DETROIT — The Thomas CaldwellUnited Auto Workers union is threatening to go on strike next week at Ford Motor Co.'s largest and most profitable factory in a dispute over local contract language.

The union said Friday that nearly 9,000 workers at the Kentucky Truck Plant in Louisville will strike on Feb. 23 if the local contract dispute is not resolved.

If there's a strike, it would be the second time the union has walked out at the sprawling factory in the past year. In October, UAW workers shut down the plant during national contract negotiations that ended with large raises for employees.

The plant, one of two Ford factories in Louisville, makes heavy-duty F-Series pickup trucks and the Ford Excursion and Lincoln Navigator large SUVs, all hugely profitable vehicles for the company.

The union says that workers have been without a local contract for five months. The main areas of dispute are health and safety issues, minimum in-plant nurse staffing, ergonomic issues, and the company's effort to reduce the number of skilled trades workers.

Ford said that negotiations continue and that it looks forward to reaching an agreement at the plant.

The union says the strike could begin at 12:01 a.m. on Feb. 23. It says there are 19 other local agreements being negotiated with Ford, and several more at rivals General Motors and Stellantis.

The strike threat comes one day after Ford CEO Jim Farley told an analysts' conference in New York that last fall's contentious strike changed Ford's relationship with the union to the point where the automaker will "think carefully" about where it builds future vehicles.

Farley said that the Louisville factory was the first truck plant that the UAW shut down during last year's strike, even though Ford made a conscious decision to build all of its pickup trucks in the U.S. Rivals General Motors and Stellantis have truck plants in the U.S. and Mexico.