The Environmental Protection Agency yesterday increased by 133 the number of abandoned hazardous waste dumps that have top priority for cleanup because they pose imminent danger to human health or the environment.

The agency has now identified 546 dumps to be cleaned up with help from the $1.6 billion "Superfund," created by Congress to address the nation's most dangerous toxic waste sites. Officials said the list of locations to be cleaned up may eventually number more than 1,000. None of the sites added yesterday is in the Washington area.

Meanwhile, EPA officials also said that the amount of hazardous waste generated in the United States each year is four times greater than the agency had figured.

The new estimate is 30 billion gallons, based on a recent EPA survey. Other non-EPA studies have put the figure at more than 50 billion. More than 70 percent of these wastes are generated by the chemical industry, the study says.

The two new developments sent a mixed signal on the status of the hazardous waste threat five months after the EPA was rocked by a national scandal over the issue. EPA assistant administrator Lee M. Thomas, who oversees toxic waste issues, reported solid progress in the government cleanup program.

But Thomas added that the extent of toxic contamination in drinking water and other resources is only now being discovered. He also said there is no known way to counteract certain kinds of contamination, such as high levels of the toxic compound dioxin, found throughout Times Beach, Mo., and in other communities.

"There is no quick fix to problems of this magnitude," Thomas said. He said the stepping-up of agency efforts "does not mean that bulldozers will be pulling up at the new sites tomorrow, of course."

Underlining that warning was Sharon Worrell, mayor of Florence Township, N.J., who lives 50 feet from an abandoned dump that EPA yesterday added to the priority list. The agency listed the site among those it hopes will be cleaned up by the dump's operator with limited help from federal funds. But Worrell said that a six-year effort by the state has failed to produce voluntary cleanup by the operator.

Meanwhile, she said, underground water supplies have been contaminated with methylene chloride and other toxic chemicals, forcing 10 households to stop using drinking water from wells. Neighboring Manchester township officials estimate that it will cost $10 million to install a safe water system there.

The unveiling of the expanded list of priority cleanup sites is one of the major developments since William D. Ruckelshaus took the helm of the agency and brought in a new team of top administrators. Ruckelshaus was appointed administrator in March after his predecessor, Anne M. Burford, resigned under fire.

More than 20 top agency officials resigned or were fired earlier this year amid charges of official misconduct, industry influence and political manipulation in the waste cleanup program. Rita M. Lavelle, Thomas' predecessor as chief of the Superfund program, has been indicted for allegedly lying to Congress when she denied that she had distributed grants from the fund based on political considerations.

Officials also announced several significant policy changes yesterday in the toxic waste division. Thomas said the agency will remove a ban on spending Superfund money to clean up toxic waste dumped by the federal government, believed to be the biggest violator of federal hazardous waste laws.

The Department of Defense is by far the largest generator of toxic waste in the government. Thomas said the EPA will not know for six months which federal facilities will be targeted by the program.

The Superfund program requires cleanup costs to be covered by those responsible for the contamination. If those parties do not pay for the cleanup, the EPA can use the Superfund to defray costs and can sue those responsible for three times the cost of the project.

Cleanups have been finished at only five sites identified since Congress created the Superfund in 1980, officials said. With the expansion of the list yesterday, there are now only four states with no toxic dumps on the Superfund list--Alaska, Hawaii, Nebraska and Nevada.

The new dump ranked as the greatest danger to public health in the United States is the Lipari Landfill, a six-acre former gravel pit and industrial chemical dump surrounded by fruit orchards near Pittman, N.J. Superfund director William Hedeman said the dump contains an "alphabet soup" of toxic chemicals, some of which have poisoned underground water supplies, rivers and streams.

On the new list, New Jersey has 85 dump sites, more than any other state, that are ranked as national priorities for cleanup. It is followed by Michigan with 48, Pennsylvania with 39 and Florida and New York with 29 each. Maryland has three, in Cumberland, Annapolis and Elkton, and Virginia has four, in York and Roanoke counties, Saltville and Piney River.

Thomas also said the agency has not yet decided whether to ask Congress to continue the Superfund program beyond 1985, when the $1.6 billion is to be completely spent. Burford had said she did not expect to do so, but Thomas said that position is under review.