A new, comprehensive report from Gradient examines two potential exposure pathways for hydraulic fracturing fluids to impact human health: upward migration from the shale formation itself, and surface incidents such as spills or other releases. Even by taking a conservative approach (which by design overestimates risk) the report concludes that hydraulic fracturing fluids “are not expected to pose an adverse risk to human health” and that, in the event of a spill, natural processes would dilute fluids to “below levels of human health concerns.”
The upshot? All of those scary stories we’ve heard about hydraulic fracturing supposedly threatening public health – and the alleged reason behind New York Governor Andrew Cuomo delaying approval of shale development – are not based on a credible examination of risk.
Let’s take a closer look at each of the potential pathways for health impacts, as examined by Gradient.
Upward Fluid Migration
We’ve all seen that image that so-called “green” groups use to describe hydraulic fracturing, the one where the fractures and chemicals are migrating upward from the shale formation and into groundwater (it’s sourced back to the discredited Gasland movie page). In this bizarre interpretation of reality, the fluids injected at depth are not confined to the formation, and the thousands of feet (and literally billions of tons) of impermeable rock above the shale zone – which have kept oil and gas deposits sealed at depth for millions of years – somehow provide pathways for chemicals to migrate against gravity and into groundwater.
On that claim, Gradient has what can only be described as a devastating refutation:
“[I]t is implausible that the fluids pumped into the target formation would migrate from the target formation through overlying bedrock to reach shallow aquifers.”
Put differently: Folks suggesting that hydraulic fracturing threatens water aquifers are literally arguing the “implausible.”
Need more concrete language? Gradient delivers:
“[T]here is no scientific basis for significant upward migration of HF fluid or brine from tight target formations in sedimentary basins.”
Got that? “No scientific basis.” Keep that in mind whenever you hear opponents try to claim the mantle of “science” in suggesting the hydraulic fracturing process will pollute drinking water.
The report adds that even if upward migration were somehow to occur, the dilution of fluids and additives would be enormous, and by the time anything ever reached drinking water supplies – remember, such migration would have to go through thousands of feet of various rock formations – the concentrations would be “well below health-based standards.”
Risks from Surface Releases
It’s obviously reassuring to know that the hydraulic fracturing process is safe – even if most of us already knew that, thanks to consistent affirmation from state regulatory agencies. But what happens if there’s a surface release on the wellpad? What if the waste water – the handling and transport of which is tightly regulated – spills onto the ground or roadway? What’s the risk to underground supplies of drinking water?
In short: insignificant. Here’s why.
Gradient used data from flowback samples (as well as produced water) from the Marcellus Shale in Pennsylvania and West Virginia to form the basis for its risk assessment. The report assumed zero containment measures, and that, in the event of a spill, 100 percent of the fluid would leach into groundwater. Due to a variety of geological factors, this is essentially impossible – but it was used to create an upper bound of risk for such an incident.
Those same geological factors, however, cannot be ignored in terms of assessing how spilled fluids would eventually migrate to a water aquifer. Here’s Gradient’s conclusion:
“Human health risks associated with potential surface spills of fluids containing HF constituents are expected to be insignificant with respect to both impacts to USDWs [underground sources of drinking water] and impacts to surface waters due to dilution mechanisms which are expected to reduce concentrations in potable aquifers and surface waters to levels below health-based drinking water concentrations in the event of surface spills.” (emphasis added)
So even if, somehow, all of the fluid from a spill were to reach drinking water, the natural dilution mechanisms between the spill site and point of contact with the aquifer would shrink the health-risk to below established thresholds.
To be sure, this doesn’t mean that development poses zero risks. All types of energy development involve certain risks. But the focus should not be on whether there are risks, but whether those risks can be managed — and whether those risks are large enough to warrant banning the processes involved.
In the case of shale development – and hydraulic fracturing specifically – the verdict is clear: the risks from such activity are exceedingly low, and pushing for bans or additional restrictions based on inflated fears of risks is simply not a fact-based position.