Editor,—The primary purpose of the cigarette filter is reduction of tar in tobacco smoke.1 2 Filters also keep tobacco flakes out of smokers' mouths.1 The standard filter used on cigarettes today contains 15 000 fibres per filter.1

Several studies have demonstrated that the filter material (cellulose acetate fibres) can become detached.3-7 Pauly and colleagues have recently observed cigarette filter fibres in human lung specimens, indicating that the material is respirable.8 A study of filter fibres implanted in mice for six months demonstrated that fibres resist biodegradation.5 As a result of burning tobacco, the discharged fibres are also coated with tobacco tar, which contains carcinogens.5 Such inhaled filter fibres may pose a previously undefined health risk to the smoker beyond exposure to the chemical toxins found in tobacco smoke.5

We have found no mention of the problem of filter fibre fallout in advertisements for filtered cigarettes. On the contrary, consumer surveys demonstrate that many smokers believe that filtered cigarettes reduce the risks of smoking.9-11

This study was undertaken to explore consumers' beliefs about cigarette filter safety and the ingestion/inhalation of cigarette filter fibres. Fifty three current smokers and 24 former smokers were interviewed while waiting in line at a division of motor vehicles office in Erie County, New York in the summer of 1997. Fewer than 5% of those approached refused to participate in the survey interview. Overall, the sample was 52% male and 48% female; 56% were aged 40 years or younger. A current smoker was defined as someone who has smoked 100 cigarettes in one's lifetime and currently smokes. Two thirds of the current smokers smoked more than 15 cigarettes per day. A former smoker was defined as someone who had smoked 100 cigarettes in one's lifetime, but who was not currently smoking at the time of the interview. Most of the former smokers (91%) had discontinued their smoking more than two years before the interview. All but two respondents (one current smoker and one former smoker) reported past use of filter tipped cigarettes.

The brief (approximately 10 minute) survey was administered by a trained research assistant who asked a series of questions designed to measure beliefs about the safety and benefits of cigarette filters. Table 1 displays the responses of smokers and former smokers to six questions. These data demonstrate that most consumers believe that: (1) filters make cigarettes safer; (2) are unaware of the possibility of loose fibres from cigarette filters being ingested and/or inhaled into their lungs during smoking; and (3) cigarette companies should be required to inform consumers about potential for filter fibre fallout. Also, it appears that knowledge about the filter fibre fallout problem might influence at least some smokers to give up cigarettes. Although the sample was not selected to be representative of the entire US population, the consistency of responses across different age, sex, and smoking status groups strongly suggests that the findings from this survey would be reflective of the views of most consumers.

The health benefits associated with putting filter tips on cigarettes continues to be a hotly debated issue.12-14 It is now clear that cigarette filters do not make cigarette smoking a safe behaviour and may actually introduce smokers to new risks not associated with unfiltered cigarettes.

Smokers favour being better informed about the health risks of smoking.15 Cigarette manufacturers should be required to inform consumers about the potential for ingesting/inhaling filter material during smoking. In addition, cigarette manufacturers should be encouraged and/or required to utilise technology to design cigarette filters so as to reduce the problem of filter fibre fallout.16