ST. LOUIS (AP) _ A jury has ruled that 10 former residents of Times Beach, a town destroyed by toxic waste contamination, had not been harmed by contact with dioxin-laced oil used to spray roads in the early 1970s.

The Circuit Court jury deliberated a day before returning a verdict Tuesday in favor of Independent Petrochemical Corp. of St. Louis and the now-defunct Northeastern Pharmaceutical and Chemical Co. of Verona.

The companies, along with Syntex USA and Syntex Agribusiness of Palo Alto, Calif., had been sued by former Times Beach residents in an attempt to recover damages for health problems they said were caused by their exposure to dioxin.

Syntex pulled out of the case without explanation last week. A source who spoke on condition of anonymity said that Syntex had settled out of court for $14 million to be divided among 1,230 claims in Missouri.

Lawyers for Syntex declined to confirm or deny Tuesday that a settlement had been reached.

The eight cases in the trial, involving 10 people, were chosen by Judge Michael J. Hart as test cases from among 184 claims filed by former Times Beach residents.

The trial was designed to provide guidelines for attorneys on both sides so that future trials could be handled in as short a time as possible, Hart said.

Edwin L. Noel, an attorney for Syntex, said he hoped the jury's verdict would set a precedent for dioxin claims.

''I think this will serve as a bellwether for those cases,'' he said. The verdict validated defense arguments that ''this level of exposure (to dioxin) is not cause for alarm,'' he said.

Ted Perryman, who represented Northeastern Pharmaceutical, said the verdict ''was a response to the medical case that we put on. The jury simply believed that these people weren't injured by dioxin.''

Jurors interviewed after the verdict agreed with that assessment.

''The bottom line was that, over the last seven months, there was no evidence to indicate health damage,'' said juror Alvia Chambers, 43. She said the jury believed that complaints cited by the plaintiffs, such as headaches and heart problems, had not been conclusively linked to dioxin.

Sources close to the case, which began in November, said more than 2,200 claims of harmful dioxin exposure were still pending. Those claims arose from exposure to dioxin in Times Beach and other sites.

Dioxin is a toxic byproduct of the manufacture of herbicides and other chlorine compounds. It has been linked to cancer in animals and in humans and has been associated with liver and immune system disorders and a serious skin condition called chloracne.

In 1982, the Environmental Protection Agency bought out homes and property in Times Beach because of dioxin contamination caused when waste oil tainted with the chemical was sprayed on streets and other areas to control dust in the early 1970s.

Times Beach officially ceased to exist in 1985 when its alderman voted to disincorporate the town of 2,240 residents.

Donald L. Schlapprizi, an attorney for the plaintiffs, said he was disappointed by the verdict.

''It's depressing that with all of the effort ... you go down in flames,'' he said.

Attorneys for the plaintiffs were planning a strategy to deal with Tuesday's defeat, which could include a request for a new trial.

The dioxin that contaminated Times Beach was produced by Syntex at a plant in Verona in southwestern Missouri. Syntex later transferred to Northeastern Pharmaceutical tanks that reportedly contained the dioxin-laced waste.

Northeastern contracted with International Petrochemical for removal of the waste oil. International then contracted with a waste hauler to truck the oil from Verona. The hauler later mixed the waste with other waste oil and sprayed it on unpaved roads to control dust.