Second....cat litter? How was it economical to take care of the spill with over 250 lbs of kitty litter? It's weird.. but I hope it worked I guess. Did you have that much lying around or did you show up to Petco and say "ok, load 'em up"?
You have obviously never dealt with a big oil spill before. Kitty litter is about the cheapest and best stuff you can use.