Not New Orleans, but Louisiana:
"The region is also home to America’s only supertanker port, the Louisiana Offshore Oil Port (LOOP). Located in the Gulf of Mexico just south of Fourchon, LOOP handles 800,000 barrels of crude oil each day, 12% of the U. S. supply of daily crude imports."
From Portrait of an Estuary
http://www.seagrantfish.lsu.edu/pdfs/portrait_estuary.pdf
Supertankers cannot deliver cargo at NYC or LA?
I find that VERY hard to believe.