WASHINGTON (AP) — Hundreds of electronic cigarette brands will have to seek federal permission to stay on the market under new rules that have the potential to upend a multi-billion dollar industry attempting to position itself as an alternative to traditional cigarettes.

The Food and Drug Administration on Thursday released long-awaited rules that bring the burgeoning industry under federal oversight. Among other steps, the FDA rules limit e-cigarette sales to minors and require new health warnings. In a move vigorously opposed by manufacturers, the agency said manufacturers would have to seek permission to remain on the market under a multi-tiered system. Those that don't submit the required information could have their products taken off the market.

E-cigarettes turn nicotine into an inhalable liquid vapor. Their benefits and harms haven't been extensively studied.