NORTH BAY, CALIFORNIA – Kaiser Permanente employees throughout the region will be able to officially vote on whether to remain with the Service Employees International Union – United Healthcare Workers West, the union that currently is in place, or join its rival offshoot, the National Union of Healthcare Workers, the National Labor Relations Board announced today.

The vote, which will be conducted by mail-in ballots rather than an on-sight election, will take place on Sept. 13 and will last three weeks. All ballots must be counted by October 4, according to the NLRB. The employees will also have the choice of voting for no union at all.

Nearly 43,000 Kaiser workers will take part in the vote, which is believed to be one of the largest votes in state history for a private employer. The two unions have fought bitterly for control, and the Kaiser elections are seen as pivotal to the success of NUHW as a new union, or could solidify SEIU-UHW’s position as the largest healthcare union on the West Coast.

Meanwhile, NUHW said today that 48 former SEIU shop stewards at Kaiser Santa Rosa announced they were resigning their posts with SIEU, which is the current representing union at Kaiser hospitals, to throw their support behind NUHW.

“While we make this decision with a heavy heart, we are confident that the best future for our coworkers is with NUHW and not SEIU-UHW,” the stewards said in a letter dated today. “We are confident that we will emerge from this with a strong, democratic and effective union.”

About 1,250 employees in Santa Rosa and Rohnert Park will participate in the vote; in San Rafael, about 800; in Napa, about 120; in Fairfield, about 113; in Vacaville, about 550; and in Vallejo about 1,900.