"We're preparing for what could potentially be a very strong environmental disaster," Brown said.
He added that another concern is the effect on the price of gasoline from refinery capacity temporarily lost to Katrina's impact.
Brown says the mandatory evacuations ordered before Katrina hit were "exactly the right thing to do" because "that, in the end, saves lives, even if it wasn't necessary, or people started second-guessing it."
As people left and went to shelters, Brown said he went "into disaster mode," and, "I know I need medical teams and rescue teams and all the teams that supply all the commodities, meals ready to eat, ice, water, cots, so I started jamming up the supply lanes as fast and as downward as I could, to be able to respond to anything these governors might need.
"We're hoping for the best but preparing for the worst."
Brown says FEMA's coffers are filled nicely by President Bush and Congress, and every dime is needed.
"We're still in Florida doing long-term recovery efforts" from last year's hurricanes, Brown said. "We're still in Alabama. We're now in Mississippi and Louisiana preparing for response activities. Don't let us forgot we have wildfires going out West.
"This is a very active disaster season for FEMA. The men and women of this organization are ready to respond anywhere and everywhere."