The research corroborates previous reports that EVALI cases were mostly associated with vaping products purchased on the black market.

States with higher cannabis and e-cigarette vaping use were not tied to higher rates of the e-cigarette or vaping-association lung illness (EVALI) outbreak from last year, a new study found. In fact, most states with legal marijuana access were connected with a fewer number of EVALI cases on average compared to places where it remains illegal.

The study was published in the journal Addiction this week and corroborates previous reports that EVALI was most likely connected to vaping products purchased from informal sources, or on the black market.

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Researchers examined data from the Centers for Disease Control and Prevention (CDC), which has confirmed more than 2,800 cases and 68 related deaths from the illness. When the CDC ended its investigation in February when no further EVALI outbreaks occurred, they determined vitamin E acetate was the culprit behind the illness. Often vitamin E acetate is a substance used on the black market to thin vaping liquids and sell products for higher profit margins.

“If e-cigarette or marijuana use per se drove this outbreak, areas with more engagement in those behaviors should show a higher EVALI prevalence,” study author Abigail Friedman said. “This study finds the opposite result.

“Alongside geographic clusters of high EVALI prevalence states, these findings are more consistent with locally available e-liquids or additives driving the EVALI outbreak than a widely used, nationally-available product.”

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Lung injuries from the outbreak were among the lowest in the first states to legalize recreational marijuana access, researchers found. Colorado, Oregon, Washington, Alaska, and California all saw less than one EVALI case per 100,000 resident (ages 12-64). States with the highest rates of EVALI cases — Utah, North Dakota, Minnesota, Delaware and Indiana — do not permit recreational cannabis.

Some high-prevalence states included those with legal medical marijuana access. However, those states had bans in place on smokable cannabis flower.

“If this policy led some recreational marijuana smokers to switch to vaping THC, perhaps in order to avoid detection, it would have increased their likelihood of exposure to contaminated e-liquids when those came on the market,” Friedman said. “This may have contributed to the higher EVALI prevalence in those states.”