(Reuters) - Union members at General Dynamics (NYSE: GD ) Electric Boat unit voted to authorize a strike, the United Auto Workers said on Tuesday.

The move comes amid an ongoing labor dispute post the expiration of the members’ contract on April 4 at Electric Boat, a part of the defense contractor’s marine systems segment, which assembles nuclear-powered submarines for the U.S. Navy.

The union represents over 2,400 marine drafters, who design submarines at the unit and are fighting to win cost-of-living adjustments (COLA) to keep up with inflation, along with affordable healthcare.

The union members are also seeking the restoration of pensions, as they argue that General Dynamics is pushing for increases of 52% to 161% in weekly medical insurance costs.

General Dynamics has received significant contract awards from the Pentagon for building the Navy’s Virginia-class submarines, but is years behind schedule because of skilled labor shortages, design issues, and supply chain challenges stemming from the pandemic.

"Inferior compensation at Electric Boat is leading to worker shortages and production delays," UAW said.

In January, General Dynamics CEO Phebe Novakovic flagged continued pressure on the marine systems segment’s margins owing to additional delays in quality issues from the submarine supply chain, weighing on costs.