On April 12, 2013, the United States Environmental Protection Agency (EPA) issued its proposed revisions to the New Source Performance Standards (NSPS) for the oil and natural gas sector (i.e., Quad O). The reconsidered Quad O standards are the result of several petitions for administrative reconsideration of, as well as judicial challenges to, the final rule published on August 16, 2012. EPA has agreed to reconsider portions of the rule in several phases, in exchange for abeyance of the litigation challenges pending in the D.C. Circuit. The April 12th proposal reflects the Agency's first phase of that reconsideration, and focuses largely on new requirements and compliance deadlines applicable to storage tanks. Comments are due May 13, 2013, unless a public hearing is requested, in which case comments will be due May 28, 2013.