JEFFERSON CITY – Missouri lawmakers passed a pair of bills Thursday to prevent people younger than 18 from purchasing electronic cigarettes, but opponents argue the legislation would pave the way for the nicotine products to be sold with fewer restrictions.

E-cigarettes are battery-powered devices used to heat a liquid nicotine solution and create vapor that is inhaled. Current law allows those products to be purchased by anyone, a reality lawmakers want to correct with the legislation.

But each of the bills passed by the House and Senate would also exempt e-cigarettes from the state's 17-cent per pack cigarette tax and state that they could not be regulated as tobacco products.

"This shuts the door on regulation that we may want to see going forward as a tobacco product," said Rep. Jill Schupp, D-Creve Coeur.

Supporters said lawmakers have a choice — support the bill to ensure minors cannot continue to buy e-cigarettes or insist on taxing the products and therefore kill the bill's chances of passing the Republican-led Legislature this year. They pointed to the defeat of a 2012 ballot measure to raise the state's lowest-in-the-country cigarette tax to show the lack of support for e-cigarette taxation.

"I don't think we get this across the finish line if we increase taxes," said Sen. Jay Wasson, R-Nixa, and the Senate sponsor. "I just want 18 year olds to not be able to buy it."

State and local sales taxes would still be levied on e-cigarette purchases under the legislation. It defines e-cigarettes as "alternative nicotine" or "vapor products." It would place some restrictions on those products by requiring them to be sold at licensed dealers and levying fines against teenagers who try to purchase them illegally.

But opponents question whether those and other restrictions would remain in place if the federal Food and Drug Administration were to regulate the products. The agency has said it plans to set marketing and product regulations for electronic cigarettes in the near future but hasn't done so yet.

The American Cancer Society said almost 30 other states have passed legislation similar to Missouri's that prevent e-cigarette sales to kids, but also don't subject them to the same rigorous regulations on tobacco products.

"It creates an illusion that (e-cigarettes) are safer and should be treated differently without having the science to prove it," said Stacy Reliford, a governmental affairs director with the American Cancer Society.

Reliford said the legislation is part of a concerted effort to evade regulation on e-cigarettes. She said it allows the companies to show the FDA that other states are treating the products differently from tobacco and that the agency should follow suit.

The backers of Missouri's legislation disagree and argued there is nothing to prevent the state from changing its law to tax and place additional restrictions on e-cigarettes.

"This does not do anything to close down any future regulation," said Rep. Caleb Rowden, R-Columbia, and the House sponsor.

Missouri Attorney General Chis Koster joined a group of 41 state attorneys general in signing a letter to the FDA urging regulation of the products last year. The letter said the products are growing in popularity and dropping in cost, making them more attractive to youths. It asked the FDA to prohibit them from being sold or advertised to teenagers.

The House voted 129-19 to send its bill to the Senate, where senators voted 27-4 in favor of their version. Both chambers must pass identical legislation by mid-May.