Hydraulic fracturing or "fracking" is a technique employing a highly pressurized mixture of water, sand and chemicals to extract oil and natural gas from shale deep beneath the Earth's surface. Although the basic technology has been known for decades, fracking has boomed since 1998. Fracking currently produces more than half of the oil and two-thirds of the natural gas for the United States.
From a vertical well that is drilled thousands of feet deep, a horizontal well is drilled into shale in which deposits of oil and natural gas are trapped. The fracking liquid is pumped down the well with sufficient pressure to fracture the shale and release the entrapped oil and gas. Wastewater that is pumped back to the surface is disposed by injecting it under high pressure into separate, deep wells.
Dr. Clif CleavelandIn addition to the chemicals used in extracting oil and gas, a variety of heavy metals, organic compounds and naturally occurring radioactive substances are released when shale is fractured. These contribute to the toxicity of the wastewater.
More than 300,000 wells in 21 states were in operation in 2016. A typical well and related structures occupy three to five acres. Texas, Pennsylvania, Kansas, Montana, North Dakota and Ohio lead the nation in numbers of wells. Although large shale deposits are located beneath Southeast Tennessee and Northwest Georgia, there has been little fracking activity in the region. Fracking is banned in New York, Maryland and Vermont.
Here are some points to consider about fracking.
» Earthquakes. Increased earthquake activity has been linked to the intensity of fracking. Most quakes related to fracking sites have an intensity below 3 on the Richter scale and cannot be felt. Quakes of greater strength may cause structural damage. In Oklahoma, frequency of earthquakes above magnitude 3 rose from a few annually from 1980 to 2010 to more than 500 in 2014. A magnitude 5.6 quake in Oklahoma in September 2016 was related to fracking activity. Most quakes are blamed on the process of disposing of waste- water.
» Global warming. Methane, the principle component of natural gas, is a potent "green house gas" with 30 to 80 times the heat-retaining potential of carbon dioxide. Aerial surveys over some natural gas wells have detected significant leaks of methane into the atmosphere. Concentrations of methane in the atmosphere have steadily increased since 2007.
» Air and water pollution. Hundreds of chemicals have been identified in extraction fluids and wastewater. The impact of many of these chemicals on health is unknown. The chemicals contaminate air and water. Millions of people living close to fracking sites are especially vulnerable to these pollutants. Worsening asthma has been attributed to fracking-related pollution. Methane may pollute groundwater, leading to tap water that is flammable.
Some fracking-related chemicals are known to block hormonal activity. Others possess properties of estrogen and androgens. A 2016 study from the Yale School of Public Health identified fracking-related pollutants that are known to cause cancer. Fifty-five "unique compounds with carcinogenic potential" were documented. Chemicals linked to leukemias and lymphomas were identified.
Research must be funded to determine the toxicity of all chemicals released in fracking and wastewater disposal. Close monitoring of air and water for these toxins is essential if we are to prevent widespread disease from fracking-related chemicals.
Monitoring the health of residents who live near fracking sites for malignancies, respiratory disease and metabolic abnormalities is vital. Results must be made public.
Fracking has become a vital source of fossil fuel. Protection of the public's health must not be overlooked as this industry expands. Human illness and contamination of air and water must never be viewed as acceptable, collateral damage for fracking.
Clif Cleaveland, M.D., is a retired internist and former president of the American College of Physicians. Email him at ccleaveland@timesfreepress.com.