Engineering Controls on
Brownfields Information Guide:
How They Work with Institutional Controls; the Most Common Types Used;
and an Introduction to Costs
Introduction
Engineering controls (ECs) encompass a variety of engineered and constructed physical barriers (e.g., soil capping, sub-
surface venting systems, mitigation barriers, fences) to contain and/or prevent exposure to contamination on a property.
In contrast, institutional controls (ICs) are administrative or legal instruments (e.g., deed restrictions/notices, easements,
covenants, zoning) that impose restrictions on the use of contaminated property or resources. ICs are also used to
identify the presence of ECs and long-term stewardship (LTS) requirements. Long-term stewardship refers to the activities
necessary to ensure that ECs are maintained and that ICs continue in force. Additional information regarding LTS can be
found at: www.epa.gov/brownfields/tools/lts_fs_04_2008.pdf
The need for ECs and/or ICs is identified as part of selecting a cleanup remedy and will vary depending on a number
of factors, including but not limited to, the planned activity and land use for the property, the extent and location of
contamination, and the environmental medium impacted. While it is not uncommon to find ICs without ECs, ICs are
typically an integral part of EC protectiveness. For example, the most common ICs for brownfield cleanup projects (e.g.,
deed notices/restrictions, environmental covenants, state registries) provide information or notifications that residual
contamination may remain on a property and identify ECs such as caps, mitigation barriers, or fencing, which are
intended to restrict access and exposure to contamination, and eliminate further migration of contamination. Over the
past several years environmental covenants have become an increasingly popular form of LTS to address activity and
land use restrictions and engineering control installation, operation, and maintenance. Environmental covenants provide
a mechanism to ensure that land use restrictions, mandated environmental monitoring requirements, and a wide range of
common engineering controls designed to control the potential environmental risk of residual contamination will be reflected
on the land records and effectively enforced over time as valid real property servitude. Currently 25 states have enacted
legislation to adopt a form of the Uniform Environmental Covenants Act (UECA). More information regarding UECA can be
found at: www.environmentalcovenants.org/
There are many different types of ECs and they vary from property to property, depending on the contaminants found and
the type of media impacted. The following is a list of the more commonly used ECs at brownfield properties.
• Capping in Place (Asphalt or Concrete) - The
use of paved areas (e.g., parking lots, roadways)
and building foundations as surface barriers or
caps over contaminated soil. Capping in place
involves creating and maintaining a hard surface,
usually concrete or asphalt, over contamination.
The result is a high strength, low permeability cover
that reduces surface water infiltration and stabilizes
contaminated soils. As a result, the cap prevents
contact with the contaminated soil and contaminant
mobility is limited protecting ground water.
Capping in Place (Clean Fill) - Placement of defined thickness of clean fill over an area of contaminated soil (e.g.,
2-3 feet of soil for non-residential uses, 10 feet for residential uses) to prevent contact with the contaminated soil.
Paved areas such as parking lots and roadways
can be used as caps over contaminated soil
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Engineering Controls Integrated Into
Redevelopment
An important consideration for ECs in the context of
brownfields redevelopment is the benefit of integrating
the implementation and long-term stewardship of the
ECs into the redevelopment of a property. In some
cases, elements of the redevelopment (e.g., paving,
building foundations) can serve as the EC by providing
barriers to eliminate potential exposures to soil, ground
water, and other environmental media. In cases
where ECs are an integral part of the redevelopment,
however, it may be difficult to separate the specific cost
of the EC from the redevelopment. For example, where
a parking lot is used as a cap over contaminated
soil, the cost of site preparation and paving would
have already been a consideration for the cost of
the redevelopment. The cost of the EC would be any
incremental costs that would not have been incurred
during the paving if the contaminants were not present
in the soil.
• Passive Depressurization Systems - Installation
of a passive vapor control system in conjunction with
a vapor barrier under buildings to minimize potential
migration of volatile contamination to indoor air. A passive
depressurization system relies on a natural convection
of air to draw air from the soil beneath a building and
discharges it to the atmosphere through a series of
collection and discharge pipes.
• Active Depressurization Systems - Installation of
an active vapor control system in conjunction with a
vapor barrier under buildings to minimize potential
migration of volatile contamination to indoor air. An active
depressurization system consists of a fan or blower which
draws air from the soil beneath a building and discharges
it to the atmosphere through a series of collection and
discharge pipes.
• Ground Water Migration Barriers (e.g., barrier wall,
ground water depression systems) - The use of a vertical
impermeable barrier to limit exposure by cutting off the
route and preventing migration of contaminated ground
water or leachate from a contaminated property.
Although these five ECs are the most commonly used on brownfield redevelopment projects, other types of ECs are also
used to reduce exposure to and migration of contamination left on the property. Other ECs used on brownfield properties
include, but are not limited to:
• Security Barriers and Fencing - Used to restrict access to contaminated and unsafe brownfield properties.
• Solidification/Stabilization - Occurs by injecting or mixing cement into contaminated soil to lock contaminants into
a structurally sound mass of solid material for disposal.
• Geotextile Fabric Barriers - Separate, filter, drain, or reinforce soils.
• Engineered Caps - Designed to meet specific performance and containment requirements such as permeability.
• Leachate Collection Systems - Direct and collect contaminated leachate, and then transport it offsite for disposal.
• Permeable Reactive Barriers - Walls that are built below ground and are composed of materials that remove
contaminants from ground water as it flows through the permeable barrier.
In addition, remedial actions such as ground water pump and treat systems, soil vapor extraction systems, and monitored
natural attenuation may continue beyond the change in use or redevelopment of a property. In these cases, long-term
stewardship similar to engineering controls will be required and can be incorporated into institutional controls such as
environmental covenants.
Engineering Control Use at Brownfield Properties
Each brownfield property redevelopment project is different and the need for ECs and/or ICs is based on several factors
during the selection of the cleanup strategy. Property specific factors influence the selection of the cleanup remedy and
control measures. A list of typical brownfield properties, the general types of contamination found at those properties, and
the most common ECs follows.
• Gasoline service stations and auto body repair shops
are typically contaminated with petroleum hydrocarbons
from underground storage tanks (USTs) and, in some
cases, metals associated with motor and hydraulic
oils and cleaning solvents. These properties generally
use land use and resource restrictions (ICs) along with
capping technologies and active/passive depressurization
systems to address residual contamination left on the
property.
• Industrial properties are typically contaminated with
asbestos, heavy metals, volatile organic compounds
(VOCs), semi-volatile organic compounds (SVOC), and
polychlorinated biphenyls (PCBs) from manufacturing
operations at the property. These properties generally
use land use restrictions (ICs) along with capping
technologies, active/passive depressurization systems,
and security barriers (e.g., fences) to mitigate exposure
to contamination left on the property.
• Commercial properties (e.g., dry cleaning operations)
are typically contaminated with asbestos, VOCs,
polycyclic aromatic hydrocarbons (PAHs), and PCBs from
operations at the property. These properties generally
use ICs (i.e., land use and resource restrictions) along
with capping technologies (e.g., asphalt or clean fill) to
address residual contamination left on the property.
• Landfills and dumps are typically contaminated with oils,
paints, solvents, corrosive cleaners, batteries, VOCs,
PAHs, and PCBs from the waste disposal at the property. These properties generally use ICs (i.e., land use and
resource use restrictions) along with capping technologies and ground water mitigation barriers to reduce exposure
and migration of contamination from the property.
Engineering Control Costs
The cost of installing and maintaining ECs is different for each property. In many cases, the costs of installing an EC is an
integral part of a property redevelopment (e.g., paving as capping, or a building foundation as a cap) with little additional
costs attributable to the EC. The range of costs to install and maintain ECs is, therefore, dependent upon several factors,
including but not limited to: construction activities on the property; size of the property; extent and concentration of
contamination; size of the building(s) or structure(s) on the property; location of the property; and depth to ground water.
There are three general types of costs associated with ECs: programmatic costs, capital costs, and operation and
maintenance costs.
• Programmatic costs are incurred when municipal or local governments develop and implement LTS programs.
Programmatic costs include: preliminary costs to develop the program, long-term planning for implementation,
public outreach, and developing monitoring and enforcement plans.
• Capital costs are costs incurred for the design, construction, and installation of the EC. Capital costs may include,
but are not limited to: mobilization and demobilization; monitoring, sampling, testing, and analysis; site work; design
Engineering Controls and Cleanup
ECs are typically considered a form of cleanup;
however, it is important to recognize that there
is a distinction between ECs and other forms of
cleanup. ECs are often installed during cleanup as
a condition of a no further action determination and
are generally intended to be in place for long periods
of time. In many cases, the presence and long-
term stewardship (e.g., O&M) of ECs are defined in
environmental covenants, O&M agreements, or other
instruments. Other forms of cleanup may reduce or
remove contamination in soil, ground water, and other
environmental media (e.g., soil removal and disposal,
ground water treatment, soil vapor extraction and
treatment). These remedial actions are designed to
be short term and targeted to meet a defined endpoint
(e.g., corrective action goal or risk-based concentration
in soil or ground water). While ECs are intended to be
in place beyond the no further action determination,
cleanups to reduce or remove contamination are
typically completed before a no further action
determination is made. It is important to note that in
some cases, the technology implemented for ECs
may be very similar to the technology implemented
for reduction or cleanup. For example, a ground
water pump and treat system can be used to reduce
contamination in ground water or it can be used as an
EC to control ground water migration.
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Type of EC
Capping in Place
(Asphalt or Concrete)
Capping in Place
(Clean Fill)
Passive
Depressurization
Systems
Active
Depressurization
Systems
Ground Water
Migration Barriers
Range of Capital Costs
• Clearing: $5,000 to $7,500
per acre
• 1" Sub-base: $2.50 to $7.00
per square yard
• 1.5" Surface: $12.00 to
$20.00 per square yard
• Swale: $15.00 to $25.00
per linear foot
• Excavation: $1 5 to $30 per
cubic yard
• Placement: $50 to $75 per
cubic yard
• Surface preparation
and Hydro-Seeding:
$100 to $200 per 1,000
square feet
• $2,000 to $5,000**
• $5,000 to $20,000**
• Trench barrier: $200 to
$1 ,000 per linear foot of
trench***
• Ground water depression:
$50,000 to $500,000***
Activities included in
Capital Costs
• Site clearing
• Equipment mobilization
• Initial surface compaction
• Design and engineering
• Surface preparation
• Hard surface cap layer
placement
• Edge drainage swale
preparation
• CQA program
• Site clearing
• Equipment mobilization
• Initial surface compaction
• Design and engineering
• Surface preparation
• Cap layer placement
• Edge drainage swale
preparation
• CQA program
• Irrigation system
• Equipment mobilization
• Design and engineering
• Trenching and backfilling
• Vent piping
• Passive barrier installation
• Compaction and restoration
• GeoEngineer oversight
• Equipment mobilization
• Design and engineering
• Trenching and backfilling
• Vent piping
• Passive barrier installation
• Mobilize and install active
system
• Compaction and restoration
• GeoEngineer oversight
• Equipment mobilization
• Design and engineering
• Migration wall construction
and installation
• GeoEngineer oversight
Range of O&M Costs*
• $1,000 annually
• $5,000 annually
(vegetative cover)
• $1,000 to $5,000 annually
• $1,000 to $10,000 annually
• Trench barrier: $3,000 to
$10,000 annually****
• Ground water depression:
$5,000 to $35,000
annually****
Activities included in
O&M Costs
• Long-term inspections
• Repair of damages
• Site supervision
• Security
• Site quality assurance and
health and safety
• Long-term inspections
• Repair of damages
• Watering/irrigation system
(to maintain vegetative
cover)
• Mowing
• Utilities
• Site supervision
• Security
• Site quality assurance and
health and safety
• Long-term oversight and
inspections
• Repair of damages
• Site supervision
• Site quality assurance and
health and safety
• Long-term oversight and
inspections
• Performance and site
Monitoring
• Utilities
• Repair of damages
• Site supervision
• Site quality assurance and
health and safety
• Long-term oversight and
inspections
• Repair of damages
• Site supervision
• Site quality assurance and
health and safety
* Assumes length of post-closure care is 20-30 years.
** /Assumes average building size of 4,000 square feet.
*** The capital costs of ground water migration barriers are dependent on the type of barrier installed, the depth of the barrier and other site-specific conditions. The capital costs provide
a range of costs considering the variability in these characteristics. Trenching assumes a maximum depth of 20 feet below the ground surface. Ground water depression assumes
pumping rate of 1 to 10 gpm and that extracted water will be treated prior to discharge.
**** /Assumes periodic ground water monitoring for trench barrier. Assumes periodic ground water monitoring and inspection and maintenance of pumping and treatment systems.
Note that the EC examples identified in the table do not include capital and operating costs associated with designing, installing, and operating a ground water monitoring program that
may be required. Additional information regarding EC and 1C costs can be found in An Introduction to the Cost of Engineering and Institutional Controls at Brownfield Properties at.
www.epa.gov/brownfields/tools/lts_cost_fs.pdf
and engineering; construction and installation; off-site
treatment and disposal; construction quality assurance
(CQA); and project and construction management.
• Operation & Maintenance (O&M) costs associated with
ECs should be considered throughout the lifecycle of
property cleanup and post-cleanup care. O&M activities
are conducted at a property after ECs are in place, to
ensure that the action is effective and operating properly,
and may include, but are not limited to: performance
inspections and site monitoring; operating remediation
systems, including sampling and analysis, preparing
reports, and recordkeeping; maintaining caps and
system maintenance; and site supervision.
The following table provides a range and list of costs for the
more common ECs implemented on brownfield properties.
The examples provided below only include site-specific capital
and O&M costs incurred when designing, implementing, and
monitoring ECs. The table does not include the programmatic
cost to a municipality or local government to develop and
implement a LTS program. In addition, each EC design and
implementation will incur indirect and variable costs. These
indirect and variable costs are not listed in the table and may
include, but are not limited to: project management, vendor
selection, permit preparation and fees, regulatory interaction,
and contingencies.
Sources for Estimating Costs and Additional Resources
EC capital and O&M cost estimates can be generated from several sources. Cost-estimating software and databases can
be used to calculate the capital and O&M costs of ECs. The majority of available software tools are designed to estimate the
cost for all or selected cost elements of an EC. Below is a list of several sources for estimating costs of ECs.
• Cost Estimating Guides/References - Provide costs for a wide variety of construction activities, including those
related to property cleanup. Some guides are specifically customized to estimate costs for environmental remediation
projects. Cost data in guides or references are often broken down into labor, equipment, and material categories, and
may or may not include contractor markups. Costs are typically provided on a national average basis for the year of
publication of the reference.
• Vendor or Contractor Quotes - Provide costs that are more site-specific in nature than costs taken from standard
guides and references. These quotes usually include contractor markups and are typically provided as a total
cost rather than categorized as labor, equipment, or materials. If possible, more than one vendor quote should be
obtained. Quotes from multiple sources can be averaged, or the highest quote can be used in the cost estimate if the
collected quotes seem to be at the low end of the industry range.
• Experience with Similar Projects - Engineering judgment should be exercised if cost data from another project
need to be adjusted to take into account site- or technology-specific parameters. In addition, sources of actual cost
data from government remediation projects are maintained by various federal agencies.
Local Government Planning Tool to Calculate
IC/EC Costs for Brownfield Properties
The cost calculator is designed as a voluntary guide for
municipal or local governments to assist in calculating
their expected costs of implementing and conducting
LTS of ICs and ECs at brownfield properties. In general,
primary responsibility for maintaining ICs and ECs
rests with the property owner and others responsible
for cleanup. The state response program often plays a
large role in selecting, implementing, and monitoring ICs
and ECs; however, local governments, as controllers of
local land use and zoning, often have responsibilities
associated with ICs and ECs and LTS at brownfield
properties. Each of these separate entities may have
different roles, responsibilities and costs. It is important
to calculate the full cost of LTS for ICs and ECs, both
short- and long-term to ensure adequate resources are
available for their management over time. Additional
information on the institutional and engineering control
costs calculating tool can be found in the Local
Government Planning Tool to Calculate Institutional and
Engineering Control Costs for Brownfield Properties at:
www.epa.gov/brownfields/tools/ttijucs.htm.
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Cost Estimating Software/Databases/Reports - The majority of available software tools are designed to estimate
the cost for all or selected cost elements of an alternative.
Remedial Action Cost Engineering Requirements (RACER) - A cost estimating system originally developed by
the U.S. Air Force. The system uses a patented methodology for generating location-specific program cost estimates.
RACER calculates quantities for each technology; localizes unit costs for materials, equipment, and labor; adjusts
unit prices for safety and productivity losses; and applies markups to account for indirect costs. It uses current multi-
agency pricing data, and is researched and updated annually to ensure accuracy. This software is available for
purchase at: www.frtr.gov/ec2/ecracersystem.htm
CostPro -A software program developed by EPA to estimate costs for closure and post-closure plans prepared by
Treatment, Storage, and Disposal Facilities (TSDFs) regulated under the Resource Conservation and Recovery Act
(RCRA). Under RCRA, owners or operators of interim status and permitted TSDFs must prepare and annually update
a cost estimate for closure and post-closure (if applicable) and provide corresponding financial assurance. CostPro
uses data from RS Means and ECHOS for specific cost items. EPA limits free distribution of the software only to EPA
and state personnel. Others interested in obtaining the software must pay a licensing fee to RS Means and ECHOS
that provides the right to use the data incorporated into this software. To obtain further information about CostPro or
how to obtain the software: contact Bob Maxey, EPA Headquarters, at (703) 308-7273 or maxey.robert@epa.gov.
Micro Computer Aided Cost Engineering System (MCACES) -A program used by the U.S. Army Corps of
Engineers that is linked to the Unit Price Book (UPB) database, www.hnd.usace.army.mil/traces/
Federal Remediation Technology Roundtable (FRTR) - FRTR makes data more widely available on real
experiences and lessons learned in selecting and implementing treatment and site characterization technologies to
clean up soil and ground water contamination. The remediation case study reports describe the performance and
cost of technology applications at full-scale and large-scale demonstration projects, www.frtr.gov/costperf.htm
Innovative Treatment Technologies - Provides information about characterization and treatment technologies for the
hazardous waste remediation community. It offers technology selection tools and describes programs, organizations,
publications for federal and state personnel, consulting engineers, technology developers and vendors, remediation
contractors, researchers, community groups, and individual citizens, www.epa.gov/tio/remed.htm
EPA's Cleanup Information (CLU -IN) - Provides information about innovative treatment technologies and acts as
a forum for all waste remediation stakeholders, www.clu-in.org/remediation/
A Guide to Developing and Documenting Cost Estimates During Feasibility Study (July 2000) - This guide
provides capital and O&M cost categories and details steps in calculating costs of ECs. www.epa.gov/superfund/
policy/remedy/pdfs/finaldoc.pdf
Florida Department of Environmental Protection Engineering Controls Report (1999) -This document
considers the adequacy of ECs available for use at contaminated properties; summarizes the types of ECs currently
available; evaluates the effectiveness of ECs in protecting human health, and the environment; and evaluates the
ability of ECs to achieve risk-based corrective action criteria at contaminated properties, www.dep.state.fl.us/waste/
quick_topics/publications/wc/csf/focus/engineer.pdf
For additional information regarding ECs/ICs and LTS, please visit the EPA Brownfields Program at
www.epa.gov/brownfields or contact Ann Carroll at (202) 566-2748 or carroll.ann@epa.gov.
Engineering Controls
Fact Sheet
Office of Solid Waste and
Emergency Response (5101T)
EPA-560-F-10-005
November 2010
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