New Orleans warehouses are bursting with metals such as copper, lead, aluminum and zinc as manufacturing slows down with the economy.

In 1998, New Orleans became one of a limited number of cities around the world designated by the London Metal Exchange as sites to hold metals until manufacturers are ready to use them.

Mine operators can't entirely shut down production in a bad economy, so they ship unprocessed metal to warehouses in free trade zones around the world, to sit without import duties until a manufacturer needs them.

New Orleans is now behind only Detroit, and with more copper, zinc and steel in storage than any other place in the country.