It's a pretty good bet some gamblers will travel to Indiana casinos when the Illinois smoking ban kicks in Jan. 1, industry observers believe.

"Without a doubt," said John Busam, editor of Midwest Gaming & Travel. "There's going to be a decrease in casino patrons and subsequent decrease in casino revenues," in Illinois.

lllinois casinos could see revenue decline by between 15 and 20 percent initially, Busam said.

Smokers are likely to travel not only to Northwest Indiana casinos, but to those in Iowa, just across the Mississippi River, Busam said.

"For smokers, that's definitely not a problem," Busam said. "A casino's a casino."

Historically, casino revenue has dropped in states where smoking is banned.

Since the Canadian province of Ontario imposed a smoking ban in public places in May, casinos along the border with the United States suffered a revenue drop of from 10 percent to more than 20 percent, Canadian gaming officials said earlier this year.

While a strong Canadian dollar and tougher border security played into the revenue decline, losses also were chalked up to American smokers staying in Michigan and New York to gamble.

Illinois lawmakers approved the statewide ban earlier this year, prohibiting smoking in casinos, restaurants, bars and other public places.

Illinois Casino Gaming Association Executive Director Tom Swoik said this week he's still hopeful lawmakers will make an exemption for casinos when they reconvene in January.

"It hasn't happened yet," Swoik said.

Busam believes it will.

"There's no question (Illinois lawmakers) will have to revisit it, because of the tax hit they're going to take," Busam said.

To accommodate the ban, most Illinois casinos are building outdoor smoke shelters, Swoik said.

A measure to ban smoking in some Indiana public places, but not in bars, restaurants or casinos, has been proposed.

And Gov. Mitch Daniels appeared to warm this week to a legislative push for a statewide smoking ban.

Casinos companies that operate in Indiana largely have remained silent on the issue.

But Swoik said this week he suspects Northwest Indiana casinos are gearing up.

"I'm sure they're beefing up as much as possible," Swoik said.

Busam agreed.

"The Indiana casinos are buying ashtrays right now," Busam said.

The Associated Press contributed to this story.