The findings provided a rare public resolution to one in a long series of ethics allegations that led to Pruitt's resignation last July. The EPA inspector general had ended some previous investigations, including one of his $50-a-night condo deal with the spouse of a lobbyist, without making a ruling, saying Pruitt's resignation had made it impossible for investigators to interview him.
The travel questioned by the watchdog office included $16,000 in premium-class travel to Morocco and 16 trips that were either directly to or stopping in Pruitt's hometown of Tulsa, Oklahoma.
Calls to an Oklahoma number for Pruitt went unanswered Thursday.
Pruitt previously had denied allegations that he indulged in fancy goods and travel at government expense and abused his office to gain sports tickets and other favors for himself and his family.
The EPA, now led by former coal lobbyist Andrew Wheeler, disputed many of the watchdog office's findings. It said in a statement that it believes the premium-class travel was warranted and allowed by the rules and that reimbursement would be "inappropriate."
Cleta Mitchell, an attorney and associate of Pruitt's who sometimes speaks on his behalf, noted that EPA officials authorized and supported the expenditures and Pruitt's handling of them, despite the opposing conclusion from the agency's separately funded watchdog officers.
"The agency in its review unequivocally concluded and determined that all costs associated with airfare and travel in the report were valid and proper, and appropriately, there is no action required to recover any costs," Mitchell said in a statement.
The inspector general looked at 40 trips, including six that were canceled, at a total cost of $985,000. The sum included $430,000 for travel by Pruitt's security detail alone. Pruitt was the first EPA chief to require permanent round-the-clock protection, including having a bodyguard with him when he traveled in the premium front cabins of commercial planes.
Pruitt's unusual security cautions had also featured tactical clothes and gear for his guards, motorcade travel to Washington appointments, sometimes with sirens blaring, and a $43,000 soundproof booth for his calls at the EPA office.
The inspector general's report said the EPA failed to document any specific threats that warranted the high level of protection and noted that "the agency could not provide documentation to support that the former Administrator's life was endangered when flying coach class."
Investigators recommended that the EPA tighten its travel procedures to guard against any fraud and wasteful spending.
Some of the Democratic senators pushing hardest for investigations of ethics allegations involving Pruitt and other members of President Donald Trump's Cabinet urged the administration to increase oversight of travel and "take every step needed" to try to recover the money.
"Resigning in disgrace shouldn't let you off the hook for unprecedented unethical behavior, and the latest report released by the OIG today confirms that," Sens. Tom Carper of Delaware and Sheldon Whitehouse of Rhode Island said in a statement, referring to the EPA Office of the Inspector General.
Associated Press writer Michael Biesecker contributed to this report.
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