Coast Guard Petty Officer 3rd Class Andrew Butcher walks through Aqueous Film Forming Foam (AFFF) as the top layer blows off spilled oil at a Kinder Morgan Liquid Terminal in Houston, Texas, Aug. 30, 2017 during Hurricane Harvey response. The application of AFFF is a safety measure used by oil refineries to prevent exposed petroleum from igniting. (Coast Guard photo by Petty Officer 2nd Class Paul Krug)