Organized labor launched a million-dollar campaign Saturday to stop the secession of the San Fernando Valley and Hollywood from Los Angeles, fearing a breakup would endanger thousands of union jobs and pensions.

With secessionists promoting huge cost savings from a split, most of Los Angeles' 35,000 city employees fear independent cities in the Valley and Hollywood would slash payrolls.

Unions throughout the county also worry that new cities would move against rent control and living-wage ordinances.

"We really believe that the proponents of secession have never been friends of organized labor or their families," said Miguel Contreras, head of the Los Angeles County Federation of Labor, AFL-CIO.

Organized labor is a mighty force in Los Angeles politics; an exit poll during last year's mayoral election showed 31 percent of voters came from union households.

The organization -- an umbrella group that represents 810,000 members including janitors, teachers, longshoremen and film crews, kicked off its campaign with a rally at Los Angeles Valley College that drew about 1,100 supporters.

Edith Portillo, a North Hollywood janitor who attended the rally, said she believes secession would favor only wealthy business people.

"The rich are rich, and they want the poor to stay down," she said. "I think this would be very bad for renters."

Along with dispatching thousands of volunteers to walk neighborhoods and staff phone banks, the labor movement plans to spend more than $1 million on its anti-secession drive.

The secession issue goes before citywide voters on Nov. 5.

Contreras is convinced the numbers will be on the side of labor at the polls. About 240,000 of his organization's members are registered voters in Los Angeles, he said.

Secessionists downplay union fears, saying safeguards will protect jobs.

If a breakup occurs, Los Angeles employees who transferred to either new city would have to negotiate new contracts after one year, possibly with city councils less sympathetic to labor.

Secessionists point out that the unions would face similar negotiations with Los Angeles anyway.

"It's the same process that goes on every few years in Los Angeles," Richard Close, president of the secession group Valley VOTE, told the Los Angeles Times. "No one has any guarantees."