WASHINGTON (AP) — The Environmental Protection Agency skirted some of its usual procedures and ethics rules when it overhauled key agency advisory boards, slashing the numbers of academic scientists on the panels and appointing more industry figures, the Government Accountability Office said Monday.

Senate Democrats had asked for the GAO probe. Sen. Sheldon Whitehouse, a Rhode Island Democrat and one of those requesting the review by the government watchdog, said the administration's trimming of scientists on EPA scientific panels has slowed the agency's regulatory decisions overall, and rigged the advisory boards "to favor its polluter backers."

The EPA disputed one of the key findings in Monday's GAO report, denying that the agency's senior political appointees privately picked new members for the boards in a way that shut out recommendations by career EPA staffers and left little of a paper trail.

And the agency said it is dealing with the other main GAO criticism — that EPA ethics staff skimped on proper review of financial disclosures by some of the new panel appointees. The disclosures are required to guard against conflicts of interest for panel members. The agency has doubled the size of its career ethics attorney staff to make sure all agency appointees comply with the disclosure rules, spokesman Michael Abboud said.

President Donald Trump's first EPA administrator, Scott Pruitt, remade many of the panels advising the agency. Pruitt's moves included barring scientists from serving on the advisory boards if they had received EPA research grants. Pruitt, one of the most enthusiastic agents of Trump's rule-cutting, business-friendly mission, resigned amid ethics scandals last summer.

In the first few years of the Trump administration, the share of scientists on the agency's Science Advisory Board dropped by 27 percent, the GAO said. On the Board of Science Counselors, the decline was 45 percent.

Meanwhile, the number of representatives of regulated industries on the Science Advisory Board increased from three to five, the report said. On the other board, it went from one to three.

Pruitt and other EPA political officials strayed from some of the agency's long-standing, documentation-heavy procedures of weighing staff recommendations for new appointees to the panels, the GAO said. EPA officials denied doing anything improper, saying the decisions were hashed out in briefings among senior managers instead.

Chris Zarba, who retired early last year from his EPA job coordinating two of the main advisory panels, questioned the EPA's account Monday, saying the administration's overhaul of the boards meant there were far too many candidates to consider each adequately in meetings.

"There's no way you can do that verbally," Zarba said. "That would be like designing an aircraft and doing it verbally."

Zarba has criticized the remaking of the panels' membership since leaving. "My opinion is that the intent is to make the science more favorable to special interest," he said.