Nearly 50,000 members of the International Longshoremen’s Association (ILA) are on strike Tuesday against the nation’s East and Gulf Coast ports, choking off the flow of many of America’s imports and exports in what could become the country’s most disruptive work stoppage in decades.

The union representing thousands of dockworkers from Maine to Texas launched a strike over wages and the use of automation, shutting down major seaports.

For the first time in nearly 50 years, thousands of dockworkers are walking the picket lines as they demand better pay and increased job security. A strike at East Coast and Gulf Coast ports could send ripples through the supply chain,