More research must be done to determine possible health affects.
"[While] using e-cigarettes instead of conventional cigarettes may result in less exposure to cadmium", the researchers said, they do not protect users from "other hazardous metals found in tobacco".
The scientists in the most recent study say the median level of lead found in their sample was higher than the Environmental Protection Agency's safety standard, and that levels of other metals such as nickel, chromium and manganese "approached or exceeded safe limits".
Researchers aren't sure how these metals got from the coil to the smoke, but they don't think they could be coming from anywhere else. Aerosol metal concentrations were also highest for e-cigarettes with more frequently changed coils, study authors found. Among the metals present in the aerosols, lead, chromium, nickel, and manganese are the most toxic ones when inhaled.
The study is the latest to suggest that smoking e-cigarettes is not entirely benign and that they carry their own body-damaging risks despite being significantly less harmful than smoking actual cigarettes.
Just for perspective, the U.S. Food and Drug Administration hasn't regulated e-cigarettes yet.
The heating coils inside e-cigarette devices can leak toxic metals including lead - and the metals are found in the vapour inhaled by users, a new study has found. The researchers then asked to test the levels of toxic metals in the users' e-liquid before it had been put into the device, the e-liquid in the storage tank of the device, and in the vapor that came out of the device. E-cigarette companies have often touted the devices as less risky than regular cigarettes.
The culprits, the scientists think, are the heating coils that convert the e-liquid into a vapor to be inhaled. However, high levels of arsenic were found on 10 of the devices. How the arsenic got into these e-liquids is yet another mystery-and another potential focus for regulators.
The study is rather small, evaluating devices in a random sample of 56 users, it did reveal some interesting and rather significant numbers.
The previous study blew up the significance of exposure levels since patients who use inhalers are also exposed to metals.
Support for the research was provided by the Maryland State Cigarette Restitution Fund (PHPA-G2034), the Alfonso Martín Escudero Foundation, the American Heart Association Tobacco Regulation and Addiction Center (1P50HL120163), and the National Institute of Environmental Health Sciences (5P30ES009089).