Big tobacco has played another little trick on the public, according to a paper published in the latest issue of the journal Tobacco Control. Instead of finding ways to reduce levels of harmful secondhand smoke, or environmental tobacco smoke (ETS), manufacturers chose to hide it, adding chemicals to their cigarettes that mask the smoke's odor and visibility. What's worse, those additives may actually make ETS more dangerous.

The study's four authors, all from the Massachusetts Tobacco Control Program in the Department of Health, mined the U.S. Patent and Trademark Office's online database, as well as several manufacturers' Web sites. They found that before introducing the additives, the industry conducted extensive research to see if the public would deem less smelly and smoky cigarettes as more acceptable. But they didn't look as far into the potential health affects of these cosmetic additives. Particularly worrisome, the authors note, is that whereas tobacco companies must report extra chemicals in the cigarette rod, they aren't required to disclose substances put in the paper or filter