The Petaluma City Council Thursday unanimously approved an amendment to its contract with the state retirement system to create a second tier of retirement benefits for new employees.

The changes take effect today and cover non-public safety employees of the city's largest union. Earlier, the city reached similar agreements with its police, fire and other bargaining groups.

New non-public safety employees will have to wait until age 60, instead of 55, to be able to retire with a pension equal to 2 percent of their pay per year. New police and firefighters have to work to 55, up from age 50, for a maximum of 3 percent yearly accumulation.

The two-tiered retirement system provides no immediate savings to the city and only modest savings in the coming decades as the workforce turns over.

When the ratio becomes half-and-half between first- and second-tier workers, the city will save just under $600,000 annually in its contribution to pension benefits.

Petaluma's public safety employees contribute 9 percent of their salaries to retirement, while miscellaneous employees contribute 7 percent.

You can reach Staff Writer Lori A. Carter at 762-7297 or