SPRINGFIELD - While casino workers can now breathe smoke-free air at work, the year-old indoor smoking ban in Illinois has been measurably tough on the state's riverboats.

That means attempts to allow gamblers smoke at the slots and gambling tables probably won't die with 2008.

All year, monthly reports from the Illinois Gaming Board showed a sharp decline in the amount the state's gamblers were putting on the line at casinos. So far this year, the state's boats have seen about a 20 percent drop.

Surely, some of that decline can be seen because of the country's economic recession.

But gambling hasn't fallen as sharply in casinos in states that border Illinois.

"The only other thing is smoking," said Tom Swoik, executive director of the Illinois Casino Gaming Association.

Early this year, the casino industry and some lawmakers pushed to have Illinois riverboats exempted from the indoor smoking ban. Those efforts failed, but they are not unprecedented.

When Iowa's smoking ban took effect this year, casinos were left out. The duo of smoking and gambling could remain in Iowa.

Swoik says the industry likely will keep pushing for an exemption, but Kathy Drea, director of the American Lung Association's Illinois branch, said they'll never stop defending the law.

"We just believe everybody deserves a smoke-free working environment," Drea said.

State Sen. Mike Jacobs, D-East Moline, whose district borders Iowa, said he opposed the ban in the first place, but said getting casinos taken out of the law would be tough.

"I think the exemptions are difficult," Jacobs said, "because why would we want to exempt just one business?"

All of the state's nine casinos have seen a drop in gross revenues this year. The site of a tenth casino in the Chicago area could be announced as early as Monday.