By February 2008, Johnson had reached a conclusion. In a draft to the OMB, he said the evidence for making a change to both the primary and secondary standards was "compelling."

He set the primary standard at 75 parts per billion, higher than the recommendation. He set the secondary limit for protecting plants at 21 parts per million-hours - also considerably higher.

But the OMB would have to sign off on the rulings.

On March 6, one week before the court-ordered ozone deadline, Susan Dudley, head of the OMB Office of Information and Regulatory Affairs, wrote to Johnson to say that the science did not justify a new secondary standard - one that would be expensive to put in place.

"EPA has not considered or evaluated the effects of adopting a standard on economic values, personal comfort and well-being, as specifically enumerated in the Act," Dudley wrote.

In a footnote, she noted that the EPA was obligated to consider any benefits of ozone.

The next day, EPA Deputy Administrator Marcus Peacock sent a memo to Dudley saying EPA was unaware of any beneficial effects of ozone. Further, the science supported the tougher rule and the agency was barred under the Clean Air Act from considering cost when setting standards.

Dudley sought to block the rule anyway.

With the EPA and OMB in a deadlock, Johnson turned to the White House.

Johnson has refused to discuss what happened next, but a document prepared for his meeting with the White House on March 11 called the intended lowering of the secondary standard the most scientifically defensible.

The EPA staff pointed out that in addition to the science panel, the National Academy of Sciences, the U.S. Department of Agriculture, and the National Park Service recognized the need for a separate secondary standard.

Johnson lost.

"The president has concluded that . . . added protection should be afforded to public welfare by strengthening the secondary ozone standard and setting it to be identical to the new primary standard," wrote OMB's Dudley.

Dudley's letter sparked a flurry of activity as EPA staffers were told to edit the final rule to reflect the White House's last-minute changes.

Johnson defended himself, saying the panel had gone too far; its recommendation was based on a "mixture of scientific and policy considerations." He did not have confidence, he added, in his own agency's scientific analysis. Adams, he noted, had his own reservations.

EPA staff members were appalled, calling the move "pure politics" in e-mails made public during a congressional investigation into Johnson's handling of the ozone standard. One questioned why a final version of the rule included a sentence about parks and forests, "since we're not really protecting any of them properly."

Another manager wrote: "I know how incredibly frustrated and disgusted we all are at the moment."

The last-minute shuffle also inflamed the science advisory panel.

"That's no way to set a standard, by fiat behind closed doors," Henderson said. "They have no shame."

Burnett, the former senior EPA aide who worked on the ozone decision with Johnson, said it was difficult to get the White House to understand the gravity of its decision.