Effective October 6, 2015, US EPA will list ASTM 1527-13 “Standard Practice for Environmental Site Assessments: Phase I Environmental Site Assessment Process” as the primary industry standard that “may be used to comply” with the All Appropriate Inquiry (AAI) requirements in 40 CFR 312.20. This is, according to US EPA’s final rule issued on October 6, 2014, to eliminate reference to the older standard, ASTM E1527-05, after a one-year transition period.

We previously reported that US EPA approved use of ASTM E1527-13 as meeting the AAI requirements in August 2013 and December 30, 2013, in addition to the already approved ASTM E1527-05. US EPA’s final rule now removes reference to ASTM E1527-05 “because the Agency wants to reduce any confusion associated with the regulatory reference to a historical standard that is no longer recognized by its originating organization as meeting it standards for good customary business practice.”

While the final rule removes reference to ASTM E1527-05 in 40 CFR 312.11, it does not prohibit its use, and US EPA clarified that the final rule “does not prevent parties from continuing to use other standards, methods, or customary business practices for conducing all appropriate inquiries, so long as they comply with the standards and practices set forth in the AAI Rule.” Nevertheless, given the rule, best practice remains to use ASTM E1527-13, as has been done in the vast majority of Phase I Environmental Site Assessment prepared after January 1, 2014.