In its first major policy shift endorsed by William D. Ruckelshaus, the Environmental Protection Agency yesterday made a series of changes in hazardous waste programs designed to accelerate the cleanup of the nation's most dangerous toxic dumps and to tighten control over new waste disposal sites.

The changes reverse several policies of former EPA administrator Anne M. Burford and ousted hazardous waste chief Rita M. Lavelle. The two came under fire for putting priority on saving money rather than moving quickly to clean waste sites.

Acting deputy EPA Administrator Lee M. Thomas said Ruckelshaus "supported the direction" of the changes in the $1.6 billion Superfund to clean up toxic waste.

Ruckelshaus, who is expected to win easy confirmation from the Senate next week, said in hearings this month that "there was too much emphasis at EPA on who pays as opposed to cleaning up the dump."

The new policies include acting to clean up the 419 sites ranked as the most imminent dangers to public health, deferring decisions on whether to recover costs through lawsuits or settlements with companies that generated the wastes. This debate delayed dozens of cleanups over the last two years.

The changes were welcomed yesterday by many of the EPA's harshest critics, including members of Congress leading investigations into charges of mismanagement and wrongdoing at the agency. But most said they come two years too late.

"This is all very commendable since it's what the Superfund law said EPA should have been doing from the very beginning," said Rep. James J. Florio (D-N.J.), one of the authors of the law.

One of the most significant changes removes a prerequisite, imposed by Burford, that states pay 10 percent of the cost of EPA studies to determine how their most dangerous waste dumps should be cleared. Many state governments are in financial crises, and have been unable to come up with this money, delaying hundreds of cleanup projects, according to EPA officials.

Federal law still requires states to pay 10 percent of the far more expensive task of cleaning up the sites--removing waste drums, pumping out lagoons and excavating contaminated earth. But EPA officials said yesterday's change should help get stalled projects under way, giving state officials two or three years to budget money for cleanups.

Under another new policy, EPA officials said that they will pay for partial cleanups at many sites that pose imminent danger. Previously, the agency deferred most cleanup efforts while lenghty studies were performed to determine an overall solution to contamination problems.

Superfund director William Hedeman said yesterday that this created serious health threats in areas such as Bridgeport, N.J., near Philadelphia, where lagoons bearing "an alphabet soup of toxic chemicals" were in danger of overflowing whenever there were heavy rains. Under the new approach, EPA is pumping out the lagoons, while continuing to study how to clean the entire area.

"In the past, there was a more conservative definition of what constituted an emergency, and threats to public health were essentially festering and worsening," Hedeman said.

The new policies also include increasing the number of priority sites beyond the current list of 419. And they give officials in the agency's 10 regional offices authority to spend up to $250,000 to clean up toxic spills without having to consult first with Washington officials.

Most of the shifts were recommended in an internal EPA review, completed two weeks ago, documenting severe mismanagement in the hazardous waste program. The report was requested by Burford at the peak of the EPA controversy and proceeded after she and a dozen other political appointees had resigned.

The report concluded that poor management and bickering among agency officials had prevented the EPA from protecting the public health against hazardous wastes. It said that as many as half of the 419 dumps on the priority list were in danger of bursting into flames, exploding or releasing contaminants that could reach water supplies.

Provisions in the Superfund law allowing the EPA to perform emergency cleanups at these sites were "drastically under-utilized" in the last two years, the report said.

Another set of policies aims to tighten enforcement over new hazardous waste disposal facilities, including an estimated 11,000 that do not yet have permanent permits.

The House Energy and Commerce Committee on Thursday approved a bill to control these sites--a reauthorization of the Resource Conservation and Recovery Act--that would go considerably further, however.