GOTEBORG, Sweden -- Inside a waterfront factory soaked with the acrid smell of tobacco, about half the blue-clad workers show an odd facial deformity: Their upper lips look swollen.
It's a telltale sign they are sampling some of the 20 tons of smokeless tobacco being produced here daily.
Snus (pronounced snoos) -- a Scandinavian form of moist snuff -- has been banned elsewhere in the European Union for more than a decade, but its popularity has rebounded strongly in its country of origin, where one of every nine Swedes uses it.
After falling out of style in the 1970s, the traditionally male, working-class habit has spread into all sectors of Swedish society, male and female. Grimy, used snus packets litter the otherwise clean streets and subway stations of Stockholm.
Meanwhile, the smoking rate has fallen below 20 percent in the Scandinavian country of 9 million people -- lowest in the world.
Unlike American snuff, which is placed in the lower part of the mouth, causing users to salivate and spit, a Swedish snus portion, or "prilla," is savored on the gum above the front teeth. Many users opt for snus in thumbnail-sized paper pouchs, to prevent the tobacco from spreading around the mouth.
"I don't think there's any question that Sweden is a model for safer use of tobacco products," said Dr. Brad Rodu, a smokeless tobacco advocate at the University of Alabama-Birmingham. "The only consequential risk of smokeless tobacco is mouth cancer, and historically, that risk is extremely small."
Rodu spent six months researching snus in northern Sweden and claims it's a much safer alternative for smokers who can't kick the nicotine habit. He noted several studies have failed to link snus to cancer, which Swedish Match, the top snus maker, attributes to its efforts to remove carcinogens during manufacturing.
But critics say there are other concerns.
Apart from causing stained teeth and bad breath, snus raises the pulse and blood pressure. Some studies have linked it to increased risk of heart disease, diabetes and premature births in pregnant women.
"I'm not interested in whether it causes cancer," said Dr. Gunilla Bolinder, chief physician at Karolinska Hospital in Stockholm. "I think it's about quality of life. Snus is extremely addictive."
First-time snus users often feel dizzy and nauseous. Some throw up. But those who get past that find quitting is difficult.
"I've tried to stop several times, but it is awfully hard," said Rikard Palm, a television news anchor at public service network SVT, whose smile reveals a lump of the black mash.
The EU banned the sale of snus in 1992, citing a 1985 WHO study that said "oral use of snuffs of the types used in North America and western Europe is carcinogenic to humans."
A WHO committee on tobacco has acknowledged evidence is inconclusive regarding Swedish snus.
Swedish Match, the snus maker, is lobbying for an end to the EU ban and has two legal challenges before the European Court of Justice.
"It's illogical and discriminating," said Stefan Gelkner, head of the company's northern Europe division. "All other tobacco products are allowed, while snus, which is considered the least damaging to health, is prohibited."