Fibers released from cigarette filters: an additional health risk to the smoker?

Tests of 12 popular brands of cigarettes manufactured by 6 companies from the United States have shown that fibers were released from the filters and that there exists probable cause to suggest that fibers are inhaled and/or ingested. Filter fibers, made of cellulose acetate, were implanted in mice for 6 months. The fibers withstood degradation and retained the tobacco-brown color and bright fluorescence of the tobacco tar that had been adsorbed from cigarette smoke. With a confocal laser scanning microscope, we have observed cigarette filter fibers in lung tissue from patients with lung cancer and who were known to be habitual smokers. These findings raise the question as to whether fibers released from cigarettes further jeopardize the health of smokers and document the need to test components of cigarette filters for toxicity and tumorigenicity.