Unlike tobacco cigarettes, e-cigarettes don't "burn".
As of September 11, an additional three states have reported cases of the severe lung illness linked to vaping, raising the total to 36 states plus the U.S. Virgin Islands, the agency said. Many who got sick said they had vaped liquids that contain THC, the high-inducing ingredient in marijuana.
And there is "substantial evidence" that the vapor contains traces of metals, either from the coil used to heat the liquid or from other parts of the device. Many officials say, however, that many cases appear to involve the vape product THC, a compound found in marijuana. Hundreds of individuals have been hospitalized with lung-disease symptoms like shortness of breath, nausea, vomiting and fevers, and many are in need of intensive care and help breathing through oxygen devices. The illnesses are likely associated with a chemical in the vape liquids, but this is not yet proven, Meaney-Delman said.
While THC could be a large contributor, recent studies by NY state health officials say that almost all of the vape products that is has tested containing THC also contained vitamin E acetate, an oil-like substance that is harmful if inhaled. Federal authorities however have yet to identify a single substance common to all cases.
Doctors say the illnesses resemble an inhalation injury, with the body apparently reacting to a caustic substance that someone breathed in.
The revised total now only includes confirmed and probable cases.
In June, San Francisco became the first USA city to ban the sale and manufacture of electronic cigarettes, and has since been followed by Richmond, Virginia.
It also notes, "Until a definitive cause is known, persons should consider not using e-cigarettes".
That claim is true, according to a study in the New England Journal of Medicine on 886 patients in Britain's National Health Service published in February.
But the conversions are not all in one direction.
The illnesses are seen as a new phenomenon, and it's taken weeks for CDC officials to come up with a case definition and for states to start following it. Thursday's tally from the CDC was the first based on the new case definition, which counts only breathing illnesses with abnormal chest x-rays, a recent history of vaping, and lab work done to rule out infectious diseases or other possible causes. E-cigarettes are already illegal to sell in the U.S. to people under 18 or 21, depending on the state.
But bans also deprive adults addicted to smoking of a valuable tool to quit, the industry says.