The US Environmental Protection Agency issued rules December 30, 2013 approving the American Society for Testing and Measurement (ASTM) E1527-13 standard practice for Phase I environmental site assessments. This is an “all appropriate inquiries” standard, which defines and limits what types of site conditions require inquiry, allows parties to rely on agency letters indicating they approve of site cleanup as done or in process, and otherwise provides standards for Phase I study elements. Such studies are needed before closing on most mergers, acquisitions, or refinancing deal closings since the new owners, banks, and insurance companies can be liable for cleanup if they take title to a site with hazardous materials or arrange for disposal of such things. Copies of the new regulation are available at http://www.gpo.gov/fdsys/pkg/FR-2013-12-30/html/2013-31112.htm. Copies of the new standard are available for purchase at http://www.astm.org/Standards/E1527.htm.