On September 17, 2014, EPA further revised its policy regarding start-up, shut-down, and malfunction (SSM) events, issuing a Supplemental Notice of Proposed Rulemaking (SNPR) that would remove the availability of an affirmative defense for air emission exceedances resulting from malfunction events. EPA's SNPR carries significant implications for thousands of air emission sources across the country, including the potential for more stringent permit limits as well as costly changes to sources' operations and air control equipment. Comments on the SNPR must be received by EPA on or before November 6, 2014. A public hearing on the SNPR will be held on October 7, 2015 in Washington, D.C.
The SNPR supplements EPA's February 2013 proposal, in which EPA, responding to a 2011 petition for rulemaking filed by the Sierra Club, proposed significant changes to the treatment of excess emissions during start-up and shut-down events. DGS published a client alert on EPA's February 2013 proposal indicating that the action would fundamentally alter the way most states, including Colorado and North Dakota, treat SSM events in their State Implementation Plans (SIP). That proposal, known as a "SIP call," required revision and resubmission of non-conforming SIP-based affirmative defense provisions, effectively disallowing penalty mitigation through an affirmative defense for start-up and shut-down events. It did not, however, affect similar affirmative defense provisions for malfunction events.