Hydraulic fracturing, or fracking, affects the environment in several significant ways: it releases methane into the atmosphere, consumes millions of gallons of water per well, generates toxic wastewater, fragments wildlife habitat, and has triggered earthquakes in regions with heavy drilling activity. The scale of these impacts varies by region and operator, but the cumulative effects are well documented.
Methane Leaks and Air Pollution
Fracking’s biggest climate impact comes not from the burning of natural gas but from methane that escapes before it ever reaches a power plant or home. Methane is a potent greenhouse gas, trapping far more heat than carbon dioxide over a 20-year period. The federal government has estimated that about 1% of gas production leaks into the atmosphere from oil and gas facilities. But a Stanford University study surveying major U.S. production regions found the real average is closer to 3%, with some areas far worse. In the New Mexico portion of the Permian Basin, nearly 10% of total methane volume produced in 2019 escaped directly into the atmosphere.
About half of those emissions come from midstream infrastructure, the pipelines, compressor stations, and processing plants that move gas from the wellhead to market. This means the problem extends well beyond the drilling site itself. In addition to methane, fracking operations release volatile organic compounds that react with sunlight to form ground-level ozone, a key ingredient in smog. Communities near dense drilling zones often report degraded air quality as a result.
Water Use at an Enormous Scale
Each fracked well requires between 1.5 million and 16 million gallons of water, according to the U.S. Geological Survey. The wide range depends on the rock formation, whether the well is vertical or horizontal, and how many stages of the well are fractured. In arid regions like West Texas and eastern New Mexico, this level of consumption competes directly with agriculture, municipal water supplies, and natural ecosystems that depend on the same sources. During drought conditions, the strain intensifies.
What Goes Into the Ground
Fracking fluid is mostly water and sand, but it also contains a cocktail of chemical additives. A congressional investigation identified hundreds of products used in fracking operations. The most common additive was methanol, a hazardous air pollutant found in 342 different fracking products. Isopropyl alcohol appeared in 274 products, and ethylene glycol in 119. Some operations have used diesel fuel, which contains benzene, toluene, xylene, and ethylbenzene, all regulated contaminants under the Safe Drinking Water Act. Benzene is a known human carcinogen.
Other chemicals found in fracking fluids include lead, which is particularly harmful to children’s neurological development, and hydrogen fluoride, a highly corrosive substance that can cause severe tissue damage. The exact mixture varies by operator and well, and companies have historically resisted full disclosure of their formulations.
What Comes Back Up
After a well is fracked, a portion of the injected fluid returns to the surface along with water that has been trapped underground for millions of years. This “produced water” is far more hazardous than what went in. It picks up salts, heavy metals, and naturally occurring radioactive materials from deep rock formations. Lab analysis has identified 266 different organic compounds in produced water, including carcinogenic polycyclic aromatic hydrocarbons and 29 elements including chromium, cadmium, lead, and uranium. The salt concentration alone can reach four times that of ocean water.
Federal rules prohibit the direct discharge of this wastewater into rivers and streams, and since 2016, facilities are also banned from sending it to public sewage treatment plants, which aren’t equipped to handle the contaminants. Most produced water is disposed of by injecting it deep underground into disposal wells, which creates its own set of problems.
Earthquakes From Wastewater Disposal
Injecting millions of gallons of wastewater underground increases fluid pressure along existing faults, reducing the friction that keeps them locked in place. The result is induced seismicity. Oklahoma, which was historically one of the least seismically active states in the country, experienced four earthquakes of magnitude 5.0 or greater linked to fluid injection, three of them in 2016 alone. The largest induced earthquake documented in scientific literature was a magnitude 5.8 event in central Oklahoma in September 2016. Similar quakes have struck Arkansas, Kansas, and the Raton Basin in Colorado.
These are not trivial tremors. A magnitude 5.8 earthquake can crack walls, topple chimneys, and damage older buildings. The connection between disposal well activity and earthquake frequency is strong enough that Oklahoma eventually imposed volume limits on injection wells in the most affected areas, and seismicity dropped in response.
Risks to Drinking Water
The question of whether fracking contaminates drinking water is more nuanced than headlines suggest. The fracking process itself happens thousands of feet below most freshwater aquifers, and direct upward migration of fracking fluid through solid rock is unlikely. The more common pathway for contamination is faulty well construction. When the steel casing or cement seal around a well is defective, methane and other gases can migrate into shallow groundwater.
This is exactly what happened in Dimock, Pennsylvania, where aquifer contamination was traced to casing leaks in at least three wells rather than to the fracking process itself. The distinction matters practically, because it means the risk is tied to construction quality and oversight rather than to something inherent in the technique. But for homeowners whose well water starts bubbling with methane, the cause is academic. The result is the same: undrinkable water.
Habitat Loss and Fragmentation
A single well pad and its associated roads, pipelines, and cleared areas remove about 8.8 acres of forest in Pennsylvania’s Marcellus Shale region. But the true footprint is larger. After accounting for ecological edge effects (changes in light, temperature, and moisture that ripple outward from a cleared area), each pad affects roughly 30 acres of forest. Multiply that by thousands of wells across a region, and the cumulative damage to wildlife habitat is substantial.
Fragmentation does more than shrink the total acreage available to animals. It severs migratory pathways, isolates populations from one another, and creates corridors for invasive species to spread. Pipelines alone can introduce thousands of meters of hard edge into previously continuous forest, altering the microclimate and increasing nest predation for birds. Species that need large, unbroken tracts of forest, like certain warblers and forest-interior songbirds, are especially vulnerable.
Soil Damage From Brine Spills
Spills of produced water, sometimes called brine, are one of the most persistent environmental problems associated with fracking. The high sodium chloride content destroys soil structure. Sodium causes clay particles in the soil to swell and then disperse, collapsing the tiny air pockets that allow water to infiltrate and roots to grow. Once this happens, the soil becomes prone to erosion and essentially hostile to plant life. Chloride levels in and around spill areas are toxic to many biological species, and seeds exposed to high-salinity soil can’t absorb enough water to germinate.
Cleaning up a brine spill is expensive and often only partially successful. The salts can leach into deeper soil layers and persist for years, continuing to suppress vegetation long after the surface has been treated. In states like North Dakota, where thousands of wells produce enormous volumes of brine, even small, routine spills accumulate into a significant long-term problem for agricultural land and native grasslands.