The House is poised to take up a bill that would put a hefty 75% tax on the increasingly popular products.
The devices heat a liquid solution to create a vapor that delivers a dose of nicotine. Tax supporters say they still create a nicotine addiction.
"When people find out what the vaping's all about, they're not only not going to tax it and regulate it, they're going to hopefully maybe even support it," Rep. Dick Muri said.
Opponents argue it's a healthier alternative to smoking, and lawmakers are moving too fast.
"There's a misconception that when you put something in your mouth and exhale, that you are basically smoking," vapor shop owner Linda Thompson said.
The FDA has not completed any research on the potential risks of e-cigarettes.