WASHINGTON (AP) — Senior officials in the Food and Drug Administration's tobacco center were blindsided by a recent decision that opens the door to allowing more unauthorized electronic cigarettes and nicotine pouches onto the U.S. market, The Associated Press has learned.

The guidelines, posted days before former FDA Commissioner Marty Makary resigned, will allow companies to launch certain nicotine-based products before they've been fully vetted by regulators.

READ MORE: Marty Makary resigns as Trump's FDA chief

Some FDA officials tasked with enforcing vaping regulations were not consulted on the changes and only learned of them the night before the document was published earlier this month, according to two staffers who spoke to the AP on condition of anonymity to discuss confidential agency matters. The document's sudden appearance sparked internal confusion about how the policy came about and who authorized it, the staffers said.

In recent days, agency officials have convened hourslong meetings grappling with how to implement the six-page memo, which breaks with longstanding FDA policy requiring scientific verification of health benefits for smokers before any new products are introduced.

It's highly unusual for the FDA to draft new policies without input from the staffers who oversee them.

"It begs the question of whether the true subject matter experts may have actually opposed this policy and were ordered to do it anyway," said Mitch Zeller, who retired as the FDA's tobacco director in 2022. "And that goes to the ability of the public to have trust and faith in institutions like FDA."

The vaping guidelines bypassed a federally required period that allows for public comment and revisions. Instead, the FDA published them as a finalized policy hours after media reports surfaced that President Donald Trump had approved a plan to fire Makary. He resigned from the FDA last week following months of complaints from industry lobbyists close to the White House.

A Health and Human Services spokesperson did not address the origins of the guidance in a written statement.

"This approach strengthens protections against youth nicotine addiction while supporting evidence-based alternatives for adult smokers seeking to move away from combustible tobacco products," Andrew Nixon said in a statement.

Messages seeking comment from Makary were not immediately returned Friday.

FDA eyes new approach to vaping flavors

Most health researchers agree that e-cigarettes are significantly less harmful than traditional cigarettes, and the products have been promoted in the U.K. and other European countries as an alternative for smokers.

In the U.S., the FDA has struggled to police the market for over a decade. The agency has authorized vaping products from five companies while rejecting millions of other applications, mainly due to the presence of fruit, candy and other sweet flavors that were deemed appealing to kids. And yet, unauthorized vapes are widely available.

But recent changes in Washington and across the U.S. reflect a shifting landscape.

Underage vaping among U.S. teenagers has fallen to its lowest level in more than 10 years, following the disruptions of the pandemic and new state and federal restrictions.

WATCH: How a free, anonymous texting program may help teens quit vaping

Trump came to power last year after vowing to "save" the vaping industry. Major tobacco companies, such as Reynolds American and Altria, have contributed millions to political action committees supporting Trump and other administration priorities, including Trump's inauguration and his proposed White House ballroom. Both companies have invested heavily in e-cigarettes and nicotine pouches, in addition to cigarettes.

Despite the influence campaign, vaping issues took a backseat at FDA under Makary. On rare occasions when Makary addressed e-cigarettes, he voiced skepticism about the data showing declining underage use.

Even as FDA staffers were poised to shift course on flavors, Makary and other agency leaders intervened.

In February, one of Makary's deputies blocked an FDA decision that would have authorized the first fruit-flavored vapes, according to internal memos later released by the agency. FDA reviewers had determined the products were unlikely to be used by children when combined with digital age-verification technology.

The mango- and blueberry-flavored products were finally OK'd during Makary's last full week heading the FDA, just days before the agency posted the new guidelines allowing unauthorized nicotine products.

Under the guidance, the FDA is supposed to publish a list of e-cigarettes and pouches that are not yet authorized but will be subject to "enforcement discretion," meaning they can be sold without regulators targeting them for removal. While there is no public list of products that might qualify, the policy is expected to allow for new flavors that had previously been blocked by regulators.

"What we're seeing is a broader opening up and responsiveness to flavored products by the agency both in terms of a stronger appetite for authorization but also less appetite to take enforcement action against flavored products," said Brian King, former FDA tobacco director now with the Campaign for Tobacco-Free Kids.

U.S. stores are already packed with illegal flavored vapes

While FDA's new approach breaks with precedent, it may have little impact on the flavors already available at gas stations, vape shops and convenience stores.

The U.S. market has been flooded for years by unauthorized vapes containing mango, gummy bear, strawberry and dozens of other flavors.

These disposable e-cigarettes filled the vacuum left by Juul when it pulled its high-nicotine flavored products from the market, after they became ubiquitous in U.S. schools beginning around 2017. Currently, the company only sells FDA-authorized e-cigarettes in tobacco and menthol flavors.

Juul and other companies now see the chance to directly compete with disposable Chinese vapes, which by some estimates account for 80% of U.S. sales.

"The choice we face is not whether flavored vaping products should be sold in the U.S. They already are," said Robyn Gougelet, a Juul vice president. "The choice is whether those products should be regulated and responsibly marketed — or illegal, untested, and smuggled into the country."

Rather than targeting flavors, the FDA said its new enforcement approach will focus on vapes with specific youth-appealing features, such as designs that resemble children's toys.

"The reality is they're just deluged by illegal products coming across the border," said Jonathan Foulds, a tobacco-addiction specialist at Penn State University. "So they're making it clear what should be common sense: 'We're going to focus on the worst actors.'"

New policy may create winners and losers among vaping firms

It's far from clear whether FDA's new approach will be embraced by the vaping industry at large, which includes multinational tobacco companies alongside hundreds of smaller companies selling imported devices from China.

As written, the guidance suggests only e-cigarettes that are under "scientific review" will qualify to launch without FDA authorization. Only a small number of applications typically reach that stage, which requires detailed health data on smokers who switch to the new product, King noted.

"This is certainly going to benefit the larger tobacco companies, which have the resources to get far enough into the application review process and thus won't be prioritized for enforcement," King said.

Lobbyists for smaller companies say it's too early to tell whether the policy will be help or hinder their clients, but they fear being left behind.

"The big companies would love nothing more than to see their largest swath of competitors out of the marketplace," said Tony Abboud of the Vapor Technology Association.