The union representing U.S. dockworkers has signaled that 45,000 members will walk off the job at midnight, kicking off a massive strike likely to shut down ports across the East and Gulf coasts.

Dockworkers at dozens of U.S. ports are digging in for a massive pay increase, seeking to flex their power in a strike that aims to strangle the flow of trade across much of the country.“This is going down in history what we’re doing here,

The International Longshoremen’s Association signaled 45,000 members were walking off the job at midnight, kicking off a strike that would cost billions a day.