WASHINGTON — Two top aides resigned Wednesday from the Environmental Protection Agency as its administrator, Scott Pruitt, faced mounting allegations of misusing his authority, including by seeking a Chick-fil-A fast-food franchise for his wife.

Millan Hupp, Pruitt’s scheduler, and Sarah Greenwalt, a senior counsel to the administrator, have come under scrutiny in recent weeks in connection with Pruitt’s spending and ethics concerns.

Before joining the agency, both Hupp and Greenwalt worked for Pruitt in Oklahoma, where he served as attorney general. Both aides later received substantial raises at the EPA, bypassing the usual White House procedures. Pruitt told Congress he neither knew about nor approved of the raises, and he told lawmakers he reversed the raises when he learned about them.

The departures come as Pruitt faces fresh questions about his management decisions. On Monday, Democrats on the House Oversight Committee, which is conducting one of 12 investigations into his spending and ties to lobbyists, released a partial transcript of an interview with Hupp showing that Pruitt asked her to do personal errands for him, including apartment hunting and asking the Trump International Hotel if Pruitt could purchase a used mattress.

Emails obtained under public records laws also showed that Pruitt had asked Sydney Hupp, Millan Hupp’s sister and the administrator’s former scheduler, to facilitate a meeting with the chief executive of Chick-fil-A regarding a “potential business opportunity.” That turned out to be a possible franchise for Pruitt’s wife, Marlyn.

In an interview with the Nexstar Media Group on Wednesday, Pruitt defended the effort, which was first reported by The Washington Post. He also praised the Chick-fil-A chain.

“My wife is an entrepreneur herself. I love, she loves, we love Chick-fil-A,” he said, calling it a “franchise of faith and it’s one of the best in the country. So that’s something we were very excited about and we need more of them in Tulsa, we need more across the country.”

The Hupps’ work for Pruitt potentially violates a prohibition on having subordinates perform personal duties. In the case of Chick-fil-A, using one’s position for a personal benefit could be a crime, according to government ethics experts. Even Pruitt’s public praise of Chick-fil-A might be problematic, said Austin Evers, executive director of American Oversight, a government ethics advocacy group, because federal regulations prohibit officials from endorsing products.

“No matter how much Scott Pruitt might like Chick-fil-A, public officials are strictly prohibited from using their public positions for the private gain of others, such as endorsing their products,” Evers said.

Pruitt, in a statement Wednesday, called Millan Hupp a “valued member of the EPA team” and a “colleague, friend and trusted partner.”

Jahan Wilcox, a spokesman for the EPA, did not comment on the departure of Greenwalt. Two former agency officials, who asked to remain anonymous in order to discuss personnel, confirmed she had submitted her resignation.

Some Senate Republicans said Wednesday that their support for Pruitt remained steadfast. Sen. Bob Wicker of Mississippi called the recent revelations “nitpicking.” Others said there was growing frustration in their ranks about Pruitt’s behavior.

Sen. John Kennedy, R-La., said Pruitt was “acting like a moron.”

“I think he’s hurting his boss, and when he hurts his boss, he’s hurting the American people,” Kennedy said.

But Pruitt’s boss, President Donald Trump, appears to be satisfied.

“Thank you, Scott, very much. EPA is doing really, really well. And you know, somebody has to say that about you a little bit,” Trump told him Wednesday during a briefing on the coming hurricane season. “People are really impressed with the job that’s being done at the EPA. Thank you very much, Scott.”