Sonoma County supervisors on Tuesday appointed a leader in the Sonoma County Taxpayers Association to the board that runs the county public pension system, despite complaints from labor groups that his organization is hostile to union interests.

"I don't think we should start down that road of picking and choosing what affiliated organizations one should belong to before being assigned to a particular committee, board, or commission," Chairman David Rabbitt said before the vote confirming retired Chevron executive Bob Williamson to the pension board. "I think that is a dangerous place to go."

Williamson, a Mark West area resident, worked for more than 30 years for Chevron, including five years running that company's retirement plan, among other senior financial positions. Rabbitt and other supervisors said he had unusual expertise to bring to the nine-member board of the Sonoma County Employees' Retirement Association.

Labor leaders, however, said they were disturbed by the fact that Williamson has publicly criticized the size of public pension payments and is a board member for the Taxpayers Association, which has accused unions of deliberately running up pension benefits at the expense of other government services.

"Somebody who's got that strong a point of view, can he just set that aside and participate and not have it have an impact?" said Bill Robotka, a retired county worker and a union representative for about 235 current employees who belong to the Engineers and Scientists of California, Local 20.

Robotka asked the supervisors to probe Williamson's positions and background more thoroughly. He also criticized Williamson for not explicitly including his membership in the Taxpayers Association on his application for the vacant position on the SCERA board.

Williamson conceded that he has been critical of the cost of public employee pensions, but he said that is irrelevant to the mission of the SCERA board, which is a technical oversight panel, guiding investments, administration, and planning for the pension system.

"It really has nothing to do with policy, the benefit policy, which is established by the (supervisors)," he said. "The job of SCERA is to take whatever is given to us and ensure that the assets are well managed with respect to the balance of risk and return, that the actuarial (projections) are accurate, that the actual benefits are paid and managed in an efficient fashion."

As for disclosing his Taxpayers Association membership, he said, "I just didn't put it on there because it is not important," though he pointed out that he did include association President Jack Atkin as a reference, so the connection was not a secret.

As a SCERA board member, "my job is make sure it is run well, run safely and the money is well cared for," he said, "and I think I can do that irrespective of my thoughts on the level of pension benefits that are out there. Those are two separate issues, in my view."

The SCERA board manages about $2 billion in assets on behalf of more than 8,000 current and retired county workers. Most of the nine members on the board are county employees or elected officials, but two — Williamson and Petaluma CPA Donna Beels — have no connection to county government.

Four members of the board are appointed by county supervisors, two are elected by retirees, one is elected by law enforcement and other public safety employees, and two are elected by active civilian employees.

The county pension system has been a closely watched political issue, with supervisors trimming pension benefits in 2012 for future employees to contain taxpayer costs. The pension system's unfunded liability — the difference between current assets and projected payments to retirees — was $527 million at the end of 2012, the last official report.

The official numbers for 2013 won't be released until May and pension officials say they hope to see a lower unfunded liability due to improving returns on investments, though they will not predict how much it may improve.

The supervisors approved Williamson's appointment unanimously, with Supervisor Susan Gorin absent. Several said they were sympathetic to concerns of labor, but they were satisfied that Williamson is qualified and would help administer the pension system productively.

Robotka said he was willing to give Williamson a chance to prove his impartiality, though he remained troubled after Tuesday's vote. He complained that the voice of active union members has never been strong on the board - most of the recent members who are county workers have been management rather than current rank-and-file employees.

Even under the best of circumstances, he said, Williamson will simply perpetuate that non-union orientation.

"I expect him to be the most conservative and least retiree- and employee-oriented voice on the board," he said.

You can reach Staff Writer Sean Scully at 521-5313 or sean.scully@pressdemocrat.com. On Twitter @BeerCountry.