Overriding the strong recommendation of its general counsel, the Environmental Protection Agency agreed last fall to a private settlement that may enable 24 major companies to avoid millions of dollars of liability for cleaning up a large Indiana hazardous waste dump.

The agreement, involving the Seymour Recycling Corp. dump near Seymour, Ind., was announced by Rita M. Lavelle, then head of the agency's hazardous waste cleanup program. Lavelle, who was fired from the EPA Monday, called it a "major accomplishment" that "has no equal in EPA history."

The Seymour agreement, and others like it, are central to the current controversy surrounding EPA. Four congressional panels are investigating whether the agency is making "sweetheart" deals with polluters or failing to be aggressive in protecting the public from hazardous wastes.

The Seymour agreement was made over the strenuous objections of EPA general counsel Robert M. Perry, who argued that the agency should go to court to seek damages against companies responsible for dumping 60,000 drums of toxic industrial wastes at the site, according to an EPA official familiar with the case.

In a meeting with Lavelle, Perry argued that, because of the large number of companies that had dumped poisons at the site, the agency needed a legal consent decree to ensure that the cleanup was carried out, according to the EPA source.

Lavelle insisted that court action was unnecessary, this source said, and reportedly argued that she had already met with some of the companies involved, that they wanted to avoid a lawsuit and that they had offered to provide $7 million toward the cleanup.

Perry maintained that the companies simply wanted to settle the dispute with Lavelle to avoid the adverse publicity that a lawsuit might bring, the source reported. Perry argued that a voluntary settlement with the EPA had no "teeth" and that the agency would have no way of enforcing the agreement in future years if the companies failed to live up to the terms.

The agreement eventually was taken to a federal judge for approval.

Later, in a draft memo that was instrumental in her dismissal, Lavelle attacked Perry for taking a "hard line beyond previously agreed limits" with the Seymour companies in a meeting with some of their representatives.

The memo complained that Perry's action nearly scuttled the discussions, and "it required a major effort to bring the settlement together. Private attendees expressed great alarm at Perry's lack of skill."

Lavelle could not be reached for comment yesterday, despite repeated efforts.

Ken Jacobson, a spokesman for E.I. du Pont de Nemours & Co., one firm involved in the settlement, said his company was "anxious to settle" the case, and that the federal judge who reviewed it found it both legal and reasonable. "It was a fair settlement in terms of the public interest," he said.

An IBM official said his firm agreed to the voluntary settlement to avoid "a long drawn-out process that would end up in the courts."

But the secrecy with which the agreement was made has raised doubts among state officials and environmentalists. "It was all held behind closed doors," said Indiana state Rep. Baron Hill, who lives in Seymour. "We tried to get in, but we weren't allowed. They just wouldn't let us in."

Of particular concern to Hill, and the 340 other firms who were identified as having dumped waste at Seymour, is whether the settlement will be enough to clean up the site, or whether more money will have to come from somewhere else--perhaps the city of Seymour, the state of Indiana or the companies who have not yet settled.

Those remaining uncertainties help explain why Seymour, a community of 13,000 people about 50 miles south of Indianapolis, greeted the settlement with a mixture of delight and worry. The Seymour Recycling Corp. dump, a sea of drums and tanks abandoned since 1977, when its operator went bankrupt, according to Hill, has been a neighbor of the town for 12 years. At first the dump just sat there. "Then the neighbors noticed strange clouds over the dump," recalls Hill. "There were odors, and the drinking water started to taste bad."

The state board of health came in to take a look, and that's when Seymour found out it was living next door to more than 60,000 drums containing such highly toxic industrial wastes as polychlorinated biphenyls (PCBs), toluene, a poisonous residue of petroleum manufacturing, and benzene, as well as more than 500,000 gallons of liquid wastes stored in rusting metal tanks.

In 1979 some of the drums spontaneously burst into flames.

"Then a big rainstorm came up," spreading the toxic wastes with rivulets of water, said Hill. "An immediate emergency developed."

The EPA came in under its existing emergency response authority and cleaned up the worst of the leaking and exploding drums. But more than 50,000 were left, along with most of the liquid waste.

The site made EPA's "short list" of 418 sites regarded as the worst toxic dumps in the country. As such, it was eligible for cleanup funds under the $1.6 billion Superfund law passed in 1980.

But because of its location--on an old airport site, once federally owned and deeded to the city decades ago--Superfund will pay no more than 50 percent of the cost of cleanup, and then only if the city or state comes up with a matching 50 percent. As EPA interprets the law, that's the limit of Superfund responsibility on government-owned land.

So even if the surface cleanup is completed with the $7.7 million in hand, the residents of Seymour aren't sure how the rest of the cleanup will be accomplished, or how soon.

Hill says a town of 13,000 isn't likely to find $7 million easily, and the state of Indiana, beset by unemployment and recession problems, doesn't have the cash either.

Indiana's congressional delegation in Washington is trying to get the EPA's interpretation of the law changed to give Seymour the same 90 percent funding that other dump sites get, and, if that doesn't work, Hill hopes to get the money from a state-level "superfund" enacted by the legislature last year.

That will take time. The taxes that feed into the fund took effect Jan. 1, and there won't be enough money to meet Seymour's needs until July, 1984.

The current cleanup has been turned over to Chemical Waste Management Inc., which agreed in its contract to pick up any additional costs for the surface cleanup. A subsidiary of Chemical Waste, Waste Resources of Tennessee, was one of the 24 firms whose money will go to pay for the contract.

Don Reddicliffe, a spokesman for Chemical Waste, said the company's contract is with the 24 firms, not the EPA, and his company thinks $7.7 million is adequate to deal with the above-ground problems at the dump.