The future of the long-stalled Jefferson Parkway was thrown further into disarray this week after elected leaders in Broomfield signaled the city plans to withdraw from the organization overseeing the planned $250 million highway.

In a unanimous vote Tuesday night, the Broomfield City Council formally gave notice to the Jefferson Parkway Public Highway Authority that it wants out after being a voting member of the authority for nearly 12 years.

Broomfield cited an elevated reading of plutonium discovered last summer in the proposed path of the highway — adjacent to the Rocky Flats National Wildlife Refuge and former nuclear weapons manufacturing plant — as the chief reason behind its decision to withdraw.

“After that soil sample, I think it would be irresponsible to move forward with this alignment,” Councilman William Lindstedt said minutes before he cast his vote Tuesday.

What Broomfield’s departure means for the fate of a project that has generated a steady helping of controversy over the last decade or more isn’t clear. But Andrew Goetz, a professor of geography at the University of Denver who is with the school’s Transportation Institute, said Broomfield’s decision is a serious setback.

“It’s a major blow to the project to have a long-standing member decide they don’t want to do this anymore,” Goetz said. “If it’s not the death blow, it’s still a major blow.”

The professor said what’s most in doubt is whether the parkway will have to find a new alignment should Broomfield try to stymie the portion of the proposed tollway that lies within its borders.

Bill Ray, the parkway authority’s executive director, said he was unable to comment on what Broomfield might do going forward. He also said it’s too soon to determine what the city’s move might mean for the overall project, a 10-mile segment of toll road that would run between Broomfield and Golden and serve as one of the last major segments in Denver’s still-elusive beltway.

“Withdrawal requests are governed by the terms of the Establishing Contract creating the Authority,” Ray told The Denver Post. “The ability to withdraw requires unanimous consent of all the member governments.

“Once that negotiation is completed, Jefferson County and Arvada will separately consider the next steps for the parkway. The establishing contract does contemplate both expanding the board or reducing it to as few as two members.”

What the separation likely means in immediate terms is that Broomfield will have to pony up some money to the authority to settle any obligations it has, the council was told by city staff Tuesday.

The city and county has yet to pay the authority the $2.5 million it owes in annual dues for 2019.

According to the Jefferson Parkway Public Highway Authority, Arvada and Jefferson County have each put approximately $6.25 million into preliminary work for the parkway since the authority’s inception in 2008, while Broomfield has contributed $3.4 million in that time.

Arvada Mayor Marc Williams said he was “disappointed” in Broomfield’s decision to head for the exits.

“I would have preferred that they not take any action until we had the analysis completed by the (state) health department,” Williams said Wednesday.

But Councilwoman Guyleen Castriotta was blunt about Broomfield’s dashed faith in the Jefferson Parkway. Rocky Flats, where workers assembled plutonium triggers for the nation’s Cold War arsenal for nearly 40 years, left a legacy of fires and leaks that spread toxic contaminants throughout the site and beyond.

“I can’t believe they built anything there — it should never have been touched,” she said of the land surrounding Rocky Flats that has slowly filled with neighborhoods over the last decade. “Now we have a council that is health and safety first.”

The Jefferson Parkway has faced strong headwinds in the past year, starting with the elevated plutonium reading discovered in August along the eastern fence line of the refuge and inside the corridor for the proposed highway. Then in December, the Jefferson Expressway Group said it was dropping out of consideration as a private-sector partner to design and build the parkway.

The firm said “anticipated (toll) revenue potential does not adequately support the Project’s costs by a sizable gap” and it also cited “ongoing environmental challenges” as a reason for pulling out. There are still two consortiums in the running to build and operate the parkway.

While the plutonium hot spot made headlines, all of the other soil samples taken on or next to the Rocky Flats National Wildlife Refuge — a total of 350 or so — show levels of radioactive contamination well within the federal government’s safety threshold.

Several Broomfield City Council members on Tuesday fretted about losing a seat at the table by withdrawing from the parkway authority.

“It ends the conversation to some extent, as far as Broomfield is concerned. It limits our input on the project going forward,” said Councilman Stan Jezierski.

But Councilwoman Heidi Henkel said the city was accustomed to being outvoted on the board by Arvada and Jefferson County.

“With my experience on the board, we’ve always been outnumbered 2 to 1,” she said.

Most of the people in council chambers Tuesday seemed to be of one mind on Broomfield’s decision to withdraw from the parkway authority: The vote was met by loud applause.