U.S. ports from Maine to Texas could shut down Tuesday if a union representing about 45,000 dockworkers carries through with a threatened strike. A lengthy shutdown could raise prices on goods around the country and potentially cause shortages and price increases at big and small retailers alike as the holiday shopping season — along with a tight presidential election —

Approximately 50,000 ILA union longshoremen were walking off the job at East Coast and Gulf Coast ports starting at 12:01 a.m. ET on October 1 after failing to reach an agreement with ports ownership on a new contract.