"U.S. EPA [Monday] released the final version of closely watched guidelines intended to make it easier for states to get a pass on air pollution violations outside their control because of 'exceptional events.'

The guidance covers 'exceedances' stemming from wildfires, volcanic eruptions, stratospheric ozone intrusions and other natural events. While it applies to all pollutants covered by the National Ambient Air Quality Standards, EPA officials have stressed its value as a tool to help meet the tighter ozone benchmark put in place last October.

The new rule updates criteria put in place in 2007. Among more than a half-dozen changes summarized in an agency fact sheet, the revisions clarify 'fire-related definitions and demonstration components'; more clearly define the scope of the exceptional events rule and the types of regulatory actions it covers; and clarify 'the analyses, content and organization' for exceptional events waiver applications."

Sean Reilly reports for Greenwire September 19, 2016. [2]