The letters say that in early 2017, Ryan Jackson - now Pruitt's chief of staff but then a top congressional aide - wanted the GSA to look for office space in Tulsa, 250 miles from the EPA regional headquarters in Dallas. ABC News first reported the resignation on Tuesday.
After spending most of his career as a banker in Oklahoma, Kelly joined Pruitt at EPA a year ago to revitalize the agency's cleanup of toxic sites. Mr. Perrotta's influence placed him at the center of inquiries by the E.P.A. inspector general's office into excessive spending and possible violations of contracting rules by Mr. Pruitt's administration, according to senior officials at the E.P.A., who spoke on condition of anonymity for fear of retribution. Kelly, a friend of Pruitt's from his days in Oklahoma, was barred by the Federal Deposit Insurance Corporation from working at any US financial institution after unspecified violations while working at a bank in that state.
Perrotta had also hired a business associate from a firm where he also works to carry out a $3,000 security sweep of Pruitt's office, which internal staff said did not meet national security standards. "In just over a year he has made a tremendous impact on EPA's Superfund program, serving as chair of the Superfund Task Force and presiding over the development of the steps necessary to implement the recommendations in the report", Pruitt said in a statement.
Kelly gave no reason for his departure and did not immediately respond to a text message seeking comment.
President Donald Trump has not indicated whether the investigations would affect Pruitt's tenure.
The EPA head faced lawmakers during a hearing last week, during which he didn't deny that he knew about raises given to two top longtime aides despite the White House having rejected the pay increases.
Several Republicans in the House who have embraced Pruitt's deregulatory agenda said Pruitt was unfairly grilled by Democrats, but others said his answers to some key questions were vague. Frank Pallone calls the memo proof that Pruitt misled the public. But, according to the letters, Jackson sent an email on January 31, 2017, to the EPA inquiring about a Tulsa office at the behest of Pruitt.