Inhaled cellulosic and plastic fibers found in human lung tissue.

We report the results of studies undertaken to determine whether inhaled plant (i.e., cellulosic; e.g., cotton) and plastic (e.g., polyester) fibers are present in human lungs and, if so, whether inhaled fibers are also present in human lung cancers. Specimens of lung cancer of different histological types and adjacent nonneoplastic lung tissue were obtained from patients undergoing a lung resection for removal of a tumor. With the protection of a laminar flow hood and safeguards to prevent contamination by extraneous fibers, fresh, nonfixed, and nonstained samples of lung tissue were compressed between two glass microscope slides. Specimens in these dual slide chambers were examined with a microscope configured to permit viewing with white light, fluorescent light, polarizing light, and phase-contrast illumination. Near-term fetal bovine lungs and nonlung human tumors were used as controls. In contrast to the observations of these control tissues, morphologically heterogeneous fibers were seen repetitively in freshly excised human lung tissue using polarized light. Inhaled fibers were present in 83% of nonneoplastic lung specimens (n = 67/81) and in 97% of malignant lung specimens (n = 32/33). Thus, of the 114 human lung specimens examined, fibers were observed in 99 (87%). Examination of histopathology slides of lung tissue with polarized light confirmed the presence of inhaled cellulosic and plastic fibers. Of 160 surgical histopathology lung tissue slides, 17 were selected for critical examination; of these, fibers were identified in 13 slides. The inhalation of mineral (e.g., asbestos) fibers has been described by many investigators; we believe, however, that this is the first report of inhaled nonmineral (e.g., plant and plastic) fibers. These bioresistant and biopersistent cellulosic and plastic fibers are candidate agents contributing to the risk of lung cancer.

Release of carbon granules from cigarettes with charcoal filters.

OBJECTIVE: To inspect cigarettes with a triple granular filter for charcoal granules on the cut filter surface and, if present, to determine whether the charcoal granules on the filter are released during smoking. DESIGN: 400 Lark cigarettes in 20 packs were examined individually by each of three investigators for the presence of charcoal granules on the cut surface of the cellulose acetate filter. Without removing the cigarettes from the pack, the filters were examined with a stereo zoom microscope for charcoal granules. The percentage of cigarettes that had charcoal granules was defined, and charcoal granules on each filter were counted. Randomly selected cigarettes were then smoked by consenting adult smokers to assess whether the charcoal granules were released during smoking. Lark cigarettes were smoked with a conventional cigarette holder that had been configured to contain an in-line membrane. After smoking, the membrane was analysed microscopically for charcoal granules and other components of the filter that had been released during smoking. RESULTS: Charcoal granules were observed in 79.8% (319/400) of the cigarettes examined. The number of granules per cigarette was 3.3 (SD 3.7). Gaps between the tipping papers--the wrapping papers that surround the filter--were often seen (70%; 242 (71); n = 400 cigarettes). Further, the charcoal cavity was about 60% empty. For all smokers (n = 8/8), charcoal granules were released during smoking. The number of charcoal granules captured on the membranes was 22.5 (16.2) per cigarette. CONCLUSIONS: Charcoal granules are incorporated into cigarette filters to aid in removing toxins in cigarette smoke. In studies of Lark, a popular American cigarette with a charcoal filter, charcoal granules were observed on the filter surface, and were released from the filter when the cigarettes were smoked. During smoking, the toxin-containing charcoal granules are inhaled or ingested. The specific adverse health effects of inhaling or ingesting carbon granules have not been addressed; nevertheless, the smoker, as an educated consumer, should be informed of the possible health risks.