WASHINGTON >> The two top officials in charge of security and toxic-waste cleanups at the Environmental Protection Agency have abruptly left their jobs, days after EPA administrator Scott Pruitt told lawmakers his subordinates were to blame for ethics problems that have imperiled his political future and prompted more than a dozen federal investigations.

In statements today, Pruitt praised the two men — Pasquale “Nino” Perrotta, the security chief, and Albert Kelly, who ran the EPA’s Superfund program — and gave no reason for their unexpected departures.

Perrotta was expected to appear Wednesday for a transcribed interview by staffers of the House oversight committee, one of the congressional bodies and federal organizations probing reports of excessive spending by Pruitt and other issues at the agency. Committee aides said Perrotta’s resignation was not expected to derail his appearance.

EPA spokesman Jahan Wilcox said that the departures were unrelated to the ongoing federal investigations and that the agency was fully cooperating with the congressional probe, led by House oversight chairman Rep. Trey Gowdy, R-S.C.

Pruitt’s spending on security and some of the security contracts with Perrotta are among the topics of the federal probes involving the EPA under Pruitt, a former Oklahoma attorney general. Pruitt, an ardent advocate of minimizing regulation, has survived the kind of scandals that have brought down several other Cabinet appointees of President Donald Trump’s.

At House hearings last week, Pruitt weathered six hours of scathing questions, criticism and a couple of calls from congressional Democrats to resign over the steady flow of news reports and announcements of new investigations allegations of ethical lapses at his agency. They include spending on Pruitt’s behalf for round-the-clock security guards, first-class plane tickets and a $43,000 soundproof telephone booth.

Pruitt repeatedly deflected blame last week, describing subordinates as going too far in carrying out their duties, in excesses that occurred without his knowledge.

In the case of the $43,000 booth, for example, Pruitt acknowledged to lawmakers he had asked for a private and secure phone line when he arrived at the agency, but he said staffers took it upon themselves to spend tens of thousands of dollars on it. It was security officials, not Pruitt, who decided he should fly first class, he said.

Pruitt pledged last week to take care of the problems. “Ultimately, as the administrator of the EPA, the responsibility of identifying and making necessary changes rests with me and no one else,” Pruitt told lawmakers then.

Notably, most Republican lawmakers at the hearings declined to join the Democratic dogpile on Pruitt.

It was unclear today whether lawmakers from Pruitt’s majority party would take the internal shakeup as a needed and promised house-cleaning by Pruitt or an indication of even greater trouble at the agency.

“I don’t know how to take this, yet,” Rep. Ryan Costello of Pennsylvania, one of the few Republican lawmakers last week to fault Pruitt on expenditures such as taking bodyguards with him to Disneyland and the Rose Bowl, said in a statement by email. “I’m waiting on more details … to shed more light on what, if anything, to make of it.”

Pruitt said in his statements that Perrotta was retiring after a 23-year government career that included time in the Secret Service and under previous EPA administrators. He praised Perrotta for hard work and dedication.

Pruitt thanked Kelly for what he said was his “tremendous impact” in Kelly’s year overseeing the nation’s Superfund program, charged with handling the cleanup of toxic waste sites.

Pruitt hired Kelly, an Oklahoma banker, at the EPA after federal banking regulators banned the man from banking for life. Regulators have not publicly specified the actions that led to the banking ban. Days ago, Rep. Scott Peters, D-Calif., pressed Pruitt for more details about why Kelly had been sanctioned.

“I think Mr. Kelly, if he’s willing to share that with you, he should do that,” Pruitt said Thursday.

The Federal Deposit Insurance Corp., believing Kelly “violated a law or regulation,” a year ago fined him $125,000. The undisclosed incident involved a loan by SpiritBank — which Kelly’s family has owned for generations — allegedly made without FDIC approval.

Democrats in Congress also are asking for federal investigations of Kelly’s reported loans to Pruitt while the two were still in Oklahoma. Kelly is not among the EPA officials summoned by House oversight committee members for questioning.

Rep. Don Beyer, D-Va., who has pushed for investigations of ethical problems under Pruitt, said in a statement today that “Pruitt should be the next to go.”

“Albert Kelly was never qualified to run Superfund, his banking ban was a huge red flag and his resignation is a positive development,” Beyer said.

Separately, three House Democrats raised allegations today that staffers working on Pruitt’s behalf in early 2017 looked into the possibility of opening an EPA office in Tulsa, a city of 400,0000 and Pruitt’s home. Pruitt has drawn criticism for frequent trips home to Tulsa at taxpayer expense.

The Democrats provided no supporting documentation. None of the people supposed to have knowledge of the alleged request could be reached for comment at the close of the business day, when the Democrats released the letter with the allegations.

Wilcox, the EPA spokesman, said the EPA has an office in Tulsa, which Pruitt has never used.