WASHINGTON (Reuters) - The U.S. Environmental Protection Agency announced on Tuesday it will bar certain scientists from serving on its independent advisory boards, a move critics say could open the way to more industry-friendly advisors on the panels.

Environmental Protection Agency Administrator Scott Pruitt speaks during an interview for Reuters at his office in Washington, U.S., July 10, 2017. REUTERS/Yuri Gripas

The EPA barred scientists who have won agency-awarded grants in the past, billing the step as a way to preserve the independence and diversity of the boards, which provide the scientific input for agency decisions around pollution and climate change regulation.

“Whatever science comes out of EPA, (it) shouldn’t be political science,” EPA Administrator Scott Pruitt, said in a release, adding that committee members will be “financially independent” from the agency.

Senator Tom Carper, the top Democrat on the Senate environment committee, said Pruitt’s decision was part of an EPA effort to “delegitimize the work of nonpartisan scientists.” Carper added, “this crusade endangers the health of every American, and it cannot be tolerated.”

Pruitt signaled the move during a speech last week at the conservative Heritage Foundation, when he questioned the independence of scientists who have won past EPA research grants, and promised to “fix” the situation.

During his election campaign last year, Republican President Donald Trump promised to roll back environmental regulations from Democratic President Barack Obama’s administration, including those limiting carbon dioxide emissions blamed for global warming, to make government more friendly to the drilling, mining, and manufacturing businesses.

The advisory boards were created by Congress to serve as a check on EPA policies and research. They include the EPA Scientific Advisory Board, the Clean Air Scientific Advisory Committee, and the Board of Scientific Counselors.

Last year, the SAB questioned an EPA report that concluded that hydraulic fracturing - an oil and gas drilling technology that frees petroleum from underground shale formations - had no "widespread impacts" on drinking water despite evidence of problems in several states. (reut.rs/2h2GTrD)

In June, Pruitt decided not to renew the terms of nine members of a separate body, the 18-member Board of Scientific Counselors. One of those members, Michigan State University professor of community sustainability Robert Richardson, told Reuters the move came as a surprise because the work they were doing was “apolitical.”

The EPA is also expected to announce three new members of the Clean Air advisory committee on Tuesday.

Pruitt is an outspoken doubter of mainstream climate science, a consensus of scientists that carbon dioxide from human use of fossil fuels is a primary driver of global warming, triggering more frequent volatile storms, sea level rise, and droughts.

Pruitt has said he wants to set up a televised debate about the science of climate change between scientists who believe it is driven by humans and those that do not.