EPA's Oil & Natural Gas Website [epa.gov] - contains rule summaries and regulatory information.
(See attached file: 4O - EPA Fact Sheet - 2018-02-23 - Amendments.pdf)
(See attached file: 4O - EPA Fact Sheet - 2017-11-01 - Notice of Data Availabilty for Proposed Stays.pdf)
(See attached file: 4O - EPA Fact Sheet - 2017-06-16 - Proposed Stay of Certain Requirements in the 2016 NSPS.pdf)
(See attached file: 4O - EPA Letter - 2017-04-18 - Reconsideration of Rule.pdf)