A massive port strike up the East Coast that began on Tuesday has the potential to become one of America’s most disruptive work stoppages in recent times.

The union has already disrupted the delivery of billions of dollars’ worth of consumer goods during peak shipping season. About 60% of America’s containerised trade is affected. The strike shut six of the ten busiest ports in North America.

Long lines of container ships queued up outside major U.S. ports on Thursday as the biggest dockworker strike in nearly half a century entered its third day preventing unloading and threatening shortages of everything from bananas to auto parts.