In the two years since Carney Hospital shuttered amid the collapse of its former owner, Steward Health Care, Dorchester residents have grappled both with grief over the loss of a community institution and with longer trips to receive emergency medical care.

Now, the real estate firms tasked with revamping the nearly 13-acre health care campus on Dorchester Avenue near Lower Mills are kicking off the city’s formal development process.

The HYM Investment Group and My City at Peace, led by veteran developer Thomas N. O’Brien and the Rev. Jeffrey Brown, respectively, this week expect to notify the city’s planning department of their intent to demolish the now-empty hospital and build a five-building, $850 million campus with a health care facility, apartments and senior housing, and an education center. That process will kick off a series of community meetings and eventually a vote by the Boston Planning and Development Agency board.

If approved, the project would be built in phases, with the health care facility coming first, Brown and O’Brien said this week. They are in talks with a number of health care networks to lease the expected 350,000-square-foot property, among them Mass General Brigham, Beth Israel Lahey Health, BMC Health System, and Brown University Health, O’Brien said.

Brown and O’Brien stressed the health care facility would not be a hospital. Its final uses will be determined in collaboration with the future tenant, along with the state and city, and could include offerings such as an emergency room, MRI and X-Ray machines, and behavioral health beds. A 2025 community health report co-chaired by Boston Public Health Commissioner Dr. Bisola Ojikutu and Michael Curry, chief executive of the Massachusetts League of Community Health Centers, recommended that a redeveloped property incorporate emergency services, primary care, and behavioral health services, among other suggestions.

“The community wants this to be a robust health facility,” O’Brien said. “We feel an obligation to make sure that we work to deliver on the aspects that the community has asked for.”

The shuttered Carney Hospital in Dorchester sits on 12.7 acres. (Danielle Parhizkaran/Globe Staff)
Danielle Parhizkaran/Globe Staff

New York-based real estate private equity firm Apollo Global Management owns the Carney campus, and last year tapped HYM and My City at Peace to redevelop the property. Beyond the health care facility, the campus is expected to include 50,000 square feet of retail, a 50,000-square-foot educational facility — possibly for hands-on nursing or health care training — and 500 residential units.

The housing would include at least 200 apartments, along with another 100 units that could be either apartments or condominiums. The campus would include a separate senior living building, with 200 units of independent and assisted living and memory care. There’s a demand for senior housing that includes different methods of care under one roof, Brown said.

“I live in Dorchester, and I know that the residents of Dorchester are getting older,” he said.

Since last year, Brown and O’Brien have been to 35 community meetings, including more than a dozen civic associations and neighborhood councils. The meetings so far have been filled with emotion, they said, as the Dorchester community has collectively grieved the loss of the Carney. Beyond people losing jobs and access to health care, losing the Carney also meant losing a community institution where families gathered for meals and the legendary 15-minute Mass held in the hospital’s chapel.

Carney Hospital earlier this month.Danielle Parhizkaran/Globe Staff

The meetings were rough but necessary, Brown said.

“We thought it was an important part of the process to listen and to hold all of that, so that we can get to what we can do now as a result of the loss of this hospital,” Brown said. “The goal is to revive the sense of community that was lost in the old Carney.”

If one of the health care systems signs onboard, O’Brien said, the project’s first phase could be ready to start construction by the end of next year and be ready to open by mid-2030.

“We think the window is now,” O’Brien said.

Catherine Carlock can be reached at catherine.carlock@globe.com. Follow her @bycathcarlock.