A date has been set for a do-over in labor elections between the National Union of Healthcare Workers and Service Employees International Union--United Healthcare Workers West at Kaiser Permanente facilities in Northern California, including more than 4,700 workers in the North Bay.

In another twist to one of the largest intra-union battles in decades, the National Labor Relations Board has scheduled a re-run for roughly 45,000 employees. Ballots are scheduled to be mailed on April 5 and returned the NLRB regional office in Oakland by April 29. A vote count will begin on May 1. Employees -- largely medical assistants, respiratory therapists, medical records clerks and others -- can also vote for no union at all.

In Santa Rosa, about 1,250 employees will be included; in San Rafael, about 800; in Napa, about 120; in Fairfield, about 113; in Vacaville, about 550; and in Vallejo about 1,900.

The issue stems from NUHW's contesting the results of a 2010 election, in which SEIU won a super-heated battle for membership, along with about $40 million in annual dues collected. But NUHW, an offshoot of the larger SEIU, alleged that its rival interfered in the election.

An administrative law judge with the NLRB agreed, recommending that the election be set aside based upon certain conduct by SEIU.