WASHINGTON - Several past leaders of the Environmental Protection Agency, including officials from both Republican and Democratic administrations, plan to criticize the agency's shrinking size and ambition in testimony Tuesday, June 11, on Capitol Hill, saying the agency has moved away from its core duties under President Donald Trump.

"There is no doubt in my mind that under the current administration, the EPA is retreating from its historic mission to protect our environment and the health of the public from environmental hazards," Christine Todd Whitman, a Republican who led the agency during the George W. Bush administration, said in written testimony submitted to the House Energy and Commerce Committee.

"This administration, from the beginning, has made no secret of its intention to essentially dismantle the EPA," she said. "Everything I've seen over the past two and a half years suggests that this remains the Trump administration's goal."

Similar worries dominate the testimony of Gina McCarthy, who led the EPA during the final years of the Obama administration and has been an outspoken critic of the current administration.

"What is happening at EPA today is, simply put, not normal," McCarthy said in her prepared testimony.

Like Whitman, she bemoans the exodus of veteran EPA employees and what she calls sinking morale of many career staffers. She and others plan to raise questions about whether the Trump administration is failing to adequately rely on science to drive its policy decisions, and she said the White House has ignored the threat of climate change amid an aggressive push to scale back environmental regulations.

"With every passing day, EPA seems to be losing valuable career staff while agency leadership has been on a seemingly unstoppable crusade to roll back rules with seemingly little regard to the health impacts of their rollbacks," McCarthy wrote. "In short, EPA is going backwards on health protections in favor of lowering costs to polluting industries at every turn."

The EPA did not immediately respond to a request for comment on the upcoming testimony from former administrators. Earlier this year, the agency touted its work during the first two years under Trump, highlighting dozens of deregulatory actions and saying that it had "continued to deliver on its promise to provide greater regulatory certainty while protecting public health and the environment."

Tuesday's hearing is intended to "address the mission and future" of the agency, according to committee Chairman Rep. Frank Pallone Jr., D-N.J. It comes after seven past EPA chiefs, representing Republican and Democratic administrations, wrote to House lawmakers in April, offering Congress help with oversight of the agency.

"We are united that there has never been a more important time for us to put aside our differences and advocate collectively for public health and the environment," they wrote in the letter, which was first reported by E&E News.

The letter was signed by the EPA's first administrator, William Ruckelshaus, a Republican who also has been critical of the Trump administration's approach, as well as a host of other past leaders.

Four of the letter's seven authors are scheduled to appear Tuesday at the House hearing.

"Is [EPA] seeking input from key scientific advisory committees? Is it coordinating actively with the broad scientific community on research surrounding environmental issues? I don't think they do," wrote Lee Thomas, who led the EPA during the final years of President Ronald Reagan's tenure. He added, "Is the agency coordinating internationally to address global environmental issues? I don't think they are."

Former administrator William Reilly, who served under President George H.W. Bush, in his prepared testimony, called for Republicans and Democrats alike to recognize the key role the EPA plays in protecting the nation's environment, despite their sharp policy differences.

"This is not the first time our political leaders have had to reconcile competing or conflicting points of view," he wrote. "I'm convinced not only that we can do it, but we must. Our children, their children and generations to come stand to inherit this good earth and the productive resources that have sustained us."

This article was written by Brady Dennis, a reporter for The Washington Post.