U.S. health officials will ban most flavored e-cigarettes popular with underage teenagers, but with major exceptions that benefit vaping manufacturers, retailers and adults who use the nicotine-emitting devices.

The Trump administration announced Thursday that it will prohibit fruit, candy, mint and dessert flavors from small, cartridge-based e-cigarettes that are popular with high school students.

But menthol and tobacco-flavored e-cigarettes will be allowed to remain on the market.

The flavor ban will also entirely exempt large, tank-based vaping devices, which are primarily sold in vape shops that cater to adult smokers.

Associated Press health reporter Matthew Perrone explains that together, the two exemptions represent a significant retreat from President Donald Trump's original plan announced four months ago.

"This is a big step back from what Trump said he was going to do in September when he said that they going to ban all flavors in all types of products," said Perrone.

"There are a number of carve outs here that seem to be favorable to industry who have been lobbying him pretty aggressively in recent months, not to ban all these flavors."

The new policy will preserve a significant portion of the multibillion-dollar vaping market.

And the changes are likely to please both the largest e-cigarette manufacturer, Juul Labs, and thousands of vape shop owners who sell the tank-based systems, which allow users to mix customized flavors.

E-cigarettes are battery-powered devices that typically heat a flavored nicotine solution into an inhalable aerosol.

They have been pitched to adults as a less-harmful alternative to traditional cigarettes, but there is limited data on their ability to help smokers quit.

The Food and Drug Administration has struggled for years to find the appropriate approach to regulating vaping. Under current law, all e-cigarettes are supposed to undergo an FDA review beginning in May. Only those that can demonstrate a benefit for U.S. public health will be permitted to stay on the market.

The flavor ban applies to e-cigarettes that use pre-filled nicotine cartridges mainly sold at gas stations and convenience stores.

Juul is the biggest player in that market, but it previously pulled all of its flavors except menthol and tobacco after coming under intense political scrutiny. Many smaller manufacturers continue to sell sweet, fruity flavors like “grape slushie,” “strawberry cotton candy” and “sea salt blueberry."

The flavor restrictions won't affect the larger specialty devices sold at vape shops, which typically don't admit customers under 21.

These tank-based systems allow users to fill the device with the flavor of their choice. Sales of these devices represent an estimated 40% of the U.S. vaping business, with sales across some 15,000 to 19,000 shops.

"Today's announcement taking a number of these flavors off the market, A number of products is actually a pretty huge step from what came before," said Perrone.

"E-cigarettes and vaping have been pretty much unregulated in the US for many years, and FDA is still trying to figure out how exactly they're going to regulate this space.

In the latest government survey, more than 1 in 4 high school students reported using e-cigarettes in the previous month, despite federal law banning sales to those under 18. Late last month Trump signed a law raising the minimum age to purchase all tobacco and vaping products from 18 to 21 nationwide.

ARCHIVE: New York - 18 September 2019

1. Various of people vaping

Washington DC - 2 January 2020

2. SOUNDBITE (English) Matthew Perrone, Associated Press Reporter:

"The Trump administration is banning most flavors in small cartridge based e-cigarettes that are popular with teens, but they're keeping flavors available for products that a lot of adults use and that are sold in vape shops."

ARCHIVE: New York - 18 September 2019

3. Various of products on a table

ARCHIVE: Biddeford, Maine - 3 September 2019

4. STILL of electronic cigarette pods displayed for sale in shop

ARCHIVE: San Francisco - 17 June 2019

5. STILL of cashier displaying a packet of tobacco-flavored Juul pods

ARCHIVE: New York - 16 September 2019

6. Sign of advertising nicotine content of Juul vaping products

Washington DC - 2 January 2020

7. SOUNDBITE (English) Matthew Perrone, Associated Press Reporter:

"This is a big step back from what Trump said he was going to do in September when he said that they going to ban all flavors in all types of products. There are a number of carve outs here that seem to be favorable to industry who have been lobbying him pretty aggressively in recent months, not to ban all these flavors."

ARCHIVE: New York - 18 September 2019

8. Various of couple vaping

9. Various of people vaping

Washington DC - 2 January 2020

10. SOUNDBITE (English) Matthew Perrone, Associated Press Reporter:

"When Trump first announced that he was planning to ban nearly all flavors, there was a lot more pressure on the federal government at the time. There was an outbreak of lung illnesses tied to vaping. We now know that that problem was tied to illegal marijuana based vaping products. So there's a little less pressure on the federal government now that that's been determined."

ARCHIVE: Washington DC - 22 November 2019

11. President Donald Trump in listening session at the White House on vaping

12. SOUNDBITE (English) Donald Trump, US President:

"This is a very big subject and it's a very complex subject. Probably a little bit less compless than some people think. But I'm here to listen and I have very divergent views."

13. Cutaway of listening session

Washington DC - 2 January 2020

14. SOUNDBITE (English) Matthew Perrone, Associated Press Reporter:

"E-cigarettes and vaping have been pretty much unregulated in the US for many years, and FDA is still trying to figure out how exactly they're going to regulate this space. So today's announcement taking a number of these flavors off the market, a number of products is actually a pretty huge step from what came before."

ARCHIVE: New York - 16 September 2019

15. Various of Jubilee Vape and Smoke in New York CIty

16. Various of vaping solution and vaporizers on shelf of store

Washington DC - 2 January 2020

17. SOUNDBITE (English) Matthew Perrone, Associated Press Reporter:

"This is an announcement that almost no one is going to be entirely happy with it. I think probably the most disappointed will be the health groups, anti-tobacco groups. They wanted Trump to ban all flavors. They think the flavors are what attracts kids to e-cigarettes and vaping. So leaving some of these flavors on the market in any form, they're going to, they're going to view as a failing of the Trump administration."

ARCHIVE: New York - 16 September 2019

18. Various vaporizers on the shelf at NYC Smoke Shop

Washington DC - 2 January 2020

19. SOUNDBITE (English) Matthew Perrone, Associated Press Reporter:

"Today's announcement will allow Trump to say that he took action on teen vaping, and that's probably a political win. I think he's going to continue to be pressured by the vaping industry. They have a deadline coming up next year for all of their products to be reviewed by the FDA. They want that pushed back or eliminated entirely. So you're going to continue to see lobbying and pressure from the vaping industry in Washington."

ARCHIVE: Marietta, Georgia - 5 May 2016

20. Various of people smoking e-cigarette