Federal researchers have found traces of a potent cancer-causing chemical in hundreds of liquor products sold in the United States, including dozens with levels so high they would not be legal for sale in Canada.

The products, including American-made bourbons and sherries and imported fruit brandies and sake, contain urethane, a chemical that is used as an industrial solvent and a known carcinogen in laboratory animals.

According to federal and industry officials, the chemical forms naturally during the fermentation process, although its level can be reduced through manufacturing changes. The United States does not regulate urethane in liquor, but began testing liquor products for the chemical 18 months ago when Canada adopted legal standards for urethane contamination.

The Center for Science in the Public Interest, a Washington-based consumer group that obtained the test results with a Freedom of Information Act request, said 95 of the 802 wines and spirits tested would not meet Canada's standards. Hundreds more showed lesser levels of contamination that the group contends still pose an unacceptable health hazard.

Janet Flynn, a spokeswoman for the Distilled Spirits Council of the United States, accused the center of "grandstanding." She said, "There continues to be no real risk. There never has been, and in our opinion these products continue to be safe."

The center, which released the names of 43 urethane-contaminated products last November, has been pressing the Food and Drug Administration to inform the public about urethane in alcohol products and to halt sales of liquors with unsafe levels. It obtained brand names from the Treasury Department's Bureau of Alcohol, Tobacco and Firearms, which also provided the list yesterday to The Washington Post.

Spokesman Jim Greene said the FDA does not believe urethane poses an imminent health risk and will wait for the industry to "make the proper adjustments" in manufacturing processes before setting standards.