"The (Office of Inspector General) is not a decision maker for EPA", Elkins wrote, adding that Pruitt's staff began pushing for his office to assess threats against Pruitt within days of his arrival in Washington.
"I'm being asked, really constantly asked, to comment on security and on housing and on travel".
Sen. Lisa Murkowski (R-Alaska), the subcommittee's chairwoman, huddled Thursday with her appropriations staff to prepare for the hearing.
A House committee, the EPA's inspector general and the GAO all are investigating various allegations against Pruitt or his administration at EPA.
Chuck Grassley warned Tuesday he may call on Environmental Protection Agency Administrator Scott Pruitt to resign if his agency does not take a fairer approach to issuing waivers to the large refineries that allow them to skirt biofuels regulations.
Udall tells Pruitt he's treating his position of public trust "as a golden ticket for extravagant travel and fine dining".
Pruitt in April showed his ability to bat away ethics questions from Democrats when he appeared before two House panels.
Protesters sitting behind Pruitt silently rose up twice in the first minutes of the hearing, once waving signs and once simply standing up in unison, wearing green T-shirts with slogans saying "Impeach Pruitt".
1st day of interviews for NY attorney general's job set
He said he and his colleagues take their constitutional duties seriously and are "unbowed" by the pressure. The pool applicants for interim attorney general include several other women.
EPA Inspector General Arthur Elkins said in letters to Democratic senators that Pruitt himself initiated the 24-hour protection, which far exceeds the part-time security afforded to past EPA administrators. Elkins says the 2017 summary was requested by Pruitt's office and not meant to justify tighter security.
Despite the mounting investigations, Trump has said he supports Pruitt. He reportedly used tens of thousands of taxpayer money for flying first-class for unspecified security reasons.
The EPA has spent about $3 million on Pruitt's 20-member full-time security detail.
A top Republican senator worries that the ethical cloud hanging over President Donald Trump's top environmental official is overshadowing the administration's pro-business regulatory moves.
After the White House aide sounded the alarm about the potential public relations consequences of releasing the study, EPA chief of staff Ryan Jackson coordinated responses between HHS, EPA and the Pentagon, Politico reported.
Leahy belittled Pruitt's claim that he needed to fly first class because of security concerns.
At one point, the lawmaker asked Pruitt to provide details on how he had enlisted aide Millan Hupp to help locate local apartment rentals for him last summer.
"Nobody even knows who you are", Leahy told the EPA chief.
"Unlike Scott Pruitt's Pollution Protection Agency, there is still one government agency clearly trying to safeguard the public from these risky chemicals", said EWG President Ken Cook. "Forget about your own ego and your first class travel and your special phone booths that just make you a laughingstock and your agency a laughingstock".