BOSTON-- The tobacco industry appears to be using chemical cigarette additives to hide secondhand smoke by improving its odor, making it less visible or irritating, or decreasing the amount of it, a recent report from the Massachusetts Public Health Department suggests.[1]

The authors of the report examined internal data from four major tobacco manufacturers to find information on cigarette additives. Their search revealed about 250 documents describing the testing of roughly 60 such additives, including potassium citrate, anethole, and other compounds. "However, we found essentially no research about the additives' toxicity," said lead investigator Gregory N. Connolly, DMD, MPH, Director of the Tobacco Control Program at the Massachusetts Department of Public Health. "It was clear that the tobacco companies really did not care about reducing exposure to the carcinogens in secondhand smoke."

These companies started experimenting extensively with cigarette additives after research in the early 1980s first confirmed the health risks of secondhand smoke. Dr. Connolly suggested that the tobacco companies, fearing a decline in cigarette sales, hoped the additives would make smoking more socially acceptable by making environmental tobacco smoke (ETS) less objectionable to nonsmokers. "It is like putting sugar in rancid meat," he told RESPIRATORY REVIEWS. "It is classic adulteration of a consumer product to conceal the risk."

TWO TYPES OF DATA

The report is based on two data sources: records on patents for cigarettes that mask secondhand smoke (from the US Patent and Trademark Office database) and internal industry documents from four companies: Brown & Williamson, Lorillard, Philip Morris, and RJ Reynolds (see below). The tobacco industry documents, which included strategic plans, research, and internal memorandums, were made available to the public as a result of recent litigation.

MASKING VISIBILITY

These data suggest that the tobacco industry has focused more on masking secondhand smoke than on decreasing secondhand smoke emissions. For instance, Philip Morris' strategic plan for the years 1993 to 1997 proposed reducing secondhand smoke visibility and odor through the use of cigarette paper additives, such as magnesite and calcium carbonate. "However, the plan does not call for reducing ETS particulates, nor does it state the need to test the smoke for altered toxicity," the investigators noted.

In fact, many additives that are claimed to cut down on secondhand smoke really only reduce its visibility. In patents obtained in 1985 and 1990, for example, RJ Reynolds and Brown & Williamson described how they added such agents as potassium citrate, aluminum hydroxide, attapulgite clay, and other chemicals (alone or in combination) to cigarette wrappers. It was clear from the patents that such agents simply convert secondhand smoke into an invisible gas without decreasing overall smoke emission.

Other wrapper additives that were used to reduce ETS visibility included magnesium oxide and calcium carbonate. However, the most effective approaches for lowering the visibility of secondhand smoke were changing the wrapper's porosity, coating it with water-soluble substances, and substituting alternative nonsoluble fillers.

IMPROVING ODOR

With the help of Duke University Medical Center researchers, Philip Morris studied the role of the trigeminal and olfactory nerves in ETS perception. The goal was to develop cigarettes with secondhand smoke that had a desirable odor and produced a minimal trigeminal response. That research led to a 1988 memorandum discussing anethole, acetylpyrazine, and nine other additives that had been selected for testing because they were likely to have low odor thresholds and few or no components that would trigger trigeminal nerve activity.

Philip Morris also tested deodorizing additives, though without much success. RJ Reynolds, however, found that the compounds polyanethole and cinnamic aldehyde pinanediol acetal effectively improved ETS odor. Tobacco companies have also attempted to improve smoke odor with food derivatives, such as vanillin, cinnamon extract, and nutmeg oil.

REDUCING EMISSIONS

Cigarette paper modifications have been the main focus of efforts to decrease ETS emissions. In 1990, for example, Brown & Williamson developed a coating solution that contained a film-forming agent (such as ammonium alginate or sodium carboxymethylcellulose) and a burn additive (such as potassium succinate and/or potassium citrate). These solutions reduced the permeability of cigarette paper, allowing less secondhand smoke to escape during smoldering.

Other emission-reducing tactics include adding sodium magnesium carbonate to cigarette paper (also to decrease permeability) and making cigarette paper out of a multilayer cellulose material, which inhibits ETS emissions by making the cigarette burn more slowly. Carbonized tobacco filler was used to reduce such emissions by diluting the tobacco blend.

TARGETING YOUNG WOMEN

Although the Massachusetts investigators found no evidence that the tobacco companies had undertaken standard toxicity testing to determine the health impact of cigarette additives, they did discover that efforts to develop the additives often targeted younger women. "The tobacco companies seemed concerned, for example, that a young woman with a child might quit smoking," Dr. Connolly said.

In fact, project summaries from RJ Reynolds actually describe "Project YW" (for Young Women) and "Project TF" (for Tomorrow's Female). Philip Morris had "Project Cosmo," aimed at stylish young women. RJ Reynolds tested 54 smoke aromas to find those that appealed most to younger women, including vanilla, toffee, and milk chocolate. Although these flavorants do not appear to have been successful, RJ Reynolds and other tobacco companies did introduce new cigarettes aimed at young women.

MONITORING ADDITIVES

Currently, it is nearly impossible to monitor the additives actually being used in cigarettes. Although litigation has forced the tobacco companies to release some information, most tobacco industry documents describing additive use are protected as trade secrets. Also, the federal government only requires tobacco companies to report the additives in the tobacco rod itself, not in the wrapper or filter, and they do not have to reveal the quantities of additives in each cigarette brand.

In 1996, Massachusetts passed the Tobacco Disclosure Act, requiring tobacco companies to provide cigarette ingredient lists. However, a federal court recently declared the law unconstitutional.

"This is all very distressing because it keeps us from knowing what these companies are doing," remarked Dr. Connolly. "But the evidence strongly suggests that they are using cigarette additives and need supervision by an independent regulatory body, particularly the US Food and Drug Administration."

--Timothy Begany

Reference
1. Connolly GN, Wayne GD, Lymperis D, Doherty MC. How cigarette additives are used to mask environmental tobacco smoke. Tob Control. 2000;9:283-291.