Past the city ballfields, the swimming pool, and the low-income neighborhood of Northend, a pungent chemical smell leads the way to the abandoned Chem-Dyne toxic waste dump site.

Inside an unguarded perimeter fence, men wearing white protective suits and breathing apparatus are repacking chemicals from rusting and leaking drums into $150 containers with sealed lids. Deodorized cat litter, hauled in by the ton, is poured into the drums to solidify the liquids.

In the old days, when thousands of gallons were hauled here from at least 289 producers of poisonous waste -- practically every source east of the Mississippi -- the disposal methods were cruder. The Environmental Protection Agency says that unknown thousands of gallons were poured into massive open-air tanks and allowed to evaporate, broken open with pickaxes and left to drain or leak into the ground, or, as a last resort, tipped into the nearby Great Miami River, via a conveniently located canal.

Chem-Dyne, a 10-acre toxic waste dump classified by the government as the worst environmental hazard in Ohio and one of the worst in the nation, is the site of the first "voluntary" cleanup under new environmental superfund legislation passed last year. Federal investigators tracked down the companies that generated the wastes dumped at Chem-Dyne and tried to make them pay the $3.4 million cost of mopping them up. Most did, and the 16 that refused are being sued in U.S. District Court in Cincinnati. The Chem-Dyne Corp. was forced into receivership in 1979.

Chem-Dyne, standing out from the multitude of toxic-waste dumps because of its extremely hazardous location and the magnitude of the clean-up task, is nevertheless almost a case study of the difficulties and dangers associated with toxic wastes: The exact nature of some of the chemicals is unknown, and so is their source. The contamination is believed to have spread far beyond the dump site and the assets of the company are completely inadequate to pay for the damage.

Nobody knows the extent of the damage to the health of local residents. Some of them, especially the Appalachian migrants who make up the bulk of the population of the Northend community adjacent to the dump side, say they dare not think about the consequences for their family's health because they need the local jobs.

"I am astonished that despite the millions allotted to the cleanup, nothing is being spent on a public health survey," said Bill Dauer, outgoing director of the Appalachian People's Service Organization.

Many residents say that they want to see a door-to-door survey of respiratory diseases and other illnesses, including cancer, which they think are unusually prevalent.

An underground river flows beneath Hamilton, and while this is a boon for local agriculture, the chemical dump sits above it and scientists are concerned that ultimately some of the chemicals could penetrate the river. If this happens, the effects could last for generations. Traces of a poison were recently discovered in an underground river in England that were almost certainly used to kill rats during the 17th century bubonic plague.

"Some parts of the soil are highly contaminated and have been taken away for further testing," according to Dave Strayer, site coordinator for the Ohio environmental protection agency. "Probably every time it rains it gets a little worse and leaches out of the soil into the ground water," he said.

The city's water wells are 100 feet or more below ground level and thought to be clear of any contamination. However, no regular screening has been done, only periodic surveys. Independent chemists have pointed out that the city does not have the equipment to test the drinking water for the kind of chemicals it could contain. "I would not drink the water," said Harry Marks, professor of chemistry at the University of Cincinnati. He was appointed by the state in January 1980 to make an inventory of the site. "There's no way of knowing what's in the drinking water without very sophisticated tests."

When William Kovacs and Bruce Whitten moved into the Hamilton area in 1975 nobody took much notice. Their business started as Spray-Dyne, and they made anti-freeze by recycling waste nobody else wanted to handle. The following year they expanded to form Chem-Dyne, a company to collect and dispose of waste. Chem-Dyne later spawned sister companies from offices in the middle of the dump. Hal Shepherd, the Hamilton city manager's assistant who monitored the site for the city, said he saw casual day laborers and ex-convicts undergoing rehabilitation at a Ohio training center working at the site. None of them, he said, was wearing protective clothing or breathing apparatus when he saw them.

Although the company and its affiliates were forced to close their business three years ago, more than 150,000 gallons of poisons ranging from PCBs to arsenic, cyanide and DDT, remain on the site.

Both Kovacs and Whitten have left the area. Kovacs works as a salesman in Toledo, Ohio, and Bruce Whitten lives in Somerset, Pa. Neither could be reached for comment on the Chem-Dyne story.

Randy Rogers, their former attorney in Hamilton, said, "I don't think either of them wants to make public statements, they want to put it all behind them." He added that Kovacs was "not happy" about being forced out of business and would have liked to see the cleanup completed.

The activities of Chem-Dyne first drew public attention in 1976 when a Shell Oil Co. tanker started to fume and the city's fire department was called in. The fuming continued for four days and Shell's experts who flew from Houston, Tex., were baffled. Tests showed that the chemicals had been mixed with something else on the site. The Cincinnati Post reported the finding of traces of phosgene, which the newspaper characterized as a gas believed to have been used in chemical warfare.

The city and fire officials were alarmed at what they saw on site. Led by Hal Shepherd, the city manager's assistant, they tried to monitor what was going on. "The most frustrating part of all was not having any laws to work with at that time," said Shepherd, who estimated that approximately 50 percent of his time had been dominated by the activities of the Chem-Dyne operation. His inquiries, which often took place at night when the company's trucks would arrive, resulted in a $30 million suit lodged by Chem-Dyne against the city for "harassment." Many local people think the suit prevented the local officials from being aggressive about the site.

Throughout Chem-Dyne's operations, there was no legislation under which any of the authorities could force the dumping to cease. The law at the time said that activities on private property could be stopped only if they posed a direct danger to public health, and the danger had to be proved in court.

A civil suit was was filed by Ohio environmental officials against Chem-Dyne when fish kills began to occur and city officials obtained a remarkable set of secretly shot photographs which showed an employe pouring thousands of gallons of poison into a storm drain from a large tanker. Measurements taken at the nearby river showed that the chemical pollution had spread 37 miles downstream, according to the suit. Chem-Dyne was charged with illegally polluting public waters and endangering public health. Altogether there were at least five known fish kills between 1976 and 1979 and the company was fined $375,000 after a state environmental investigation. "Unfortunately nothing stopped Chem-Dyne from operating at this point," said Shepherd, adding that during the summers of '77, '78 and '79 numerous residents complained about the chemical odors

Hamiltonians still recall that there were many days when they did not wash their clothes and hang them outside. "The fumes were something terrible. You just couldn't breathe, you'd have to go inside if the wind was blowing that way," said 65-year-old Margaret Peters.

In July 1979, Ohio State and Chem-Dyne reached an out-of-court settlement under which the original fine was reduced to $75,000 on the condition that the company clean up the site within 12 months. The state thought it had made a bargain but when officials went back to look, Shepherd reported that the amount of chemical waste on site had increased as the months went by. Within a month of this agreement, however, fire broke out among approximately 100 barrels. All of the city's fire equipment and 75 firefighters managed to contain the blaze, but six firefighters were taken to the adjacent Mercy Hospital overcome by the poisonous fumes. The Hamilton Journal reported that the fire was believed by local fire officials to have been started by an arsonist who was never caught.

When the state began to suspect that Chem-Dyne was ignoring the court order to decrease its activities Ohio environmental officials filed suit, asking that the company be placed in receivership. This took place in February 1980, by which time only $135 remained in the company's account. The records were in shambles, according to Jack Garretson, the receiver's attorney. The firm, however, had some assets -- land in Michigan and some trucks, and limited dumping continued on the site to raise money to allow the receiver to clean up some of the most poisonous chemicals. Still on site were 30,000 barrels and about 15 enormous tankers of poisons.

The receiver, Jack Zettler, and Garettson, his attorney, removed 17,000 barrels during the next 18 months, mainly by persuading the generators to dispose of their waste a second time. Priority was given to the leaking barrels although many of these were unlabeled and untraceable. In November 1981 the receivership ran out of money and although it had been remarkably successful, as far as locals were concerned, thousands of drums were still there.

Marks, the University of Cincinnati, chemist, said he was aghast when he discovered how the chemicals had been stored on site. "The leakages were atrocious. I've been a chemist for 25 years and I've seen nothing like it. I was appalled at what was going on right in the middle of the city," he said.

The concentration of the chemicals had been so high in the ground water that although the temperature was below freezing, no ice formed on the site. "They had everything you could think of," he said, adding that one truck arrived from Michigan having leaked its contents all the way down the highway. "From what we could see the drums were axed and opened and allowed to drain into the ground and poured into a railroad siding and allowed to evaporate," he said.

Shepherd leaned back on his chair and surveyed the files of documents about the "Chem-Dyne case." "We're talking about one little factory," he said.

Garettson said, "They left the city and the state and the government to clear up a problem that will probably affect generations to come and require the efforts of hundreds of people."