United States
Environmental Protection
Agency
Office of Solid Waste and
Emergency Response
(5102G)
&EPA A Citizen's Guide
to Fracturing
The Citizen's Guide Series
EPA 542-F-01-015
May 2001
www.epa.gov/superfund/sites
www.cluin.org
EPA uses many methods to clean up pollution at Superfund and other sites. If you live, work, or go to school near
a Superfund site, you may want to learn more about cleanup methods. Perhaps they are being used or are pro-
posed for use at your site. How do they work? Are they safe? This Citizen's Guide is one in a series to help
answer your questions.
What is fracturing?
Fracturing is a way to crack rock or very dense soil, like clay, below ground. It is not
necessarily a cleanup method in itself. Rather, fracturing is used to break up the ground to
help other cleanup methods work better. The cracks, which are calledfractures, create
paths through which harmful chemicals can be removed or destroyed.
How does it work?
Harmful chemicals can travel deep below the ground surface. As a result, reaching the chemi-
cals to clean them up can be difficult. Fracturing helps create paths through rock and dense soil
to where the chemicals are located. Then the harmful chemicals can be pumped out of the
ground through wells and treated (See A Citizen's Guide to Pump and Treat [EPA 542-F-
01 -025]). Or cleanup materials, like microbes and oxidants, can be pumped down into the
polluted area to destroy the harmful chemicals (See A Citizen's Guide to Bioremediation
[EPA 542-F-01-001] and A Citizen's Guide to Chemical Oxidation [EPA 542-F-01-013]).
There are three ways to fracture soil and rock:
Hydraulic fracturing uses a liquid—usually water. The water is pumped under pressure into
holes drilled in the ground. The force of the water causes the soil (or sometimes rock) to crack.
It also causes existing fractures to grow larger. To fracture soil at greater depths, sand is pumped
underground with the water. The sand helps prop the fractures open and keep them from closing
under the weight of the soil.
Pneumatic fracturing uses air, to fracture soil. It also can help remove chemicals that
evaporate or change to gases quickly when exposed to air. When air is forced into the soil,
the chemicals evaporate and the gases are captured and treated above ground. (See the
figure on page 2.)
Air can be forced into the ground at different depths within a hole. When air is forced near
the ground surface, the surface around the holes may rise as much as an inch, but will settle
back close to its original level. In both pneumatic and hydraulic fracturing, equipment placed
underground directs the pressure to the particular zone of soil that needs to be fractured.
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For more
information
write the Technology
Innovation Office at:
U.S.EPA(5102G)
1200 Pennsylvania
Ave., NW
Washington, DC
20460
or call them at
(703) 603-9910.
Further information also
can be obtained at
www.cluin.org or
www.epa.gov/
superfund/sites.
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Blast-enhanced fracturing uses explosives, such as dynamite, to fracture rock. The explo-
sives are placed in holes and detonated. The main purpose is to create more pathways for
polluted groundwater to reach wells drilled for pump and treat cleanup.
Is fracturing safe?
When properly used, fracturing is a safe way to help cleanup methods work better. Before
fracturing is used, EPA studies the site and tests the method to confirm it can work.
EPA does not conduct fracturing near underground pipelines or above-ground
structures that can be damaged.
- How will it ?
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. The time it takes to clean up a site depends on
several factors:
• size and depth of the polluted area
• types and amounts of harmful chemicals present
• type of soil or rock
• cleanup method used
Why use fracturing?
Fracturing is used to help reach chemicals in rock and dense soil so they can be cleaned up
faster. It offers a way of reaching pollution deep in the ground where it would be difficult or
costly to dig down so far. Fracturing can reduce the number of wells needed for certain cleanup
methods, which can save time and reduce cleanup costs. Often fracturing is used to help clean
up non-aqueous phase liquids orNAPLs—chemicals that don't dissolve readily in the ground-
water. NAPLs are difficult to clean up where there are few fractures in the ground. Fracturing
has been used in cleanups at many sites throughout the country.
NOTE: This fact sheet is intended solely as general guidance and 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.
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