Scott Pruitt began receiving round-the-clock security from the moment he set foot inside the Environmental Protection Agency in February 2017, the agency's inspector general revealed Monday.

"EPA's Protective Service Detail began providing 24/7 coverage of the Administrator the first day he arrived," Inspector General Arthur Elkins wrote in response to inquiries from Democratic Sens. Sheldon Whitehouse and Thomas Carper about what threats prompted Pruitt's nonstop security, which has cost in excess of $3 million. "The decision was made by the Office of Criminal Enforcement, Forensics and Training after being informed that Mr. Pruitt requested 24/7 protection once he was confirmed as Administrator."

The inspector general's office, which investigates threats made against any EPA employees, "played no role in this decision," Elkins added.

The EPA could not be reached for comment. But agency officials, including Pruitt, have said he has experienced notably more threats than previous administrators.

"A threat to a federal employee's personal security is extremely serious, but so is using security as pretext for special treatment on the public dime," Whitehouse and Carper said. "Now more than ever, Mr. Pruitt should come clean about his spending of taxpayer dollars on all manner of extravagances, and our colleagues on both sides of the aisle should demand he do so."