A federal judge ruled yesterday that the plaintiffs in a suit brought by a cancer victim against tobacco makers could make public information they obtained from the companies.

U.S. District Judge H. Lee Sarokin in Newark, N.J., who handed down the decision, said the First Amendment to the Constitution gives the public "a right to know what the tobacco industry knew and knows about the risks of cigarette smoking and what it did or did not do with regard to that knowledge."

The suit was brought against the Liggett Group Inc., Philip Morris Inc. and Loew's Theatres Inc., successor to P. Lorillard Inc.

The plaintiffs are Rose D. Cipollone and her husband Antonio. Mrs. Cipollone started smoking -- a pack a day -- when she was 16 and died of lung cancer last year, 42 years later, after the suit was filed.

Sarokin upset an order barring the plaintiffs from disclosing documents, testimony and other materials obtained through depositions and other pretrial discovery. He said that the sweeping nature of the order, issued in March by Magistrate Robert E. Cowen, "diminishes the First Amendment rights" of the general public and other plaintiffs.

In appealing Cowen's order, Marc Z. Edell, the couple's lawyer, claimed that the discovery process has revealed the industry's knowledge of the harmful effects of smoking, as well as its efforts to conceal and offset that knowledge and to enlist the aid of legislators and the medical profession and mislead the public.

The judge emphasized that he was making no finding as to the truth or falsity of the allegations, but said that he "cannot be a party to their suppression if they are true." Sarokin said that the defendants' role, "if any, in concealing or misrepresenting information regarding the risks of smoking is not entitled" to the protection afforded business secrets.

He gave an additional reason for his ruling: the existence of numerous other smokers' product-liability suits. "The court cannot ignore the might and power of the tobacco industry and its ability to resist the individual claims asserted against it," he said. "To require that each and every plaintiff go through the identical, long and expensive process would be ludicrous."