Wells Fargo employees who review customer complaints and workplace issues have voted to unionize.

The move is the latest in a campaign to organize workers at the San Francisco bank, which is notable in an industry that historically has had low rates of unionization.

After a legal back-and-forth over the vote, in which the bank contested the validity of ballots cast by former employees, the National Labor Relations Board certified the election results Tuesday. Members of the conduct management department voted 21-16 in favor of joining the union.

“We look forward to creating an open dialogue with Wells Fargo to improve working conditions in our department,” said Roslynn Berkeland, an investigations associate at Wells Fargo, according to a news release by the Communications Workers of America, the parent union affiliated with Wells Fargo Workers United.

The lead-up to the vote was contentious. After workers announced in early September their intent to hold a vote, bank officials disparaged the union drive in meetings and in emails to employees, current and former members of the conduct management department told The Times in interviews. On Oct. 1, the bank laid off 11 employees in the department.