The recent e-cigarette, or vaping, product use–associated lung injury (EVALI) crisis led to hospitalization and death in US youth and young adults (Blount et al. 2020, US FDA 2019). Most EVALI cases were apparently linked to the vaping of e-liquids that contained vitamin E acetate (VEA) and tetrahydrocannabinol (THC) (Blount et al. 2020). At the same time, not all vapers who inhaled VEA- or THC-containing aerosol have developed EVALI symptoms, therefore other factors, such as an individual’s health status, differences in puffing behaviors, or types of vaping devices, may be important.