The five-member Sonoma County Board of Supervisors voted unanimously Tuesday to shift a larger share of health care premiums to retirees and non-union county workers.

The vote came after a three-hour hearing that included passionate pleas from retirees that the board was about to tamper with promises of future health care benefits. More than 300 retirees and supporters crowded into the Board chambers and spilled into the hallway outside. Some even stood in the plaza outside the administration building.

Supervisors conceded their vote would be unpopular with the 2,500 retirees and 650 non-workers that will be affected by the cost restructuring beginning in June.

Board Chairman Mike Kerns said, "This is a very emotional issue. I probably can't change your mind, but we do care."

Supervisor Mike Reilly, struggling to hold back tears as he read a prepared statement, said, "We have not found a way to resolve the issue without adversely affecting retirees."

As supervisors were voting, several hundred union employees gathered in a demonstration at nearby parking lot. Union leaders criticized similar health care premium changes that the county is proposing in contract negotiations.

County officials began Tuesday's hearing with a 90-minute presentation. They recommended a gradual reduction over the next five years in the county's contribution to retiree and unrepresented employee health benefits to $500 a month. Current employees would receive an extra $600 a month, which could go toward salary or health premiums. Changes would take effect next June.

County officials say cuts are necessary to make up a $15 million annual deficit in funding commitments for health care premiums, expected to total $414 million over the next 30 years.

Currently, the county pays 85 percent of an employee's choice of health plans. For retirees, it pays 85 percent of the county lowest-cost health plan.

Retirees have protested the cuts, saying that during labor contract negotiations and at time of retirement, they were assured that the county would continue contributions to fund health benefits. During contract negotiations, unions have been given similar health premium cuts, which they, too, oppose.