A recent Short Communication by Cummings et al. raised a number of criticisms regarding Eclipse cigarettes (1). Because it is not possible in letter format to address all of the criticisms raised in the Cummings et al. article, this response is limited to the most significant issues raised in that article.
Eclipse is a new cigarette that produces smoke by primarily heating, rather than burning, tobacco. A glass mat insulator is an essential component of the heat source assembly used in Eclipse. The glass mat insulator is composed of continuous filament glass fiber and a binder.
Some scientists have expressed concern that continuous filament glass may be present on the outer surface of the Eclipse cigarette (2). RJRT1 has previously responded to these concerns (3). Furthermore, RJRT has acknowledged that continuous filament glass may be present on the external surface of Eclipse cigarettes. However, the assertion that the utilization of continuous filament glass in Eclipse represents a potential toxicological concern to smokers is based on assumption and/or speculation rather than fact. To date, no evidence exists that demonstrates smokers are exposed to continuous filament glass at a level that may be construed to be biologically meaningful.
The potential transfer of continuous filament glass to Eclipse mainstream smoke has been studied. Subsequent to handling procedures that were designed to simulate commercial shipping conditions, cigarettes were machine-smoked using an exaggerated puffing regimen (relative to the United States Federal Trade Commission puffing regimen). These conditions were used specifically to maximize the probability that any potential transfer of continuous filament glass to Eclipse mainstream smoke would be detected. The results of studies conducted at RJRT indicate that a maximum of 0.143 filaments per cigarette are transferred to Eclipse mainstream smoke (4, 5). For perspective, survey data demonstrates that consumers are potentially exposed to literally thousands of glass filaments daily as a result of nonoccupational environmental exposure (6). It should be intuitive that any Eclipse-related exposure would represent a small fraction of potential background exposure. In short, the results of the transfer studies consistently indicate that, relative to background, biologically significant transfer of continuous filament glass to Eclipse mainstream smoke does not occur.
The assertion by Cummings et al. that the continuous filament glass used in Eclipse is respirable is inaccurate. The continuous filament glass used in Eclipse was designed to be nonrespirable. The continuous filament glass mat insulator is made from continuous glass filaments having an average diameter of 8.5 μm (range, 5.5–14 μm). These filaments are chopped to a length of 9500 μm and subsequently converted into a mat. The calculated aerodynamic diameters, parallel and perpendicular, of these filaments would be ∼53 μm (range, 35–84.4 μm) and 40.2 μm (range, 26.7–64.2 μm), respectively (7). It is generally accepted that structures with aerodynamic diameters greater than 7 μm (8, 9) are unlikely to reach the pulmonary region of the respiratory tract.
In a practical sense, if exposure does not occur, there can be no risk. The significance of this specific issue has not been lost on competent organizations that have addressed the potential toxicological activity of fibrous materials. The position taken by the National Toxicology Program (NTP) of the United States Department of Health and Human Services clearly indicates that the physical characteristics and, therefore, the respirability of glass filaments are relevant. In 1994, the NTP specifically listed glass wool (respirable size) as a substance “that may reasonably be anticipated to be a carcinogen” in the Seventh Annual Report on Carcinogens. It is noteworthy that the potential carcinogenicity of glass filaments (nonrespirable) in humans was not addressed.
The assertion by Cummings et al. that fibrous glass materials are as potent or more potent than asbestos is also inaccurate. Chronic inhalation studies have been conducted with rat respirable fractions of representative glass fibers (10, 11). In these studies, rats were exposed by nose-only to a rat-respirable (size-selected) fraction of two representative glass fibers (MMVF 10 and MMVF 11). Although crocidolite asbestos (the positive control) was demonstrably carcinogenic to rat lung, no statistically significant increase in fibrosis or lung tumors was observed subsequent to exposure to either MMVF 10 or MMVF 11 (10, 11). It is noteworthy that the intent of the study was, in fact, to deliver large numbers of “rat-respirable” fibers to the lungs of the rats studied.
In summary, transfer data and the unique physical characteristics of the filaments demonstrate that significant exposure of the smoker will not occur. The available environmental survey data clearly demonstrate that Eclipse smokers are extremely unlikely to be exposed to continuous filament glass at a level representing an increase relative to background exposure levels. Furthermore, the chemical composition and dissolution characteristics of the filament used in Eclipse demonstrate similarity to glass fiber compositions that have failed to produce either tumors or fibrosis in chronic inhalation studies conducted in rats. In short, exposure of Eclipse smokers to continuous filament glass is extremely unlikely to occur at a level that may be construed to be of biological significance. A formal safety assessment addressing this topic has been published in the peer-reviewed literature (12).
RJRT remains committed to providing accurate information to interested members of the scientific community. I would encourage interested parties to contact me directly for any further clarification required.
The abbreviation used is: RJRT, R. J. Reynolds Tobacco Company.
To whom requests for reprints should be addressed at, Department of Cancer Prevention, Epidemiology & Biostatistics, Roswell Park Cancer Institute, Elm & Carlton Streets, Buffalo, NY 14263. Phone: (716) 845-8456 Fax: (716) 845-8487; E-mail: Michael.Cummings@Roswellpark.org
J. L. Pauly and Mark Higuchi, personal communication.
We are pleased that the R. J. Reynolds Tobacco Company (RJR) has finally acknowledged the validity of our 1998 publication documenting that the filters of Eclipse are contaminated with glass fibers and glass particles (1). However, Dr. Swauger’s letter (2) regarding our recent paper (3) on consumer perception of risk associated with glass-contaminated filters illustrates that RJR does not consider the health concerns of consumers about the glass contamination of the Eclipse to be relevant.
Dr. Swauger cites recent studies (4, 5) conducted by RJR scientists who attempted to quantify the transfer of glass fibers into mainstream smoke. In these investigations: (a) five different prototypes, each identified by a code number only, were used; none of the prototypes were described, and they are not current market prototypes of Eclipse sold today; (b) in diverse assays, significant differences for the five prototypes were observed; yet no explanations were presented for the variability recorded; (c) a laboratory standard using earlier Eclipse prototypes was selected, and the studies did not include a proof-of-principle model that test-marketed Eclipse from partially filled packs that had been transported by smokers for several days; (d) values for glass fibers and glass particles on the filters of the various prototypes before and after smoking was not provided; and (e) the multistep and complex assay procedure used for assessing glass fiber transfer was associated with many shortcomings, some of which were acknowledged by the investigators (5). Inexplicably, RJR scientists have not replicated our original study protocol, which involved testing packs of Eclipse purchased from retail outlets as consumers would do. Moreover, our ability to respond to RJR’s published studies on the transfer of glass to mainstream smoke has been blocked by the company’s refusal to supply us with samples of the prototypes used in their studies.2 In denying this request, RJR has declared that: “We have only some of the prototypes available and they are considered proprietary in nature”.2 For any company or investigator to invoke claims of unique materials in peer-reviewed publications and to not make the materials available to others for a confirmatory study is a breach of scientific conduct. This contemptuous behavior is disdainful to members of academic communities, scientific organizations, regulatory bodies, and others. Some journals (6) enforce this policy with a required submission form that must be signed by authors submitting manuscripts, in which they pledge that, “Unique materials described in this manuscript will be made available to qualified investigators.”
We find RJR’s assertion that there is no health risk from exposure to glass from Eclipse because the carcinogenicity of glass filaments in humans is still the subject of scientific debate to be imprudent. In science, there is an old saying that the “absence of evidence is not evidence of absence.” Dr. Swauger’s bias in reviewing the literature of glass fiber harm is illustrated by his failure to cite any epidemiological studies, animal experiments, or ex vivo research that have associated glass fibers with lung cancer and non-neoplastic pulmonary diseases or studies that have documented the presence of glass fibers in the lungs of rats (7) and human beings (8). We also do not believe that it is appropriate to make judgements about health risks based upon studies evaluating exposure to glass fibers in the environment when the actual exposure in question involves the use of a product that is intentionally and repeatedly placed directly into the consumer’s mouth while inhaling deeply. RJR’s safety claim for Eclipse also ignores the likelihood that many users of Eclipse will already have damaged airways from years of smoking conventional cigarettes, thereby rendering them more susceptible to any potential health risks associated with exposure to glass fibers and particles.
Finally, Dr. Swauger ignores the main point made in our paper, which is that consumers perceive filters contaminated with glass to be a health concern (3). Whether or not RJR accepts the view that the inhalation of glass fibers poses a health risk is irrelevant to their obligation as the product manufacturer to inform consumers about their likely exposure to glass from smoking Eclipse and the unknown or potential risks that might result from such exposure.
In summary, RJR has advertised “reduced risk” health claims for a cigarette-appearing nicotine delivery device termed Eclipse that is available currently from retail stores and the Internet. RJR’s claims are based upon studies of prototypes that RJR has refused to release to independent laboratories for objective analysis. RJR’s reduced risk health claims of Eclipse promoted to smokers who cannot or will not quit smoking, many of whom seek a less harmful cigarette, has become a prime example illustrating the necessity to have an independent regulatory authority for tobacco products that will put the interests of the consumer before that of the manufacturer.