It is well understood that hydraulic fracturing, also known as fracking, has the potential to increase the supply of natural gas available in the US and many other nations. However, many believe that the benefits of hydraulic fracturing are outweighed by the environmental risks of the method and seek to stop the proliferation of hydraulic fracturing wells.
The hydraulic fracturing is a method is where millions of gallons of water, sand and chemicals are pumped underground to break apart the rock and release the trapped gas. The pressure fractures the rock layers and releases gas, petroleum or water that otherwise would not be accessible. But organizations such as the Sierra Club and hundreds of small local citizen groups are against hydraulic fracturing believing that the process causes air, water, climate, and public health issues.
The hydraulic fracturing process can cause some smog and soot forming pollutants to emanate from the well. The Environmental Protection Agency (EPA) has proposed regulations are designed to eliminate these. They have proposed new controls on storage tanks, transmission pipelines and other that would reduce the amounts of cancer causing air pollution and methane. The EPA was sued in 2009 by environmental groups for their failure to act in the control of air pollutants from wells. In March 2011, pollution from natural gas drilling in the Upper Green River Basin in Wyoming triggered levels of ground level ozone worse than those recorded in Los Angeles.
However, the pollutants are not always the same at each well. A study found that in Dish, Texas, the state's environmental regulators detected levels of cancer causing benzene, sometimes at levels dangerous to human health, likely coming 60 drilling wells, gas production pads and rigs, and other facilities. But in Pennsylvania study of air quality near Marcellus Shale drilling sites found no emissions at levels that would threaten the health of nearby residents or workers.
The EPA has been investigating complaints that some hydraulic fracturing has been contaminating water supplies. The most notorious report is concerning the water testing in Pavillion, Wyoming. For many years local residents complained about smells and odd tastes in their drinking water drawn from wells near a natural gas field owned by EnCana Corp of Canada. The EPA performed a study of the water in Pavillion and reported that the best explanation for the pollution was that fluids used in hydraulic fracturing process, migrated up from fracking operations and contaminated an aquifer. The chemicals found included benzene, alcohols and glycols. The EPA also stated that Wyoming was much more vulnerable than other areas of the country to water contamination from fracking chemicals because drilling there often takes place much closer to the surface than in other states.
Although companies have said that the chemicals used in hydraulic fracturing are safe, and states require companies to disclose chemicals they pump underground, many say that the combination of chemicals are a trade secret and therefore exempt from disclosure. Despite this some states, such as Michigan, have found that some unnamed chemicals are used have safety information that indicate that the chemical is extremely harmful to humans.
In Texas, it has been found that the largest well servicing companies that worked in the state withheld the most information about hydraulic fracturing processes. Halliburton and Baker Hughes were found to average more than nine trade secrets were well. The lack of information hinders environmental agencies performing tests in water sources, as they have no information on what to look for.
Many local environmental groups are challenging hydraulic fracturing in countries all over the world, but on a larger scale there is a concern that hydraulic fracturing could lead to climate change issues. The natural gas extraction by hydraulic fracturing can lead to methane gas leaking into the air during extraction. In addition, carbon dioxide is released during methane burning, and is a greenhouse gases (GHG) that contributes to global climate change. With new fracking technologies that allow for the extraction of more gas, the possibility of increased greenhouse gases being generated could be a concern for longer term climate change.
As more states look into legalizing hydraulic fracturing, one question that is frequently asked is about public health and safety. There have been studies on water and air pollution but little data on how hydraulic fracturing has affected the local population. Because much of the hydraulic fracturing wells are quite recent, the long-term effects of hydraulic fracturing on the public are relatively unknown. There have been studies focusing on possible increases in asthma, but there is no concrete evidence as yet. In ten or twenty years the affects of hydraulic fracturing on the public health may become clearer.