The authors refer to an outbreak of 53 cases of e-cigarette and vaping–related lung injury, in which 84% of the cases admitted to the use of tetrahydrocannabinol products. The remaining 16% may have concealed the use of an illegal product, or not known what they were using. In those cases of e-cigarette and vaping–related lung injury where bronchoalveolar lavage was performed, 100% of the specimens were positive for vitamin E acetate, a dangerous contaminant in tetrahydrocannabinol oil. This outbreak is troubling but it is unrelated to the use of legal nicotine-based vaping products.
From Safer nicotine wiki