EPA and environmental groups have long had their eyes on limiting emissions during periods of "startup, shutdown or malfunction" (SSM). Two recent decisions have strengthened their hands on this issue.

In the first, Luminant Generation Co. LLC v. EPA, No. 1060934 (5th Cir. July 30, 2012), the Fifth Circuit upheld EPA's partial approval of the Texas State Implementation Plan (SIP) provisions governing SSM. The court first concluded that it was reasonable for EPA to (1) approve Texas' creation of an "affirmative defense" against civil penalties for excess emissions during unplanned SSM events, and (2) disapprove that affirmative defense for planned SSM events.

In the second opinion, US Magnesium, LLC v. EPA, No. 119533 (10th Cir. Aug. 6, 2012), the Tenth Circuit reached a similar conclusion. In this case, EPA had "SIP call" to Utah asserting that Utah's socalled "unavoidable breakdown rule" was inconsistent with Clean Air Act requirements because it actually authorized excess emissions during equipment malfunctions (as opposed to the affirmative defense approach that Texas had adopted). The Court found EPA's action to be reasonable and consistent with the Clean Air Act.

These decisions clarify how EPA and states will be addressing SSM emissions. First, they confirm EPA's view that excess emissions during unplanned SSM events are not permitted, but that emitters can assert as a defense against civil penalties that such emissions were unpreventable and out of their control. Second, they confirm EPA's view that excess emissions are not permitted at all, and no affirmative defense exists, for planned SSM events (e.g., when restarting a unit after a turnaround). As a result, sources will need to carefully document their excess emissions during unplanned SSM events and take steps to ensure that emissions during planned SSM events remain within permit limits. Indeed, relying on these decisions, environmental groups in Texas have already requested that EPA take action against several sources alleged to have illegal excess emissions. Stricter SSM requirements are likely to lead to increased enforcement.