Updated

A new warning about vaping published in Environmental Health Perspectives says there may be toxic levels of metals, including lead, that could be leaking from the heating coils of e-cigarettes.

Researchers from Johns Hopkins School of Public Health found metal traces in the aerosols inhaled by users, known as vapers.

The team tested liquids in the refilling dispensers from 56 Baltimore area vapers and found potentially unsafe levels of arsenic, chromium, manganese, nickel and lead.

Test results also showed that aerosol metal concentrations were highest for e-cigarettes with more frequently changed coils. Study authors pointed out that chronic inhalation of these metals has been linked to lung, liver, immune, cardiovascular and brain damage, and even cancers.

"It's important for the FDA, the e-cigarette companies and vaper [users] themselves to know that these heating coils, as currently made, seem to be leaking toxic metals — which then get into the aerosols that vapers inhale," said study senior author Ana María Rule, assistant scientist in the Bloomberg School's Department of Environmental Health and Engineering.

The Food and Drug Administration has the authority to regulate e-cigarettes, but has not issued any rulings on the matter so far.

More research is planned to determine possible health effects.