Union leaders and company executives are negotiating a new work contract that will affect thousands of employees at Northrop Grumman shipyards in Pascagoula and New Orleans.

They’re supposed to reach a deal by March 4, the last work day under the current contract. Previous contract negotiations at the shipyard in Pascagoula have pushed close to the deadlines.

In 2003, federal mediators extended the contract two weeks, and the last of the unions voted for a new four-year package on the day before the deadline.

In 1999, when some unions rejected the contract proposal, the small independent machinists union put up a picket line and others followed. The Pascagoula yard, then owned by Litton Industries, went through a three-week strike.

Top issues then were wages and the cost of workers’ health care.

Negotiations started Jan. 8. Each of the 13 unions has at least one representative at the table, even though nine are represented under the Metal Trades Council and vote together. Some have their business agent plus an international representative and others. The number of negotiators for Northrop Grumman varies depending on the topic being discussed. There can be up to 70 people in the room.

Northrop Grumman, with 11,800 workers in Mississippi, is one of the largest private employers in the state.