The new document, a road map laying out the issues involved in regulation, is to be signed by Stephen L. Johnson, the agency’s administrator, and published as early as Wednesday.

Image A refinery in Torrance, Calif. The state has sought federal permission to impose stricter limits on greenhouse gas emissions. Credit... Jamie Rector/Bloomberg News

The derailment of the original E.P.A. report was first made known in March by Representative Henry A. Waxman, Democrat of California, chairman of the House Oversight and Government Reform Committee. The refusal to open the e-mail has not been made public.

In early December, the E.P.A.’s draft finding that greenhouse gases endanger the environment used Energy Department data from 2007 to conclude that it would be cost effective to require the nation’s motor vehicle fleet to average 37.7 miles per gallon in 2018, according to government officials familiar with the document.

About 10 days after the finding was left unopened by officials at the Office of Management and Budget, Congress passed and President Bush signed a new energy bill mandating an increase in average fuel-economy standards to 35 miles per gallon by 2020. The day the law was signed, the E.P.A. administrator rejected the unanimous recommendation of his staff and denied California a waiver needed to regulate vehicle emissions of greenhouse gases in the state, saying the new law’s approach was preferable and climate change required global, not regional, solutions.

California’s regulations would have imposed tougher standards.

The Transportation Department made its own fuel-economy proposals public almost two months ago; they were based on the assumption that gasoline would range from $2.26 per gallon in 2016 to $2.51 per gallon in 2030, and set a maximum average standard of 35 miles per gallon in 2020.

The White House, which did not oppose the Transportation Department proposals, has become more outspoken on the need for a comprehensive approach to greenhouse gases, specifically rejecting possible controls deriving from older environmental laws.

In a speech in April, Mr. Bush called for an end to the growth of greenhouse gases by 2025  a timetable slower than many scientists say is required. His chairman of the Council of Environmental Quality, James Connaughton, said a “train wreck” would result if regulations to control greenhouse gases were authorized piecemeal under laws like the Clean Air Act and the Endangered Species Act.