OAKLAND -- A dispute over who gets a $7.5 million Alameda County contract is sowing division between the Hispanic Chamber of Commerce and a pair of black-owned businesses.

After months of legal appeals and behind-the-scenes lobbying, the Board of Supervisors is expected to vote Tuesday to award the lucrative three-year contract for work to recruit hundreds of temporary county employees and handle their payroll.

The county's top pick is TeamPersona, a staffing agency owned by Walnut Creek businesswoman Ginny Velasquez. But two rival firms, both owned by African-American men, are alleging that the process to select Velasquez was unfair and might violate county rules and California's 1996 affirmative action ban.

"You can't give preferential treatment to a Hispanic female business over a black male business," said rival bidder Clarence Hunt, owner of Oakland-based HR Management Inc. "Proposition 209 is the law of the land. Whether we like it or not, it protects everybody."

Velasquez's supporters, including the county administrators who recommended her firm, counter that TeamPersona is getting the award simply because it scored highest on an evaluation that considers the bid price and other objective factors.

The dispute is the latest involving Alameda County's procurement process, which was twice criticized by a civil grand jury in 2011 and 2012. The five-member Board of Supervisors votes to award millions each year to hundreds of private firms and nonprofit organizations for work meant to advance the county's mission. The grand juries have found a lack of oversight in how contractors are chosen.

This is also the second personnel contract award that Hunt's firm has protested this year, bringing unusual attention to a process that rarely attracts public scrutiny.

Standing behind Velasquez is the Hispanic Chamber of Commerce of Alameda County, which has mobilized supporters to speak on her behalf at county meetings. Many say they consider Velasquez to be a role model for successful Latina business owners in the Bay Area and beyond.

Velasquez declined to be interviewed before the board votes on the contract but she voiced her frustrations at a board meeting last week, pointing out the length of time since the bid notice went out in January.

"Why bother if this is what you're going to go through?" she said.

For eight years, Velasquez's firm shared the contract with other firms, including Hunt's, but county administrators recommended this year to give all the work to a single contractor. The work involves recruiting and hiring temporary employees, including those who work for the Registrar of Voters during election season and others who substitute for permanent county workers on maternity leave.

The two rival businesses, HR Management Inc., and Paradigm Staffing Solutions, lodged a protest letter on May 6. Both Oakland-based businesses are owned by African-Americans. They sought to overturn the county's recommendation to give TeamPersona the entire contract and asked instead to split it up as it had been before.

The county's General Services Agency said in June that the claims were unfounded and denied the protest. Days later, the two firms appealed to the county Auditor-Controller's office, which denied the appeal on July 25.

Proposition 209 has for more than 15 years banned public agencies from considering race in hiring and contracting, but Alameda County does give preference to "small, local and emerging businesses," which includes many minority-owned firms.

The rival firms, however, argue that TeamPersona should never have received extra points for being local because its Oakland address was a barely-used "virtual office," not a real one. Apparently heeding those complaints, TeamPersona recently moved to a new office in downtown Oakland with great fanfare: the Hispanic Chamber of Commerce hosted an open house and wine tasting there on Nov. 21.

Matt O'Brien covers Alameda County. Contact him at 510-208-6429 or Twitter.com/AlamedaCoNews.