Brownfields All Appropriate Inquiries

All Appropriate Inquiries, or AAI, is the process of evaluating a property's environmental conditions and assessing potential liability for any contamination. Every Phase I environmental site assessment conducted with EPA Brownfields Assessment Grant funds must be conducted in compliance with the AAI Final Rule at 40 CFR Part 312. The AAI Final Rule provides that ASTM International Standard E1527-21 (“Standard Practice for Environmental Site Assessments: Phase I Environmental Site Assessment Process”) and E2247-23 (“Standard Practice for Environmental Site Assessments: Phase I Environmental Site Assessment Process for Forestland or Rural Property”) are consistent with the requirements of the final rule and can be used to satisfy the statutory requirements for conducting AAI. AAI may be conducted in compliance with either of these standards to obtain protection from potential liability under the Comprehensive Environmental Response, Compensation, and Liability Act as an innocent landowner, a contiguous property owner, or a bona fide prospective purchaser.

 

Background on All Appropriate Inquiries 

The 2002 Small Business Liability Relief and Brownfields Revitalization Act (the “Brownfields Amendments”) to CERCLA, also known as Superfund, required EPA to promulgate regulations establishing standards and practices for conducting AAI. The AAI final rule was published in the Federal Register on November 1, 2005 (70 FR 66070) and went into effect on November 1, 2006.

What are All Appropriate Inquiries?

AAI is the process of evaluating a property’s environmental conditions and assessing potential liability for any contamination.

Reasons for conducting All Appropriate Inquiries

Under CERCLA, persons may be held strictly liable for cleaning up hazardous substances at properties that they either currently own or operate, or owned or operated in the past. Strict liability under CERCLA means that liability for environmental contamination may be assigned based solely on property ownership.

The Brownfields Amendments amended CERCLA to provide liability protections for certain landowners and potential property owners who did not cause or contribute to contamination at the property and can demonstrate compliance with specific provisions outlined in the statute, including conducting AAI into present and past uses of the project. CERCLA provides protection from liability for certain landowners and prospective purchasers of real property, including:

  • Innocent landowners are persons who can demonstrate, among other requirements, that they “did not know and had no reason to know” prior to purchasing a property that any hazardous substance that is the subject of a release or threatened release was disposed of on, in, or at the property. Innocent landowners must meet the criteria set forth in CERCLA §101(35)(A).
  • Contiguous property owners are persons who own property that is contiguous or otherwise similarly situated to a facility that is the only source of contamination found on the property. Such persons must demonstrate that they had “no reason to know” prior to purchasing a property that any hazardous substance that is the subject of a release or threatened release was disposed of on, in, or at the property. Contiguous property owners must comply with the criteria set forth in CERCLA §107(q).
  • Bona fide prospective purchasers may buy property with knowledge of contamination, provided they bought the property after January 11, 2002 and meet the criteria set forth in CERCLA §101(40) and 107(r).
  • Units of state or local government that acquire ownership or control involuntarily through bankruptcy, tax delinquency or abandonment, CERCLA Section 101(20)(D).
  • Government entities that acquire property through eminent domain, CERCLA Section 101(35)(A)(ii).

Persons subject to the All Appropriate Inquiries requirements

  • Commercial and government entities purchasing property, and all individuals purchasing property for non-residential use, who may, after purchasing a property, seek protection from CERCLA liability for releases or threatened releases of hazardous substances.
  • Any party who receives a Brownfields grant awarded under CERCLA Section 104(k)(2)(B) and uses the grant to conduct site characterization or assessment activities.

Related Resources

Highlights of the All Appropriate Inquiries Rule

The final AAI rule is a performance-based standard. The objective of the standard is to conduct inquiries into past uses and ownerships of a property and visually inspect the property to identify conditions indicative of releases and threatened releases of hazardous substances on, at, in, or to the subject property.

Who can perform AAI?

Many AAI-required activities must be conducted by, or under the supervision or responsible charge of, an individual who meets the definition of an “environmental professional.” The AAI rule defines an environmental professional as someone who possesses the specific education, training, and relevant experience necessary to exercise professional judgment to develop opinions and conclusions regarding conditions indicative of releases or threatened releases of hazardous substances on, at, in, or to a property. The definition includes persons who have:

  • A state or Tribal issued certification or license and three (3) years of full-time work experience.
  • A bachelor’s degree or higher from an accredited institution of higher education in a relevant discipline of science or engineering and five (5) years of full-time relevant work experience.
  • Ten (10) or more years of relevant, full-time work experience.
  • All Appropriate Inquiries Environmental Professional Fact Sheet (pdf) (851.39 KB, 2017, EPA-560-F-17-191)

When must AAI be conducted?

  • AAI must be conducted or updated within one year before the date of acquisition of a property.
  • Certain aspects or provisions of AAI (i.e., interviews of current and past owners, review of government records, on-site visual inspection and searches for environmental cleanup liens) must be conducted or updated within 180 days before acquiring ownership of a property.

What specific activities does the AAI rule require?

  • Interviews with current and past owners, operators, and occupants. In the case of abandoned properties, interview one or more neighboring property owners.
  • Review of historical sources of information.
  • Review of federal, state, Tribal and local government records.
  • Visual inspection of the facility and adjoining properties.
  • Review of commonly known or reasonably ascertainable information about the property.
  • Assessment of the degree of obviousness of the presence or likely presence of contamination at the property and the ability to detect the contamination.
  • Identification of any significant data gaps in information collected that affects the ability of the environmental professional to identify conditions indicative of releases or potential releases of contaminants.
  • The results of an AAI investigation be documented in a written report, signed by an environmental professional.

Additional inquiries that must be conducted by or for the prospective landowner or grantee include searches for environmental cleanup liens, assessment of any specialized knowledge or experience of the prospective landowner (or grantee), and assessment of the relationship of the purchase price to the fair market value of the property if the property was not contaminated.

Brownfield Grantees and All Appropriate Inquiries Requirements

EPA’s Brownfields Program provides direct funding, in the form of competitive grants, for brownfields assessments and cleanup, for the capitalization of revolving loan funds, and to support environmental job training programs. Eligible entities for brownfields grants include states, tribes, local governments, regional governments, and quasi-governmental entities.

Brownfields grantees are prohibited from using grant money to pay response costs at a brownfields site for which the grantee is potentially liable under CERCLA. To be eligible for an EPA Brownfields grant to address contamination at brownfields properties, eligible entities must demonstrate that they meet one of the liability protections or defenses set forth in CERCLA by establishing that they are an innocent landowner, contiguous property owner, bona fide prospective purchaser, or government entity that acquired the property involuntarily through bankruptcy, tax delinquency or abandonment, or by exercising power of eminent domain. To claim protection from liability as an innocent landowner, contiguous property owner, or bona fide prospective purchaser, property owners, including state and local governments, must conduct AAI before acquiring the property and comply with all continuing obligations after acquiring the property.

The specific documentation and reporting requirements for AAI are provided in 40 CFR §312.21 (Results of Inquiry by an Environmental Professional) and §312.31 of the final rule, in ASTM E2247-23 and in ASTM E1527-21. The fact sheets below summarize the required reporting requirements and provide a checklist to assist Brownfields grantees in assuring compliance with the provisions of the AAI rule.

Format for Reporting the Results of All Appropriate Inquiries

The final rule requires no specific format, length, or structure of the written report. However, EPA offers the following suggestions regarding the potential content of a written report. The following suggestions are generally consistent with recommendations published in ASTM E1527-21. The ASTM E1527-21 standard is consistent with the requirements of the final rule and may be used to comply with the provisions of the rule. The following are suggestions regarding the format and content of an all appropriate inquiries written report. Please note that the suggestions below do not represent regulatory requirements. Prospective landowners and environmental professionals may design their own format for a written report, as long as the report contains the four documentation requirements listed above (and as noted below).

  • Introduction. An introduction could include descriptions of: the purpose and objectives of the assessment; scope of services provided; methodology used to complete the inquiry; any significant assumptions made; limitations and exceptions; any modifications or deviations from the final rule requirements or from the ASTM E1527-21 process; special terms and conditions; and information obtained from the landowner or user. The environmental professional and the person(s) who conducted the site reconnaissance and interviews may be identified.
  • Site Description. This section may describe the property location; site and vicinity characteristics; structures, roads, site improvements, and utilities; current and historic use(s) of the property; site topography, geology, and surface/ground water resources; and current and historic use(s) of adjacent properties.
  • User-Provided Information. The report may describe any information provided by the prospective landowner, or user, to the environmental professional. This information may include: title records; information of recorded environmental cleanup liens; recorded activity and use limitations (e.g., engineering controls, land use restrictions, institutional controls); specialized knowledge or experience held by the user related to the property or nearby properties; commonly known or reasonably ascertainable information; and relationship of the purchase price to the fair market value of the property, if it were not contaminated.
  • Records Review. The written report may include a section that summarizes the information found during the records review. This section may describe records that were reviewed to complete the inquiry including: physical setting sources (e.g., topographic maps); historical use sources (e.g., aerial photographs, fire insurance maps, street directories, newspaper archives); federal, State, Tribal, and local records or databases of government records; and other environmental record sources (e.g., prior investigation reports, tank/transformer inventories, spill records, permits, etc.).
  • Site Reconnaissance. The written report may include a section dedicated to describing the methodology used to conduct the visual inspection of the subject and adjoining properties. The description may include: when and who performed the reconnaissance; physical imitations (e.g., snow-covered ground, limited access, safety concerns, etc.); general site setting; exterior observations; and interior observations. Additional information on evidence of staining, spills, odors, stressed vegetation, corrosion, pools of liquids, discolored water, ground surface alterations, and other conditions that might suggest a release or threatened release of hazardous substances also may be provided.
  • Interviews. A summary of the interviews conducted could include a description of when and with whom the interviews were conducted (e.g., current property owner and occupants, site manager, attorneys, financial manager, local/state/federal government officials, past site owners and occupants) and the method used to conduct the interviews (e.g., in person, written, telephone). If the property is abandoned, this section may describe which neighboring property owners were interviewed and, if applicable, which past owners and occupants were interviewed.
  • Findings. A findings section could describe the results of the assessment, including the identified known or suspected recognized environmental conditions, historical recognized environmental conditions, and de minimis conditions. This section also may include findings related to, but not limited to: current and historic site usage; adjoining and nearby properties; hazardous substances and petroleum products; non-hazardous, solid, and hazardous waste management; water pollution; pits, ponds, and lagoons; drains and sumps; waste water; wells; septic systems; spills or releases; air emissions; storage tanks and drums; soil and groundwater contamination, polychlorinated biphenyls (PCB) contaminants, or other contaminants.
  • Opinion of the Environmental Professional. In compliance with the All Appropriate Inquiries Final Rule at § 312.21(c)(1), the written report must include the environmental professional’s opinion(s) as to whether the inquiry identified conditions indicative of releases or threatened releases of hazardous substances on, at, in, or to the subject property. The opinion will likely be based on conditions identified during the inquiries (and potentially noted in a findings section), and include a discussion of the logic, reasoning, and rationale used by the environmental professional in developing the opinion. The environmental professional also must include in the final report an opinion regarding additional appropriate investigation to detect the presence of contamination at the property, if the environmental professional has such an opinion.
  • Data Gaps. As required in § 312.21(c)(2) of the final rule, the report should document and discuss significant data gaps that affect the ability of the environmental professional to identify conditions indicative of releases or threatened releases.
  • Conclusions. A conclusions section may be included that summarizes all identified conditions indicative of releases or threatened releases of hazardous substances (or recognized environmental conditions) connected with the property. The final rule does not require that any specific statements be made regarding these conditions, however, ASTM E1527-21 requires that the report include a statement substantially similar to one of the following written statements:
    • “We have performed a Phase I Environmental Site Assessment in conformance with the scope and limitations of ASTM Practice E1527 of [insert address or legal description], the property. Any exceptions to, or deletions from, this practice are described in Section [ ] of this report. This assessment has revealed no evidence of recognized environmental conditions in connection with the property,” or 
    • “We have performed a Phase I Environmental Site Assessment in conformance with the scope and limitations of ASTM Practice E1527 of [insert address or legal description], the property. Any exceptions to, or deletions from, this practice are described in Section [ ] of this report. This assessment has revealed no evidence of recognized environmental conditions in connection with the property except for the following: (list).”
  • Additional Services. If applicable, it may be useful to include a description of any additional services performed as part of the assessment that are beyond the scope of the final rule and were contracted for between the user and the environmental professional. Additional services could include, but are not limited to: non-scope considerations (e.g., lead-based paint, mold, radon, asbestos, regulatory compliance assessment, indoor air quality, etc.); broader scope of assessment; liability or risk evaluations; Phase II sampling and analysis; health and safety; evaluation of remediation techniques; etc.
  • References. A reference section may be included that lists the published sources relied upon to complete the assessment.
  • Signature(s) and Qualifications of the Environmental Professional(s). Include the statements and environmental professional(s) signature required by § 312.21(d), as discussed above in “What are the Documentation Requirements for All Appropriate Inquiries?”
  • Appendices. Appendices could include: regulatory records documentation; environmental database report; site map/plan; vicinity maps; site photographs; historical source documentation (building department records, local street records, chain of title documents, property tax records, zoning/land use records, aerial photos, fire insurance maps, USGS topographical maps); interview documentation; and qualifications of the environmental professional(s).

Brownfields and Land Revitalization

Contact Us about Brownfields and Land Revitalization
Contact Us about Brownfields and Land Revitalization to ask a question, provide feedback, or report a problem.
Last updated on May 7, 2026