Natural Exceptions or Exceptional Natures? Regulatory Science and the Production of Rarity

The Exceptional Events Rule (EER) of the Clean Air Act was intended to address “exceptional” air quality events but, in practice, the way the rule is employed has significant impacts on regulatory data sets that are used to understand and manage air quality. Through this rule, the Environmental Protection Agency is entangled in the politics of classification, striving to separate the unnatural from the natural and the exceptional from the common with important consequences for air quality data and regulation. If deemed exceptional, the data can be removed from the regulatory record, not only altering our understanding of air quality—and, importantly, risk and exposure—but also the management of it. By analyzing regulatory data sets, texts, and appeals, this article explores the consequences of the rule’s data exclusions. I argue that the act of producing “natural exceptions” has another unintended consequence: It inadvertently creates exceptional natures; that is, natures that despite their common occurrence are deemed rare. By repeatedly removing data, the EER changes understandings of normal or expected events and becomes a powerful tool for deregulation. Ironically, even as regulations produce exceptional natures, they are simultaneously undermined by them, leading to regular and repeated surprises, unnoticed hazards, undetected exposures, and deregulation.