Boeing has locked out its private force of firefighters who protect its aircraft-manufacturing plants in the Seattle area and brought in replacements after the latest round of negotiations with the firefighters’ union failed to deliver an agreement on wages.

The company said Saturday that it locked out about 125 firefighters and a facility about 170 miles (275 kilometers) away in central Washington. The firefighters serve as first responders to fires and medical emergencies and can call in help from local fire departments.

“Despite extensive discussions through an impartial federal mediator, we did not reach an agreement with the union,” Boeing said in a statement. “We have now locked out members of the bargaining unit and fully implemented our contingency plan with highly qualified firefighters performing the work of (union) members.”