In a statement through his spokesman, Mr. Hart said his wife’s status as Mr. Pruitt’s landlord had no bearing on his relationship with the E.P.A. “As I have said repeatedly, I never received any special treatment from Administrator Pruitt or had any undue influence over the Environmental Protection Agency,” Mr. Hart said. He called Mr. Jackson “an old friend” from before his time at the E.P.A. who “has never performed a special favor on my behalf.”

The emails about Mr. Guiliano continued in May when Mr. Hart, copying his wife, Vicki, emailed Mr. Jackson to say that the applicant would soon be in town. “Would you have time to meet with him?” Mr. Hart asked.

There is no response to that from Mr. Jackson in the emails released, and it is unclear whether a meeting happened. But Mr. Guiliano did not get a job at the E.P.A., according to an agency spokesman.

Mr. Guiliano did not respond to a request for comment sent via Facebook.

Jahan Wilcox, a spokesman for Mr. Pruitt, said in a statement that the correspondence did not indicate any impropriety on the part of the E.P.A. or Mr. Jackson. He noted that Mr. Hart and Mr. Jackson have known one another for years. “Many of these emails were unsolicited and did not impact any agency policy outcomes,” Mr. Wilcox said.

Regarding Mr. Guiliano, he said, “The agency accepts career recommendations from a number of acquaintances. Ultimately, Mr. Guiliano was not hired.”

According to the newly released E.P.A. emails, on Aug. 21 last year, Mr. Hart emailed Mr. Jackson on behalf of Coca-Cola to oppose regulating a class of chemicals called hydrofluorocarbons, or HFCs, which are used in refrigeration, car air conditioning and aerosols. Replacement chemicals raise problems for companies, he wrote, and he cautioned that they may be dangerous.

“Some large U.S. companies like Coca-Cola have to make long-term investment decisions relating to their refrigerated beverage machines,” Mr. Hart said. “There are all sorts of technical issues that arise when you get rid of HFCs. One is consumer safety. I kept hearing that the replacement technology had some problems — exploding vending machines. Thoughts?”