There Are Only 63 Proton Therapy Buildings on Earth, and Connecticut Just Fought Two Lawsuits Over Building Its First

Connecticut spent nearly a decade and two lawsuits fighting over a single proton therapy building, exposing how state Certificate of Need regulators function as de facto developers of one of the rarest building types on Earth.

Landlord Ledger Publications • Market • 2026-06-18

Building a proton therapy center requires solving a structural engineering problem before anyone treats a single cancer patient, and Connecticut spent nearly a decade and two separate lawsuits proving how hard that problem is.

Proton beam therapy delivers radiation with a precision that conventional X-ray treatment cannot match, depositing its dose almost entirely inside a tumor instead of scattering it through the surrounding tissue. A 2017 Canadian health technology assessment counted only 63 facilities capable of delivering it anywhere on the planet, with the global buildout still gated by a problem most hospital construction never has to solve: the structure has to physically contain a particle accelerator. That number has grown since, but the scarcity has not disappeared, and Connecticut spent most of the 2020s as living proof. As of early 2025, the state had zero operating proton therapy centers, forcing its cancer patients toward facilities in Boston and New York that were already at capacity and turning people away.

A Building Designed Around a 225-Ton Machine

A proton therapy facility is built around a cyclotron, a particle accelerator that spins protons to roughly two-thirds the speed of light before firing them at a patient with submillimeter accuracy. The machines weigh up to 225 tons, comparable to a fully loaded Boeing 757, and because the acceleration process throws off secondary radiation, the room housing the cyclotron has to be shielded by concrete walls up to 13 feet thick with ceilings as thick as 6 feet. At the Provision CARES proton center in Knoxville, Tennessee, contractors needed specialized engineering just to coordinate the placement of a 225-ton cyclotron inside walls poured to that specification. At the Texas Center for Proton Therapy in Irving, the 220-ton cyclotron had to be welded to the floor of the ship that carried it from Belgium because a shift in its position mid-voyage risked capsizing the vessel; once it reached Texas, the truck hauling it from the port took three days to cover a normal four-hour drive, rerouted around bridges that could not bear its weight.

None of this is incidental to the architecture. The choice of proton equipment manufacturer determines shielding specifications, foundation depth, and HVAC requirements before a single wall goes up, meaning the building and the multi-million-dollar machine inside it are designed together rather than one after the other. That interdependency is part of why total project costs for a single facility can range from roughly $25 million for a compact single-room system up to $200 million or more for a full multi-gantry center, a spread wide enough that the same diagnosis can produce wildly different real estate depending entirely on which manufacturer's machine gets selected.

Eight Years, Two Denials, and a Lawsuit Over the Land

Danbury Proton LLC first proposed a facility at 85 Wooster Heights Road in Danbury in 2020, on a three-acre site overlooking Danbury Municipal Airport. The project cleared local land-use approval in 2021, but Connecticut's Office of Health Strategy, which administers the state's Certificate of Need program, denied the application in 2022, ruling that the nonprofit had not demonstrated a clear public need or shown the facility would be affordable. Danbury Proton appealed, lost the appeal, refiled an entirely new application in 2023, and lost again.

The same regulatory cycle produced a federal lawsuit. In October 2022, Wooster Mountain Realty LLC, the landowner tied to the Danbury Proton site, sued Danbury Proton LLC, an earlier corporate entity called Northeast Proton LLC, and project principal Stephen Courtney in U.S. District Court for the District of Connecticut, a contract dispute that played out in parallel with the second Certificate of Need fight over the same project. Hartford HealthCare and Yale New Haven Health System, meanwhile, had already secured CON approval in 2022 for a jointly owned proton center in Wallingford and broke ground on the $75 million facility in October 2025, a project state regulators found financially feasible for a smaller patient population than the one Danbury Proton had proposed serving.

When the Regulator Becomes the Developer

In January 2025, Connecticut's Office of Health Strategy did something it had never done before: rather than issue a third denial, it opened confidential settlement talks with Danbury Proton, the first time the agency had used that process for a Certificate of Need application. The talks produced a signed agreement just eleven days later, allowing Danbury Proton to build what was by then a $96 million facility, but only with a single treatment room, a condition the agency said was necessary to "ensure use of the treatment when supported by the scientific literature." Danbury Mayor Roberto Alves and the City Council voted 17-2 in March 2026 to approve $130 million in revenue bonds to finance construction, clearing the way for Danbury Proton to start building on a site it had been trying to develop since 2018.

That settlement is the clearest illustration of what a Certificate of Need program actually does to a building category like this one. CON laws require healthcare providers to get permission from a state board before opening or expanding a facility, a Depression-era-descended idea meant to prevent costly duplication and keep healthcare spending under control. For ordinary outpatient clinics or imaging centers, the regulatory ceiling is mostly invisible. For proton therapy, where a single facility represents a $25 million to $200 million capital commitment tied to one piece of irreplaceable equipment, the state board is not just approving a medical service. It is deciding, room by room, how much square footage of an entire category of building the state's population is allowed to have. Connecticut's OHS did not simply regulate Danbury Proton's application; it negotiated the exact number of treatment rooms the building would be permitted to contain, a degree of granular control over physical capacity that a planning department rarely exercises over any other type of structure.

The economic research on whether that control accomplishes its stated goal is unflattering. A federal Reserve Bank working paper by economists James Bailey and Tom Hamami found that roughly 10.5 percent of the national increase in per-capita healthcare spending between 1996 and 2019 was associated with Certificate of Need laws, and a 2020 systematic review covering 90 studies concluded that CON regulation tends to increase health expenditures and overall elderly mortality, while only modestly reducing mortality from heart surgery. As of late 2025, fifteen states had repealed their CON programs entirely, and Connecticut's own multi-year fight over a single building category in Danbury supplies a case study for why: an applicant spent the better part of a decade and two formal Certificate of Need denials trying to get permission to build a structure whose underlying need, the regional shortage of treatment slots, was never seriously in dispute.

The Math the Regulators Were Actually Fighting Over

The argument inside Connecticut's CON process never centered on whether proton therapy worked. It centered on a population calculation. Danbury Proton's attorney told regulators that roughly 992 patients a year in the surrounding region could use the treatment, a figure that did not include patients who might travel from neighboring New York. OHS had approved the Wallingford facility for a base of patients drawn primarily from the Hartford HealthCare and Yale New Haven Health networks, but determined that Danbury Proton's larger projected demographic, spanning a swath of southwestern Connecticut and adjacent parts of New York and Massachusetts with a combined population in the tens of millions, made the project's underlying financial assumptions less credible rather than more.

That inversion is the structural detail buried inside the dispute: the bigger the patient population a proton therapy applicant could plausibly serve, the harder Connecticut's regulators were on the application, because a larger market made the facility's revenue projections theoretically riskier to model rather than easier to justify. Drew Crandall, Danbury Proton's director of community engagement, has pointed to the practical consequence of all that scrutiny in plain terms: patients in the region were getting turned away from proton therapy because there was no space for them, not in Connecticut, and not in the Boston and New York centers absorbing the overflow.

Construction on the Danbury facility, designed by Boston-based proton specialist SCI.X Science Studio working with East Hartford firm Russell & Dawson, is expected to take about 18 months once bond proceeds close, with an opening targeted for late 2027 or early 2028. The building will include 18 geothermal wells and partially below-grade geothermal walls, an unusual design choice that doubles as thermal mass working alongside the mandatory radiation shielding. By the time it opens, the facility will be using equipment from Mevion Medical Systems, a 250-ton-class system whose physical footprint, like every proton cyclotron before it, was determined years before the first concrete truck arrived on site.