WASHINGTON — Some career staffers concerned about the reputation of the Environmental Protection Agency believed that Administrator Stephen Johnson would have to consider resigning if he turned down California's request to reduce vehicle greenhouse gas emissions, newly released documents show.

Johnson denied the waiver request in December. In doing so, he blocked California and at least 16 other states from implementing the reductions.

The internal discussions were a part of transcripts released Tuesday by Sen. Barbara Boxer, D-Calif., who is investigating that decision.

Among them is a staff memo prepared for the head of EPA's Office of Transportation and Air Quality, Margo Oge, to present to Johnson. It urged Johnson to grant the waiver or find a compromise.

"You have to find a way to get this done. If you cannot, you will face a pretty big personal decision about whether you are able to stay in the job under those circumstances," said the memo, written by a deputy to Oge, who is a career agency employee.

"This is a choice only you can make, but I ask you to think about the history and the future of the agency in making it. If you are asked to deny this waiver, I fear the credibility of the agency that we both love will be irreparably damaged," said the October memo.

"The eyes of the world are on you," it said.

"It is obvious to me that there is no legal or technical justification for denying this," the memo added.

It's not clear from the document who would ask Johnson to deny the waiver, which was also opposed by the auto industry, which said that it favored a national approach.

In denying the waiver, Johnson said that a national approach would be better and that California had not demonstrated a compelling need for the law, which would have forced automakers to cut greenhouse gas emissions by 30 percent in new cars and light trucks by 2016.

Boxer's staff also released a memo with a portion of Johnson's schedule showing he was scheduled to meet at the White House apparently to discuss the California waiver issue.

Critics of the administration have said that it has been too slow to embrace the concept of a global warming threat and that its environmental policy generally has been too pro-industry.

The EPA, which has been sued by California and other states over the decision, has yet to release communications between EPA and the White House on the waiver issue, saying they are under legal review, Boxer said.

EPA spokesman Jonathan Shradar said he was not aware of any such outstanding documents.

"All these documents, all that we've produced in accordance with the committee's oversight responsibilities, all they show is a continuance of what we've talked about — the administrator was fully informed, he had great career and political staff giving him options, and he followed what he saw was the law," Shradar said.