DES MOINES - The Iowa House volleyed a proposed statewide smoking ban back to the Senate Wednesday after drastically overhauling the bill to exempt for bars and casinos, jeopardizing its chances.

"We lost a battle," said Rep. Janet Petersen, D-Des Moines. But Petersen, a longtime smoking ban advocate, said she was optimistic the changes wouldn't stick.

The House changes, approved on a 59-40 vote, would require most businesses - but not casinos or bars - to go smoke-free. Restaurants with liquor licenses could allow smoking during designated hours if closed to people under the age of 21 at the time.

The amendments slash the effectiveness of the original proposal, which advocates frame as a public health initiative to prevent workers and the public from hazardous secondhand smoke.

Wednesday's vote ships the proposal back to the Senate. Senate Majority Leader Mike Gronstal, D-Council Bluffs, doesn't think there's any way his chamber will accept the modified version.

Should the Senate reject the bar and casino exemptions, the bill goes to a bipartisan panel designed to hash out the two chambers' differences. The panel would craft another plan which would be sent to each body for a final up-or-down vote.

If the House and Senate can't agree on that version, the proposal dies.

Petersen said it is premature to think lawmakers will leave the Capitol this year without approving a statewide law, but she wasn't pleased with the exemptions added Wednesday.

"Hopefully level heads will prevail in conference committee and move us forward instead of backwards," Petersen said.

Both chambers had rejected previous attempts to exempt bars from the bill.

The original legislation, drafted and narrowly approved by the House, would have banned smoking in almost all public places except casinos. But the Senate sent that bill back to the House after removing that casino exemption and adding a provision to allow smoking on some farm equipment.

Business and bar owners bombarded lawmakers with warnings their sales would suffer if forced to go smoke-free.

During debate, Rep. McKinley Bailey, D-Webster City, cited these fears when pushing for the exemptions.

"This is the only way most of these businesses can continue to operate," Bailey said.

But Petersen said the businesses' lobbying campaign drowned out the silent majority - the 80 percent of Iowans, according to some polls - who support the legislation.

Backers brushed off Wednesday's vote as a speed bump on the road to a comprehensive ban.

"I don't think it endangers the bill as a whole," said Rep. Tyler Olson, D-Cedar Rapids. "[But] it obviously is going to take us a little longer to get to our end goal."

Contact Whitney Woodward at (515) 243-0138 or whitney.woodward@lee.net.