Environmental Protection Agency Administrator Scott Pruitt had one of his top aides reach out to Chick-fil-A's CEO last year to discuss a "potential business opportunity," according to emails released by the Sierra Club and obtained by NBC News on Tuesday.

That "business opportunity" was actually an effort to help Pruitt's wife become a franchisee of the popular fast food chain, Carrie Kurlander, the company's vice president of public relations, confirmed to The Washington Post. The newspaper first reported that while Pruitt never succeeded in speaking with Chick-fil-A CEO Dan Cathy directly, he did talk to someone in the company's legal department, revealing that the "potential business opportunity" was one he sought for his wife, Marlyn Pruitt.

Kurlander told The Washington Post that though Pruitt expressed interest in his wife becoming a franchisee, she never completed the application.

According to the emails, obtained by the prominent environmental group through a Freedom of Information Act request, Sydney Hupp, then the EPA chief's executive scheduler, reached out to Cathy in May 2017 to schedule a meeting at the administrator’s request. The exact topic is not disclosed in the subsequent back-and-forth between Hupp and the Chick-fil-A aides tasked with coordinating a meeting or phone call between the two men.

"The Administrator would like to talk about a potential business opportunity with Mr. Cathy," Hupp wrote in a May 2017 email. “Nothing very pressing, just hoping to connect sometime in the next month or so.”

Hupp has since left the EPA. Chick-fil-A did not respond to a request for comment from NBC News. The EPA also did not respond to a request for comment Tuesday.

It's the latest development in series of ongoing ethics scandals plaguing Pruitt. Earlier this week, newly released congressional testimony revealed that another senior EPA aide — Millan Hupp, Sydney Hupp's sister — was asked to help Pruitt obtain an “old mattress” from the Trump International Hotel and help scout new apartments.

He has also been accused of excessive spending, which includes lavish trips, first-class travel and purchasing a $43,000 phone booth for his office. In addition, he received widespread criticism for reports that he received a sweetheart deal on a Capitol Hill condo rental tied to a lobbyist with business before the EPA, bypassed the White House to inflate the salaries of political appointees and retaliated against staffers who questioned him.

President Donald Trump has continued to express confidence in Pruitt, who previously served as Oklahoma's attorney general. But Democratic lawmakers and watchdogs seized on the Chick-fil-A report and called for his ouster.

"Scott Pruitt's abuse of the public trust and his corrupt attempts to leverage his position for personal gain have reached a disgraceful new low," the Sierra Club, which obtained and released the new emails, said in a statement Tuesday. "This is the clearest example yet of Pruitt unethically and illegally seeking personal benefits because of the job Donald Trump has entrusted him with."

Senator Jim Inhofe, R-Okla., a longtime defender of Pruitt, suggested Tuesday the latest reports of questionable behavior could spell bad news for the EPA chief — if proven true.

"If that is true, that is not going to be served in his advantage and it would not be a good thing," Inhofe said Tuesday, responded to a question about Pruitt reportedly trying to help his wife get a Chick-fil-A franchise. "The problem is, I’ve known him for so long and I just can’t see him doing something like that. So I’m going to assume that it's not true because there are a lot of accusations."

However, Inhofe conceded, "there’s a lot of smoke and there could be some fire."

There are currently at least 15 ongoing federal or congressional investigations into Pruitt's actions as head of the EPA, according to an NBC News count.

Democratic Rep. Mark Pocan of Wisconsin needled Pruitt in a tweet Tuesday with a twist on Chick-fil-A’s “Eat Mor Chikin” advertisement.

 "So much for @realDonaldTrump's promise to #DrainTheSwamp," Pocan tweeted.