There's been widespread belief the so-called "heat-not-burn" electronic cigarettes are safer than conventional ones... as they heat tobacco to a temperature high enough to create vapor not smoke.
But that may not be true, as health authorities in the nation announced there's no reason to believe these relatively new devices are less toxic.
Our Ko Roon-hee explains further.
It's been a little over a year since so-called "heat-not-burn" electronic cigarettes came onto the Korean market, and they've caught on quickly among smokers.
According to the Ministry of Strategy and Finance, as of this April, heat-not-burn products had a cigarette market share of almost 10 percent.
However, the Ministry of Food and Drug Safety released analysis Thursday... saying there is no evidence that these products are less harmful than conventional cigarettes.
Together with outside researchers, the ministry studied three popular e-cigarette products -- the Lil by local tobacco company KT&G, the Glo by British American Tobacco, and the iQOS by Philip Morris.
In them, it found five substances classified as five substances classified as "first level carcinogens" by the International Agency for Cancer.
However, the amounts were only between zero-point-3 percent and 28 percent of those found in conventional smokes.
The amount of nicotine was similar to that found in ordinary cigarettes -- between a tenth and one half of a milligram.
The ministry added that two of the products, though, contained more tar.

"Some of the heat-not-burn electronic cigarettes contain more tar than regular ones.
This means these e-cigarettes could contain other toxic substances...not found in regular tobacco."
But the report was met with a backlash from manufacturers, who've called it meaningless.
They say it's not appropriate to simply compare amounts of tar... because tar is produced when tobacco is burned, which their devices don't do.
This isn't the first warning from the government about heat-not-burn cigarettes.
The health ministry announced last month that twelve new written and graphic warnings will be put on heat-not-burn cigarettes starting this December.
The government is also working on a law to make manufacturers submit a full list of the ingredients and toxic substances in the heat-not-burn cigarettes and disclose the information to the public.
Ko Roon-hee, Arirang News.