A key federal rule was recently amended that will impact environmental due diligence in real estate transactions. Real estate developers, lenders, and others are working to adjust their approaches to conform to the new American Society for Testing and Materials (“ASTM”) standard E1527-21. The US Environmental Protection Agency finalized a rule providing that this new standard may be used to satisfy the All Appropriate Inquiries rule, a key step in pursuing a shield against certain environmental liabilities. In this article, published in the Columbus Bar Lawyers Quarterly, Squire Patton Boggs attorney Rees Alexander evaluates the new standard and discusses the differences between the new standard and its predecessor. He discusses advantages, obligations, and practical considerations when transitioning to the new approach.