Shale gas drilling is being blamed for contaminating water and causing other environmental problems in several states. Yet according to a recent ProPublica article, there are ways to extract natural gas from shale that are far less harmful to the environment than the methods now most commonly in use. Unfortunately, the gas drilling industry has been slow to adopt these methods.
Natural gas is extracted from shale in a process known as hydraulic fracturing. While gas drillers have used this fracturing process for decades, its use has expanded in the past few years as energy companies began exploring shale formations. The process has proven so successful that some experts believe that the U.S. is on the cusp of a shale gas drilling boom. Boosters of shale gas drilling claim it will play a key role in pushing the U.S. towards energy independence.
Shale gas drilling involves injecting water, sand, and a cocktail of chemicals at high pressure into rock formations thousands of feet below the surface. This opens existing fractures in the rock and allows gas to rise through the wells. The practice makes drilling possible in areas that 10 to 20 years ago would not have been profitable.
The major concern with shale gas drilling is the chemicals used in the process. Because the federal Energy Policy Act of 2005 exempted hydraulic fracturing from regulation under the Safe Drinking Water Act, shale gas drillers don’t have to disclose what chemicals they use. Some chemicals commonly used in this type of drilling include benzene, glycol-ethers, toluene, 2-(2-methoxyethoxy) ethanol, and nonylphenols. All of these chemicals have been linked to health disorders when human exposure is too high.
According to ProPublica, energy companies have figured out how to drill wells with fewer toxic chemicals, and enclose wastewater so it can’t contaminate streams and groundwater. Yet these safer methods are not used very much in the 32 states where shale gas drilling is currently taking place.
Diesel, which contains the highly toxic chemical benzene, has been the most commonly used liquid in this type of drilling. According to ProPublica, some gas drillers are starting to phase out the use of diesel in a switch to “greener” chemicals, such as mineral oil. EnCana, a Canadian company that operates on both sides of the border, recently said it stopped using 2-Butoxyethanol, a solvent that has caused reproductive problems in animals BJ Services, one of the largest fracturing service providers in the world, has discontinued the use of fluorocarbons, a family of compounds that are persistent environmental pollutants.
Unfortunately, it is still too difficult to gauge how safe any given company’s drilling fluid is. According to ProPublica, most companies still keep the exact makeup of their fluids a secret from state and federal regulators, and there are no laws that dictate what chemicals can be used for drilling on U.S. soil.
Coming up with such standards however, wouldn’t be difficult. In fact, ProPublica says they already exist, at least when it comes to off-shore drilling. Both European law and U.S. regulations dictate that chemicals used in the North Sea and the Gulf of Mexico must be safe enough that they won’t kill fish and other organisms if they are dumped overboard.
Disposing of the wastewater from hydraulic drilling is another environmental problem that could be addressed with the adoption of safer methods. According to ProPublica, for the most part, waste is now collected in open, dirt-brimmed waste pits where it sits until it’s hauled off to treatment facilities or injection wells. While it awaits removal, the toxic water can seep into the ground, or even overflow the pit when there has been heavy rain or snow.
According to ProPublica, this hazard can be eliminated through the use of a closed loop system, a series of pipes that gathers the waste as it comes out of a gas well, separates some of the water for reuse, and confines the concentrated leftovers in a steel tank. The Environmental Protection Agency has found that such systems reduce the volume of drilling fluids used by 90 percent, eliminate the need for permanent pits, and greatly reduce the possibility of spills. A 2001 case study by the Texas Railroad Commission found that while the construction of a closed loop system would cost a driller more initially, savings are realized in the long term because there is no need to construct a waste pit, remediate the land after drilling is complete or haul toxic materials.
Yet in spite of the clear advantages of a closed loop system, ProPublica says the drilling industry continues to aggressively fight efforts by states to enact regulations that would encourage their use.