Ai Citizen's Guide to
Excavation of Contaminated Soil
What Is the Excavation of
Contaminated Soil?
Excavation of contaminated soil from a site involves
digging it up for "ex situ" (above-ground) treatment or
for disposal in a landfill. Excavation also may involve
removing old drums of chemicals and other buried
debris that might be contaminated. Removing these
potential sources of contamination keeps people from
coming into contact with contamination and helps
speed the cleanup of contaminated groundwater that
may be present.
How Does It Work?
Before excavation can begin, the contaminated areas
must be identified. This requires researching past
activities at the site to identify what contaminants may
have been released and where. The soil is then tested
to better define where contaminants are present.
Contaminated soil is excavated using standard
construction equipment, like backhoes and excavator
trackhoes. The equipment chosen depends on how
large and deep the contaminated area is, and whether
access is limited by the presence of buildings or
other structures that cannot be moved. Long-arm
excavators can reach as deep as 100 feet below
ground, but excavations are generally limited to much
shallower depths due to safety concerns and difficulty
Soil piles are covered with plastic tarps during excavation.
Worker collects soil samples to confirm that soil left onsite is clean.
keeping the hole open. Sometimes soil is excavated
below the water table, which requires walling off the
contaminated area and pumping out the water to keep
dry during excavation.
If excavated soil will be disposed of in a landfill, it
may be placed directly on a dump truck for transport.
If it is to be disposed of elsewhere on the site or
treated, it first may be stock piled on plastic tarps or
in containers. The soil is then covered with tarps to
prevent wind and rain from blowing or washing it away
and to keep workers from coming into contact with
contaminated soil. Excavation is complete when test
results show that the remaining soil around the hole
meets established cleanup levels.
The excavated soil may be cleaned using a mobile
treatment facility brought to the site or disposed
offsite. If the soil is treated onsite, treated soil may be
used to fill in the excavated area. Clean soil obtained
from other locations may be needed to fill in holes as
well. After an excavation is filled in, the area may be
landscaped to prevent soil erosion and make the site
more attractive.
How Long Will It Take?
Excavating contaminated soil may take as little as
one day or as long as several years. The actual time it
takes to excavate will depend on several factors. For
example, it may take longer where:
• The contaminated area is large, very deep, or
below the water table.
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• Contaminant concentrations are high, requiring extra safety precautions.
• The contaminated soil contains a lot of rocks or debris.
• Buildings or site activities limit the movement of equipment.
• The site is remote, or the treatment and disposal facilities are far away.
These factors vary from site to site.
Is Excavation Safe?
Handling contaminated soil requires precautions to ensure safety. Site workers
are trained to follow safety procedures while excavating soil to avoid contact
with contaminants and prevent the spread of contamination offsite. Site workers
typically wear protective clothing such as rubber gloves, boots, hard hats, and
coveralls. These items are either washed or disposed of before leaving the
site to keep workers from carrying contaminated soil offsite on their shoes and
clothing. The tires and exteriors of trucks and other earth-moving equipment
are also washed before leaving the site so that the soil is not tracked through
neighboring streets.
Workers monitor the air to make sure dust and contaminant vapors are
not present at levels that may pose a breathing risk, and monitors may be
placed around the site to ensure that dust or vapors are not leaving it. Site
workers close to the excavation may need to wear "respirators," which are
face masks equipped with filters that remove dust and contaminants from the
air. Contaminated soil is usually covered until it can be treated or disposed of
to prevent airborne dust or being washed away with rainwater. Contaminant
vapors may be suppressed with foams or other materials.
How Might It Affect Me?
Nearby residents and businesses may notice increased truck traffic during soil
excavation and the noise of earth-moving equipment. Excavations are fenced
off to prevent entry to the area until it is backfilled and covered with clean soil.
Why Excavate Contaminated Soil?
Excavation is commonly used where in situ cleanup methods will not work
quickly enough or will be too expensive. Offsite disposal and ex situ treatment
are often the fastest ways to deal with high levels of contamination that pose an
immediate risk to people or the environment. Excavation is also a cost-effective
approach for small amounts of contaminated soil.
Example
Soil excavation for offsite
treatment and disposal was
used to clean up the Federal
Creosote Superfund site
in New Jersey. Residential
housing and a shopping mall
had been built on the 50-acre
property after a wood-treating
facility closed in the 1950s.
Creosote and waste chemicals
that had been stored in
lagoons were buried during
construction.
Contamination was discovered
in the 1990s. Between 2002
and 2008, soil was excavated
from as deep as 35 feet near
93 homes. Some residents
were relocated, and 18 homes
were demolished to reach the
contaminated soil beneath.
A total of 275,000 tons of soil
from this area was transported
offsite for treatment and
disposal. Another 177,000 tons
were excavated from the mall
property. Clean soil was used
to fill in the excavations.
Throughout the work, workers
monitored the air. Soil was
covered with foam and plastic
sheets to reduce odors from
the creosote. Trucks were
cleaned prior to leaving the
property.
For More Information
For more information on this
and other technologies in the
Citizen's Guide Series, contact:
U.S. EPA
Technology Innovation &
Field Services Division
Technology Assessment Branch
(703)603-9910
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.
United States
Environmental Protection
Agency
Office of Solid Waste and
Emergency Response
(5102G)
EPA 542-F-12-007
September 2012
www.epa.gov/superfund/sites
www.cluin.org
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