U.S. labor mediators upheld a disputed 2010 union election for baggage handlers at Delta Air Lines Inc, dismissing claims by the machinists union that management interference led workers to vote against unionization.

Delta said the National Mediation Board decision allows it to begin aligning pay, benefits and work rules for baggage handlers and cargo warehouse employees.

The International Association of Machinists and Aerospace Workers union had sought a new election, saying that Delta management had engaged in surveillance and intimidation, making employees fearful of supporting the union.

The labor board said in dismissing the union’s interference claims that its investigation found that election conditions were not tainted in the vote by more than 10,500 workers from Oct. 14 to Nov. 18, 2010.

Elections for groups that include about 50,000 workers took place last year to resolve labor representation after the 2008 acquisition of mostly unionized Northwest Airlines by Atlanta-based Delta, the least union-represented of the major U.S. airlines.

Flight attendants, customer service agents and workers in the TechOps maintenance department at the carrier also rejected union representation in those votes. (Reuters)