NEWARK, FEB. 1 -- A jury in a key smoker-death case heard conflicting claims today about hitherto confidential testimony of tobacco executives and about documents found in the files of three cigarette companies.

In an opening statement in U.S. District Court, the plaintiff's lawyer, Marc Z. Edell, said the documents showed that the medical literature first alerted the companies to grave health hazards 65 years ago.

Yet he alleged that for three decades afterward, despite mounting evidence of danger, their response was to "intentionally deceive" the public with public relations and advertising campaigns and to "suppress" information. Meanwhile, he said, they issued no warnings until forced to do so by the government in 1966, and did no research or testing to learn the truth about the medical reports.

Defense counsel, also in opening statements, denied Edell's allegations and counterattacked.

Philip Morris Inc. lawyer Peter K. Bleakley accused Edell of having "selectively quoted {the documents} out of context ... to an astonishing extent," and denounced his allegations as untrue. "The evidence will show that this industry acted responsibly," he said.

For Liggett Group Inc., Donald J. Cohn told the jury, "There was no suppression, there was no failure to inform."

For P. Lorillard Inc., Robert C. Northrip contended the evidence will show that the lung cancer that killed Rose D. Cipollone in 1984, when she was 59, was of a rare type that hasn't been scientifically linked to tobacco.

Starting when she was 16, Cipollone had smoked about 1 1/2 packs a day. She smoked Liggett & Myers brands before federal warnings went on packs, and the other companies' brands after. Her husband, Antonio, seeks unspecified damages.

Observers consider the case important because the companies produced hundreds of thousands of internal documents in 4 1/2 years of pretrial discovery -- far exceeding the information available in other tobacco damage suits.

The opening statements, lasting more than four hours in all, came two days after a jury trying a smoker-death case against American Tobacco Co. in Lexington, Miss., had deadlocked, resulting in a mistrial.

In a statement to the jury that went unchallenged today, Edell said that Milton Harrington, a former Liggett & Meyrs chief executive, had testified that he had received no information on smoking and health between 1934, when he became CEO, and 1964, when the surgeon general issued his first annual report on the issue. Yet, Edell said, Liggett argues that smokers such as Rose Cipollone were supposed to know the risks.

Defense counsel all argued that Cipollone had freely chosen to smoke in full awareness of the risks, having heard cigarettes called "cancer sticks" in her childhood and having repeatedly received warnings from her husband and from newspaper and magazine articles.

Edell said he will offer evidence concerning the Tobacco Industry Research Committee (TIRC), which was formed in 1954 after publicity about tumors forming on the backs of mice treated with the condensate of cigarette smoke.

He said the TIRC -- now called the Committee for Tobacco Research -- had awarded $500,000 to European researchers to study the effects on mice of inhaling fresh tobacco smoke. But after the scientists found that such smoke enhanced tumor formation, TIRC "persuaded" them not to publish the findings, he alleged.

Edell also claimed that after another European who had received a $600,000 grant found smoke-induced cancer in Syrian hamsters, the sponsor "doctored" his manuscript. When he decided to disclose this, his press conference was mysteriously canceled, Edell said. Northrip said the research had been published and publicized.

Edell said that in internal Lorillard memos in the mid-1940s, chemist (and later research chief) H.B. Parmele said that "just enough evidence has been presented {in medical literature} to justify ... a presumption" that smoking causes lung cancer.