E-cigarettes are healthier for your neighbors than traditional cigarettes, but still release toxins into the air, according to a new study from USC.

Constantinos Sioutas, professor at the USC Viterbi School of Engineering,  and a team of other research scientists studying secondhand smoke from e-cigarettes discovered an overall 10-fold decrease in exposure to harmful particles, with close-to-zero exposure to organic carcinogens.

However, levels of exposure to some harmful metals in secondhand e-cigarette smoke were found to be significantly higher.

“Our results demonstrate that overall electronic cigarettes seem to be less harmful than regular cigarettes, but their elevated content of toxic metals such as nickel and chromium do raise concerns,” said Sioutas, corresponding author of the study, which was published online on Aug. 22 by the Journal of Environmental Science, Processes and Impacts.

The researchers found that much of the toxic metals did not come from the e-cigarette liquid, but most likely from the cartridge. Therefore, better manufacturing standards for the devices could reduce the quantity of metals in e-cigarette smoke.