President Donald Trump signed an executive order late Friday to cut the number of government advisory committees by a third across all federal agencies, a move that the White House said is long overdue and necessary to ensure good stewardship of taxpayers' money.

But critics said it is the Trump administration’s latest effort to undermine science-based and fact-supported decision-making.

“This is another example of how disconnected the Trump administration is from the needs of the American people and how to protect them from harm," said Mustafa Ali, who resigned in 2017 as the senior adviser for environmental justice at the Environmental Protection Agency.

Experts on the advisory committees, which were formalized under the Federal Advisory Committee Act (FACA) in 1972, give the executive branch input on issues ranging from high-level nuclear waste disposal, the depletion of atmospheric ozone, AIDS, drug addiction, school improvement and housing.

The administration has for two years been "shrinking and restricting the role of federal science advisory committees," said Gretchen Goldman, the research director with the Center for Science and Democracy at the Union of Concerned Scientists, in a statement. "Now they’re removing the possibility of even making decisions based on robust science advice. It's no longer death by a thousand cuts. It's taking a knife to the jugular.”

But White House Deputy Press Secretary Judd Deere told NBC News over email that the cuts were long overdue.

“A government-wide review of FACA committees has not been done since 1993, and the President believes it is time to once more review and eliminate ones that are not relevant and providing valuable services so that we are good stewards of the taxpayers’ money,” Deere wrote.

The government-wide review referred to is the last time such a big cut was made.

President Bill Clinton signed an executive order in February 1993 that terminated “not less than one-third of the advisory committees” created under the Federal Advisory Committee Act that were not required by statute.

The number of scientific advisory committees grew slightly under the George W. Bush and Barack Obama presidencies, but science advocates’ concern is that the Trump administration continues to distance the federal government from the fact-based decision-making that these committees are intended to uphold.

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The Union of Concerned Scientists found in a study last year that between 2016 and 2017 the number of science advisory committees across all agencies decreased by 20 percent and their membership decreased by 14 percent.

Goldman said that Trump's ordered cut will greatly exacerbate this trend.

“They’re escalating by saying they will get rid of a third of them arbitrarily,” Goldman said over the phone. “This is really nonsensical because there is not any reason to do that. It’s not costing the government much money because they’re not compensating people for their time or expertise, just mostly paying their travel expenses.”

A Congressional Research Study review of Federal Advisory Committees in October 2016 found that there were roughly 1,000 committees organized under the Federal Advisory Committee Act between 2011 and 2015. Their membership during those years ranged from 69,750 to 72,220, and the budget for all committees remained at or below $416.4 million.

More than half that budget goes toward federal support staff for the committees, the report said.

Stan Meiburg, who worked at the Environmental Protection Agency for 39 years before retiring in 2017, worked with and served on such committees under both Republican and Democratic administrations while he was a federal employee.

Advisory committee members are largely unpaid and often find creative ways for the federal government to save money, said Meiburg, a former EPA deputy regional administrator and current member of the Environmental Protection Network.

“It’s very unwise,” he said of the executive order, “and when you think of ways that money could be spent that works effectively for taxpayers, these committees carry small margins and produce tremendous returns.”

Unlike the Clinton administration’s executive order, Trump's decree also opens the door to shutting down committees created by congressional statute. The order requires agencies to create “a detailed plan” for committees' continued existence if they are “required by statute,” and to draft, “as appropriate, recommended legislation for submission to Congress” for panels that are to be changed or terminated.

This could set up a fight between the White House and Democrats, as Congress has used FACA advisory committees to provide greater oversight of the executive branch.

“The committees are reflective of a congressional interest in ensuring a broad number of perspectives are brought to bear on public policy,” Meiburg said. “That interest is still going to be there, and I think you’ll see a great amount of resistance from Congress.”

The order specifically exempts some committees, however, including those that advise on the safety of consumer products.

The required cuts don't apply to advisory panels “whose primary purpose is to provide scientific expertise to support agencies making decisions related to the safety or efficacy of products to be marketed to American consumers” or those groups “whose approval is necessary to fund an extramural research procurement contract, grant, or cooperative agreement,” the order says.

Advocates said the exemptions make it clear that Trump's order isn't about cost savings or helping American citizens, but about supporting corporations.

"That show they specifically are not wanting to cut the committees that deal with or affect private industry," Goldman said. "The ones that are left then are where science might prove to be inconvenient."