Fracking, short for hydraulic fracturing, is a drilling technique that pumps high-pressure water, sand, and chemicals deep underground to crack open rock formations and release trapped oil or natural gas. It now accounts for 79 percent of U.S. natural gas production and 65 percent of crude oil production, making it the dominant method of fossil fuel extraction in the country. More than 17.6 million Americans live within a mile of a fracked well.
How the Process Works
Fracking targets oil and gas locked inside dense rock formations, typically shale, that won’t release their resources through conventional drilling alone. The process unfolds in three main phases: drilling, completion, and production.
First, a crew clears and levels the site, then sets up a drilling rig. The rig bores a vertical hole thousands of feet deep, then gradually curves the well horizontally to run through the target rock layer. Steel pipe, called casing, is fed into the well and cemented in place to create a sealed channel.
During completion, which takes one to five weeks, the steel casing is perforated at precise intervals so the well connects to the surrounding rock. Then the actual fracturing begins. A mixture of water, sand, and chemical additives is pumped down the well at extreme pressure, enough to crack the rock. The sand grains wedge into those new fractures and hold them open like tiny doorstops, creating pathways for oil or gas to flow back up the well. A series of valves is installed at the surface to control the flow.
A single fracking operation requires enormous amounts of water. The U.S. Geological Survey puts the range at 1.5 million to 16 million gallons per well, depending on the geology and the length of the horizontal section. Once the well is producing, it can continue for 50 years or more with ongoing monitoring and maintenance. As underground pressure naturally declines over time, a mechanical pump is installed to keep drawing resources to the surface.
Why Fracking Transformed U.S. Energy
Before fracking became widespread in the early 2000s, the oil and gas trapped in shale formations was essentially unreachable. Conventional wells could only tap reservoirs where resources flowed freely through porous rock. The combination of horizontal drilling and hydraulic fracturing unlocked vast new reserves, particularly in formations like the Marcellus Shale in Pennsylvania, the Permian Basin in Texas, and the Bakken in North Dakota. The result was a dramatic surge in domestic production that reshaped global energy markets and turned the U.S. into one of the world’s top oil and gas producers.
Water and Air Quality Concerns
The environmental debate around fracking centers on two things: what goes into the ground and what comes back out.
The fluids pumped into wells contain chemical additives, and under a provision in the 2005 Energy Policy Act commonly called the “Halliburton Loophole,” fracking is exempt from regulation under the Safe Drinking Water Act’s underground injection requirements. It’s also partially or fully exempt from the Clean Water Act, the Clean Air Act, and several other major federal environmental laws. This means oversight falls largely to individual states, which vary widely in how strictly they regulate the practice.
Shale formations targeted by fracking typically sit thousands of feet below freshwater aquifers, and the industry points to that separation as a natural barrier. But concerns persist about well casing failures, surface spills of fracking fluid or wastewater, and the migration of gases through existing fractures in the rock. Studies from the National Institute of Environmental Health Sciences have found that hazardous air pollutants near oil and gas development sites can exceed health-based safety thresholds. Workers performing certain operations face exposure to high levels of volatile hydrocarbons that can be toxic.
A 2022 study found that older adults living near or downwind of unconventional oil and gas sites had a higher risk of premature death compared to those living upwind, suggesting that airborne pollutants from these operations carry real health consequences for nearby communities.
Methane Leaks and Climate Impact
Natural gas produces less carbon dioxide per unit of energy than coal or oil when burned, which is often cited as a climate advantage. But that advantage depends on how much methane, the primary component of natural gas, escapes unburned into the atmosphere during extraction and transport. Methane is 84 times more potent than carbon dioxide as a greenhouse gas over a 20-year period.
Nationally, emissions from the U.S. oil and gas supply chain amount to roughly 2.3 percent of total gas production and represent over 30 percent of all human-caused methane emissions in the country. Some production basins are far leakier. A multi-year study in one western U.S. basin found steady leakage rates of 6 to 8 percent of gas production, with some measurements reaching nearly 15 percent. At those levels, the climate benefit of switching from coal to natural gas shrinks significantly or disappears entirely. Methane also contributes to ground-level ozone formation, a regulated air pollutant linked to respiratory problems.
Earthquakes Linked to Wastewater Disposal
The fracking process itself rarely causes significant earthquakes, but the wastewater it produces does. After a well is fractured, millions of gallons of used fluid come back to the surface. This wastewater is commonly disposed of by injecting it into deep underground wells. When that fluid raises pressure levels along existing fault lines, it can trigger earthquakes.
Oklahoma experienced this firsthand. The state went from averaging a handful of earthquakes per year to hundreds after wastewater injection ramped up. The mechanism is straightforward: injected fluid increases pressure on faults that are already under stress from natural tectonic forces, and when pressure crosses a threshold, the fault slips. After regulators mandated cuts to injection rates, overall earthquake frequency dropped. But research published in Nature Communications found that larger-magnitude earthquakes declined more slowly than smaller ones, because the pressure changes from high-volume injection persist deep underground long after pumping stops.
The Regulatory Landscape
Federal oversight of fracking is unusually limited compared to other industrial activities. The 2005 Energy Policy Act created exemptions that removed fracking from the jurisdiction of several cornerstone environmental laws, including the Safe Drinking Water Act, the Clean Water Act, the Clean Air Act, and the law governing hazardous waste disposal. In practice, this means regulation happens at the state level, creating a patchwork of rules. Some states require full disclosure of the chemicals used in fracking fluid; others allow companies to withhold that information as trade secrets. Setback distances from homes and schools, wastewater handling requirements, and air monitoring standards all vary by state.
This regulatory gap has made fracking one of the most polarizing energy issues in the U.S. Supporters see it as the engine of American energy independence and a source of jobs in rural communities. Critics argue that the health, environmental, and climate costs are being externalized onto the people who live closest to the wells, often without their full knowledge of what chemicals are being used or what risks they face.