WASHINGTON - One of President Barack Obama's first acts Tuesday was to put the brakes on all pending regulations that the Bush administration tried to push through in its waning days.

The order went out shortly after Obama was inaugurated president, in a memorandum signed by new White House chief of staff Rahm Emanuel.

Former President George W. Bush's administration moved into overdrive in the last year or so on a host of new regulatory proposals. Now the Obama administration will review everything that is still pending.

In doing so, the Obama administration is taking a page out of Bush's playbook from 2001.

Within hours after Bush was sworn in, Bush advisers were seeking to reverse some late-term actions of President Bill Clinton, who in his final 20 days in office issued 12 executive orders, including directives on migratory birds and the importation of diamonds from Sierra Leone.

Eight years later, the Obama White House is making a similar move. In some cases, however, the Bush administration moved too fast for the incoming administration.

For example, just six weeks ago, the Bush administration issued revised endangered species regulations to reduce the input of federal scientists and to block the law from being used to fight global warming.

The Bush administration worked diligently to get the change in place before Obama took over, corralling 15 experts in Washington in October to sort through 250,000 written comments from the public on the revisions in 32 hours.

Obama has said he would work to reverse the changes. But because the rule takes effect before he is sworn in, he would have to restart the lengthy rulemaking process.

The changes would eliminate some of the mandatory, independent reviews that government scientists have performed for 35 years on dams, power plants, timber sales and other projects, a requirement that developers and other federal agencies have blamed for delays and cost increases.

The rules also prohibit federal agencies from evaluating the effect on endangered species and the places they live from a project's contribution to increased global warming.

Another Bush administration regulation that went in effect this month overturned a 25-year-old federal rule that severely restricts loaded guns in national parks.

For rules that have already gone into effect, the Democratic-controlled Congress might be able to help the Obama administration by using the Congressional Review Act, a legislative tool to bring new federal regulations under scrutiny.