And if the refineries leak it will further complicate rescue efforts. Since the chemicals are toxic, even more so when comingled, workers can't be sent in unless they know the area is safe. As Steven Drielak who served as a Director with the EPA's National Counter Terrorism Evidence Response Team during Katrina, told Popular Science earlier this year, "You need to picture hundreds of gasoline stations, and hundreds of chemical storage facilities all flooding out. The water enters, picks up all of these chemicals, mixes it into a huge toxic soup, and then flows through the city streets. Once the water recedes it all soaks into the ground. Now you've got this toxic material in the ground and you don't know whether it's safe or not."