A type of asbestos called crocidolite is much more life-threatening than originally believed, a Harvard medical researcher who recently published a report on the subject said yesterday.

Dr. James A. Talcott, an instructor at Harvard Medical School, studied thirty-three individuals who worked in a factory making cigarette filters with crocidolite fibers in 1953. Twenty-eight of the workers had died, three times the expected death rate.

Talcott's findings were published in Thursday's New England Journal of Medicine.

"The mortality rate from lung cancer was higher than has been reported in any other study," said Talcott, who is a clinical associate at the Dana Farber Cancer Institute. In addition to cancer, the study showed that the exposure to crocidolite caused respiratory diseases, such as malignant mesothelioma and asbestosis.

The results demonstrate the need to regulate asbestos differently in this country, Talcott said. Unlike many nations, the United States treats all types of toxic asbestos as if they were the same, he said.

"There is enough evidence that [crocidolite] should be regulated differently," Talcott said. "Our study supports the belief that it is more toxic than other types of asbestos."

Talcott said, however, that his findings did not have significant implications for limited, non-industrial exposure to the substance.

"It is important to emphasize the difference between industrial exposure and casual exposure to small, if any, amounts of asbestos," Talcott said. The workers that he studied had direct contact with the material for eight hours a day in a very dusty workplace, he added.

Individuals who spend time in areas with asbestos insulation are not at great risk,Talcott said. He cited a study which showed thatdaily exposure of children to asbestos in theclassroom would cause only one additional deathper million students each year. The risk of dyingin an automobile accident over a lifetime is tenthousand times greater, he said.

Asbestos was widely used as an insulator in theUnited States until 1973. Consequently, manybuildings on the Harvard campus still contain thematerial.

Michael N. Lichten, director of physicaloperations, said that according to governmentregulation, the asbestos is removed whenever it isfound in an exposed condition or discovered as aresult of renovation or demolition.

Lichten said the University did notdifferentiate between different types of asbestosin its removal efforts.

"If we find asbestos which is damaged we treatit, we remove it, or we encapsulate it, regardlessof type," Licheten said. But he said there is nolong term plan to entirely rid the University ofthe substance