At the center of growing turmoil inside the Environmental Protection Agency and proliferating congressional investigations of the embattled agency is a dangerous, 24-acre chemical waste dump about 20 miles northwest of Riverside, Calif., known as the Stringfellow Acid Pits.

About 170 companies disposed of poisonous chemicals there over the years and, under pressure from worried residents of nearby neighborhoods, are now negotiating with the government over who should pay for cleaning it up. Among them are several companies whose officers, former officers or stockholders have ties to the Reagan administration.

One of them, presidential counselor Edwin Meese III, is a former vice president of Rohr Industries in Chula Vista, Calif., which was among the firms that disposed of the largest amounts of chemicals at the Stringfellow dump. Its dumping stopped in the early 1970s.

Meese said last night he was at the company from January, 1975, to May, 1976. "During the time I was involved, it never came up, and I had nothing to do with it," he said.

Another company that disposed of chemical wastes at the Stringfellow dump and could be found by the government to be partially liable for cleaning it up is Dart Industries of Northbrook, Ill., headed until two years ago by Justin Dart, a close Reagan associate and member of his "kitchen cabinet."

Inquiries to Dart's Los Angeles headquarters were referred to its Illinois offices, where Romer Wilsek, director of regulatory affairs, confirmed the company was responsible for some dumping at the Stringfellow site and is negotiating with the EPA over the cleanup.

Attorney General William French Smith and his wife are listed in financial disclosure statements as shareholders in two of companies that have disposed of wastes at the Stringfellow dump, Northrop Corp. and General Electric Co.

Tom DeCair, a spokesman for Smith, said the attorney general has not seen a list of the companies that used the dump and are now negotiating with the government. The stock was purchased before Smith became attorney general and is now in a blind trust.

Rita M. Lavelle, the EPA official fired this week by the administration, is a former employe of Aerojet-General Corp., another user of the Stringfellow dump. At the EPA, she had direct responsibility for enforcing a cleanup of the dump and did not recuse herself from official decision-making on it until last June, after which other EPA officials said she continued attending meetings on the subject.

Such connections should not be surprising. A large number of administration officials and advisers come from the southern California area, where the dump is located. Many also are wealthy people with investments in businesses that are likely to include industries producing toxic wastes legally deposited in dumps like Stringfellow without then knowing the danger they posed.

Richard Madsen, counsel for Rohr Industries, said that for the years his company used the dump, it was licensed by the state. "As far as everyone knew, it was a proper place to put the material," he said. "Then one day you wake up and find that retroactively they've made it improper."

Congressional attention has focused on Stringfellow and companies that used it because documents concerning the EPA's approach to its cleanup are among those that EPA Administrator Anne M. Gorsuch, at the direction of President Reagan, refused to give to congressional oversight committees.

This prompted an unprecedented House vote to cite her for contempt, beginning an unresolved constitutional confrontation between the Reagan administration and Congress.

In California, the Stringfellow Acid Pits, soaked by 32 million gallons of dangerous chemicals over a 16-year period, have become known, in the words of one state senate staff member, as "the Love Canal of the West."

In a small canyon in the Jarupa Mountains just north of the Pomona Freeway, Stringfellow is the first abandoned waste dump on the West Coast large and potentially dangerous enough to ring public alarm bells. Riverside County officials are preparing to study for the first time the complaints from nearby Glen Avon residents about illnesses they fear are connected to the dump.

James Stringfellow, who once owned the pits and sold the dumping rights, said he does not remember all the firms that deposited chemical wastes there. He retired to Newport Beach in the early 1970s, when the dump became unprofitable because of growing public opposition to it.

Stringfellow, now 57, said he opened the canyon site for waste dumping in the mid-1950s near a gravel quarry he operated. The deposited chemicals were to be left to evaporate in open pools. Few local residents complained until heavy rains in 1969 caused an overflow of residue acids, chromium and other chemicals.

The resulting protests led to calls for new restrictions on Stringfellow, and then a revocation of its permit. These actions "forcibly retired me," said Stringfellow. His leading competitor bought the quarry then failed to pay taxes on the site. So the state took it over.

Complaints about the dump hit a new peak after heavy rains in 1978 overflowed from the dump into nearby neighborhoods. Residents later complained of urinary tract infections, headaches and seizures.

"I don't know anyone who doesn't know someone with asthma or some respiratory infection," said Penny Newman, leader of a citizens' group that has sought a cleanup of the dump.

Last August the EPA was negotiating to pay $6.1 million to clean up the dump and the EPA regional office in San Francisco assured California it would be funded, according to sources. It appeared so certain that then-California Attorney General George Deukmejian wrote a letter printed in an EPA journal that discussed the promised funding.

But by September, the EPA had decided not to fund it, reportedly because the manager of the Stringfellow dump had such meticulous information about companies that had deposited chemicals there that the EPA would sue them for the money instead.

But some EPA officials and congressional sources have suggested that the Stringfellow case may have been been manipulated for political purposes. They have charged that Gorsuch did not want to do anything that might have helped then-Gov. Edmund G. (Jerry) Brown Jr., a Democrat, in his campaign for the U.S. Senate.

One former Brown aide said his office was telephoned last summer by a distraught EPA aide saying orders had been given to delay funding for a clean-up of the Stringfellow dump and others in California until after the November election.

James W. Anderson, executive officer of the state water quality control board's Santa Ana region, said about $7.5 million has been spent so far to try to seal cracks in the bedrock and surround the site with clay barriers to prevent chemicals from leaking out.