Public perceptions of fracking are shaped by controversies between an industry that has downplayed the risks of fracking and citizens alleging that fracking and attendant activities have polluted air, contaminated drinking water, and scarified landscapes. This tension was particularly apparent in Pennsylvania more than a decade ago, when fracking was catapulted to the national stage. Homeowners were videoed igniting their methane-laced tap water, and protesting citizens were photographed with jars of green well water, presumably polluted from nearby hydraulic fracturing operations. Industry rebutted, claiming that the contamination predated the arrival of fracking operations and that it was not responsible. People within communities hosting fracking were scared and looking to experts to make sense of this issue. While experts were easy to find, facts, data, and definitive answers were in short supply. Deployment of hydraulic fracturing and supporting technologies had raced ahead of the science needed to illuminate its potential impacts on water quality. 
 
Now, more than a decade later, concern over hydraulic fracturing still simmers but is no longer a frequent subject of media reporting. Why did fracking slip from national attention? Did the environmental damage prophesized by some fail to materialize or did communities simply acclimate to the disruptions and risks posed by the practice? Did new science lead to decisions and policies that eliminated vulnerabilities people encountered in the early phases of the fracking boom? By drawing from the Pennsylvania experience, I explore these questions and use the lessons learned to prescribe a science-based approach to management of fracking activities as they continue to evolve into the twenty-first century.
 

Pennsylvania’s Experience: The Good, the Bad, and the Unpleasant

The shale gas boom revitalized many of Pennsylvania’s small towns that had long been suffering from shrinking budgets and services, disappearing jobs, and falling populations. Still, not everyone was happy. Residents grew frustrated with traffic snarls caused by the surge in the number of slow-moving trucks that hauled freshwater and wastes to and from drilling sites, while those living near drilling sites were unprepared for the noise, bright lights, and dust. Tensions mounted between residents that held lucrative natural gas leases and those forced to endure inconveniences of natural gas development without benefiting from the financial windfall. And the public was becoming increasingly concerned about its water.
 
Hydraulic fracturing is thirsty. Anywhere from four to eight million gallons of water are jetted underground to frack a single horizontal gas well. In Pennsylvania, the lion’s share of this water was pumped from rivers and streams, leading to concerns that these waterways — particularly smaller streams with lower flows — could be sucked dry in support of hydraulic fracturing. Fortunately, the Pennsylvania Department of Environmental Protection, together with inter-state basin commissions, had rules in place to protect streams against excessive withdrawals. According to independent scientific reviews, these regulations appear to be accomplishing their purpose.

Although water withdrawals for hydraulic fracturing were not imposing undue stress on Pennsylvania’s streams and rivers, problems arose when industry tried to put this used water back. Ten to eighty percent of the water injected during a frack job is quickly regurgitated from the well, whereupon the well will continue to produce water at a gentler pace throughout its operational lifetime. This wastewater is exceptionally salty, often three to five times more saline than seawater, and may contain naturally occurring radioactive materials, such as radium, in addition to various hydrocarbon compounds. Particularly in the early phases of Marcellus Shale development, much of this wastewater was trucked from drill sites and discharged to streams and rivers after processing at wastewater treatment facilities.
 
The treatment plants were not equipped to handle these briny wastewaters. Trouble sprouted in 2008, when monitoring of the Monongahela River in southwestern Pennsylvania revealed that the waterway was growing saltier and carrying elevated loads of bromide, a precursor in the formation of cancer-causing brominated disinfection by-products (Br-DBPs). This discovery was alarming. The Monongahela River hosts intakes for more than a dozen drinking water plants that serve one million people, and, at the time, several of these plants were reporting high levels of Br-DBPs in their finished water. The problem extended beyond the Monongahela and persisted. Two years later, the Pittsburgh Water and Sewer Authority observed dramatic increases in Br-DBPs in the distribution systems’ drinking water, which were linked to rising bromide levels caused by discharge of partially treated Marcellus Shale brines into the Allegheny River and its tributaries. 
 
Fears of contamination stemming from intentional discharges were compounded by uncontrolled releases of fracking fluids, drilling fluids, and wastewater into the environment. Leaks from flow lines, storage pits, and storage tanks were the most common causes of uncontrolled releases at drill sites. Trucking accidents and illegal dumping led to offsite releases of fracking fluids and wastewater. Nearly 1,300 spills, releasing more than one quarter of a million gallons of various fluids, were reported to the Pennsylvania Department of Environmental Protection between 2005 and 2014. Evidence from forensic analyses, though not definitive, suggests that contaminants from some of these spills leached into groundwaters tapped for residential drinking water supply. Moreover, a small fraction of unintentional releases resulted in the transmission of wastewater and hydraulic fracturing solutions to streams. 
 
Spills and stream salinization raised anxieties among regulators and the public alike, but what was happening underground was far more dramatic and, more than any other issue, galvanized antipathy to hydraulic fracturing. Methane, the primary component of the natural gas slurped up from the Marcellus Shale, was detected in dangerously high levels in well wasters of eighteen households in Dimock, a small town tucked into the Endless Mountains of northern Pennsylvania. The homeowners blamed nearby gas wells that were drilled and fracked by Cabot Oil and Gas. Methane is terrific for heating homes and for generating electricity, but its presence in drinking water has no upside. While not toxic, methane is flammable and its outgassing into the enclosed air space at the top of a water well can lead to explosion. Norma Fiorentino, a Dimock resident, experienced this phenomenon fist-hand when her water well blew up in 2009. Luckily, her water supply was the only casualty. The calamity of was carried widely by local and national media. Cabot Oil and Gas eventually reached a settlement with most of the eighteen homeowners but, as part of the settlement terms, was not required to acknowledged responsibility for the contamination. 
 
The first scientific study published after the Dimock incident received considerable attention, even making its way into public discourse. By leveraging chemical fingerprinting techniques, the scientists attributed the source of methane present in a subset of sixty groundwater samples collected in the region around Dimock to industry activities. Other scientists countered, demonstrating with data that methane occurred ubiquitously and naturally in freshwater aquifers of northern Pennsylvania long before hydraulic fracturing entered the picture. The two sets of conclusions are not mutually exclusive. That there are natural sources of aquifer methane does not let industry off the hook. Groundwater contamination by methane has been traced unequivocally to shale gas development. A recent analysis of Pennsylvania environmental records revealed that thirty-nine wells drilled into the Marcellus Shale between 2004 and 2015 allowed methane migration that impacted 108 drinking water supplies. But, contrary to popular belief, the hydraulic fracturing process itself was not to blame. Instead, the weak link was poorly constructed and sealed gas wells that allowed natural gas — either from the Marcellus Shale or from overlying bedrock formations — to seep upward along the outside of gas wells and into groundwater aquifers plumbed for drinking water.
 

Pennsylvania’s Regulatory Response

The problems encountered at the outset of the shale gas boom did not arise, as its critics and media narratives sometimes portray, from an utter lack of regulation. Pennsylvania was not a wild west, where fracking companies operated at will and fossil fuel production proceeded unchecked in the absence of environmental protections. In fact, the state had a regulatory framework in place that was built around more than a century’s experience with conventional oil and gas extraction, during which time hundreds of thousands of wells were drilled into hydrocarbon-bearing formations above and below the Marcellus Shale. And, though bad actors surely existed, most natural gas producers did not operate with careless disregard for the environment, but instituted practices expected to protect surface water and groundwater. Nevertheless, neither the state nor industry was fully prepared for the new management challenges posed by the rapid diffusion of hydraulic fracturing. 
 
As awareness of fracking-related impacts grew, the regulatory community reacted by strengthening policies intended to safeguard freshwater and human health. To address rising surface water salinities, the state banned shipments of Marcellus wastewaters to municipal treatment plants unless the waste was pretreated to new, more restrictive standards. Regulations for storing and containing wastewaters, drilling fluids, and fracking solutions were updated to lower the likelihood of uncontrolled releases at drill sites. The state also issued new rules of well construction intended to reduce incidences of methane leakage and migration. Additionally, the state increased protective setback distances of gas wells from water supplies, established disclosure requirements for fracking chemicals, and expanded presumptions of operator liability for drinking water contamination. 
 
These regulatory improvements have not put Pennsylvania in the clear. The frequency of private water supply impacts attributed to oil and gas activities has declined, yet remains stubbornly above zero. In the five years since regulations were strengthened, the Department of Environmental Protection has documented 132 new cases of water supply contamination caused by shale gas operations. This figure may underestimate the real extent of the problem because settlements reached between industry and homeowners with impaired water supplies need not be disclosed. To compound these present dangers, new threats to freshwater quality and supply may emerge as gas wells, pipelines, and supporting infrastructure age and industry practices evolve to minimize costs and maximize fossil fuel recovery.  
 
Pennsylvania’s experience suggests that the challenge of safeguarding freshwater resources from hydraulic fracturing will persist in one form or another as long as fossil fuels continue to be pulled from the ground. Meeting this challenge willy rely, at least in part, on management and policy approaches that better leverage data and science in decision-making.
 

Smart Management Needs Good Measurements and Sound Science

Uncertainties remain. The truth must be acknowledged if we are to improve management of unconventional oil and gas development. Most, though perhaps not all, of the principal risks posed to freshwater resources by unconventional development have been identified. Yet, these risks have defied quantitation. Moreover, the effectiveness of policies and practices that aim to prevent known causes of contamination has not been thoroughly demonstrated. These shortcomings are not just a Pennsylvania problem. They plague the dozens of other states that now host oil and gas extraction by hydraulic fracturing. So-called expert opinion offers no remedy to this dilemma.
 
Management in the midst of this uncertainty should be done adaptively. Adaptive management is not new. Nor is it trial and error. Instead, adaptive management is a scientific, data-driven way of learning while doing. It is an iterative process that begins by identifying actions or management interventions that might solve a defined problem, followed by monitoring the outcomes of those interventions, and then making adjustments to resolve any of their inadequacies. The process, repeated as necessary, builds understanding and leads to continuous improvement. This adaptive framework could address numerous management goals, including reducing the risk of groundwater contamination by gas well drilling, minimizing stray gas migration from completed wells, and limiting sediment runoff to streams during well site construction. 
 
The success of adaptive management depends on stakeholder participation. Industry must engage with managers and, in particular, scientists from the environmental community to execute it. The track record for this collaboration is not especially strong, but there are encouraging signs and legitimate reasons for hope.
 

Can We Work Together?

The adage “oil and water don’t mix” captures the relationship between the fossil fuel industry and environmental scientists affiliated with universities and other research organizations. The nature of interactions between these two groups typically ranges from disregardful to hostile. Environmental scientists have, according to their job description, focused on unconventional oil and gas development’s effects on water and air quality, with studies that show adverse effects gaining the greatest attention and industry scorn. Industry has responded to studies of water quality impacts by trying to discredit them, inviting criticism that they are more invested in covering up problems than addressing them. This adversarial relationship hurts industry and environmental scientists alike. By not cooperating, environmental scientists are excluded access to monitoring sites, operational information, and other industry data that would strengthen their research. Industry also misses out, scuttling the opportunity to partner with environmental scientists on problem-solving and giving up the chance for constructive dialogue over scientists’ interpretations. The tendency for each group to remain in its own silo has engendered mistrust, leading to gridlock and disagreement that can paralyze decision-making and progress toward better environmental management. 

Cooperative arrangements with industry enabling scientific assessment of fracking impacts, though rare, have been forged. For example, a consortium of companies have engaged with universities (coordinated largely by the Environmental Defense Fund) in the assessment of atmospheric methane emissions from oil and gas operations. On the freshwater side, researchers at Yale have leveraged a collaboration with industry to explore potential groundwater impacts of shale gas development in Pennsylvania. A formal agreement with Southwestern Energy gave Yale researchers the schedules and locations of gas well projects for the company’s Marcellus acreage. With this information, the Yale researchers installed groundwater monitoring wells immediately adjacent to gas wells and measured changes in water quality over two years as several gas wells were drilled, fracked, and brought into production.
 

Going Forward, Together

The Yale/Southwestern Energy study is a proof of concept, demonstrating that collaborative, scientific analysis of freshwater impacts of fracking-related activities is feasible. But this study is insufficient by itself. It serves as a template that must be replicated with different production companies that operate in different regions and that collectively employ a variety of practices and methodologies. 
 
Coordination of this science is critical so that outcomes from different studies can be compared, adaptive management can proceed, and knowledge can be exchanged with policymakers. An advisory board — chaired by a delegate from the host state’s department of environmental protection (or equivalent) and composed of industry members, as well as qualified scientists from universities and environmental organizations — could manage the process. 

Someone has to pay for this science, of course. The Yale/Southwestern Energy study cost just over $500,000, which may seem expensive but is less than one-quarter of the cost incurred to put one Marcellus well into production. Mid-major and major production companies may elect to pay for these studies, recognizing that the investment helps build trust within local communities and contributes to science-based regulation that may be less burdensome to them. Alternatively, or additionally, state taxes on oil and gas extraction could pay for the science. Consider that just 1 percent of Pennsylvania’s 2018 natural gas impact fee would pay for the first year of eight studies similar to the one conducted by Yale and Southwestern Energy.
 
More science is essential, but alone is not enough to either guarantee clean drinking water in areas with fracking or determine how and where unconventional oil and gas development should proceed. Policy-making institutions must listen and be responsive to new science. Policymakers must also make resources available to ensure that policies are, as they evolve, adequately enforced. And we must make a faithful accounting of fracking costs and benefits that reflects our best knowledge. Although science is only part of the solution, its proper role in the management of unconventional oil and gas development is to lead the way by providing decision makers with credible information on environmental impacts and innovative approaches for addressing them. When environmental policy builds on careful science, rigorously analyzed data, and solid facts — pursued without fear of upsetting interested parties or overturning prevailing wisdom — innovative solutions often emerge.