TUESDAY, Dec. 7 (HealthDay News) -- Electronic cigarettes should be banned until safety concerns have been addressed, University of California researchers say.

Their study adds more fuel to the controversy over the battery-operated devices that contain nicotine, flavorings and other chemicals. The issue heated up this fall when the U.S. Food and Drug Administration cited five e-cigarette distributors for poor manufacturing practices and falsely claiming that the products help people stop smoking.

The study found serious flaws in e-cigarette products and health claims. The researchers evaluated six different brands of electronic cigarettes that were bought online and found that:

  • Fluid containing nicotine leaked out of most cartridges.
  • The devices were difficult to take apart or put together without getting nicotine all over the user's hands.
  • Nicotine cartridge labeling was poor, with most replacement packs lacking any indication of cartridge content, expiration date, or health warnings.
  • Cartridges that claimed to have no nicotine content looked identical to those that claimed to have high nicotine content, making them indistinguishable once removed from their packs and wrappers.
  • All brands had "ambiguous amounts of nicotine," with stated levels ranging from 6 milligrams to 24 mg.
  • None of the instruction leaflets or product Web sites offered adequate instructions for proper disposal of used cartridges.
  • Safety features did not always work correctly.
  • Print and Internet material often contained information or claims that could not be backed up by scientific evidence. Examples included: "Be careful to avoid inhaling any significant quantity of fluid. Although it gives you a slight tingling sensation, it is not harmful," and "Within two weeks your lung capacity will increase by 30 percent ... Wrinkles in your skin will become less noticeable."

Because electronic cigarettes are smokeless, they are marketed to smokers for use in non-smoking areas.

But the researchers concluded that they should not be marketed at all -- at least until they were safe to use. "Our observations," they wrote, "provide evidence that regulators should consider removing [electronic cigarettes] from the market until design features, quality control, disposal and safety issues have been adequately addressed."

The study was released online Tuesday in the journal Tobacco Control.

More information

The U.S. Food and Drug Administration has more about electronic cigarettes.