The U.S. Postal Service is studying whether to move the sorting of Helena’s outgoing mail to Great Falls, about 90 miles away, a possibility that disturbs the postal workers union. The city is the only Montana location among 40 places nationwide where relocation of sorting is being considered, a Postal Service spokesman said Thursday. Efficiency is the goal, Al DeSarro said, and Great Falls postal facilities have greater capacity and sorting capability than the Helena facilities. If Helena’s outgoing mail is sorted in Great Falls, the mail will be picked up earlier and delivered later in the capital city and at the area’s 11 smaller post offices, said Janet Kosnik, president of American Postal Workers Union Local 649. Kosnik was among about 30 participants in a protest Wednesday outside Helena’s main post office. “If there’s any major impact on service, (the change) probably would not be approved,” DeSarro said. Some postal jobs that now exist in Helena would move to Great Falls if the sorting is reassigned, he said, but overall there would be no loss of Postal Service employment. About 100,000 pieces of mail originate in Helena daily and the city receives about 200,000 pieces, DeSarro said. Not all the outgoing mail must be sorted, because major mailers such as state government “prep” their mail, he said.