State of California's decision to legalize marijuana was touted as a victory for those who had argued that the state needed a system to decriminalize, regulate and tax it.

But the new law, approved by voters on Nov. 8, also could be a boon to the tobacco industry at a time when cigarette smoking is down and cigarette companies are looking for ways to expand their market, according to researchers in Los Angeles County and around the state.

They warn that unless the state proceeds carefully, the legalization of marijuana for recreational use could roll back some of the gains California has made in reducing the use of tobacco.

Another ballot initiative passed by voters last week could push the smoking rate even lower. Prop. 56 will add $2 per pack to the tax on cigarettes and increases taxes on electronic cigarettes that contain nicotine and other tobacco products. The money will help pay for health care and increase funding for tobacco control and prevention.

The marijuana initiative, Prop. 64, allows adults ages 21 and over to grow, buy and possess small amounts of marijuana for personal use. It also regulates recreational marijuana businesses and imposes taxes that will help pay for drug education and prevention programs.

Marijuana is already the most widely used illegal drug among adolescents. Many young people consider marijuana and blunts, which are marijuana rolled with a tobacco leaf wrapper, to be more socially acceptable and less risky than cigarettes, according to a recent study co-authored by Halpern-Felsher. The study also found that youths who saw messages about the benefits of marijuana were more likely to use it.

Blunts are particularly worrisome because they contain nicotine as well as marijuana, Halpern-Felsher says. Many young people may not understand the risk of blunts or marijuana, she notes, and once they start thinking that smoking one product is acceptable, they may believe it's OK to smoke other things as well. "That's my concern," she says. "I do think people are going to generalize."

From the tobacco industry's point of view, marijuana could serve as a "smoke inhalation trainer," and thus become a gateway to tobacco use, says Robert K. Jackler, a professor at the Stanford School of Medicine who researches tobacco advertising. He says tobacco and marijuana are marketed in similar ways - as products to help people relax and ease

In fact, the tobacco industry considered getting into the marijuana market in the 1960s and 70s and could easily do so, says Stanton Glantz, a professor at University of California, San Francisco School of Medicine. Glantz believes that even as the newly approved tobacco tax reduces California's smoking rate further, legalized marijuana will help sustain the tobacco market. He says he expected to see mass marketing and branding of marijuana over time.

The initiative should have included higher taxes, graphic warning labels, provisions to keep demand low and a broad-based education campaign like there is on tobacco, Glantz argues. "The ideal situation is where it's legal so nobody is thrown in jail, but nobody wants to buy it."

Legalization supporters said they don't believe the tobacco industry will get involved in the marijuana market until and unless federal prohibition ends. Marijuana is still illegal under federal law.