WASHINGTON -- The Trump administration is scrutinizing studies and data published by scientists at the Environmental Protection Agency, while new work is under a "temporary hold" before it can be released.

The communications director for President Donald Trump's transition team at EPA, Doug Ericksen, said Wednesday the review extends to all existing content on the federal agency's website, including details of scientific evidence showing that the Earth's climate is warming and man-made carbon emissions are to blame.

Ericksen clarified his earlier statements he made to The Associated Press, which reported that the Trump administration was mandating that any studies or data from EPA scientists undergo review by political appointees before they can be released to the public. He said he was speaking about existing scientific information on the EPA website that is under review by members of the Trump administration's transition team.

He said new work by the agency's scientists is subject to the same "temporary hold" as other kinds of public releases, which he said would likely be lifted by Friday. He said there was no mandate to subject studies or data to political review.

Former EPA staffers under both Republican and Democratic presidents said the restrictions imposed under Trump far exceed the practices of past administrations.

Ericksen said no decisions have yet been made about whether to strip mentions of climate change from epa.gov

"We're taking a look at everything on a case-by-case basis, including the web page and whether climate stuff will be taken down," Erickson said in an earlier interview with the AP. "Obviously with a new administration coming in, the transition time, we'll be taking a look at the web pages and the Facebook pages and everything else involved here at EPA."

Asked specifically about scientific data being collected by agency scientists, such as routine monitoring of air and water pollution, Ericksen responded, "Everything is subject to review."

Trump press secretary Sean Spicer appeared to distance the president from the issue, telling reporters the communications clampdown at EPA wasn't directed by the White House.

Trump's nominee for EPA administrator, Scott Pruitt, said during his Senate confirmation hearing last week that he disagreed with past statements by the president alleging that global warming is a hoax perpetrated by the Chinese to harm U.S. economic competitiveness. But like Trump, Pruitt has a long history of publicly questioning the validity of climate science.

William K. Reilly, who was EPA administrator under Republican President George H.W. Bush, said what seems to be happening with science at the agency is "going down a very dark road."

The EPA's 14-page scientific integrity document, enacted during the Obama administration, describes how scientific studies were to be conducted and reviewed in the agency. It said scientific studies should eventually be communicated to the public, the media and Congress "uncompromised by political or other interference."

The scientific integrity document expressly "prohibits managers and other Agency leadership from intimidating or coercing scientists to alter scientific data, findings or professional opinions or inappropriately influencing scientific advisory boards." It provides ways for employees who know the science to disagree with scientific reports and policies and offers them some whistleblower protection.

George Gray, the assistant administrator for EPA's Office of Research and Development during the Republican administration of President George W. Bush, said scientific studies were reviewed usually at lower levels and even when they were reviewed at higher levels, it was to give officials notice about the studies -- not for editing of content.

"Scientific studies would be reviewed at the level of a branch or a division or laboratory," said Gray, now professor of public health at George Washington University. "Occasionally things that were known to be controversial would come up to me as assistant administrator and I was a political appointee. Nothing in my experience would go further than that."

"There's no way to win if you try to change things," Gray said.

The AP and other media outlets reported earlier this week that emails sent internally to EPA staff mandated a temporary blackout on media releases and social media activity, as well as a freeze on contract approvals and grant awards.

Ericksen said Tuesday that the agency was preparing to greenlight nearly all of the $3.9 billion in pending contracts that were under review. Ericksen said he could not immediately provide details about roughly $100 million in distributions that will remain frozen.

The uncertainty about the contract and grant freeze coupled with the lack of information flowing from the agency since Trump took office have raised fears that states and other recipients could lose essential funding for drinking water protection, hazardous waste oversight and a host of other programs.

The agency also took a potential first step Tuesday toward killing environmental rules completed as President Barack Obama's term wound down. At least 30 were targeted in the Federal Register for delayed implementation, including updated pollution rulings for several states, renewable fuel standards and limits on the amount of formaldehyde that can leach from wood products.

Jared Blumenfeld, who served until last year as EPA's regional administrator for California and the Pacific Northwest, compared what is happening to a "hostile takeover" in the corporate world.

"Ericksen and these other folks that have been brought in ... have basically put a hold on everything," said Blumenfeld, who regularly speaks with former colleagues still at the agency. "The level of mismanagement being exercised during this transition is startling and the impact on the public is alarming."

For example, he said EPA employees aren't clear whether they can direct contractors who handle all of California's Superfund sites. Some EPA employees have taken to their own social media accounts to say what's happening inside the agency, despite fears of retaliation.

"There's a strong sense of resistance," Blumenfeld said.

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Associated Press writer Ellen Knickmeyer contributed from San Francisco.