According to numbers updated today, 1,888 cases of vaping-related lung injuries, including 37 deaths, have been reported to the Centers for Disease Control and Prevention (CDC) as of October 29. The CDC is now referring to these acute respiratory illnesses as cases of "e-cigarette, or vaping, product use associated lung injury (EVALI)," which is not only cumbersome but also misleading. While the term

e-cigarette typically refers to legal vaping devices, such as Juul, that deliver nicotine, the vast majority of the lung injuries have been linked to black-market cannabis products.

In cases where the information was available, according to a new CDC study, just 11 percent of patients said they had vaped only nicotine. The study notes that "data on substances used…were self-reported or reported by proxies and might be subject to recall bias, as well as social desirability bias because nonmedical marijuana is illegal in many states." In other words, since patients or their relatives may be reluctant to report illegal drug use, the role of black-market THC vapes could be even greater than the numbers suggest. The CDC also notes that patients may not actually know what was in the products they consumed, especially if they bought them online or off the street from illegal distributors.

"Use of THC-containing products was reported for 86% of patients who survived and 84% of patients who died," the study says. "Reports from Illinois, Utah, and Wisconsin suggest that patients have typically obtained their THC-containing e-cigarette, or vaping, products through informal sources, such as friends or illicit in-person and online dealers."

The CDC does not discuss the sources of nicotine products used by patients. But assuming that such products are in fact implicated in some cases, it seems likely that they also came from "informal sources" offering e-liquids of unknown provenance and composition. As psychiatrist Sally Satel, a resident fellow at the American Enterprise Institute, noted in her congressional testimony this month, "Consumers have been using commercially available vaping devices and nicotine products for 10 years without a single recorded death or any surge of illnesses…until this summer." The timing, she said, "is consistent with a relatively acute contamination" by additives or byproducts in illicit vapes. "The lung injury problem is a story of the dangers of the black market, not of vaping," Satel observed.

The CDC has gradually adjusted its advice to reflect the conspicuous role of black-market cannabis products in the lung disease outbreak. "Because most patients reported using THC-containing products before symptom onset, CDC recommends that persons should not use e-cigarette, or vaping, products that contain THC," it now says. "Persons should not buy any type of e-cigarette, or vaping, products, particularly those containing THC, off the street and should not modify or add any substances to e-cigarette, or vaping, products that are not intended by the manufacturer."

But the CDC still adds that "because the specific compound or ingredient causing lung injury is not yet known, and while the investigation continues, persons should consider refraining from the use of all e-cigarette, or vaping, products." That is not a sound recommendation for people who have switched to vaping from smoking, a far more hazardous source of nicotine.

The CDC implicitly acknowledges as much. "If you are an adult using e-cigarettes, or vaping, products, to quit smoking," it says, "do not return to smoking cigarettes." Yet the CDC's muddled messaging, including the unfounded insinuation that legal e-cigarettes might be deadly, continues to obscure the crucial point that they are much less dangerous than the conventional combustible kind.