Before Maine Medical Center can undertake its proposed $512 million expansion, it first must prove to state regulators that the project is necessary and won’t duplicate existing services or increase the cost of health care.

Maine Med will have to justify its expansion by applying to the Maine Department of Health and Human Services for a Certificate of Need, an important hurdle the hospital needs to clear before construction could begin.

An official at the Maine Hospital Association says the DHHS generally approves Certificate of Need applications, although some expansion or renovation plans have been scaled back after review.

The complex process overseen by the DHHS Division of Licensing and Regulatory Services, which could take several months, is designed as a check against unneeded hospital expansions.

“We believe a Certificate of Need is an important process to have in place and that’s why most states have them,” said Emily Brostek, executive director of Consumers for Affordable Health Care, an Augusta-based health advocacy group. Thirty-five states require a Certificate of Need approval before projects can go forward.

“If hospitals are going to open up more services, it needs to be done for the overall benefit of the state,” Brostek said.

Maine Med’s expansion – expected to be completed by 2022 – would increase the footprint of the hospital’s main campus by about 25 percent and add 20 new operating rooms and 128 single inpatient rooms. The cornerstone of the expansion would be a 270,000-square-foot building fronting Congress Street that would serve as the hospital’s main entrance and include 64 inpatient beds and the operating rooms. The project also would include construction of a new parking garage, demolition of a parking garage built in 1972, relocation of the helipad, a two-floor addition to the East Tower and an off-site investment in outpatient services.

The expansion would be the largest in Maine Med’s history, and would be among the costliest in the nation since 2014, according to Revista, a Maryland medical real estate consultant.

Because the hospital would be closing double-occupancy rooms, the overall capacity of Maine Med would remain the same at 637 beds, although hospital officials say having more single rooms will improve the hospital’s efficiency and ability to accept patients who need a single room.

Jeffrey Austin, vice president of governmental affairs for the Maine Hospital Association, said the process has been fair over multiple state government administrations and results in important discussions about the size and quality of health care systems in Maine.

“By and large, the Certificates of Need tend to be approvals,” Austin said. “We don’t think it’s inappropriate for the government to be asking these questions. The kinds of questions that are asked through the CON are usually the types of questions that officials are asking internally anyway.”

Austin said that when hospitals ask for expansion of services, the questions by state officials become more pointed.

“You get to a second level of questions when you want to increase capacity,” he said. “They start asking about market forces.”

Austin said one reason for the extra scrutiny is that the state doesn’t want health care systems to overbuild and then result in some facilities closing.

“If you have a hamburger stand and it closes, it doesn’t have the same impact on a community as if a nursing home closes and you have a lot of elderly people who are suddenly homeless,” Austin said.

Austin said there have been times when the state has approved projects with modifications, notably when MaineGeneral Medical Center’s new hospital in Augusta was reduced from 226 beds to 192 beds.

Four months after it opened in late 2013, MaineGeneral officials complained about a bed shortage, with patients who had been in the emergency room waiting in hallways for rooms to open up.

The bed shortage has since been alleviated, said Joy McKenna, MaineGeneral spokeswoman, although demand for beds is still high.

“We have a high census, but we’ve worked hard and have efforts in place that have helped us to reduce the number of patients who are waiting in our emergency room for an inpatient bed to become available or need to be transferred to another hospital,” McKenna said. She said the hospital opened a “short stay” unit for patients staying only one night, and have made patient discharges more efficient and timely.

In another high-profile case, state regulators originally imposed conditions on Lincoln County Healthcare in May 2014 requiring that a 24/7 urgent care center be operated at the Boothbay Harbor medical facility after its emergency room closed. However, state regulators ultimately reversed that decision in November 2014.

Lincoln County Health closed the emergency room in Boothbay Harbor after it purchased the former Miles Memorial Hospital, touching off a community controversy. Lincoln County Health is a division of MaineHealth, Maine Med’s parent company.