Compliance News Safety

Toxic Ketene Gas, Vitamin E Acetate, & the EVALI Outbreak

Written by Derek Johnson

Vaping has exploded in popularity over the last decade. And although vaping products can be obtained legally, the black market is and has been responsible for many of the products available to interested consumers.

Unfortunately, some of these illegal products have resulted in great harm and death to consumers, which ultimately led the Centers for Disease Control and Prevention (CDC) in 2019 to coin a new disease called e-cigarette or vaping product use-associated injury, or EVALI. By February of 2020, nearly 3,000 individuals had been hospitalized for EVALI-related problems and 68 had died.

From the beginning of the outbreak, the healthcare community and governmental health organizations, including the CDC and the Food and Drug Administration (FDA), struggled to determine the culprit causing damage to consumers’ lungs. Vitamin E acetate (VEA) was strongly suspected early on because it was found in most of the fluid samples taken from sick consumers’ lungs and was absent in healthy lung samples. VEA is a popular additive to some black-market vaping products. That said, VEA had not been proven to be a direct causative agent of EVALI.

However, in a study completed early in 2020, researchers Dan Wu and Donal O’Shea looked deeper into VEA and vaping. [1] According to their research, ketene gas may be produced when VEA is heated with vape pens. Ketene is highly toxic, is primarily used in heavy industry, and is lethal in high concentrations. They explain, “As vitamin E acetate contains a similar acetate functional[ity] found in phenyl acetate, it appeared plausible to us that it too may produce ketene upon pyrolysis.”

Figure 1. Schematic showing the pyrolysis reaction of phenyl acetate to produce ketene and the conversion of vitamin E acetate to ketene from heating and aerosolization in a commercial vaping device. (From reference [2] Strongin RM. Toxic ketene gas forms on vaping vitamin E acetate prompting interest in its possible role in the EVALI outbreak. Proc Natl Acad Sci USA.; Reprinted with permission from PNAS.

Wu and O’Shea also discovered that heating VEA can also produce benzene, a well-known carcinogen.

Although VEA wasn’t definitively proven to be one of or the sole culprit for the EVALI cases, this research demonstrates that it warrants further study. [1] Additionally, this work underscores the necessity of further research regarding other substances inhaled by consumers during vaping, such as flavoring agents like diacetyl, which has been linked to popcorn lung.

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  1. Wu D, O’Shea DF. Potential for release of pulmonary toxic ketene from vaping pyrolysis of vitamin E acetate. Proc Natl Acad Sci U S A. 2020;117(12):6349-6355. [Impact Factor: 9.412; Times Cited: 26 (SemanticScholar)]
  2. Strongin RM. Toxic ketene gas forms on vaping vitamin E acetate prompting interest in its possible role in the EVALI outbreak. Proc Natl Acad Sci U S A. 2020;117(14):7553-7554. [Impact Factor: 9.412; Times Cited: 1 (SemanticScholar)]

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Derek Johnson

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