The machinists union, hoping to represent some 600 Delta Air Lines workers at Salt Lake City International Airport, announced Friday that it has submitted papers to the National Mediation Board that could ultimately delay unionization.

The delay, however, could actually work in the International Association of Machinists and Aerospace Workers' favor, as the mediation board, a federal agency that's over union-management relations in the railroad and airline industries, is considering changing rules for what constitutes majority rule in a union election.

The union said Friday that it told the board to withdraw its request to recognize Delta and Northwest Airlines as one carrier, the first step toward holding elections among Delta and NWA employees about whether they wanted to join the union.

Union spokesman Joseph Tiberi said in a phone interview that since the single-carrier request was made in August, "both Delta and the machinists union had to file briefs of the matter. And that's where Delta repeatedly argued they could not move forward" unless other employee groups that the union wants to represent were also part of the single-carrier application.

The union's August request was on behalf of fleet service employees, those who load and unload freight, bags and mail below a plane's wings. But the union also represents the passenger service group, which includes ticket agents and those who work behind the counters and make airline reservations, and the office and clerical group, which are people who work in business administration. At NWA, all three employee groups are represented by the union. At Delta, none of them are.

The union says that while the fleet services employees from both companies have been working as one company, the other employee groups have not.

Local fleet worker Bruce Church said there are 600 Delta and NWA fleet workers in Salt Lake City, where Delta has a hub.

Atlanta-based Delta released a statement Friday calling the timing of the union's actions suspicious.

"The IAM's action is repugnant, and is nothing more than the continuation of a pattern of stalling resolution of union representation among our work groups," Mike Campbell, Delta executive vice president of human resources and labor relations, said in the statement. "The IAM communicated to Delta employees in early August that it could file for elections for the remaining 20,000 employees 'within weeks.' Now, months later, and on the one-year anniversary of our merger, the IAM instead withdraws its application claiming that we are not a single carrier."

e-mail: lhancock@desnews.com