Legislation approved in this week by the Senate Appropriations Committee would prevent the FDA from requiring retroactive safety reviews of e-cigarettes already on the market. It would exempt some premium and large cigars from those same regulations.

The provision to undercut the FDA rules was attached to legislation funding the agency’s budget for the fiscal year starting in October.

Supporters say implementing such regs would effectively force smaller e-cig manufacturers out of business rather than undergoing expensive testing. On the flipside, opponents contend that by baring regs, the FDA would never be able to put the genie back in the bottle, so to speak, unable to regulate — or even know what is in — these products, forever.

The FDA rules will require e-cigarette brands marketed since February 2007 to undergo premarket reviews retroactively. The FDA will then ensure the product is “appropriate for the protection of the public health.” If not, the agency could take it off the market.