E-cigarette liquids and vapors contain metals and metalloids at levels likely to be harmful to people’s health, and people who vape have higher levels of these elements in their blood and other bodily fluids than cigarette and cigar smokers do, according to a review of data from 24 studies (Environ. Health Perspect. 2020, DOI: 10.1289/EHP5686).
These smoking devices use a metal coil to heat a nicotine solution, generating a vapor. The coil itself is a metal source; so are solders inside the liquid reservoir. Several of the studies show that total metal levels rise after the liquid in these devices gets heated, lending support to the theory that the heating process is what releases the elements. Further, the metal levels in the aerosols that users inhale tend to be higher than those in the liquids.
Studies of samples from users, including blood and urine, showed that e-cigarettes are a source of exposure to a large list of metals, including lead and arsenic. With the exception of cadmium, e-cigarette users had more of all metals studied in their bodily fluids than smokers did. Metal exposure can increase the risk of cancer and other diseases; it can also directly damage lung tissue.
“The e-cigarette market is constantly evolving, and we are doing our best to investigate what users are currently vaping,” says Angela Aherrera, a public health researcher at Johns Hopkins University who led the review. She notes that disposable “pod” devices such as Juul have surged in popularity over the past 2 years and says she’s studying how much metal they deliver compared with earlier designs.