As we discussed in our prior blog the new ASTM standard E1527-13 had been promulgated and that industry was critical of EPA for accepting both standards, despite the fact that E1527-13 was expressly drafted to resolve continuing issues with E1527-05. On December 30, 2013, however, EPA published a final rule finding that ASTM E1527-13, released on November 6, 2013 meets the requirements for “all appropriate inquiries” (AAI) under CERCLA and the AAI regulations. Although EPA did not eliminate reference to the prior standard the final rule notes that the new standard contains improvements over the previous version. The final rule EPA recommends that parties use ASTM E1527-13 and states that it intends to issue a proposed rule to remove ASTM E1527-05 as an option to meet AAI.