The Clean Water Act requires EPA to promulgate effluent limitation guidelines and standards that reflect pollutant reductions that can be achieved by categories or subcategories of industrial point sources using specific technologies. This includes airports. On August 28, 2009, EPA published a proposed rule recommending that best available technology (BAT) be installed at most large airports capable of collecting up to 60% of aircraft deicing fluids and treating the collected fluids. A public comment period was provided until February 26, 2010. EPA is now in the process of finalizing the rule. When performed without adequate discharge controls in place, airport deicing operations can result in significant adverse impacts on water quality, such as reductions in dissolved oxygen (DO), which can lead to fish kills and other aquatic ecosystem problems. Aircraft deicing fluids also contain additives, and some of these have potential aquatic life and human health impacts due to their toxicity. In addition, deicing fluid discharges have been shown to affect drinking water treatment processes and the quality of finished drinking water. This presentation will discuss the data and information on the environmental impacts of deicing discharges EPA has accumulated during the rule-making process.