Hydraulic fracturing, or “fracking” as it’s more commonly called, has become the topic of heated debates in recent years. Its proponents claim that it’s a totally safe and necessary process that will help with energy independence and boost local economies by providing jobs. Its detractors fear environmental and ecological disaster if fracking is allowed to continue and to expand into new regions. With accusations flying back and forth, it’s hard to know what to believe. Let’s take a look at current scientific knowledge of the process to get a better grasp on the true situation.
Before we get into the implications of fracking, we need to understand the process better. Natural gas generally forms deep below the earth’s surface as long-buried organic matter decays (though it can also form near the surface in areas such as swamps and landfills where there is a lot of decay). Gas is lighter than rock, so it bubbles up through permeable rock layers until it hits an impenetrable one. To oversimplify somewhat, conventional natural gas wells drill through that layer and collect the gas as it rises to the surface. Natural gas can also bubble out of oil wells as the pressure on the liquid is released.
Hydraulic fracturing comes into play for gas that is trapped inside semipermeable rock layers rather than underneath a solid layer. In the US and Canada, one of the most frequently discussed formations is the Marcellus Shale, which underlays parts of Ontario, New York, Pennsylvania, New Jersey, Maryland, Virginia, West Virginia, Kentucky, Tennessee, and Ohio. Since merely drilling a hole into the shale won’t release the gas that’s trapped inside pockets within the rock, the rock has to be broken apart to release the gas. This is where fracking becomes necessary. Water is forced into the rock at extremely high pressure to crack it and allow the gas to escape, but water alone isn’t enough to do the job. Sand is added to the mix to hold the fractures open after the water is pumped out, and various chemicals are added to reduce friction, prevent microbial contamination, change the surface tension or viscosity of the liquid, and protect the drilling equipment (this mix is sometimes called “slurry”). The contaminated water then has to be pumped out and disposed, generally by being deposited into separate disposal wells.
There are many concerns about the effects of hydrofracking. Hundreds of different chemicals can be used in the process, and while some are perfectly safe, many more are known carcinogens, toxins, or neurotoxins (and some are radioactive). A large number of the compounds used are classified as proprietary chemicals which don’t have to be disclosed and may not have gone through rigorous third-party testing to verify if they are safe or not. Even governmental studies on the effects of fracking have been somewhat limited in scope due to pressure from politicians who support the industry and from major players in the industry itself. With so much secrecy surrounding the operations, it’s hard to determine the true effects, leading to even more concern in areas where gas companies want to put new wells. If the chemicals are as safe as the drillers claim, why won’t they let them be independently tested? It’s hard to trust the word of companies who stand to make billions of dollars from gas extracted by fracking.
Another major concern is groundwater contamination from the drilling and the disposal wells. Not all of the slurry that is injected into the wells can be extracted, and there have also been leaks from disposal wells (not to mention to potential for leaks as the wastewater is transported). Those chemicals and radioactive particles can migrate into nearby aquifers, contaminating the drinking water for residents of the area. The gas itself can also wind up in drinking water, leading the the famous flammable water seen in the anti-fracking documentary Gasland (skip to 2:16 in the trailer below for a really scary demonstration of this). This effect is worsened by the horizontal drilling employed in hydrofracking wells; typical wells go straight down into the earth, whereas in fracking the wells go down to the depth of the trapped gas and then branch out sideways. Even if you refuse to put a well on your land, if your neighbor allows it, you can have drilling directly underneath your home. In rural areas where people depend on wells on their own land rather than municipal water supplies, this can be particularly devastating.
Air pollution is also an ongoing problem with natural gas mining, both from methane and other gasses escaping directly from the wells and from emissions from processing the gas. While burning natural gas to produce energy is cleaner than burning coal or petroleum, it still has dangerous byproducts such as carbon dioxide, carbon monoxide, and particulate matters. The components of the gas itself are also dangerous; volatile organic compounds (VOCs) can cause ozone to form, leading to increased asthma rates and other respiratory illnesses, and on their own VOCs can lead to cancer, brain damage, and birth defects. Methane leaks from the wells can lead to increased greenhouse warming, possibly making these wells worse in the short-term than burning oil and coal depending on how much gas escapes. In a bit of good news, the EPA just issued new rules to curb emissions from gas wells and production.
Perhaps the strangest and least-expected side effect of fracking is increased seismic activity. In some regions where fracking has been introduced in recent years, there have been six times as many earthquakes as there were just a few years ago. We briefly discussed this back in December before the research was complete, and a new study released last week confirmed that it’s the disposal wells causing the earthquakes rather than the actual gas wells (which isn’t terribly comforting, as the two go hand in hand). Most of the quakes to date have been so weak as to barely be detectable and certainly not strong enough to do property damage, but it’s highly disconcerting to be having earthquakes at all in areas that aren’t along major fault lines. More study is needed to determine what circumstances cause the seismic activity (since not all wells are affected), but it isn’t currently thought that they can cause earthquakes anywhere near the scale of those found on plate boundaries like the San Andreas fault in California.
It’s pretty clear from the scientific evidence that fracking in its present state can be extremely dangerous, both for residents near the wells and for the general public. It’s possible that tighter controls on the chemicals used and the disposal methods could alleviate many of the problems, but right now, the glowing ads about clean energy production are misleading if not downright propaganda for the gas companies.