In pleadings recently filed with the Federal Court of Appeals for the D.C. Circuit, EPA has defended the “Exceptional Events” rule issued by the Obama Administration last October. The rule is designed to excuse exceedances of national ambient air quality standards (NAAQS) where they are caused by natural events such as wildfires or dust storms. It is particularly important in western states where such events occur frequently.
EPA revised the rule in response to state and industry complaints that the prior rule was overly cumbersome and unevenly applied. Various environmental groups challenged the new rule in the D.C. Circuit, arguing that it excuses some events that are caused at least in part by human activity, such as windblown dust from construction or mining activities. EPA counters that Congress did not define “natural event” in the relevant statute, and that the agency opted for a middle ground that covers events in which human activity plays little or no direct causal role. The agency also notes that the rule only allows the exclusion where” reasonable emission controls” have been adopted.
The exceptional events rule is likely to play a critical role in evaluating NAAQS exceedances caused by the recent hurricanes and western wildfires. Under EPA’s current interpretation, it cannot excuse violations of permit or SIP provisions, but it can be used to ensure that future SIP or permit provisions are not based on extreme conditions. Historically, the primary tool for excusing SIP or permit violations caused by natural disasters has been provisions that excuse violations caused by startup, shutdown or malfunction (SSM) conditions. But those protections have been eroded as a result of recent court decisions and related Obama Administration policies that the Trump Administration is now trying to revise. Much of the regulatory response to the recent disasters in the air quality arena will be shaped by the fate of the exceptional events and SSM rules, which will in turn be shaped by the occurrence of the disasters and the likelihood that we will continue to experience them.