U.S. East and Gulf Coast port workers are set to go on strike at midnight on Monday with no talks currently scheduled to head off a stoppage threatening to halt container traffic from Maine to Texas and cost the economy as much as $5 billion a day. The labor contract between the International Longshoremen's Association (ILA) union representing 45,000 port workers and the United States Maritime Alliance (USMX) employer group expires late Monday, with negotiations at an impasse over pay. A port strike will go ahead starting Tuesday at 12:01 a.m. ET, the ILA said on Sunday.