By Jim Melwert

PHILADELPHIA (CBS) – A study from the CDC finds tobacco use among teens continues to decline, but there is some alarming news in this study.

The government study shows more teens are smoking pot than are smoking cigarettes.

The study from the Centers for Disease Control and Prevention surveys over 15,000 teens across the country looking at all kinds of risky behavior in 2011.

And while only 18 percent of teens reported smoking a cigarette in the past 30 days, a higher percentage – 23 percent — say they smoked marijuana in the past month.

Tianda, a high school junior here in Philadelphia says she’s not surprised by the findings, and says students are rarely warned about the dangers of marijuana.

“I just hear a lot of dangers of cancer and cigarettes and I think that’s why a lot of teens look to marijuana.”

Tianda says she doesn’t smoke pot, but guesses that’s why other students do. “You don’t really get cancer, it’s less than a cigarette would be, and I think that’s why a lot of teens do it.”

Registered nurse Tina says many teens think like Tianda, “but it’s a myth kids tell each other. They don’t know the real facts.”

Tina says teens should be warned of marijuana just as much as they are about cigarettes. “Absolutely, I think there should be just as much emphasis on that.”

A study from the University of Michigan supports that, with researchers there saying teens have been taught cigarettes are bad for you, but they seem to feel marijuana is less harmful.

The CDC study still finds alcohol is still the most common drug among teens, more than 1 in 3 high school students reported current alcohol use in 2011, with 1 in 5 high school students reported binge drinking.