Fairfax County’s Board of Supervisors late Tuesday gave unanimous approval to Inova Mount Vernon Hospital’s expansion but also provided additional protections for the historic African-American enclave of Gum Springs.

The most important ensures that the New Gum Springs Civic Association would have a say with the Mount Vernon district supervisor and other public officials in how to spend approximately $2 million that Inova has agreed to pay to mitigate increased traffic congestion.

The project’s other conditions, some of which were agreed upon before Tuesday’s meeting, would require Inova to return to the Board for further approvals on later phases of its expansion.

“What we got is a seat at the table for each phase of the development,” said Queenie Cox, president of the New Gum Springs Civic Association. She accused Inova of ignoring concerns of Gum Springs until the community rose up.

Over the weekend, Cox mounted a last-minute petition drive that collected about 200 signatures demanding that the Board impose stricter controls on Inova Mount Vernon’s redevelopment. In particular, Gum Springs residents complained that plans to expand Sherwood Hall Lane to four lanes between Route 1 and Parker Drive would shunt most of the increased traffic toward Gum Springs but will spare whiter and wealthier neighborhoods to the east.

But Inova and Fairfax County officials assured the community that the first phase of Inova Mount Vernon’s expansion would not increase traffic, and that later phases would require further approvals. They also challenged the assertion that Gum Springs’ concerns had been ignored.

“We’ve been working with Gum Springs for some time,” said Sarah Hall, an attorney for the hospital. Hall also could not say when Inova might move toward its second phase of expansion.

Supervisor Gerald W. Hyland (D-Mount Vernon), saying he had been somewhat puzzled by Gum Springs’ late objections, said Gum Springs had been included in more than a dozen meetings or presentations made by Inova or government officials since February.

Among them was a May 11 meeting with Del. Scott A. Surovell (D-Fairfax) and Sen. Linda T. “Toddy” Puller (D-Fairfax), and a two-hour meeting on July 11 with Mount Vernon planning commissioner Earl Flanagan, county staff, and Brett W. Kenney, who is Hyland’s chief aide. As recently as July 21, Cox told Hyland she was “comfortable” with the application, his staff said.

But Hyland told Cox during the meeting that he would make sure that the community flourishes and that its concerns would be heard.

“I can assure you that your community will be at the table,” Hyland said.

Inova Mount Vernon Hospital, whose 26-acre campus includes a 237-bed building, a helipad and an assisted-living complex, has been operating at the site since the early 1970s and has expanded several times. In 2008, the hospital announced plans for a $14 million expansion and renovation that would increase its capacity by about 22 percent, to 289 beds.

Owing to its location in a residential area, the hospital must obtain special zoning exceptions for each major project. A condition of approval is that the applicant’s actions have no adverse effects on its neighbors.

The Planning Commission last week voted to endorse the hospital’s expansion plans with certain conditions, including a provision that would give the Mount Vernon district’s supervisor oversight of about $2 million the hospital is paying for transportation adjustments.

On Tuesday, the Board granted the special zoning exception to Inova to build two towers — one three stories tall, another four stories — for patients’ rooms, a parking garage, an expanded emergency room and two ambulatory care centers.

The Mount Vernon Council of Citizens Associations, which includes Gum Springs, has pushed for modifications to the hospital’s plans but has otherwise agreed not to oppose the expansion.

Cox said following Tuesday’s meeting that she was satisfied with the outcome.

“Gum Springs did not want to stop Inova from expanding,” Cox said, adding that the community only wanted further protections from the expected increase in traffic.

But Ronald Chase, who is president of the Gum Springs Historical Society, said he believed the conditions did nothing to ensure that the community will not be overwhelmed by the side effects of Inova’s growth, including traffic in a part of the county whose main corridor, Route 1, is already choked with vehicles.

“It’s a rotten game that was just played inside,” Chase said after leaving the meeting.

Jennifer Siciliano, a vice president for governmental relations for Inova Health System who attended Tuesday’s meeting, declined to comment afterward.