At a recent shale gas symposium in South Africa, an anti-fracking environmentalist asked, “If hydraulic fracturing is so safe, why do drilling operators working in Pennsylvania’s Marcellus shale play dispose the backflow out of state in Ohio?” The question, satirically proposed, was intended to show that even a natural gas–producing state wants nothing to do with the fracking wastewater.
Hydraulic fracturing (fracking) requires from 3 to 5 million gallons of fluid per well. The fracturing fluid is a proprietary mixture consisting of at least 98% water and sand with the remaining 2% or less consisting of chemical additives, each having a specific function.
Although there are hundreds of chemicals that could be used as additives, typically there are no more than 12 used in the fracturing process. Most are chemicals found in commonly used household or personal care items and pose little or no health risks. However, a limited number are classified as hazardous substances.
After stimulation, about 20% to 40% of the fluid flows back to the surface and must be disposed of. The most common disposal options are recycling, treatment and discharge to surface waters, underground injection, and storage in open-air pits. When injection is the most practical solution, the flowback is injected into deep—up to 10,000 feet—underground porous rock formations and sealed above and below by unbroken, impermeable strata.
The answer to the question posed in South Africa has nothing to do with Pennsylvania’s supposed disdain for fracking fluid but is rather a matter of simple geology. Pennsylvania’s tightly formed, low-porosity underground geology is not suitable for deep injection disposal wells. Ohio’s geological underbelly, in contrast, is composed of deep, cavernous permeable rock formations ideally suited for injection.
This is why Ohio is home to 176 injection disposal wells operated by more than 80 companies. Compare that with just six active wells in neighboring Pennsylvania. And, nationwide, there are more than 150,000 such injection wells in operation, injecting more than 2 billion gallons of fluid every day. These wells are regulated by the Environmental Protection Agency (EPA) under the Safe Drinking Water Act, and over the past 50 years, there have been only a handful of known incidents of direct contact or chemical migration into ground water.
The potential harmful effects of fracking fluid for people and the planet should not be minimized. But there are few, if any, known cases of anyone being hospitalized or harmed from contact with fracturing fluid or its flowback. Evolving best practices, when consistently employed to select sites with the proper geology, construction and casing, and management of the handling, injecting and disposal of the fluid have all but eliminated problems and complaints.
In addition, the brouhaha over fracturing fluid, as reflected in that question about disposal of Pennsylvania’s wastewater, is lacking some perspective.
One of the reasons wastewater much be carefully disposed of is because of its high salt content, as the water can bring up underground salt from geologic formations. But consider: Salt is the most commonly used deicing chemical in the United States, and is spread at a rate of approximately 20 million tons per year. The EPA has acknowledged that "special consideration and best management practices are needed to protect reservoirs and other drinking water supplies near treated highways and salt storage sites from contamination with road salt runoff.” Yet the salting goes on.
One of the most toxic chemicals used in fracturing fluid (to prevent scaling in the drill pipe) is ethylene glycol. According to the Centers for Disease Control (CDC), consuming around 150–1,500 milliliters (ml) of it may be fatal. In humans, the lethal dose is in the range of 1,400–1,600 milligrams per kilogram (mg/kg).
Not something you want in your drinking water, but even so, ethylene glycol is commonly present in many household products, such as antifreeze, deicing products, detergents, paints, and cosmetics. Again, per the CDC, ethylene glycol vapor concentrations have been measured in the air at airports during de-icing operations at up to 22 mg/m3. Ethylene glycol has also been detected in airport runoff.
And the reality is that people expose themselves to far worse things every day. Perchloroethylene, the most commonly used chemical in dry cleaning clothes, is a carcinogen that has been linked to serious health problems, particularly for workers or nearby residents who inhale the fumes, or who drink water contaminated with it. The substance remains on your clothes after they come home from the dry cleaners, and has been shown to build up over time.
Then there’s toothpaste. Yes, toothpaste; the sodium fluoride found in almost every tube of fluoridated toothpaste is more hazardous and toxic than any of the additives in hydraulic fracturing fluid. That’s why, since 1997, the Food & Drug Administration has required all fluoride toothpastes sold in the U.S. to carry a poison warning label, as a single tube of toothpaste contains enough sodium fluoride to kill a child. While toothpaste-induced fatalities are thankfully extremely rare, several hundred people every year call poison control hotlines after someone in the household consumes too much toothpaste.
In closing, it’s convenient and easy to point fingers at hydraulic fracturing as another activity that if, not curtailed, will destroy humanity. The ascent of man is one of risk management and ultimately doing the right thing. Controls, oversight, and improvements are necessary when our future is at stake. But let’s deal in facts rather than the mindless cut and pastes that naysayers proclaim to a public who go about brushing their teeth, driving behind salt spraying trucks, sitting in aircraft during deicing procedures, and sending their clothes to the local dry cleaner, without thinking of the potential harm they are doing to themselves and Mother Earth. Time to put fracking in proper perspective.