Lungs are collapsing. People are being rushed off to hospitals by the hundreds. Some are even being sent to an early grave. And no one really knows why.

In fact, until this week, no one even had a lead on a likely theory — now, though, thanks to a Colorado lab, the answer might be at our fingertips.


It’s been the biggest health story of 2019 so far: the sudden and unexplained outbreak of “Vape-Related Lung Injuries” (VAPIs). This vaping “epidemic” has been as mysterious as it has been terrifying, affecting teenagers and twenty-somethings around the country: California has experienced well over 100 of these cases; Minnesota, Wisconsin, Indiana and Texas have all experienced over 50 each. Nationally, the number of cases has reached 1080 (as of October 1st), 18 of which were fatal.

All of these cases showed similar symptoms: fevers, headaches, chills, coughing, chest pain, shortness of breath, muscle pain, nausea, diarrhea and vomiting. Most cases progressed to hypoxemia, some progressed as far as respiratory failure. But beyond these similarities, no clear pattern has emerged as to the specific cause.

When I spoke to the CDPHE a few weeks ago, they said simply: “We don't have the smoking gun yet.”

But now, maybe we do. Just this week a lab out of Denver called Colorado Green Lab, published a blog that suggested a new theory as to the root cause of VAPI’s. An insofar unexplored idea that could be that smoking gun, the CDC and the CDPHE have so far failed to find. They believe that these VAPI’s are the result of cheap materials interacting with the oily e-liquid when vaporized. Specifically, a type of silver-solder often used by manufacturing companies, that could be causing something called “Metal Fume Fever.”

Unless you're a metalworker, work for OSHA, or, in my case, previously employed at a respiratory hospital, you've probably never heard of Metal Fume Fever,” writes Frank Conrad, in his blog post on the Green Lab website.  

It’s an illness that’s almost always associated with people with extremely specific occupations (like welders). It’s caused by inhaling metal-containing fumes like zinc oxide or cadmium oxide (which comes from soldering or welding things).

“It’s is almost only ever diagnosed because the doctor knows the patient was exposed to metal fumes in an occupational setting,” Conrad tells me.

Which is to say, unless doctors have a reason to believe that a patient is inhaling metal fumes on the regular, they won’t suspect metal fume fever as a likely affliction. And the symptoms of metal fume fever are very similar to VAPI’s. Eerily similar: fever, headache, chills, aches, dizziness, and [importantly] gastrointestinal symptoms like nausea, vomiting and diarrhea.

“The fact that all the vaping patients have these gastrointestinal and systemic symptoms, there are not many things that can cause something that appears across your whole system like that, and also causes respiratory problems,” says Conrad.

He acknowledges that both viral and bacterial infections could do that, but both the CDC and the FDA have ruled those possibilities out, Conrad says. Which leaves only a few possible alternatives. And Conrad suggests that, in the case of the less severe VAPI’s, zinc-oxide metal fume fever is a likely suspect. The symptoms of VAPI superficially resemble those of zinc oxide inhalation, Conrad says, but it rarely progresses to actual lung damage.

In those more severe cases, however, Conrad points to something called cadmium pneumonitis, a much more severe form of metal fume fever and which can cause significant lung damage, and even death. Cadmium is present in the silver solder used to make many of the cheaper cartridges, as it’s more cost effective and has certain fluid properties that cadmium-free solder does not. Manufacturers who want to cut costs and cut corners often use this stuff to fix metal to metal on their cartridges, and Conrad found, after systematically dismantling many of these kinds of carts, that large globules of cadmium-containing silver solder were present on both positive and negative heating elements within the vape.

“So, the very cheap cartridges have a vent hole that goes directly into the battery,” Conrad explains. “That is the cheapest form that is made it’s the cheapest to manufacture, and it’s off patent. That is the type of cartridge that we think is most associated with this.”

And it is important to note: none of the cases reported to the CDC, out of 1080, have been strictly correlated to cannabis or nicotine, black market or store-bought cartridges. As far as patterns go, there aren’t any there. The cases that have been reported are spread almost evenly across these variables.

“No consistent factors have been across the board,” Conrad says. “This affects people who use nicotine only and cannabis only.”

He adds that the most common cases have been a combination of the two, but regardless, there is no observable correlation. It’s not the kind of e-liquid that’s being vaporized, but something else that is common to both types of vape.

Like the cheap silver solder used to make them.

If Green Lab’s Conrad is correct, this could be huge news. Because it would mean that this VAPI epidemic has an easy fix. It could be solved simply by outlawing the cheaply made cartridges that use cadmium or zinc in their soldering material. Lives and lungs could be easily saved.

But correlation doesn’t equal causation, as Conrad himself admits. While this seems like a hot lead, it’s only that: a lead. There are still no hard answers concerning this mysterious outbreak, and no advice to give expect: maybe stop vaping as much until this is all sorted out.  

While Green Lab’s metal fume fever hypothesis is a hopeful one, it isn’t yet proven to be the case.