important factors necessary to make such a bold claim as this study does were simply unable to be examined.

#3: This study is in search of an overly simple solution for a complex disease

Leukemia is a complex and tragic disease. Yet it does a disservice to try and hypothesize an underlying cause based on extremely limited information and data.

Take the researchers own words, which highlight the genetic emphases that cause Leukemia:

“Current evidence suggests that for most cases, ALL develops due to multiple genetic insults, such as chromosomal translocations or alterations.”

“Although the genetic and molecular processes behind the disease have been delineated, the upstream etiological agents triggering such biological insults remain poorly understood.”

#4: Study cites complementary data that has been disavowed

To boost its showing, the study in question says its results “complement those reported by the McKenzie et al. study in Colorado,” which claimed to find an association between oil and natural gas development and childhood cancer.

However, the Colorado Department of Public Health and Environment responded to this study with the following statement:

“We support studies that evaluate the potential impact of environmental contaminants on public health, and certainly, Benzene exposure has been proven to increase risk of certain types of cancers, including leukemia. However, this study’s conclusions are misleading in that the study questions a possible association between oil and gas operations and childhood leukemia; it does not prove or establish such a connection.” (emphasis added)

#5: Not the first time these researchers have made dubious claims

The Yale School of Public Health team that includes Nicole Deziel have long tried to paint fracking as responsible for major public health concerns. In 2020, Deziel and two of the same researchers involved in this study published a study linking hydraulic fracturing operations to two sexually transmitted infections in Texas – though notably found “no statistically significant associations for any STIs” in other heavy oil and gas producing states and ignored national STI trends.

It’s perhaps telling that the findings in their most recent study come with the disclaimers that they have “not been formally reviewed by the U.S. EPA,” and the “content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH.”

Bottom Line: This epidemiological study relies on modeling rather than scientific sampling and evidence. The very same researchers have done studies that disprove water as an exposure pathway and rather, highlight fracking as a safe and environmentally tested method. While this study likely served its desired purpose of generating click-bait headlines, it does little to advance this important health dialogue.