Career officials at the Environmental Protection Agency who oversaw the funding and construction of a controversial secure phone booth for Administrator Scott Pruitt's office were acting at the behest of political appointees and security staff, documents obtained by CBS News show.

The documents show that the project started soliciting bids at an estimated $13,500 last summer. It eventually cost $43,000, which included painting, floor and ceiling work and prepping the room. Presented with four pricing options ranging between $20,560 and $24,570, career officials chose the most expensively priced because it included "expedited materials and working outside regular business hours."

Yet the emails also indicate that flags may have been raised.

In one email, dated June 28, 2017, Gayle Jefferson, Director of Facilities Management and Services Division, says "The secure room for the Administrator appears to be taking on a life of its own."

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On that same e-mail chain, on June 27, staffers were trying to determine whether the floor would be able "to handle the weight of the booth", later described as a "600-800 LB box." Sebastien Guilmard, whose LinkedIn page describes him as a Senior Project Architect for the EPA, says that another staffer "brings up a good point about the weight. But we may also be able to use white noise to achieve same goal."

On September 27, deputy chief of staff Reginald Allen was told in an e-mail that "the booth made it to the news…It is a legal purchase but will be scrutinized." Allen replied: "Understand this was a requirement directed by the Administrator[']s political and Security team that they demanded, they (Kevin C and Nino P) spoke with several times about this asking to speed delivery. They must address any questions or concerns as to the requirement."

Allen is referring to Kevin Chmielewski, former deputy chief of staff and a political appointee, and Pasquale Nino Perrotta, who is Pruitt's lead security detail and who oversaw the increased spending on security including first class travel that has now become the focus of investigations in Congress, the White House and the EPA's Inspector General.

The New York Times has reported that Allen, who was the highest ranking career official, was reassigned after he voiced concerns about spending directly with Pruitt. Chmielewski has told Democratic lawmakers that he was put on administrative leave agency after questioning Pruitt's spending.

EPA officials point out that the documents show Allen and Chmielewski were on the string of emails. Yet, dozens of other career officials were also part of the decision making process, the emails show.

"Administrator Pruitt simply requested a secure phone line, but never asked for a soundproof booth, nor did he have knowledge of its purchase. As required by law, career EPA employees authorized the purchase and installation," said EPA spokesman Jahan Wilcox.

The documents provide an incomplete picture as they don't show any communication from the administrator or any of his aides making that initial request.

Yet in another email, Jefferson tells another career staffer: "I want to make certain we are bringing you in the loop since I believe you were the primary point of contact on this issue for the Administrator, and getting an understanding of his expectations for this space."

The secure phone booth has come under scrutiny in part because of its cost and also because the building houses another secure communications area on a separate floor. Earlier this week the Government Accountability Office said the EPA broke the law by neglecting to inform Congress of the expense – which is required when agencies spend more than $5,000 to outfit the office of an agency head.

"EPA disagrees with GAO's legal conclusion that this expenditure also required notice to Congress, but we are addressing GAO's concern with regard to Congressional notification," Wilcox said.

Allen, Chmielewski, Jefferson and Guilmard did not respond to requests for comment.