Daniel Reifsnyder, a 25-year State Department veteran, knew even before President Obama was elected that U.S. environmental policy was going to change. So in early November, he called a couple of his Environmental Protection Agency counterparts about drafting documents to lay the groundwork for endorsing a treaty to curb global emissions of toxic mercury.

Environmental Protection Agency Administrator Lisa Jackson speaksat the National League of Cities conference, Monday, March 16 2009, in Washington. (AP Photo/Manuel Balce Ceneta) The Bush administration had resisted proposals for a United Nations-sponsored mercury treaty since at least 2005 on the grounds that voluntary measures were sufficient, but Reifsnyder told his fellow career officials that they had an opportunity to quickly formulate a new U.S. position in time for an upcoming meeting in Nairobi. They knew that as a senator, Obama had sponsored legislation banning the export of mercury overseas and that he was likely to be sympathetic to the treaty proposal.

"To anyone who was aware of what was happening, it was pretty clear the chances of the Bush administration position continuing into the new administration was pretty remote," recalled Reifsnyder, who is deputy assistant secretary of state for the environment and jokes that he started working at the department "before Moses parted the waters."

By Feb. 20, the efforts of Reifsnyder and dozens of other rank-and-file federal employees had borne fruit: After the United States voiced support for the idea of a new, binding mercury treaty, the world community embraced it in Nairobi.

The rapid policy reversal is just one of more than a dozen environmental initiatives the new administration has undertaken in its first two months. In nearly every case, the decisions were based on extensive analysis and documentation that rank-and-file employees had prepared over the past couple of years, often in the face of contrary-minded Bush administration officials.

After years of chafing under political appointees who viewed stricter environmental regulation with skepticism, long-serving federal officials are seeing work that had been gathering dust for years translate quickly into action.

Whether that is a good thing depends on one's point of view.

"It is kind of how government works, at its best," said Eric Schaeffer, who headed the EPA's office of regulatory enforcement before resigning in protest in 2002. He now runs the Environmental Integrity Project, an advocacy group. "With government bureaucrats, we fuss at them, but in this case I think they're doing some good."

Businesses facing new regulation, however, often call it a case of unelected government employees running amok.

"It's safe to say [that] within the regulatory bureaucracy, there's a built-in inclination to draft regulations, because that's what they do," said Hank Cox, a spokesman for the National Association of Manufacturers. "With some of these bureaucrats and activist groups, there's an obliviousness to the costs of these regulations. We're more comfortable with having people high up in government taking a fairly tough line on new rules."

After years of behind-the-scenes disputes with their superiors who favored regulatory restraint, many longtime federal workers are now what Cox calls "more in sync" with the new political hires running their agencies.

This shift has helped produce broad policy reversals that encompass such issues as writing new regulations and prosecuting violators of old ones, with still more in the pipeline. Drawing on earlier spadework, the administration has issued a proposal to create a national greenhouse gas registry; filed a lawsuit accusing a coal-fired power plant in New Roads, La., of violating the Clean Air Act; and put electric utilities on notice that they may have to account for their greenhouse gas pollution.

Political appointees have also asked career employees for background material on how to regulate pollution from cement kilns; whether refineries have done enough to curb their harmful emissions; and whether the federal government should grant California and more than a dozen other states the power to curb greenhouse gas emissions from vehicles.

Margo Oge, director of the EPA's office of transportation and air quality, said the approximately 400 people who work in her division have drawn on "thousands of pages" of documents that they drafted during the past administration to advise new EPA Administrator Lisa P. Jackson quickly on questions such as whether the agency is obligated to regulate gases that contribute to global warming and how it might accomplish that.

Bush officials had extended the public comment period on the question, in part because they thought a positive finding would trigger an elaborate regulatory scheme that would harm the economy. On March 20, the EPA sent a finding to the White House that greenhouse gases endanger public health and welfare, based in part on the work that Oge's office had done.

"There is a sense of urgency by the president and the administrator to address climate change," Oge said. "The agency is in a very good position to provide technical assistance to the president, to Congress and to the administrator."

In many instances, career officials have spent a couple of years preparing the reports and briefings they are now delivering to Obama officials. Under Bush, for example, senior EPA officials such as former deputy administrator Marcus Peacock made it clear that the government would not devote significant resources to prosecuting coal-fired power plants for Clean Air Act violations because the administration was more interested in curbing air pollution through regulatory reform.

But according to a Justice Department official, who spoke on the condition of anonymity to discuss ongoing litigation, career employees continued to research such allegations in the hope of securing settlements or bringing cases in the future.

On Feb. 18, less than a month after Obama was sworn in, the United States filed a complaint against the Big Cajun 2 Power Plant charging that for more than a decade it has operated without required pollution controls; the case was based in part on about 2,000 boxes of documents from the EPA's enforcement office.

The Justice official said the fact that EPA employees continued to research these sorts of complaints kept a 1999 federal initiative aimed at coal-fired utilities "alive, and that's what gives us the ability now to file a couple of these cases."

In some cases, agency officials have been able to revive proposals that languished under the previous administration with the tiniest of changes. A proposal to establish a national greenhouse gas registry stalled at the Office of Management and Budget for three months because Bush administration officials did not think the EPA should use its authority under the Clean Air Act to establish the monitoring system. Within two weeks of Jackson taking office, however, career officials briefed her on the matter, and she agreed that they could base the rule on the act. The registry proposal that the EPA issued this month is nearly identical to the one it sent to the OMB in September.

Scott Segal, a lobbyist for coal-fired utilities at the law firm Bracewell & Giuliani, said the fact that Obama has yet to fill many sub-Cabinet appointments at federal agencies has created "a power vacuum in which career employees fill in the gap."

"The old joke about EPA employees is they would either write the rule, or if they couldn't, they would leak the draft," Segal said. Now, he added, they seem to be getting their chance to write the rules.