According to the CDC, no specific product or compound has been linked to all of the cases of pulmonary illness. Agency officials have said many who got sick said they vaped THC, but some said they vaped only nicotine. Health officials are advising people not to vape at all until more is known.
Poison control officials have been concerned about exposure to vaping products, including e-cigarettes and liquid nicotine, in recent years due to the high concentration of nicotine they contain compared with other tobacco products, according to the American Association of Poison Control Centers.
Association officials said that, as of Aug. 31, poison control centers have managed 2,961 cases connected to e-cigarette devices and liquid nicotine this year. Last year, officials fielded 2,470 such cases, according to figures from the association.
The Associated Press contributed to this report.