Contingency planning for a potential work stoppage at U.S. East and Gulf coast ports in the event of failed labor talks is extremely difficult for shippers because the cost of routing cargo to other parts of the country may be prohibitively expensive, especially for some exporters, the head of a major port said Monday. The International Longshoremen's Association is negotiating a new multi-year labor deal with the U.S. Maritime Alliance representing shipping lines, termin...