BISMARCK, N.D. (AP) - North Dakota senators have begun examining a proposal to ban smoking in bars and truck stops, which are virtually the last public places in the state where a smoker may legally light up.

More than 150 people showed up Tuesday for a Senate Judiciary Committee hearing on the measure. Dozens wore buttons with the image of an American flag and the word, "Freedom."

Two years ago, the North Dakota Legislature voted to ban smoking in most buildings that have access to the public. Bars and enclosed areas of truck stops were exempted from the legislation.

This year's proposed law would drop that exemption, and ban smoking in public buildings altogether.

Dr. Jim Hughes, a Bismarck lung disease specialist, said smoking "steals your freedom."

"It causes addiction, the most lethal addiction there is, and the most common cause of avoidable death there is," Hughes said. "There is nothing about tobacco being equivalent to freedom."

Rep. Lee Kaldor, D-Mayville, said the existing law presents enforcement problems for businesses.

"This enforcement issue can be resolved in one way, and that is to make all public places smoke-free," Kaldor said.

Robert Harms, a spokesman for the North Dakota Hospitality Association, said the question was not a public health issue, but how far the state should go in regulating someone's behavior.

If smoking is banned in bars, anti-tobacco activists will not stop there, Harms said. Other states are considering whether to ban smoking in outdoor public places, and whether to prohibit adults from smoking in a vehicle when children are present.

"We can imagine all sorts of steps in the name of public health that we might dictate the personal behaviors of people, and otherwise limit their freedom, whether it's the food they eat, the carbonated beverages we serve our children, the amount of alcohol we drink, or the exercise we all know we should take," Harms said.

The bill is SB2164.