RICHMOND -- Contra Costa County has secured a major infusion of state funds for a new health exchange call center, but the big question is what city gets the investment.

The state last month chose the county as the site for one of three California Health Benefits Exchange Call Centers, but after weeks of study and debate, county supervisors appear divided on whether the center should be in Richmond or Concord.

The board is set to vote Tuesday.

"We need to have a side-by-side comparison and consider all the elements," said District 3 Supervisor Mary Piepho, who represents the eastern portion of the county. "The staff was pushing for Richmond, but this needs a full deliberation and a decision by the board."

The new site will house a call center with more than 200 employees. The center is aimed at supporting the eligibility and enrollment aspects of the state-level Affordable Care Act programs, including assisting uninsured Californians in purchasing insurance. The center will be funded by state and federal dollars.

Supporters of putting the center in Richmond note that the city was touted as a preferred site in the county's successful bid. One of the criteria for the preferred site was that it should provide employment in an area where unemployment rates are persistently high.

Unemployment in Richmond is at 14 percent, one of the highest rates in the county.

But Concord supporters say that city is more centrally located for workers and residents in the heart of the county, in closer proximity to other county services and accessible by public transit.

"The most overarching issues are cost-effectiveness and acceptability to the most amount of people looking for a job," said District 4 Supervisor Karen Mitchoff, who represents an area of Central County that includes Concord. "West County has a higher unemployment rate than Concord, yes, but when you combine areas of East and Central County, the difference is not that big."

The uncertainty heading into Tuesday's meeting is a marked change after county staff had settled on a preliminary site in Richmond for the new center. In December, the board voted unanimously to search for a site in San Pablo, Pittsburg or Richmond. But now Piepho wants to consider other options. She led the charge to explore other sites and bring the decision before the board.

"We were just being told (by staff) that Richmond was the site," Piepho said. "I stood up against that."

According to a staff report released late Thursday, the cost to occupy the proposed site at 1450 Marina Way South in Richmond would be $3.4 million, and the cost at the Concord site, 2500 Bates Ave., would be $4.25 million.

District 1 Supervisor John Gioia, who represents West County, said the staff report makes clear that Richmond is the optimum site.

"(The Richmond site) is $860,000 less than Concord and is located in the highest unemployment area of the county," Gioia said, adding that he's concerned the county may have to pick up the difference for the higher-priced option. Piepho and Mitchoff dispute that contention.

The 31-page report prepared by county staff avoided a direct recommendation but appeared to favor the Richmond site overall and noted that the owners of the Richmond site submitted a superior proposal.

"The Bates Avenue proposal did not meet a significant portion of (the minimum) requirements, and instead suggested the county change its requirements ..." the report said.

Richmond's City Council on Tuesday passed a unanimous resolution urging the county to choose Richmond.

Mitchoff on Friday disputed the notion that the Richmond site would provide cost savings or that the county may be on the hook for some costs if the Concord site is selected. She called the Concord site, a former Comcast call center, the more move-in-ready facility.

"I am not looking at this from a territorial perspective," Mitchoff said. "I want what is best for all the county."

Contact Robert Rogers at 510-262-2726. Follow him at Twitter.com/roberthrogers