On November 1, 2005, the US Environmental Protection Agency (USEPA) published the final All Appropriate Inquiries (AAI) Rule (70 FR 66070) titled "40 CFR Part 312, Standards and Practices for All Appropriate Inquiries; Final Rule." Download the final rule at http://www.epa.gov/brownfields/regneg.htm.

The final rule establishes specific regulatory requirements for conducting all appropriate inquiries into the previous ownership, uses, and environmental conditions of a property for the purposes of qualifying for certain landowner liability protections under CERCLA. The final rule will be effective on November 1, 2006, one year following the date of publication. Until November 1, 2006, parties may use either the requirements set forth in the all appropriate inquiries final rule (see below), or the requirements of the interim standard for all appropriate inquiries established in the Small Business Liability Relief and Brownfields Revitalization Act (the Brownfields Amendments to CERCLA) to satisfy the statutory requirements for all appropriate inquiries. The interim standard is the ASTM E1527-00 Phase I Environmental Site Assessment Process. Parties also may use the newly revised ASTM standard, ASTM E1527-05 standard.

After November 1, 2006, parties must comply with the requirements of All Appropriate Inquiries Final Rule, or follow the standards set forth in the ASTM E1527-05 Phase I Environmental Site Assessment Process, to satisfy the statutory requirements for conducting all appropriate inquiries. All appropriate inquiries must be conducted in compliance with either of these standards to obtain protection from potential liability under CERCLA as an innocent landowner, a contiguous property owner, or a bona fide prospective purchaser.