As discussed in a prior post, U.S. EPA had issued a direct final rule approving the use of the new ASTM Standard E 1527-13 "Standard Practice for Environmental Site Assessments:  Phase I Environmental Site Assessment Process."  The final rule was set to take effect on November 13, 2013.

If the rule had gone into effect, it would have allowed use of either ASTM Standard E 1527-13 or the old ASTM Standard E 1527-05 to comply with due diligence requirements associated with the "All Appropriate Inquiries Rule," (AAI), a necessary step to establishing certain affirmative defenses to CERCLA liability.  However, just prior to the September 16, 2013 comment deadline, adverse comments were filed by some influential practitioners.  

Concerns were expressed with regard to the practical effect of EPA’s proposal to allow either ASTM standard to be followed.  E 1527-13  is believed to be more costly than the old standard because it enhances the requirement for environmental professionals to perform agency file reviews as part of the Phase I process.  It also contains more definitive language requiring evaluation of potential vapor intrusion migration pathways. In addition, each ASTM standard uses different definitions. Adverse comments expressed concern that the use of the different definitions will lead to confusion or inconsistent practices in the due diligence community by allowing two different standards to satisfy AAI.

It is still unclear what U.S. EPA will do in response.   The Agency issued a proposed rule at the same time as the final rule.  The proposed rule contains the same option to utilize either ASTM standard.  It is possible EPA could sunset E1527-05 when it finalizes the proposed rule.  Or it could address the adverse comments in the final preamble to the rule.

Right now there is no clear direction from U.S. EPA with regards to this critical aspect of due diligence. 

UPDATE:  On October 29th, U.S. EPA did officially withdraw the direct final rule.  Currently, E1527-05 remains the only officially sanctioned guidance to meet the "All Appropriate Inquiry Rule."