House Democrats are poised to vote on imposing a new federal excise tax on e-cigarettes—but without a tax increase on traditional cigarettes—leading some public-health experts to warn that the provision could push vapers back to cigarette smoking.

The House bill includes a measure intended to tax vaping products on par with the existing federal cigarette tax rate of $1.01 per pack. It would raise about $9 billion over a decade. The nicotine tax would apply to e-cigarettes, vaping liquids and oral nicotine pouches. It wouldn’t apply to nicotine gums, patches or other smoking-cessation aids approved as medical products by the Food and Drug Administration.