DES MOINES, Iowa (AP) - Air pollution in buildings that allow smoking is 17 times greater than in buildings that ban tobacco, according to a study released Tuesday.

The study, by the Commission on Tobacco Use Prevention and Control, also shows that the pollution was 15 times greater than what's considered safe.

The group said the study shows that efforts to separate smokers and nonsmokers doesn't work.

"This study provides further evidence that indoor smoking causes exposure to harmful levels of indoor air pollution that can lead to cardiovascular and respiratory disease and even death," said Gary Streit, vice chairman of the commission.

In the study, officials tested the air in 21 bars, restaurants and casinos in the state from November through January. They found the level of fine particle pollution was 122 parts per million, compared to seven parts per million in places that banned smoking. The typical outdoor air reading was 11 parts per million, and federal environmental officials have set the safe exposure level at 15 parts per million.

"This study provides further evidence that … comprehensive smoke-free air policies prohibiting indoor smoking are the only effective means to eliminate the health risks from this exposure," the study said.

The Legislature is debating new restrictions on indoor smoking and the House and Senate have approved far different bills.

The Senate has approved a strict ban that would virtually eliminate indoor smoking, while the House has carved out broad exemptions for bars, restaurants, casinos and veterans facilities.

The House is scheduled to debate the measure again on Wednesday. Leaders said they are likely to stick with their exemptions and send the issue to a House-Senate conference committee to work out a compromise.

One of the prime arguments for a strict ban is that workers in a business that allows smoking are forced to work in an unsafe environment, and several workers made their case Tuesday.

"No one should have to choose between their health and a good job," said Jennifer Barrer, who worked at a casino to pay for college.

Joel Smits, who waits tables at a Des Moines establishment where smoking is allowed, said he feels the effects of secondhand smoke.

"Every morning I wake up and I'm wheezing," Smits said. "It's like I smoked a pack of cigarettes the night before."