United States Office of Solid Waste and EPA 542-F-01-015

Environmental Protection Emergency Response May 2001

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

www.cluin.org

A Citizen’s Guide

to Fracturing

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 proposed 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.

  	
	


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 called fractures, create

paths through which harmful chemicals can be removed or destroyed.

   	

Harmful chemicals can travel deep below the ground surface. As a result, reaching the chemicals 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-F01-025]). 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.
2

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 more pathways for

polluted groundwater to reach wells drilled for pump and treat cleanup.

 	
	
 

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.

  	
	


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 or NAPLs—chemicals that don’t dissolve readily in the groundwater. 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.

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



	


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.

air blast

ground surface

sand

chemical evaporates and

gas rises through the soil

air treatment system

Pneumatic Fracturing

clay

fractures