A nonprofit foundation that funds innovative arts endeavors wants to rehabilitate a nearly 300-year-old Madison home into what it calls a philanthropic and education center, but more than a dozen homeowners are fighting what they fear is commercial intrusion into a pastoral, sparsely populated part of town.

The Emily Hall Tremaine Foundation contends that it would vastly improve a badly deteriorated but historically and culturally significant property, and promises that it wouldn’t create a public museum or gallery at 6 Opening Hill Road.

But a group of residents appeared entirely unconvinced, with some telling town planners that permitting the operation would threaten Madison’s upscale residential character, worsen traffic, and potentially jeopardize wildlife and water quality in an area that’s close to Gould’s Pond and a nature preserve.

This month, the rhetoric became more vehement even as the foundation stepped up its public outreach efforts.

“What the foundation is seeking approval for is not much different from having the circus permanently encamp at 6 Opening Hill Road,” neighbors Carolyn and John Dugan wrote in a letter to the town earlier this month.

“These plans sound more like the commercial enterprises of a RJ Julia Bookseller or a Cafe Allegre than an owner of a residential property in the woods of Madison,” wrote Ed and Joanne Arrandale, whose Kachina Way home is about a third of a mile from the foundation’s property.

One neighbor even argued that a prominent architect who supposedly took part in an expansion of the original house had a history of being a Nazi sympathizer — in the 1930s.

“While (Philip) Johnson’s contributions to architecture are undeniable, his controversial beliefs and associations cast a dark shadow over his legacy,” Kachina Way resident Frank Rizzo wrote. “As stewards of our community’s integrity and values, we must carefully consider whether honoring such a legacy aligns with our principles of inclusivity, equality and tolerance.”

The foundation was scheduled to present its request for a special zoning exception in a public hearing during the planning and zoning commission’s April 18 meeting, but requested a postponement until May 16. The session is scheduled for 7 p.m. at the town campus and also can be viewed on Zoom.

The foundation currently maintains headquarters in downtown New Haven, but wants to move its small staff to the Madison property. In February of last year, it paid about $924,000 for the house and surrounding 6.2-acre property, according to town records.

In a letter to neighbors, the foundation said the site had been part of a 76-acre property owned by the Tremaine family from 1938 to 1994. During that time, the 1720-built main house took on several additions.

“Through improvements by Burton Tremaine Sr. and Emily Hall Tremaine, the site became a unique mix of colonial and modernist architecture, including design work from four notable professionals: architects Alberta Pfeiffer, Philip Johnson and Landis Gores, and lighting designer Richard Kelly,” the foundation wrote. “In addition, modernist architecture also created a harmonious connection between indoor and outdoor spaces, making landscape architecture integral to the site.”

Paintings, sculptures and prints from the Tremaine Art Collection were on display there for 40 years, the foundation said. After the deaths of Burton Tremaine Sr. and Emily Hall Tremaine, heirs subdivided the property and sold the house and surrounding 6.2 acres.

“The site changed hands again in 2002 and then fell into disrepair around 2019. Bank of America foreclosed on the site in late 2019, performed clean-up, conducted environmental assessments, and made several functional improvements” before the foundation purchased it, according to the foundation’s letter.

It now wants to use the property for “philanthropic and educational use” involving the arts, architecture and more, with educational exhibits, meetings, tours, onsite residencies, events, a studio and collaborative space as well as a gallery store, according to its application.

In a mid-April letter to neighbors, foundation President Michelle Knapnik and board Chair Palmer DePetro assured the plan isn’t for any form of public museum or gallery. The facility wouldn’t be open to the public, but they acknowledged it would host occasional events: “academic and educational gatherings” of 13 to 25 people as often as four times a month, and events of 26 to 150 up to three times a year.

The museum and gallery store would only be for invited guests, they said. Future plans include having up to eight people reside at the house including staff, invited artists-in-residence and guests seeking an immersive arts experience.

Knapnik and DePetro wrote that the foundation appears to be the only entity willing to put enough money into restoring the house and its various additions. In a previous memo to the town’s economic development commission, the foundation made a case for why the property is significant to the entire community.

“While New Canaan is a hub of modernist architecture, we know of no other location that can highlight modernist additions to colonial structures, thus making the town of Madison distinct in this period of architecture,” the foundation said.

The economic development commission endorsed granting a zoning exception to let the foundation proceed, and the foundation last week hosted an open house to answer public questions. The planning and zoning commission hearing will show whether neighborhood opposition has been reduced.

“Recent developments pose an existential threat to the residential quality of life which we have enjoyed in our neighborhood for the past 22 years,” the Dugans wrote. “Ours has always been a quiet, peaceful, pleasant residential neighborhood, with friendly neighbors and abundant wildlife. The homes are on 1-acre-plus lots, and today they are million-dollar homes.”

“There should be no exceptions to residential zoning in Madison,” wrote Brittany Lee Bowdren of Opening Hill Road. “Approving this application would be tantamount to opening Pandora’s Box to future exceptions that could fundamentally change the residential character of the town of Madison as a whole.”