In the first part of this blog series (Metal Fume Zebra), I used the example of Metal Fume Fever (MFF) to introduce the cadmium exposure hypothesis, and that lead to some confusion. Hot metal work (brazing, welding, etc) and inhalation of the accompanying metal fumes *is* the most common type of exposure. MFF can also develop from exposure to metal dust particles produced during cold sanding processes, particularly if the metal is highly toxic and readily soluble in the lungs (read: cadmium). I could have gone into the various strange forms of metal dust pneumonias (Kelleher P, 2000), but I figured Metal Fume Fever was weird enough territory to cover in one blog post. Look up beryllium disease. Very weird, multi-factorial illness, with genetic component.
For those who are interested, the free full-text "Inorganic Dust Pneumonias: The Metal-Related Parenchymal Disorders" can be found here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1637664/
Melting Point of Cadmium
I received a few indignant emails and replies about the impossibility of reaching the melting point of cadmium (766.8°C) or cadmium oxide (1,559°C) while vaping in the range of 185°C to 250°C.
Right you are!
Aside from the "thermal event" that occurred while deconstructing a vape pen, no metal fumes or searing vapor are implicated here.
Metal particles can be shed, and inhaled during vaping without ever coming close to the melting/boiling point of the metal or alloy.
Typical vape device heating coils are made of nichrome, an alloy of nickel (Ni) and chromium (Cr). The melting point of nichrome is 1,400°C. Vape coils rarely exceed 215°C. Nonetheless, nickel and chromium from the coil are shed into vape fluid, aeresolize in vape devices, and are inhaled by those using the device (Aherrera et al 2017). Exposure to nickel and chromium through vaping was not reported, however, to cause the illness now known as EVALI. That is consistent with what is known of inhalation exposure to nickel and chromium particles, and that is why I have never suggested nichrome wire is to blame for the illness (millions would have EVALI and that is not the case).
I appreciate the feedback. The best way to gain knowledge is to exchange knowledge. Fact-check me at will, and cite your sources. I'll continue to do the same.
Aherrera, A., Olmedo, P., Grau-Perez, M., Tanda, S., Goessler, W., Jarmul, S., . . . Navas-Acien, A. (2017). The association of e-cigarette use with exposure to nickel and chromium: A preliminary study of non-invasive biomarkers. Environ Res, 159, 313-320. doi: 10.1016/j.envres.2017.08.014
Kelleher P, P. K., Newman LS. (2000). Inorganic dust pneumonias: the metal-related parenchymal disorders. Environ Health Perspect., 108, 685-696. doi: https://doi.org/10.1289/ehp.00108s4685