A Citizen’s Guide to

Fracturing for Site Cleanup

What Is Fracturing For Site Cleanup?

Fracturing creates or enlarges openings in bedrock or 

dense soil, such as clay, to help soil and groundwater 

cleanup methods work better. The openings, called 

“fractures,” become pathways through which 

contaminants in soil and groundwater can be 

treated in situ (in place, underground) or removed 

for above-ground treatment. Although fractures can 

occur naturally in soil and rock, they are not always 

wide or long enough to easily reach underground 

contamination using cleanup methods. Fracturing can 

enlarge the cracks and create new ones to improve 

the speed and effectiveness of the cleanup. Fracturing 

is most commonly used with several in situ cleanup 

methods. (See A Citizen’s Guide to Bioremediation 

[EPA 542-F-12-003], In Situ Chemical Oxidation [EPA 

542-F-12-011], In Situ Chemical Reduction [EPA 

542-F-12-012]), and Soil Vapor Extraction and Air 

Sparging [EPA 542-F-12-018]).

How Does It Work?

There are three ways to fracture soil or rock: 

• Hydraulic fracturing pumps water or a water-based 

fluid under pressure into holes drilled in the 

ground. The force of the water causes soil (or 

sometimes rock) to fracture. The water or fluid can 

be pumped with sand or other “propping agents.” 

Propping agents help keep the fractures open 

during cleanup. 

• Pneumatic fracturing injects air or other gases into 

the holes to fracture dense soil. Air forced into the 

soil also can promote evaporation of chemicals 

that change to gases quickly when exposed to air. 

The gases may be captured and treated above 

ground. 

• Blast-enhanced fracturing uses explosives, such 

as dynamite, to fracture rock. The explosives are 

placed in holes and detonated. The main purpose 

is to create fractures for pump and treat cleanup. 

Both pneumatic and hydraulic fracturing can 

direct pressure to specific underground zones, but 

blast-enhanced fracturing cannot. 

How Is Fracturing for Environmental 

Cleanup Different from Fracturing 

to Recover Oil and Gas?

Oil and gas hydraulic fracturing is used to stimulate 

the recovery of oil or natural gas from underground 

geologic formations. Oil and gas hydraulic fracturing 

works by pumping a mixture of fluids and other 

substances into the target formation to create and 

enlarge fractures. Such operations are much larger, 

use different equipment and chemical additives, occur 

at greater depths, and use higher volumes of fluid 

than fracturing for site cleanup. Fracturing to clean 

up a contaminated site rarely exceeds a depth of 100 

feet, and the affected area around the fracturing well 

usually is less than 100 feet in any direction. However, 

wells to extract oil and gas often are drilled hundreds or 

thousands of feet downward and sometimes horizontally into the oil- or gas-bearing rock. Fractures may 

extend over 500 feet from these wells.

Nitrogen Gas

Bedrock

Packer

Sandy Soil

Gas Injected

Nitrogen gas is injected for pneumatic fracturing of bedrock.
United States Office of Solid Waste and EPA 542-F-12-008

Environmental Protection Emergency Response September 2012

Agency (5102G) www.epa.gov/superfund/sites

www.cluin.org

NOTE: This fact sheet is intended solely as general information to the public. It is not intended, nor can it be relied upon, to create any 

rights enforceable by any party in litigation with the United States, or to endorse the use of products or services provided by specific 

vendors. The Agency also reserves the right to change this fact sheet at any time without public notice.

Example

Pneumatic fracturing was used 

to help clean up an area of the 

Hunters Point Naval Shipyard 

Superfund site in California. For 

years the site was used for ship 

building and maintenance, which 

contaminated groundwater with 

fuels, pesticides, heavy metals, 

industrial solvents, and other 

chemicals. 

To clean up solvents from the 

groundwater, EPA needed to inject 

small particles of iron underground 

over an area larger than an acre 

to reach contaminants from 5 to 

25 feet below ground. Pneumatic 

fracturing by high-pressure 

injection of nitrogen gas was used 

to create and widen fractures in 

soil. The fractures allowed the 

injected iron to spread more widely 

and evenly underground and 

treat more of the contaminated 

groundwater. After 12 weeks, 

solvent concentrations within the 

treatment areas decreased by 

an average of 87 to 99 percent. 

Additional monitoring is being 

conducted as part of the site-wide 

groundwater monitoring program.

For More Information

For more information about this 

and other technologies in the 

Citizen’s Guide Series, visit:

www.cluin.org/remediation

www.cluin.org/products/

citguide

www.cluin.org/techfocus/

default.focus/sec/Fracturing/

cat/Overview/

How Long Will It Take?

Fracturing rock and soil does not take very long. It may only take a few days. 

However, even with the help of fracturing, actual cleanup may take months or 

years, depending on several factors. For example, it will take longer where: 

• The contaminated area is large or deep.

• Contaminant concentrations are higher.

• Groundwater flow is slow.

Is Fracturing Safe?

When properly used, fracturing is a safe way to make cleanup methods faster 

and more efficient. Because fracturing affects the soil and bedrock, it is not 

typically used where it can affect building foundations and underground utilities. 

To be sure fracturing does not damage nearby structures, special monitoring 

equipment is used to measure any movement of the ground. When fracturing 

is conducted at shallow depths, the ground surface around the holes may rise 

as much as an inch, but will eventually settle back close to its original level if 

fractures are not propped open. 

How Might It Affect Me?

Residents near the site may see increased truck traffic when fracturing 

equipment and materials needed for cleanup are delivered to the site. 

Residents also may hear noise from the detonation of explosives and from 

machines used to inject water or air underground.

Why Use Fracturing For Site Cleanup?

Fracturing is used to help 

reach contaminants in rock 

and dense soil so that they 

can be cleaned up faster 

and more completely. It 

offers a way of reaching 

contamination deep in the 

ground where it would be 

difficult or costly to excavate. 

Fracturing can reduce the 

number of wells needed for 

certain cleanup methods, 

which can save time and 

reduce cleanup costs. 

Fracturing has been used in cleanups at over 15 Superfund sites and many 

more sites throughout the country.

Pneumatic fracturing at the Hunters Point Naval Shipyard

Superfund site