Longshoremen at docks along the U.S. East and Gulf coasts have gone on strike for the first time since 1977 as the union takes a hard-line stance against automation found at other ports around the world.

The International Longshoreman’s Association halted negotiations in June with the U.S. Maritime Alliance, a group representing port operators and ocean carriers.

The union said an Alabama port operator’s use of new gate technology that scans and processes containers without worker involvement violated their existing contract. The ILA said it wouldn’t return to the bargaining table until the "issue is resolved,” idling some 45,000 dockworkers who are also pressing for higher wages.