A brownfield is any former industrial or commercial site where future use is affected by real or perceived environmental contamination. Brownfields can be as large as an abandoned factory or as small as a closed dry cleaning business.

Older structures, such as schools or office buildings where asbestos is present are also considered brownfields.

Unsafe levels of environmental contamination on a brownfield may result from past or current industrial, commercial, residential, agricultural or recreational uses and practices. Contaminants may be found in soil, water or air. Cleaning up contaminants on a brownfield reduces or eliminates potential health risks to residents, workers, pets and the surrounding environment. How much cleanup is needed depends on the specific contaminants found at the brownfield, the extent of contamination, and how the property will be reused.

Risk-based cleanup methods focus cleanup resources on the reduction of risk and harm prevention, based upon the intended reuse of a property. A typical result of a risk-based cleanup is that some contamination is left on site. In such cases, engineering controls, institutional controls, or land use restrictions may be implemented to reduce human and environmental exposure to any remaining on-site contamination.

Brownfields can be repurposed for any use, and the type of reuse often determines the amount of clean-up of a site that will be necessary. Brownfields can be redeveloped for residential use, green space, commercial use, or new industrial use.

States use a risk-based cleanup approach to determine the required level of cleanup necessary at brownfield properties.

The three most common contaminants found in brownfields are lead, petroleum, and asbestos, but there are many other possible less common contaminants including volatile organic compounds (VOCs) and arsenic.

A brownfield assessment is an evaluation of cleanup options and/or cost estimates based on future uses and redevelopment plans of a brownfield site.

The Phase I Environmental Site Assessment (ESA) uses existing information to help a community understand the property conditions by examining current and historical uses of the site and potential threats to human health or the environment. Environmental assessments must be completed or overseen by an environmental professional, which may include a licensed geologist, engineer or site professional. During a Phase I, the environmental professional will:

1. Review records. Examine past and current land uses through property photographs, maps and historical records.

2. Review government databases. Examine ownership and environmental records related to managing or disposing of hazardous substances and petroleum products.

3. Visually inspect the site. Visit the site and nearby properties to observe current conditions.

4. Interview owners, neighbors and past workers. Find out what they know about site operations involving wastes and chemicals.

A Phase I Environmental Site Assessment also helps determine who is potentially liable for environmental contamination found on a property. Performing a Phase I Environmental Site Assessment prior to owning a property is often equivalent to conducting All Appropriate Inquiries (AAI), a necessary practice for obtaining liability protection under CERCLA for prior contamination. When a potential owner conducts AAI (in compliance with the regulations at 40 CFR 312) on a brownfield, he/she may have a defense to liability if contamination is later discovered.

If evidence of known or potential contamination is found at the property, further investigation (a Phase II Environmental Site Assessment or additional assessment) is needed.

If little to no evidence of potential contamination is found at the property, often the next step is to proceed with reuse or redevelopment.

The Phase II Environmental Site Assessment (ESA) is recommended if the Phase I Environmental Site Assessment results reveal known or potential contamination found on the property, sometimes called recognized environmental conditions (RECs). An environmental professional develops a sampling plan to evaluate the potential presence of contamination from hazardous substances and petroleum on the property and determines the sources and exposures. Environmental professionals may also consult with state brownfield programs regarding required assessment activities.

During a Phase II assessment, environmental professionals will:

1. Identify chemicals of concern. Determine contaminants likely to be present in soils, groundwater or vacant structures based on property history.

2. Sample and test soil, groundwater and other media. Develop a sampling plan for the property. Collect and analyze samples to determine type and distribution of contaminants.

3. Further investigate areas of concern. Review results and target sampling to find localized hot spots (high-risk areas) and extent of contamination.

4. Develop plans for cleanup, if needed. Cleanup for reuse prevents and minimizes exposures. The plan considers layout of structures, open areas, slope of the property and contaminants.

If the contamination found at the property exceeds risk thresholds for the proposed reuse, consult with state or tribal response program staff to develop a cleanup plan. The plan uses assessment information to develop an analysis of brownfield cleanup alternatives that considers RECs. The selected cleanup approach should reduce risks and remain protective over time.

If little to no contamination that will impede property reuse is found, the next step is to consult with state response program staff before proceeding with reuse or redevelopment.

While a Phase II Environmental Site Assessment typically follows a Phase I Environmental Site Assessment, the site assessment process is not always linear. If redevelopment plans change or more than 180 days have passed since the Environmental Site Assessment, additional assessment may be needed. In some cases, an updated Phase I or Phase II Environmental Site Assessment may be needed. Additional assessment gives confidence to the community and investors and ensures a safe reuse.

There are three stages to a brownfield assessment.

1. Pre-development

2. Development

3. Management

Each stage requires specific actions, funding and/or financing.

Pre-development activities lay the foundation for a successful brownfield redevelopment project.

The developer (or local government, for a publicly funded project) conducts several analyses, assesses the feasibility of a project and decides whether the project should move forward. This is the riskiest phase for potential private developers because they are investing money upfront without a guarantee of any return.

Steps taken during the pre-development phase include:

1. Conduct due diligence

2. Conduct analyses

3. Determine any fatal flaws

4. Develop the proforma and agreement for purchase of property

5. Use the proforma to refine the site design

6. Prepare a redevelopment plan

7. Identify sources of funding

8. Acquire environmental insurance

This phase includes permitting, environmental cleanup, construction, financing, and marketing activities that culminate with completion of the project and a formal opening.

During the development phase, the developer usually does the following:

1. Obtain permits and necessary approvals

2. Conduct environmental cleanup and site preparation activities

3. Conduct marketing and pre-leasing activities

4. Complete construction and open the project

During the management (or operational) phase, the developer decides whether to:

1. Hold the property. Developer/owner assumes ownership and management responsibilities, or

2. Sell the Property. Buyer assumes ownership and management responsibilities.

Identify the planned reuse for the site and seek out experts who can help you navigate the cleanup process.

Through experience, U. S. EPA and state cleanup programs have learned a great deal about cleanup and contaminated site reuse. State programs oversee cleanups to ensure safe reuse standards are met.

Cleaning up a brownfield requires assistance from an environmental professional to create a site cleanup plan based on assessment findings and to conduct the cleanup according to state and local requirements.

The specific approach used to clean up a site depends on the way the site will be reused. Site reuse will dictate the need for clean soil; geotextile or cover/cap; land use controls; and whether lead or asbestos abatement is required.

Various technologies are available to clean up contaminated properties. The technology selected will largely depend on cost and contamination characteristics of the site. The following are some of the commonly-used methods for cleaning up brownfields and other contaminated sites.