Updated on: September 18, 2024 / 7:21 AM EDT / CBS/AP Determined to thwart the automating of their jobs, about 45,000 dockworkers along the U.S. East and Gulf Coasts are threatening to strike on Oct. 1, a move that would shut down ports that handle about half the nation's cargo from ships.

A strike by unionized dockworkers along the East Coast starting overnight is highly likely, top state officials and those at the Port of New York and New Jersey said Monday, and it would dramatically upend the supply chain for billions of dollars' worth of consumer goods going into the busy holiday shopping season.

The contract between the ports and about 45,000 members of the International Longshoremen’s Association expired at midnight, and even though progress was reported in talks on Monday, the workers went on strike. The strike affecting 36 ports is the first by the union since 1977.