Environmental Protection Agency Administrator Scott Pruitt announced Tuesday that he will block scientists who receive agency funding from serving on advisory boards.

The directive applies to members of all of the EPA’s 22 advisory committees, including three major ones: the Science Advisory Board, Clean Air Scientific Advisory Committee, and Board of Scientific Counselors.

Pruitt, in a session with reporters before publicly announcing the directive, said members of those three boards have received a total of $77 million in EPA grants over the last three years.

“It is very very important to ensure independence, to ensure we receive advice and counsel independent from the agency,” Pruitt told reporters. “These boards are intended to be independent. By definition, that’s impossible to achieve if the agency is providing $77 million over a three-year period [to some of its members]. Whatever science we do here shouldn’t be political science. There needs to be confidence there is not a nexus there.”

People receiving EPA grants who currently serve on the boards will have to choose whether to keep the grant or continue their work on the boards. Most board members serve three-year terms.

“You have to choose, are you going to continue getting a grant or serve the agency,” Pruitt said. “They can’t do both.”

Pruitt’s directive was instantly criticized by environmentalists and Democrats who say the EPA under Pruitt does not respect science.

The Washington Post reported that Pruitt will appoint at least some industry experts and government officials from conservative states to the boards.

The Union of Concerned Scientists said the EPA’s announcement could mean the end of independent oversight at the agency.

“In the end, the consequences of these decisions aren’t just bad for a few scientists,” said Andrew Rosenberg, director of the Center for Science and Democracy with the science group. “This could mean that there’s no independent voice ensuring that EPA follows the science on everything from drinking water pollution to atmospheric chemical exposure. This opens the door to political interference in science and, ultimately, puts us all at risk.”

Republicans long complained that the Obama administration favored filling EPA's advisory boards with scientists who backed its policies on climate change.

House Republicans have unsuccessfully pursued legislation in recent years that would prevent recipients of agency grants from serving on EPA's boards.

“CEI strongly supports EPA Administrator Pruitt’s sensible and long-overdue reforms of the agency’s numerous advisory boards,” said Myron Ebell, director of the Center for Energy and Environment at the free-market Competitive Enterprise Institute, who led President Trump’s EPA transition team. “The scientific advice the administrator receives from these boards must be objective and free from even the appearance of conflicts of interest. The fact that some of the EPA’s advisory boards are filled with members whose research receives millions of dollars of funding from the EPA is an obvious conflict of interest that should never have been allowed to develop.”

Pruitt said the EPA has not finished choosing new members for the boards. But he named the chairmen of each of the three major committees.

Michael Honeycutt, who heads the Texas Commission on Environmental Quality’s toxicology division, will lead the agency's Scientific Advisory Board.

Tony Cox, an independent consultant in quantitative risk analysis, will lead the Clean Air Scientific Advisory Committee. And Paul Gilman, chief sustainability officer at Covanta Energy and a former EPA official under President George W. Bush, will head the Board of Scientific Advisers.

Pruitt said more than 430 people have applied to the Board of Scientific Counselors and more than 130 individuals have applied for the Scientific Advisory Board. Forty-two people have applied for seven positions with the Clean Air Scientific Advisory Committee.

Some scientists reapplied and are returning to the committees.

“Many of those folks who have served historically have reapplied,” Pruitt said. “Some of those very same folks are going to continue serving.”

Pruitt said the applicants represent a broader geographic area than in previous boards. He said his goal is to provide more “fulsome” representation on the boards.

Critics say that means the EPA will fill the boards with corporate interests who support Pruitt’s deregulatory agenda.

In response to those concerns, Pruitt acknowledged his new policy does not bar people from serving on boards who have received funding from the energy industry.

“We can’t control where they get other grants from,” Pruitt said.

But he said all nominees will continue to go through an ethics process to ensure that they are not in conflict with rules they advise on.

“If they receive grants to an area where they are providing counsel, I am sure there will be steps to recuse [them],” Pruitt said.