AUDIE CORNISH, HOST:
Health investigators are zeroing in on THC-based vaping products as a major source of lung injuries that have sickened more than 800 Americans and killed at least 12 people. These products make up a murky market, and that's complicating efforts to track down whatever is causing these lung injuries. NPR science correspondent Richard Harris reports.
RICHARD HARRIS, BYLINE: Imagine you are a disease detective responsible for finding a commonality among hundreds of people who are sick. They all ate food at the same restaurant chain. That's a big lead. But here's the reality for disease investigators, such as Jennifer Layden at the Illinois Department of Public Health. She and colleagues in Illinois in Wisconsin interviewed 86 people who suffered lung disease after vaping.
JENNIFER LAYDEN: Two hundred and thirty-four unique e-cigarette or vaping products across 87 different brands were reported.
HARRIS: That doesn't narrow the search very much. One name did stand out, she said in a telephone briefing today.
LAYDEN: Prefilled THC cartridges labeled under the brand name Dank Vapes was the most common, with 66% of all patients reporting this name.
HARRIS: Clearly, Dank isn't the whole story. And to the extent it is, Dank Vapes appears to be a catchall name that all sorts of operations use to sell their product. Nicotine vapes are not exonerated in this latest study. Sixteen percent of people who were sick said they only used those products, not those with THC. And Layden says for the THC-based products, consumers have no way to tell the difference between those prepared and regulated in legal markets versus those sold on the black market.
LAYDEN: Of all the THC-based products that were used and reported to us, 96% were prepackaged, prefilled cartridges.
HARRIS: Those data are reported in the latest issue of the Centers for Disease Control and Prevention's weekly journal. CDC official Anne Schuchat offered a caveat about this latest investigation by the two state health departments.
ANNE SCHUCHAT: We do not know at this time if the products linked with disease in Illinois and Wisconsin are also linked to cases in geographically remote parts of the country. And this is a key issue for further investigation.
HARRIS: But the findings certainly underscore how challenging it is to track down the source of the problem. These products come from a mishmash of legal and illegal operations with little oversight, unreliable product labeling, and many different products and substances in play.
SCHUCHAT: This may be more complicated even than we think, in terms of more than one product being risky, more than one label on the product and more than one substance within the product. So I think we have to have a very open mind and recognize how dynamic this marketplace is right now.
HARRIS: Schuchat's advice to consumers is evolving along with the news. The CDC has dropped the qualifier that only people concerned about the situation should refrain from vaping. The new message?
SCHUCHAT: CDC recommends people consider refraining from use of e-cigarette or vaping products, particularly those containing THC.
HARRIS: Nicotine products are not absolved of suspicion, even as health officials dig deeper into THC-based vaping products.
Richard Harris, NPR News. Transcript provided by NPR, Copyright NPR.