Abstract: | The Clean Air Act (CAA) controls routine emissions at petroleum refineries, by creating limits and penalties for excess emissions. The CAA offers provisions for upset events, air emissions released because of unforeseen or unavoidable circumstances, if companies report the emissions and take corrective action. States enforce upset event rules and many states provide exemptions for a variety of circumstances, which may allow upset emissions to become a substantial, yet mostly unregulated source of emissions. We catalog the quantity and type of emissions generated during upset events at 18 Texas petroleum refineries from 2003 to 2008. We find that upset events occur frequently at these facilities and are collectively large in magnitude, emitting a combined total of 75 million lbs of emissions. In a select number of cases, single upset events exceeded annual emissions reported to the Toxics Release Inventory. Future research should assess the accuracy of upset event reporting and impact of upset events on environmental health. |