ARLINGTON, Va. (AP) _ A panel of scientific experts supports an Environmental Protection Agency proposal to classify secondhand tobacco smoke as a known cause of lung cancer in nonsmokers, the panel's chairman said Wednesday.

The panel also supports the EPA's conclusion that parents who smoke increase the risk of respiratory disease in their children, said the chairman, Morton Lippmann of New York University.

''It seemed to me that there is a consensus ... that would make the case for a class A carcinogen,'' said Lippmann.

A ''class A carcinogen'' is the EPA's designation for a known cause of human cancer.

A draft report released by the EPA last summer concluded that cigarette smoke ought to be designated officially a cause of lung cancer in nonsmokers.

The panel's apparent concurrence with that view, despite considerable criticism of technical details of the report, makes it likely the final version of the EPA report will reach the same conclusion, EPA officials said.

The final report is likely to be completed early next year, said Robert Flaak of the EPA's science advisory board.

The tobacco industry criticized the panel's deliberations.

Brennan Dawson, a spokeswoman for the Tobacco Institute, said the human evidence did not support the classification of tobacco smoke as a class A carcinogen.

She said she expected that ''anti-smokers will continue to use the document in its draft form to push for restrictions'' on smoking.

The EPA report is likely to prompt the Occupational Safety and Health Administration to establish regulations for smoking in the workplace, said Roy Clason Jr., OSHA's director of policy.

''The findings of this report are very important in the future direction OSHA will take,'' he said.

OSHA has been planning for some time to establish rules on indoor air quality ''in which we would place a very high emphasis on the issue of smoking,'' Clason said.

The EPA smoking report concluded that lung cancer from passive smoking kills 3,800 Americans each year. (The number was later revised to 3,700.)

The expert panel raised questions about that number, and Lippmann said that it could change.

He added, however, that ''we're not disagreeing with their analysis that there's likely excess cancer associated with ETS (environmental tobacco smoke).''

Robert Axelrad, director of the EPA's indoor air division, said the panel's comments had been useful.

''These are all well known and respected scientists. Their criticism will ultimately result in a stronger and better document,'' he said.

Gary Giovino of the Office on Smoking and Health, which prepares the surgeon general's reports on smoking, said the EPA report validates conclusions reached in earlier studies by the National Research Council and the surgeon general.

''They've come to the conclusion that previous scientific bodies have, with more data,'' said Giovino.

The EPA's report is a review and analysis of available research on the health risks of passive smoking.

EPA officials consider it to be an update of the passive smoking reports by the surgeon general and the National Research Council, both issued in 1986.

In addition to identifying passive smoking as a cause of cancer, the report associates passive smoking with bronchitis, pneumonia, wheezing and middle ear disease in children.

The report also concludes that the children of mothers who smoke have impaired lung growth and development.