You may be surprised to learn metals from using an e-cigarette damage lungs. New evidence shows toxic metals can leach into the vaping liquid, causing the user to experience a serious lung issue normally restricted to that seen in metal industry workers.

The European Respiratory Journal published a report on a 49-year-old California woman who was experiencing coughing, wheezing and shortness of breath. As in other cases of EVALI, the newly discovered lung illness among the vaping population, a sample of her lung tissue was examined.

The woman’s lung cells looked different from those found in other cases of EVALI. Damaged lung cells had completely swallowed her other lung cells, resulting in the creation of huge cells in the lung tissue. This type of damage is usually found in patients suffering from hard-metal lung disease after working in a factory.

NBC News spoke with the case report’s co-author Dr. Kirk Jones, who is a professor of pathology at the University of California, San Francisco.

Dr. Jones said of the hard-metal lung disease, “It has a distinctive and unusual appearance that is not observed in other diseases. When we diagnose it, we are looking for occupational exposure to metal dust or vapor, usually cobalt, as a cause.”

Metals from E-cigarette Damage Lungs

According to the study, the woman was a dog walker who had never worked in a factory. She had purchased and used a ZenPen brand vaping pen for about six months before she began experiencing symptoms of illness.

Doctors who tested the vaping juice left inside the ZenPen found remnants of nickel, aluminum, manganese, lead, cobalt and chromium. Jones said he had seen cobalt cause similar damage in a mill worker he had treated many years ago.

Jones and fellow case report authors believe the e-liquid became contaminated with metals when the heating coil in the vaping pen reached a certain temperature. When marijuana is placed in a vaping device, the device must reach a much higher temperature to turn THC into an aerosol compared to the temperature needed to turn nicotine into an aerosol.

The authors said toxic metals leaching from the e-cigarette damage lungs. The evidence provides greater urgency to regulate vaping devices, especially with the increasing number of states that are legalizing marijuana for medical and recreational use, said the authors.

In many cases of EVALI, the Centers for Disease Control and Prevention (CDC) has found that Dank Vapes, which it calls “a class of largely counterfeit THC-containing products of unknown origin,” was most often the brand patients said they had used prior to becoming ill. Other potential causes include the brands TKO, Smart Cart and Rove.

In their ongoing investigation, the CDC has found people also have used marijuana based e-cigarette liquids containing vitamin E acetate, which should not be inhaled.

At least 52 people have died and thousands have been hospitalized due to vaping related lung illnesses. Even though e-cigarettes have been available in the U.S. for about 10 years, the industry exploded in popularity when Juul Labs introduced a vaping device that looks like a USB drive in addition to sweet-flavored vaping liquids full of nicotine.