The chairs of a congressional working group on nuclear arms announced Tuesday a late July hearing on the controversial Sentinel missile program, which has blown past its budget and triggered concerns among more progressive lawmakers on Capitol Hill.

Members of the Nuclear Weapons and Arms Control Working Group, co-chaired by Democrats Sen. Ed Markey (Mass.) and Reps. John Garamendi (Calif.) and Don Beyer (Va.), said the July 24 hearing would focus on testimony from experts in the nuclear arms world.

Garamendi said at a press conference that the goal of the hearing is to try to “engage Congress in its constitutional responsibility.”

Beyer added that he wants to “raise the alarm about our unsustainable, reckless nuclear posture.”

“We all understand the need for adequate nuclear deterrence,” said Beyer. “But our spending process and nuclear posture are becoming increasingly divorced from reality — a reality of scarce resources and a variety of competing national security priorities.”

The Tuesday press conference was also attended by former Rep. John Tierney (D-Mass.) and Daryl Kimball, executive director of the Arms Control Association.

“In the United States, there seems to be a sense of inevitability around the need to build up our own stockpile,” Tierney said, adding he was “demanding answers to questions about the programs that cost taxpayers hundreds of billions of dollars without making us one iota safer.”

Tierney said it was the duty of Congress to conduct oversight, but that many of his former colleagues were “eager to simply rubber stamp multibillion dollar programs without asking even the most basic questions.”

In January, Sentinel overshot its projected budget by 37 percent, forcing the Pentagon to step in and review the program.

The program, which is being led by defense contractor Northrop Grumman, is now expected to cost around $130 billion, up from initial projected costs of around $60 billion in 2015. It is also expected to be delayed by at least two years.

Most of Congress supports modernizing the nuclear arsenal and views land-based intercontinental ballistic missiles (ICBMs) as a vital part of nuclear deterrence, along with the other legs of the so-called triad: bomber planes and submarines.

Proponents argue the Sentinel program is a national security priority, especially with China and Russia modernizing or increasing their nuclear arms. Still, progressive Democrats have raised alarm about the ballooning costs and feasibility of the program.

The congressional working group on Tuesday called for the Pentagon to conduct a candid review of Sentinel, which Garamendi and Sen. Elizabeth Warren (D-Mass.) have previously pushed for.

And Markey called for the Pentagon to declassify the 2014 Analysis of Alternatives report that found it would be cheaper to create new Sentinel missiles than to life-extend the more than 50-year-old Minuteman III ICBMs. The Air Force has kept the report, which would detail how they arrived at that conclusion, classified.

Markey also pushed for a review of the costs for modernizing the entire nuclear triad and stressed his concerns about the “insanity” of spending hundreds of billions of dollars on updating nuclear weapons under the “guise” of protecting against national security risks.

“That is simply not an excuse to open up the federal government’s bank account to write a blank check made out to nuclear bombmakers with no transparency,” he said. “We have a responsibility to ensure we put the Sentinel program on the chopping block.”

Sentinel will replace the 400 Minuteman III ICBMs scattered across the rural Western U.S. in missile silos and deploy them through 2075. The program is a huge overhaul and involves a major real estate effort across several states that is driving up costs.

Garamendi tried to pass several amendments to rein in the Sentinel program in the annual defense bill that the House Armed Services Committee passed last month, but they were ultimately blocked aside from one requiring the Government Accountability Office to audit the Pentagon’s review of the program.

Garamendi has raised concerns about the difficulty to get Congress to conduct more oversight of the program.

“We want Congress to do its job,” Garamendi said.