The American Press Institute building in Reston, designed by acclaimed 20th-century architect Marcel Breuer, which preservationists are trying to save from being demolished to make way for townhouses and an apartment building. (Antonio Olivo/The Washington Post)

With its bulky, waffled window grids, the American Press Institute building in Reston stands as Virginia’s sole example of the brutalist style of Marcel Breuer — an acclaimed 20th-century architect who also designed the federal Department of Housing and Urban Development headquarters in Washington.

But because the vacant concrete building in Reston was never targeted for preservation, it is being considered for demolition to make way for 34 townhouses and an apartment building a short walk from Metro’s Wiehle-Reston East station on the Silver Line.

That possibility has stirred an outcry, revealing the fact that a 2013 Reston master plan crafted around the Silver Line did not account for the unique architecture of several low-slung 20th-century buildings that collectively are a trademark of the celebrated planned community.

“History in Virginia is more than just Colonial history,” said John Burns, a member of Fairfax County’s Architectural Review Board, which has petitioned local officials there to require that the API building be incorporated into any new development.

“If the county can’t protect the heritage of its development over time — and especially a building by an internationally acclaimed architect — what can they protect?” Burns said.

During a public hearing scheduled for Tuesday, the Board of Supervisors will consider a proposal to demolish the 48,200-square-foot API building and rezone the land for high-density residential use — weighing the concerns of preservationists against the desire to create vibrant neighborhoods around the Silver Line.

Reston, where the modernist-inspired Lake Anne Center was designated a historic district in the early 1980s, is struggling to strike a balance between those forces. As construction continues along the Silver Line toward Dulles International Airport and beyond, new townhouses and apartment buildings rise near the sprawling houses and winding paths that have long defined the area.

Hoping to establish the right mix, the county’s planning commission recommended that the development project be rejected and that county officials survey Reston properties for historical significance as soon as possible.

Several members of the Planning Commission expressed frustration over not knowing about the building’s architectural relevance sooner and, now, jeopardizing a multimillion-dollar development project in the works for nearly a year.

“On this one, it’s particularly difficult, because we messed up — we, collectively, the county,” Planning Commissioner James R. Hart (At Large) said at a meeting about the proposal last month, according to county minutes. “This structure should have been identified at some point along the way, and it wasn’t.”

At the same meeting, developer John Sekas — hired to build the new homes by a Florida-based limited-liability company that bought the property for $5 million in 2013 — sounded exasperated, saying he had put off razing the building to address other concerns by the county’s Planning and Zoning Department, which ultimately endorsed the project.

“I stuck my neck way out on the limb on this application because the owner wanted to take the building down before we filed the application,” said Sekas, who did not return calls seeking comment. “And if this process goes any further, my neck is getting cut off. And that’s a developer of 30 years in the county.”

Supervisor Catherine M. Hudgins (D-Hunter Mill), who represents the area, did not return several messages seeking comment.

Sharon Bulova (D), chairman of the Board of Supervisors, said it’s unlikely that the building will be saved unless a private foundation or some other group steps in to buy and renovate it.

“I would love to see the building preserved, but I don’t see the county purchasing it, especially in light of our other capital needs for renovation of schools and fire stations, transportation needs,” Bulova said. “Sadly, the building could be removed.”

Local residents argued that the county should be doing more to preserve the serene character of Reston that many worry is being overrrun by new development around the Silver Line.

When the API building was completed in 1974, it helped set a template for architecture in Reston, where many structures are set amid natural landscapes and have earth-tone exteriors and windows allowing in natural light.

Breuer, a student of the Bauhaus school of architecture who also designed St. John’s Abbey Church in Minnesota and a former home of the Whitney Museum of American Art in New York, was drawn to Reston’s charm, local historians say.

“He was interested in the idea of doing something in a small town,” said Cheryl Terio-Simon, widow of Reston founder Robert E. Simon Jr. and vice chair of the Reston Museum. “Its brutalism has more of a human scale. It’s not a monument like his other works. But the way he brought light in was beautiful — just beautiful.”

Shrouded by trees, the API building served as home to the American Press Institute until that organization merged with the Arlington-based Newspaper Association of America Foundation and shut its Reston operations in 2012.

Journalists from around the world convened there, attending seminars inside the building’s swooping conference rooms and sharing worries about their struggling industry on the structure’s shaded patios.

Today, the building is mostly gutted, with a plywood board covering a hole in one of its windows.

“There are thousands of people who considered that building their second professional home,” said Carol Ann Riordan, who helped coordinate seminars at the API building while working there for 26 years. “There is a very deep and passionate love for that building. Once it’s gone, it’s gone.”